WO1995027494A1

WO1995027494A1 - DEFECTIVE HERPES AND DEFECTIVE ADENO-ASSOCIATED VIRUS VECTORS WITH p53 FOR THE TREATMENT OF CANCER

Info

Publication number: WO1995027494A1
Application number: PCT/US1995/004418
Authority: WO
Inventors: Myrna R. Rosenfeld; Michael G. Kaplitt; Patricio Meneses
Original assignee: Sloan-Kettering Institute For Cancer Research
Priority date: 1994-04-11
Filing date: 1995-04-11
Publication date: 1995-10-19
Also published as: AU2283895A

Abstract

This invention provides a defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) an origin of DNA replication, (c) a cleavage/packaging signal, and (d) regulatory elements, such that the defective Herpes Simplex Virus (dvHSV-p53) is incapable of autonomous replication. In addition, this invention provides a defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno-Associated Virus (dvAAV-p53) is incapable of autonomous replication. In addition, this invention provides an expressible Herpes Simplex Virus (pHSV-p53) vector, and an expressible Adeno-Associated Virus (pAAV-p53) vector. In addition, this invention provides a method of treating a subject with cancer, a method of overexpressing p53 in a cell of a subject with cancer, and a method of increasing the level of mdm2 protein in a cell.

Description

DEFECTIVE HERPES AND DEFECTIVE ADENO-ASSOCIATED VIRUS VECTORS WITH p53 FOR THE TREATMENT OF CANCER

This invention was made with support under Grant No. CA-08748 from the National Institutes of Health, U.S. Department of Health and Human Services. Accordingly, the United States Government has certain rights in the invention.

Throughout this application various references are referred to by arabic numbers within brackets. Disclosures of these publications in their entireties are hereby incorporated by reference into this application to more fully describe the state of the art to which this invention pertains. The full bibliographic citation for these references may be found at the end of this application, immediately preceding the claims.

BACKGROUND OF THE INVENTION

Genetic therapy promises to be an effective method for the treatment of human cancer and genetically determined diseases. To be useful both clinically and in the laboratory highly efficient gene delivery systems must be developed. In the case of human cancer where multiple genetic defects are involved in tumorigenesis, it may not be possible to replace all defective genes. However, the replacement of critical genes, such as wild-type p53 may suffice to suppress cell growth or induce cell death.

The nuclear phosphoprotein p53 is a tumor suppressor gene that has a central role in normal cell proliferation [40, 61] . p53 is a negative growth regulator and a transcriptional activator that suppresses transformation [17, 18, 44] . The wild-type gene also controls transit of the cell through the cell cycle [39] and is involved in programmed cell death (apoptosis) [10, 56, 67] .

Mutations or allelic loss of p53 are frequently found in a variety of human cancers [30, 41, 47] , and overexpression of mutant p53 protein is the genetic abnormality most commonly detected in human cancer [10, 41] . Mutations of the p53 gene usually occur within highly conserved domains [30] and result in abrogation of gene function [18, 15] . Germline mutations of p53 are associated with the development of tumors in the Li-Fraumeni syndrome [42] . Almost 40% of all low grade astrocytomas have mutations in the p53 gene suggesting a role in early tumorigenesis [20, 63] . Although such mutations appear to be less common in other primary brain tumors, they are also present in medulloblastomas

[74] , oligodendrogliomas [75] , and pediatric brain stem gliomas [76] . Furthermore, the clonal expansion of tumor cells that have acquired p53 mutations has been associated with brain tumor progression [57] .

Mutations of p53 are also found in carcinomas of the lung, breast, prostate, and bladder, and in some osteosarcomas and soft-tissue sarcomas suggesting a wide role for p53 in tumorigenesis.

Studies suggest that the p53 gene product plays an important role in cell growth either by controlling passage through the cell cycle [5, 64] or via control of programmed cell death. Additionally, p53 protein forms stable protein-protein complexes with the transforming proteins of SV40 [40] and adenovirus [55] . These complexes may be involved in the pathways that lead to transformation by these viruses. Mutations or loss of the p53 gene results in abrogation of gene function and leads to transformation. Replacement of the wild type p53 gene in human cancer cells has been shown to lead to suppression of the neoplastic phenotype.

Transfection is the introduction of naked DNA into cells. Transfection of wild-type p53 into a variety of tumor cell lines results in growth arrest and/or apoptosis [11, 52, 55] . Similarly, retroviral mediated transfer of wild-type p53 also results in growth suppression and induction of apoptosis [6, 24] . These gene transfer techniques are, however, of limited use in the study and potential treatment of primary brain tumors. Transfection studies are not highly efficient and most mammalian cells have low transfection rates. At most 10 to 20% of cell in vitro will take up the transfected DNA. Transfection studies are therefore usually limited to transformed cells in culture that have been genetically designed to have higher transfection rates, even then rates do not reach 100%. Transfection studies are also not useful for in vivo work as transfection in vivo is very inefficient. Therefore transfection has limited potential for therapeutic applications.

Recent clinical trials of gene therapy have used retroviral and recombinant adenoviral vectors [68-70] . However, each of these systems has important limitations. For retroviral vectors these include direct toxic effects of the vector [71, 72] and the potential for the establishment of a persistent infection that may prove harmful to the host years after initial use. In addition, the low mitotic activity of even the most malignant primary brain tumor restricts the use of retroviral vectors which optimally require rapidly dividing cells. Defective herpes simplex viral (HSV) vectors can also express foreign genes [26, 27, 37] and possess several properties that make them well suited as gene transfer vehicles. HSV vectors are incapable of autonomous replication and contain no viral genes [21] . In contrast to retroviral vectors that insert directly into the host genome, defective HSV vectors remain episomal circumventing the possibility of insertional mutagenesis. In addition, while retroviruses optimally require rapidly dividing cells, HSV vectors do not need active cell division for function [37] . The ability to transfer genetic material to non-dividing but potentially multiplying cells is important in primary brain tumors, where malignant lesions may have a low mitotic index.

Further retroviruses can only insert and replicate in actively growing cells. This limits the transformation efficiency that a retroviral vector will have in a cancer, such as a primary brain tumor with a heterogenous population of cells. Retroviruses must create a cDNA copy of their genome to express a foreign gene which further limits their use in non-growing but potentially reactivatable cells. The defective DNA viral vectors described here can enter the cell nucleus and express foreign genes in the absence of any nucleotides so that even tumor cells in G₀ are potential targets of these vectors. Expression of p53 in these cells may prevent such cells from releasing from G₀, thereby further blocking tumor progression. The absence of most viral genes in the defective DNA vectors should serve to confine alterations of the physiology of cells infected with these vectors to those mediated by the inserted gene of interest (i.e. p53) . Defective herpes simplex viral (HSV) vectors can express foreign genes in neurons in vitro [26, 27, 36] and in vivo [37] . Defective HSV vectors have several properties that make them well suited as vectors for the present invention. They are incapable of autonomous replication and contain no viral genes [21] . HSV vectors do not require actively dividing cells and are therefore useful in both dividing and non-dividing, terminally differentiated cells. Furthermore, through the use of a reduced-virulence helper virus any potential complications secondary to the presence of intact helper virus in the defective viral stock can be offset.

p53 gene transfer studies have been reported using one of two systems, either direct transfection of plasmids carrying the cDNA or through the use of recombinant retroviruses [6, 9, 23, 24] and transfection studies

[2, 7, 8, 11, 15, 18, 35, 44, 46, 48, 50, 51, 52, 56, 66] . Prior gene transfer studies with p53 have used either retroviruses or direct transfection. This invention differs by employing a defective Herpes or defective adeno-associated virus. These vectors are based on DNA viruses and can therefore be used for both dividing and non-dividing, terminally differentiated cells found in the central nervous system and many peripheral organs. While other viral vector systems retain viral genes that can still function within the recipient cell and potentially complicate any therapeutic or laboratory use the current invention contains no viral genes. The current invention only contains viral recognition signals which permit replication and packaging of the viral vector DNA. The proteins required for packaging and synthesis of the viral vector are provided by a helper virus. For the defective herpes p53 vector, replication and spread of contaminating helper virus in the viral stock is limited through the use of a mutant helper virus that will only grow under defined conditions.

The defective AAV p53 virus uses an adenovirus as the helper virus. Since the AAV vector contains a viral coat that is distinct from that of the helper adenovirus, the two viruses may be separated with complete elimination of all helper virus from the viral stock. This results in a pure stock of p53 adeno- associated vector containing no viral genes making this system particularly suited to human gene therapy.

Since replacement of wild-type p53 (wt p53) into cells that possess mutant p53 suppresses the neoplastic phenotype [1, 11, 15] and induces apoptosis [52, 56, 23] , a set of experiments was designed to introduce wt p53 into a medulloblastoma cell line (DAOY cells) that expresses mutant p53 utilizing a defective HSV vector.

The use of defective herpes viral vectors and defective adeno-associated viral vectors containing p53 offer several advantages over other systems for gene transfer such as simple transfection or the use of retroviral vectors.

SUMMARY OF INVENTION

This invention provides a defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) an origin of DNA replication, (c) a cleavage/packaging signal, and (d) regulatory elements, such that the defective Herpes Simplex Virus (dvHSV- p53) is incapable of autonomous replication.

This invention provides a defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno-Associated Virus (dvAAV-p53) is incapable of autonomous replication.

In addition, this invention provides an expressible Herpes Simplex Virus (HSV-p53) or Adeno-Associated Virus (AAV-p53) vector, comprising (a) a foreign DNA sequence encoding p53 inserted into a non essential site, (b) an origin of DNA replication recognition signal, (c) a cleavage/packaging recognition signal, and (d) regulatory elements.

In addition, this invention provides an expressible Adeno-Associated Virus (AAV-p53) vector incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno- Associated Virus (dvAAV-p53) is incapable of autonomous replication. In addition, this invention provides a method of treating a subject with cancer, which comprises administering an effective amount of the defective Herpes Simplex Virus (dvHSV-p53) or the defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, so as to thereby treat the subject with cancer.

In addition, this invention provides a method of overexpressing p53 in a cell of a subject with cancer, which comprises contacting the cell with an effective amount of the defective Herpes Simplex Virus (dvHSV- p53) incapable of autonomous replication or the defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, so as to thereby overexpress p53 in the cell of a subject with the cancer.

In addition, this invention provides a method of treating a subject with cancer, which comprises: (a) removing cells of a subject with cancer, (b) contacting the cells of the subject with cancer with an effective amount of the defective Herpes Simplex Virus (dvHSV- p53) incapable of autonomous replication or the defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, and (c) injecting the cells back into the subject, so as to treat the subject with cancer.

Lastly, this invention provides a method of increasing the level of mdm2 in a cell. BRIEF DESCRIPTION OF FIGURES

Figure 1, Amplicon plasmid pHSV-p53 (7190 bp) which contains the wild-type p53 cDNA, the cytomegalovirus promoter (CMV) , an SV40 polyadenylation signal (poly A+) , the HSV cleavage/packaging signal (HSVa) and HSV origin of replication (HSVori) , and bacterial sequences for the /3-lactamase gene (Amp r) and origin of replication (ColEl ori) .

Figure 2 Amplicon plasmid pAAV-p53 (6600 bp) which contains the wild-type p53 cDNA, the cytomegalovirus promoter (CMV) , an SV40 polyadenylation signal (poly A+) , the AAV cleavage/packaging signal and origin of replication (aav term.), and bacterial sequences for the /3-lactamase gene (Amp r) and origin of replication (ColEl ori) .

Figure 3 Southern blot analysis of viral DNA extracted from passage 3 viral stocks. Lane 1 corresponds to DNA extracted from a pure stock of helper virus

(negative control) . Lane 2 corresponds to DNA from dvHSV-p53 stock, Lane 3 corresponds to DNA from dvHSV-p53 cont stock (control virus) , and Lanes 4 and 5 correspond to DNA from the amplicon plasmids, pHSV-p53 and pHSV-p53cont

(positive controls) . Wild-type p53 cDNA was used as the probe. Markers are noted in bps. Figures 4A-4D. DAOY cells immunoreact with Abl801 demonstrating the presence of mutant p53 (Figure 4A) . These cells do not immunoreact with Abl620 which only recognize wild-type p53 (Figure 4B) . Overexpression of the wild-type p53 after gene transfer with dvHSV-p53 results in novel immunoreactivity with Abl620 (Figure 4C) and loss of the nuclear immunoreactivity with AblδOl (Figure 4D) .

Figure 5A. Sequence analysis of cDNA transcripts obtained from RT-PCR of RNA extracted from DAOY cells. cDNA from the plasmid pC53-SN3 was used for wild-type sequence. Note the G to T transversion at codon 72.

Figure 5B. Diagrammatic representation of the locations of the Alwnl restriction digest sites in wild-type p53 cDNA and in cDNA from DAOY cells. Fragment sizes in bp are given below the lines.

Figures 6A-6C. Western blot analysis of the expression of p53 protein in DAOY cells. Figure 6A shows the expression of p53 protein in DAOY cells alone; Figure 6B shows DAOY cells 24 hours after infection with dvHSV-p53; and Figure 6C shows DAOY cells after infection with dvHSV- p53cont (control virus) . The amount of protein loaded in each lane is indicated above the lanes. Cells infected with virus carrying wild-type p53 (Figure 6B) show overexpression of p53 protein when compared to equal amounts of total protein from control cells (Figures 6A and 6C) .

Figure 7 Analysis of p53 expression in DAOY cells after gene transfer with a high concentration of dvHSV-p53. Lane 1 shows cDNA from the amplicon plasmid pHSV-p53 as a control for wild-type p53. Lane 3 shows cDNA from uninfected DAOY cells as a control for the mutant p53 transcript. Lanes 2 and 4 are duplicate experiments showing cDNA obtained from DAOY cells infected with a high concentration of defective virus carrying the wild-type p53 cDNA (dvHSV- p53) . There is loss of the 713 bp band, indicating an inhibition of expression of mutant p53 by the DAOY cells.

Figure 8, Analysis of DAOY cDNA after gene transfer with a low concentration of dvHSV-p53. Twenty four hours after infection RNA was extracted and used in a RT-PCR. The resulting cDNAs were digested with Alwnl and the fragments separated on a 1% agarose gel. Lane 1 shows cDNA from the amplicon plasmid pHSV-p53 as control for wild-type p53. Lane 3 shows cDNA from uninfected DAOY cells as a control for the mutant p53 transcript. Lane 2 is cDNA from DAOY cells infected with a low concentration of dvHSV-p53. The appearance of the 515 bp band demonstrates the co- expression of both wild-type and mutant p53 transcripts in these cells.

Figure 9. Staining for apoptosis by the Tunel method to detect DNA fragmentation.

DAOY cells show evidence of apoptosis 24 hours after overexpression of wild- type p53 is accomplished by gene transfer with dvHSV-p53.

Figures 10A-10B. Immunocytochemical analysis of DAOY cells after wt p53 gene transfer. Non- transduced cells show no reactivity with p53 specific antibody (Figure 10A) . Twenty-four hours after wt p53 gene transfer, DAOY cells showed a marked increase in immunostaining with the anti-mdm2 monoclonal antibody (Figure 10B) .

Figures 11A-11F. Immunocytochemical analysis of cell cycle progression in DAOY cells after gene transfer. Non-transduced cells show reactivity with monoclonal antibodies against cyclin E, a marker for cells in late Gl and early S phase

(Figure 11A) and against cyclin A, a marker for cells in mid S phase and G2

(Figure 11B) and Ki67, a pan cyclin marker. Twenty four hours after gene transfer there is loss of both cyclin E (Figure 11C) and cyclin A reactivity (Figure 11D) . There was no loss of reactivity with Ki67 antibodies against a pan cyclin marker. Together these data confirm a lack of cell cycle progression due to a block in Gl. Figures 12A-12B. Immunocytochemical analysis of

SAOS-2 cells, p53 null cell line, after wt p53 gene transfer using an AAV-wt p53 vector. Non-transduced cells show no reactivity with an antibody against both wild-type and mutant p53 protein

(PAblδOl) (Figure 12A) . Sixteen hours after gene transfer there is the development of strong nuclear reactivity indicating novel expression of p53 protein (Figure 12B) .

Figures 13A-13B. In vivo gene transfer into leptomeningeal tumor cells using the AAV-lacZ vector. Figure 13A: DAOY tumor cells (implanted into the subarachnoid space of a nude rat) immunoreacted with an antibody against p53 demonstrate the typical nuclear immunostaining seen in cells that over- express mutant p53. A small area of • underlying brain parenchyma is seen in the upper left corner. The ventricle is in the lower left corner. Figure 13B: an adjacent section shows that four days after one injection of AAV- lacZ viral vector there is expression of β-galactosidase by the tumor cells.

DETAILED DESCRIPTION OF THE INVENTION

As defined herein dvHSV is a defective virus Herpes Simplex Virus, which may be named in the alternative defective interfering virus Herpes Simplex Virus. Further, as defined herein AAV term is an inverted terminal repeat (ITR) segment which contains the AAV origin of DNA replication and the packaging function signals.

This invention provides a defective virus incapable of autonomous replication, comprising an expressible foreign DNA sequence encoding p53 and DNA virus sequences for replication or packaging into a DNA virus, such that the defective virus is incapable of autonomous replication.

In addition, this invention provides a defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) an origin of DNA replication, (c) a cleavage/packaging signal, and (d) regulatory elements, signals, such that the defective Herpes Simplex Virus (dvHSV-p53) is incapable of autonomous replication. More specifically, the DNA origin of replication is HSV ori and the cleavage/packaging signal is HSVa.

In one embodiment of the above invention, the dvHSV contains p53 in combination with a second gene. In a second embodiment dvHSV contains p53 in combination with a plurality of genes, which include but are not limited to: mdm.2, GADD45, and WAF1.

A number of viral vectors have been described including those made from various promoters and other regulatory elements derived from virus sources. Promoters consist of short arrays of nucleic acid sequences that interact specifically with cellular proteins involved in transcription. The combination of different recognition sequences and the cellular concentration of the cognate transcription factors determines the efficiency with which a gene is transcribed in a particular cell type.

Further, in one embodiment of this invention the regulatory element is a promoter or enhancer. The promoter may be selected from a group of eukaryotic cells consisting of but not limited to: herpes simplex virus type I, I.E. 4/5, the herpes simplex virus type I thymidine kinase, the pseudorabies virus thymidine kinase, the pseudorabies virus immediate early gene, the pseudorabies virus glycoprotein X, the pseudorabies virus glycoprotein 92, adenovirus promoter, a simian virus 40 (SV40) promoter, a mouse mammary tumor virus (MMTV) promoter, a Malony murine leukemia virus promoter, a murine sarcoma virus promoter, and a Rous ^• sarcoma virus promoter. In its preferred embodiment the promoter is a cytomegalovirus (CMV) promoter.

Cytomegalovirus (CMV) is a human CMV immediate early promoter which serves as an efficient transcription element with which to express foreign proteins. In combination with the CMV enhancer element, the CMV promoter's transcriptional activity can be increased 10 to 100-fold. The human CMV enhancers are also active in a wide variety of cells from many species.

Further, the suitable promoter may be a heat shock promoter or a bacteriophage promoter. Examples of suitable bacteriophage promoters include, but are not limited to: a T7 promoter, a T3 promoter, an SP6 promoter, a lambda promoter, or a baculovirus promoter. Also suitable as a promoter is an animal cell promoter such as, but not limited to: an interferon promoter, a metallothionein promoter, or an immunoglobulin promoter. A fungal promoter is also a suitable promoter. Examples of fungal promoters include but are not limited to: an ADCl promoter, an ARG promoter, an ADH promoter, a CYC1 promoter, a CUP promoter, an EN01 promoter, a GAL promoter, a PHO promoter, a PGK promoter, a GAPDH promoter, and a mating type factor promoter. Further, plant cell promoters and insect cell promoters are also suitable for the methods described herein.

Further, the present invention provides for a plurality of regulatory elements, i.e. promoters or enhancers, in the vector which may be turned on or off to express a protein. Further, the regulatory elements may be operatively linked to the DNA sequence. Further, the promoters may be modified or employed so as to specifically target tumor cells for delivery of the vector.

Regulatory elements required for expression include promoter and enhancer sequences to bind RNA polymerase and translation initiation sequences for ribosome binding. For example, a bacterial expression vector includes a promoter such as the lac promoter, and for transcription initiation the Shine-Dalgarno sequence and the start codon AUG. Similarly, a eukaryotic expression vector includes a heterologous or homologous promoter for RNA polymerase II, a downstream polyadenylation signal, the start codon AUG, and a termination codon for detachment of the ribosome.

In addition, the present invention provides for a defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno-Associated Virus (dvAAV-p53) is incapable of autonomous replication.

More specifically, the flanking terminal repeats, named herein AAV term, contain the DNA origin of replication and the packaging function signals. In one embodiment there are two flanking terminal repeats containing at least an origin of DNA replication and packaging function signals.

In one embodiment of the invention, the dvAAV contains p53 in combination with a second gene. In a second embodiment dvAAV contains p53 in combination with a plurality of genes, which include but are not limited to: mdm2, GADD45, and WAF1.

Further, in one embodiment of this invention the regulatory element is a promoter or enhancer as hereinabove defined.

Further, the present invention provides for a pharmaceutical composition comprising the dvAAV-p53 and a pharmaceutically acceptable carrier.

In addition, the present invention provides an expressible Herpes Simplex Virus (HSV-p53) vector, comprising (a) a foreign DNA sequence encoding p53 inserted into a non essential site, (b) an origin of DNA replication recognition signal, (c) a cleavage/packaging recognition signal, and (d) regulatory elements. More specifically, the origin of DNA replication is HSV ori and the cleavage/packaging signal is HSVa. In an embodiment, this plasmid, pHSV-p53, was deposited on April 7, 1994 with the American Type Culture Collection (ATCC) , 12301 Parklawn Drive, Rockville, Maryland 20852, U.S.A. under the provisions of the Budapest Treaty for the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. Plasmid, pHSV-p53, was accorded ATCC Accession Number 69599.

Further, the regulatory element is a promoter or enhancer as hereinabove defined.

Further, the HSV-p53 vector is capable of being replicated by a helper virus. In one embodiment HSV- p53 vector helper functions are provided by a HSV helper virus. More specifically, the HSV-p53 helper virus is a HSV1 mutant incapable of replication at physiologic temperatures. Mutant strains of HSV are included within the scope of this inventions.

In addition, this invention provides an expressible

Adeno-Associated Virus (AAV-p53) vector, comprising an

(a) expressible foreign DNA sequence encoding p53 inserted into a non essential site, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno- Associated Virus (AAV-p53) is incapable of autonomous replication.

In an embodiment, this plasmid, pAAV-p53, (which was deposited under the name pAAV-CMV-p53) (Figure 2) was deposited on April 7, 1994 with the American Type Culture Collection (ATCC) , 12301 Parklawn Drive, Rockville, Maryland 20852, U.S.A. under the provisions of the Budapest Treaty for the International Recognition of the Deposit of Microorganisms for the Purposes of Patent Procedure. Plasmid, pAAV-p53, was accorded ATCC Accession Number 69600.

Further, the AAV-p53 vector is capable of being replicated by a helper virus. In one embodiment AAV- p53 vector helper functions are provided by an AAV helper plasmid and an adenovirus. In a second embodiment AAV helper functions are provided by AAV helper plasmid pAd8 and an adenovirus. Further, alternative helper viruses which replicate the pAAV-p53 may be employed.

The preparation of pharmaceutical compositions which contain vectors or the defective virus as active ingredients are well understood in the art. Typically, such compositions are prepared as injectables, either as liquid solutions or suspensions, however, solid forms suitable for solution in, or suspension in, liquid prior to injection can also be prepared. The preparation may also be emulsified. The active therapeutic ingredient may be mixed with excipients which are pharmaceutically acceptable and compatible with the active ingredient. Suitable excipients are, for example, water, saline, dextrose, glycerol, ethanol, or the like and combinations thereof. In addition, if desired, the composition can contain minor amounts of auxiliary substances such as wetting or emulsifying agents, pH buffering agents which enhance the effectiveness of the active ingredient.

A vector or defective virus may be formulated into the therapeutic composition as neutralizedpharmaceutically acceptable salt forms. Pharmaceutically acceptable salts include the acid addition salts (formed with the free amino groups of the polypeptide or antibody molecule) and which are formed with inorganic acids such as, for example, hydrochloric or phosphoric acids, or such organic acids as acetic, oxalic, tartaric, mandelic, and the like. Salts formed from the free carboxyl groups can also be derived from inorganic bases such as, for example, sodium, potassium, ammonium, calcium, or ferric hydroxides, and such organic bases as isopropylamine, trimethyla ine, 2- ethylamino ethanol, histidine, procaine, and the like.

In addition, this invention provides a method of treating a subject with cancer, which comprises administering an effective amount of the defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication or the defective Adeno- Associated Virus (dvAAV-p53) incapable of autonomous replication, so as to thereby treat the subject with cancer.

Further, both defective Herpes Simplex Virus (dvHSV- p53) or the defective Adeno-Associated Virus (dvAAV- p53) incapable of autonomous replication, may be administered in combination with each other or in combination with other chemotherapeutic agents.

Further, the types of cancer include but are not limited to: tumors involving hematopoietic organs, bladder, brain, spleen, kidney, lung, breast, prostate, colon, soft tissue sarcomas, osteosarcomas or neuronal cancer.

Further, the subject as defined herein may be a mammal. More specifically, the mammal is selected from the group consisting of a human, monkey, dog, rabbit or rodent . In the preferred embodiment the subject is a human.

The compositions are administered in a manner compatible with the dosage formulation, and in a therapeutically effective amount. Effective amount is the amount necessary to treat the subject with cancer. For example, one viral particle of dvHSV or dvAAV per tumor cell is sufficient to treat the tumor cell. One can determine the amount or volume, of tumor cells in a subject by radiographic procedures and thereafter prepare an amount of dvHSV or dvAAV accordingly. Alternatively, the effective amount of dvHSV or dvAAV may be less than one viral particle due to the "bystander effect" . The quantity to be administered depends on the subject to be treated, capacity of the subject's immune system to utilize the active ingredient, and degree of modulation of dvHSV or dvAAV capacity desired.

Precise amounts of active ingredient required to be administered depend on the judgment of the practitioner and are peculiar to each individual.

Suitable regimes for initial administration and booster shots are also variable, but are typified by an initial administration followed by repeated doses at one or more hour intervals by a subsequent injection or other administration.

As used herein administration means a method of administering to a subject. Such methods are well known to those skilled in the art and include, but are not limited to, administration topically, parenterally, orally, intravenously, intranasally, intratumorally, intratracheally, intramuscularly, subcutaneously, inhaled or by aerosol, by catheter, or by colonoscopy. Administration of the agent may be effected continuously or intermittently such that the therapeutic agent in the subject is effective to modulate or treat the cancer.

This invention provides a method of overexpressing p53 in a cell of a subject with cancer, which comprises contacting the cell with an effective amount of the defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication or the defective Adeno- Associated Virus (dvAAV-p53) incapable of autonomous replication, so as to thereby overexpress p53 in the cell of a subject with the cancer.

In addition, this invention provides a method of treating a subject with cancer, which comprises: (a) removing cells of a subject with cancer, (b) contacting the cells of the subject with cancer with an effective amount of the defective Herpes Simplex Virus (dvHSV- p53) incapable of autonomous replication or the defective Adeno-Associated Virus (dvAAV-p53) incapable' of autonomous replication, and (c) injecting the cells back into the subject, so as to treat the subject with cancer.

Further, suitable animal cells include, but are not limited to Vero cells, HeLa cells, Cos cells, CV1 cells and various primary mammalian cells.

In addition, this invention further provides a vaccine which comprises an effective immunizing amount of a dvHSV-p53 or dvAAV-p53 vector of the present invention and a suitable carrier.

The vaccine may be administered by any of the methods well known to those skilled in the art, for example, by intramuscular, subcutaneous, intraperitoneal or intravenous injection. Alternatively, the vaccine may be administered intranasally or orally.

In addition, this invention provides for diagnostic uses for cancer treatment or therapy for the dvHSV-p53, dvAAV-p53 vectors in addition to pHSV-p53 and pAAV-p53. The ability of a cell to cause apoptosis is indicative of how a cell from a cancer subject would respond to chemotherapy. Thus, contacting a cell of a subject in culture with dvHSV or dvAAV is a diagnostic or assay for therapy of a cancer subject.

This invention provides for transfer of the wild-type p53 gene using a defective herpes simplex viral vector into a human medulloblastoma cell line which contains a mutant copy of p53. Upon gene transfer, there is a novel expression of wild-type p53 protein in the cells. In addition, the p53 protein was functionally active, since gene transfer resulted in increased levels of mdm.2 proteins and induced cell cycle arrest of the majority of transduced cells. This invention is the first that utilizes this vector system to carry wild- type p53. Defective herpes simplex viral vectors can transfer and express p53 in human primary brain tumor cells in vitro, restoring wild-type p53 tumor suppressor functions.

This invention provides a method of increasing the level of mdm2 in a cell, which comprises contacting the cell with an effective amount of the defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication, so as to thereby increase the level of mdm2 in the cell.

In the present invention, Herpes Simplex viral vector was used to introduce wild-type p53 into brain tumor cells that express mutant p53. DAOY cells, a human medulloblastoma cell line, were shown to express a mutant form of p53 by immunohistochemical analysis. The mutation was confirmed by single strand conformational analysis, and its nature was identified by direct sequence analysis. The mutation resulted in the loss of a restriction digestion site allowing identification of endogenously expressed mutant p53 and novelly expressed wild-type p53. Results demonstrated that HSV defective viral vectors can be used to transfer and express genes in human primary brain tumors cells in vitro, and that the expression of wild- type p53 in these cells inhibits expression of the endogenous mutant p53.

In addition, the present invention is a means by which the wild-type p53 gene may be transferred to cells in vitro and in vivo. This invention utilizes defective HSV and defective AAV vectors to transfer p53. The novel expression of wild-type p53 by these cells has functional effects that result in alterations of the recipient cell physiology, in some cases leading to ^• growth arrest or cell death. Since mutation of p53 is found in about half of almost all types of cancer, this makes the invention useful as a therapeutic agent in the treatment of multiple forms of cancers.

Furthermore, the present standard therapies of cancer including surgery, irradiation, and systemic or local chemotherapy each have serious adverse side effects and the present invention has the potential to be far less toxic.

This invention will be better understood from the

Experimental Details which follow. However, one skilled in the art will readily appreciate that the specific methods and results discussed are merely illustrative of the invention as described more fully in the claims which follow thereafter.

Experimental Details

Experiment I : Materials and Methods :

Cell Lines. The medulloblastoma cell line DAOY was obtained from the American Type Culture Collection (ATCC HTB 186) as were African green monkey kidney (Vero) cells (ATCC CCL 81) and rabbit skin cells (ATCC CCL 68) . Cells were grown in Dulbecco's modified Eagle's medium (DME) supplemented with 10% fetal calf serum (FCS) , non-essential amino acids and 100 ug/ml penicillin/streptomycin (pen/strept) .

Recombinant Plasmids. The plasmid pC53-SN3 containing the wild-type p53 cDNA sequence and the cytomegalovirus

(CMV) promoter was obtained from Dr. Arnold Levine

(Princeton University) . pHCl, an HSV amplicon containing the lac Z gene [37] was digested with

Xbal/PvuII and ligated to the Xbal/Hindlll (blunted) fragment of pC53-SN3 to produce pHSV-p53. The PvuII fragment of pHSV-p53 (containing most of the p53 cDNA and the polyadenylation signal) was removed to create pHSV-p53cont (a negative control plasmid) .

Immunohistochemistry, Monoclonal Antibodies, and X-gal Histochemistry. Cells were cytospun at 800 rpm for 2 minutes or plated on poly-L-lysine coated multiwell slides (Nunc, Naperville, IL) at a density of 50%. When cells reached 90% confluence they were rinsed with phosphate buffered saline (PBS) and fixed in cold methanol:acetone (1:1) for 10 minutes. Slides were sequentially incubated with 0.1% hydrogen peroxide for 10 minutes to destroy endogenous peroxidase activity and 10% normal horse serum as a blocking serum for 30 minutes. Anti-p53 antibody PAblδOl (Ab-2; Oncogene Science, Uniondale, NY) recognizes an epitope between amino acids 32 to 79 of both human wild-type and mutant p53 proteins [62] . Anti-p53 antibody PAbl620 (Ab-5, Oncogene Science) specifically reacts with wild-type p53 [54] . After washing with PBS slides were incubated with 0.05μg/ml PAblδOl or 5 /xg/ml PAbl620, or a randomly selected mouse monoclonal IgG of unknown specificity (PharMingen, San Diego, CA) at 4°C overnight . Slides were then washed and incubated with biotinylated anti-mouse IgG antibody (Vector, Burlingame, CA) for 1 hour at room temperature, followed by avidin-biotin peroxidase complex (ABC, Vector) for 30 minutes. The substrate reactions were developed with 0.05% diaminobenzidine HCl, 0.5% Triton X-100 and 0.01% hydrogen peroxide in PBS. Slides were counterstained with hematoxylin.

For X-gal histochemistry cells were fixed in 2% formaldehyde/ 0.2% gluteraldehyde in PBS and then incubated in substrate solution (1 mg/ml X-gal, 5 mM potassium ferricyanide, 5 mM potassium ferrocyanide, 2 mM MgCl₂ in PBS) and stained for 24 hours at 37°C. X- gal was prepared as a 40 mg/ml solution in dimethyl sulfoxide.

Reverse Transcription-Polymerase Chain Reactions. Cells were grown to 90% confluency in 25 cm² tissue culture flasks. Media was removed, cells were washed with PBS, and RNA was extracted using the RNAzol protocol (Cinna/Biotecx, Houston, Texas) . 1 μg of total RNA was incubated with reverse transcriptase (2.5 U/μl) for 30 minutes at 42°C in a total reaction volume of 20 μl containing: 1 mM each dNTP, 1 U/μl ribonuclease I inhibitor, and 2.5 μM random hexamer primers. Reverse transcriptase (RT) reactions were terminated by incubation at 99°C for 5 minutes. One tenth of the RT reaction was used directly for subsequent polymerase chain reaction (PCR) amplification in a final volume of 50 μl. This reaction included: 1 x PCR buffer (50 mM Tris [pH 9.5] , 1.5 mM MgCl₂, 20 mM ammonium sulfate) , 0.2 mM each dNTP, 0.5 μM each 5' and 3' primer, and 1 U Taq polymerase (Perkin-Elmer-Cetus, Norwalk, CT) . PCR was performed in an automated DNA clonal cycler (Ericomp, San Diego, CA) with the following temperature profile: 1 min at 94°C; 35 cycles of 30 seconds at 53°C, 1 minute at 72°C, and 1 minute at 94°C; 2 minutes at 55°C; and 10 minutes at 72°C. For PCR reactions that were to be used for single strand conformational analysis 5 μCi [³²P]dCTP was added to the PCR reaction. Five primer pairs were created that spanned the entire cDNA coding region and that would result in PCR products of approximately 250 base pairs each.

Single Strand Conformational Analysis (SSCP) . One microliter of the five PCR products that spanned the DAOY mutant p53 cDNA was diluted with 9 μl of loading buffer (95% formamide, 20 mM EDTA, 0.05% bromophenol blue, 0.05% xylene cyanol) and heated to 98°C for 2 minutes. The mixture was loaded onto an 8% non- denaturing acrylamide gel (17.5 cm x 30 cm) , 80:1 ratio acrylamide to methylene-bis-acrylamide and run at constant voltage of 200 V at 4°C for 16-20 hours. The gel was transferred to Whatman paper, dried, and exposed to Kodak X-Omat AR film overnight. Wild-type p53 that was amplified from the recombinant plasmid p53-HSV served as a normal control.

DNA Sequence Analysis. The full length DAOY mutant p53 cDNA was obtained from a RT reaction. This product was subcloned in an A-T tailed vector (pT7 Blue (U) T- vector; Novagen, Madison, WI) . Colonies were assayed by PCR to establish the presence of the cDNA insert.

Sequence analysis was performed using the dideoxy termination method [28] with Sequenase 2.0 (United States Biochemical, Cleveland, OH) .

Propagation of Defective Viral Vectors and Isolation of Viral DNA. Rabbit skin cells were transfected with pHSV-p53 or pHSV-p53cont using the calcium phosphate method [49] followed by glycerol shock [60] . After an overnight incubation at 37°C in 5% C0₂, the medium was removed and cells were superinfected with helper virus, a temperature-sensitive HSV1 (tsK) strain [49] (originally obtained from Dr. J. Subak-Sharpe, Institute of Virology, Glasgow, Scotland) at a multiplicity of infection of 0.1 plaque forming units per cell. Cells were washed 2 times with PBS and incubated at 31°C and 5% C0₂ in DME with 1% FCS and pen/strept. Viral stocks were harvested when all of the cells showed cytopathic effects (usually 2-3 days after superinfection) . Cells were pelleted at 1000 x g for 10 minutes, and the pellets resuspended in 150 mM NaCl/ 20 mM Tris, pH 7.5. Suspensions were frozen to -70°C and thawed to 37°C 3 times, then sonicated 5 times for 30 seconds each. Cellular debris was removed by centrifugation at 1000 x g for 10 minutes and the supernatant was stored at -85°C or used fresh. Virus was serially passaged in Vero cells at a 1 to 3 dilution. Viral DNA for PCR and Southern analysis was isolated from the viral stock by incubation in 0.5 μM EDTA, 1% sodium dodecyl sulfate (SDS) , and 200 μg/ml Proteinase K for 2 hours at 37°C, followed by extraction with phenol/chloroform, then chloroform, and precipitation with ethanol at 4°C.

Infection of Cells. Infections were done at 37°C. DAOY cells were grown in 25 cm² culture flasks to a confluency of 90%. The media was removed and the viral stock (from passage 3) was applied to the cells at a 1 to 15 dilution of the viral stock. Virus was diluted in PBS with 1% FCS. After a 1.5 hour incubation, the viral solution was removed and fresh DME was added to the cells.

Southern Blot Analysis. Extracted viral DNA was digested to completion with Sail and run in a 1.0% agarose gel. DNA was transferred to nylon filters

(Hybond-N, Amersham, Arlington Hts, IL) by the method of Southern [2δ] and hybridized (16 hours at 66°C) to wild-type p53 cDNA isolated from p53-SN3 by digestion with BamHI and labeled by random priming (Prime-It II, Stratagene, LaJolla, CA) . Blots were washed at low stringency (2x SSC) and high stringency (O.lx SSC) at room temperature.

Western Blot Analysis. DAOY cells from a confluent 25 cm² culture flask were lysed at 4°C in 1% Triton X-100, 0.1% SDS and 120 mM sodium deoxycholate in PBS. Protein content determined by the Bio-Rad assay (Bio- Rad, Hercules, CA) . Proteins were resolved in a 10% polyacrylamide-SDS gel electrophoresis and transferred to nitrocellulose [18] . The nitrocellulose was blocked with 5% Blotto (Carnation evaporated milk in PBS) overnight at 4°C, then incubated for 2 hours at room temperature with 0.05 μg/ml PAbDO-l (Ab 6, Oncogene Science) , a mouse monoclonal antibody against p53 with similar reactivity as PAblδOl [62] . After incubation filters were washed with 10 mM Tris-HCl (pH 7.4), 1% bovine serum albumin, 0.9% NaCl, 0.5% Triton X-100 (TBST) , incubated with [I]¹²⁵ protein A (0.1 μCi/ml) for 1 hour, washed again in TBST, dried, and exposed to film at -70°C. 1. Preparation of Recombinant HSV Plasmids and Propagation of Defective Viral Vectors.

Defective Herpes Simplex Viral (HSV) vector:

The plasmid pC53-SN3 containing the wild-type p53 cDNA sequence was purchased without restriction from Dr. Arnold Levine, Princeton University. The Xbal/PvuII restriction digest fragment of pHSV.SL was ligated to the Xbal/Hindlll (blunted) fragment of pC53-SN3 to produce pHSV-p53 and deposited under the provisions of the Budapest Treaty on April 7, 1994 (ATCC Accession No. 69599) (Figure 1) .

To develop the defective-HSV vectors, an HSV amplicon plasmid was constructed that contained two HSV recognition signals, an origin of replication and cleavage/packaging signal, as well as a eukaryotic transcription unit containing the HSV promoter and wild-type p53 cDNA, and bacterial sequences for ampicillin resistance and plasmid replication. This amplicon plasmid was called pHSV-p53. For use as a negative control, most of the p53 cDNA sequence including the polyadenylation signal was removed from pHSV-p53 by restriction digestion with PvuII to generate pHSV-p53cont. The structure of these recombinant plasmids is shown in Figure 1. The amplicon pHCl, containing the lac Z gene was also used as a control [37] . The genomes of the plasmids were verified by restriction mapping. Rabbit skin cells were transfected with these plasmids and superinfected 24 hours later with helper virus (Tsk, a temperature sensitive HSV mutant) . Defective virus was propagated at 31°C allowing for replication of the helper virus. Continued passaging in Vero cells at a high multiplicity of infection at the permissive temperature allowed for the generation of defective viral vector. The defective virus (dv) propagated from the pHSV-p53 amplicon as dvHSV-p53, from the control amplicon as dvHSV-p53cont and from pHCl and dvHSV-lac Z was designed.

2. Determination of the Presence of Defective-Virus in Harvested Viral Stocks.

To determine that defective virus was being generated, viral DNA was obtained at each passage and assayed by PCR and Southern blot for the presence of defective viral DNA. Figure 3 shows the Southern blot analysis of viral DNA from passage 3. Extracted viral DNA was digested to completion with Sail, an enzyme with a unique site in pHSV-p53. Digestion of pHSV-p53 and pHSV-p53cont plasmids served as positive controls while digestion of herpes viral DNA served as a negative control. Wild-type p53 cDNA was used as a probe.

Recombinant Adeno-Associated Viral (AAV) vector:

pAAVlac.26 was generated from pSul201, obtained from Dr. Richard Samulski, University of Pittsburgh. A plasmid was derived from this, pAAV-HSV-p53 (made by the applicant) . pC53-SN3 was digested with Smal and EcoRI to release wild-type p53 cDNA which was then ligated into pAAV-HSV-p53 digested with EcoRV/EcoRI yielding pAAV-p53 (previously named pAAV-CMV-p53) and deposited under the provisions of the Budapest Treaty on April 7, 1994 (ATCC Accession No. 69600) (Figure 2) . 3. Propagation of Defective Viral Vectors from the Above Constructs

Herpes Simplex constructs:

Vero (African Green Monkey kidney cells purchased from the ATCC) were maintained in Dulbecco's modified medium

(DME) supplemented with 10% calf serum and 1% pen/strept. Cells were transfected with p53-HSV by the calcium phosphate method followed by glycerol shock.

After an overnight incubation at 37°C and 5% C0₂, the medium was removed and cells were superinfected with helper virus, a temperature-sensitive HSV1 (tsK) strain

(originally obtained from Dr. J. Subak-Sharpe) at a multiplicity of infection of 0.1 plaque forming units per cell. Cells were washed 2 times with PBS and incubated at 31°C in DME/l% inactivated fetal calf serum/1% pen-strept. Viral stocks were harvested when all of the cells show cytopathic effects (usually 2-3 days after superinfection) . Cells were pelleted at 1000 x g for 10 minutes, and the pellets resuspended in 150 mM NaCl/20 mM Tris, pH 7.5. Suspensions were frozen to -70°C and thawed to 37°C 3 times, then sonicated 6 times for 30 seconds each. Viral stocks were concentrated by centrifugation at 1000 x g for 10 minutes. The supernatants were removed and centrifuged at 70,000 x g for 90 minutes. Viral pellets are resuspended in 150 mM NaCl/20 mM Tris, pH 7.5 and stored at -65°C or used fresh. Large volumes of viral stocks with high titers are obtained by serial passaging and harvesting.

Adeno-Associated constructs:

293 cells (a transformed human kidney cell line constitutively expressing the adenovirus Ela gene product) were obtained from Dr. Thomas Shenk, Princeton University and were maintained under the same conditions as the VERO cells described above. Cells were cotransfected with pAAV-p53 and pAdδ (obtained from Dr. Richard Samulski, University of Pittsburgh) using DOTAP lipofection reagent (Boehringer) . After 6 hours at 37°C and 5%C0₂, the medium was removed and cells were superinfected with adenovirus at a multiplicity of infection of 1. Two days later virus was released from cells by repeated freeze/thaw cycles. Residual adenovirus was removed by heating to 56°C, however this physical separation can also be achieved by centrifugation in a cesium chloride gradient.

4. Detection and Characterization of the p53 Mutation in DAOY Cells

Immunohistochemical studies:

DAOY cells displayed nuclear immunostaining with PAblδOl indicating the accumulation of p53 protein. To determine if this protein was wild-type or mutant, RNA was extracted from the cells and used in a RT-PCR analysis. The resulting cDNA was analysed by SSCP. This analysis revealed two regions containing potential mutations. The DAOY p53 cDNA was subcloned and these regions were sequenced. This revealed that codon 72 of the DAOY cDNA contained a previously described polymorphism [4a] . Further analysis revealed a mutation in codon 242 of exon 7, resulting in a G to T transversion (Figure 5A) . It was noted that this mutation resulted in the loss of one of two Alwnl restriction digest sites in the p53 cDNA as diagrammed in Figure 5B. This was confirmed by restriction digest analysis of wild-type and DAOY p53 cDNAs.

DAOY cells infected with dvHSV-p53 were studied by immunohistochemistry . Figures 4A-4B show the reactivity of uninfected DAOY cells with PAblδOl and PAb 1620. There is a typical pattern of nuclear immunostaining for PAblδOl. There is no reactivity with PAbl620 which only recognizes wild-type p53 protein. Figure 4C (1620) and Figure 4D (1801) and demonstrate the immunostaining of these cells 24 hours after infection with dvHSV-p53. There is loss of the nuclear immunostaining of PAblδOl. In contrast, PAbl620 now demonstrates marked nuclear immunoreactivity consistent with overexpression of wild-type p53.

Novel immunoreactivity with PAbl620 was then used to obtain titers of dvHSV-p53. DAOY cells were infected with serial dilutions of virus and immunostained with PAbl620. Titer was quantitated as one defective vector per stained cell. Since the control virus dvHSV-Pvu could not be accurately titered, a titer of dvHSV-lac Z was obtained by infection of DAOY cells followed by X-gal histochemistry. DAOY cells were then infected with an equal number of dvHSV-lac Z viral particles for 24 hours followed by immunostaining with PAblδOl and 1620. Infection with control virus does not alter the pattern of immunoreactivity indicating the absence of any effect secondary to the presence of virus.

5. Gene Transfer Leads to Overexpression of p53

Western blot analysis demonstrates overexpression of p53 protein after gene- transfer:

DAOY cells were infected with pHSV-HSV virus harvested from passage 3. Twenty four hours af er infection cells were lysed, protein extracted and measured. Protein samples were boiled for 10 minutes in an equal volume of sample buffer [0.125 mM Tris Hydrochloric acid (pH 6.8) , 4% sodium dodecyl sulfate (SDS) , 0.01% bromophenol blue, 10% 2-mercaptoethanol, and 20% glycerol] . Proteins were separated in a 10% polyacrylamide-SDS gel electrophoresis with a 5% polyacrylamide-SDS stacking gel and transferred to nitrocellulose as described by Towbin. The nitrocellulose filter was blocked with 5% Blotto overnight at 4°C.

After blocking, the nitrocellulose was incubated with a monoclonal antibody against p53 (p53 antibody 6, Oncogene Science) at 0.05 μg/ml for 2 hours at room temperature (RT) . After incubation, filters were washed 3 times with 10 mM Tris-HCl (pH 7.4) , 1% BSA, 0.9% NaCl, 0.5% Triton-X 100 (TBST buffer) for 15 minutes each, incubated with [I]¹²⁵ protein A (0.1 μCi/ml) for 1 hour at RT, washed again 3 times with TBST buffer, dried, and exposed to Kodak XAR film at - 70°C.

Figures 6A-6C shows the Western blot analysis of DAOY cells infected with pHSV-p53, p53-Pvu (identical to p53-HSV but with most of the p53 sequences removed to serve as a negative control) , and DAOY cells that were not infected with virus. Twenty-four hours after infection, cells were lysed and protein was extracted. Western blot analysis was performed using a mouse monoclonal antibody against p53 that has reactivity against both mutant and wild-type forms under denaturing conditions. Figures 6A-6C shows a titration of protein concentrations from DAOY cells alone (Figure

6A) ; DAOY cells infected with dvHSV-p53 carrying the wild-type p53 gene (Figure 6B) ; or control virus

(Figure 6C) . As demonstrated, there is overexpression of p53 protein in those cells infected with dvHSV-p53. Overexpression of wild-type p53 decreases expression of mutant p53 :

DAOY cells were infected with dvHSV-p53 or control virus harvested from passage 3, and RNA was extracted and measured. 1 ug of RNA was then used in a RT-PCR reaction using primers specific for p53 which span the sequence containing the nucleotide involved in the mutation. These PCR products were separated on an agarose gel, isolated and then digested with Alwnl . The resulting DNA fragments were separated on agarose.

To determine that the overexpressed p53 was wild-type, the loss of the Alwnl restriction site in the endogenous mutant DAOY p53 was utilized. RNA was extracted from DAOY cells 24 hours after infection with dvHSV-p53 or control virus, and treated with DNase I. The RNA was used in a RT-PCR reaction using primers specific for p53 which span the sequence containing the nucleotide involved in the mutation. The resulting cDNAs would include two Alwnl restriction sites if wild-type and one Alwnl restriction site if mutant

(Figure 5B) . These PCR products were then digested to completion with Alwnl and the resulting fragments separated on an agarose gel.

Replacement and overexpression of wild-type p53 by defective Herpes virus inhibits expression of mutant p53 :

Figure 7 shows the results when DAOY cells were infected with defective virus carrying the wild-type p53 gene (dvHSV-p53) . As controls wild-type p53 cDNA

(lane 1) , and cDNA from uninfected DAOY cells (lane 3) were used. After infection with dvHSV-p53, restriction digests of the DAOY cDNA demonstrated the expression of wild-type p53 (lanes 2 and 4) . It was noted the absence of the 713 bp fragment in these infected cells implying a decrease in the amount of the endogenous mutant transcript. Note that the 196 and 205 base pair (bp) fragments run in one band in this gel.

It is interesting to note the apparent decrease of the endogenous mutant p53 transcript in cells that now overexpressed wild-type p53. Thus, gene transfer with serial dilutions of the defective viral stock were carried out. Figure δ shows the results when a 10 fold lower concentration of defective virus was used. Wild- type p53 cDNA (lane 1) and cDNA from uninfected DAOY cells (lane 3) were used as controls. Cells infected with the lower concentration of dvHSV-p53 show expression of both wild-type and mutant p53 (lane 2) .

6. Functional Effects of the Novel Expression of Wild-type p53

Novel expression of wild-type 53 induces programmed cell death:

DAOY cells grown on glass slides were infected with p53-HSV and increasing concentrations of virus. DNA breaks that form in cells undergoing apoptosis were visualized by the method of Gavrieli. Briefly, after fixation the cells were treated with 10 μg/ml proteinase K and then incubated in buffer containing Tris, sodium cacodylate, cobalt chloride, and biotinylated dUTP (Boehringer Mannheim) . After rinsing, slides were covered with 2% bovine serum albumin and incubated with extra-avidin peroxidase. Cells were stained with 3-amino-9-ethylcarbazole and counterstained with he atoxylin. With increasing concentrations of virus (and subsequent increase in expression of wild-type p53) there was an increase in the number of apoptotic cells as compared to cells infected with increasing concentrations of control virus (Figure 9) .

Results and Discussion:

The present study demonstrates the ability of defective HSV vectors to transfer genes to primary brain tumor cell lines in vitro. DAOY cells were found to overexpress a mutant form of p53 and mapped the mutation to codon 242 of exon 7. This codon maps to one of several 'hot spots' for p53 mutations [16, 30, 41] . The mutation resulted in the loss of an Alwnl restriction site and therefore offered the unique opportunity to distinguish unambiguously mutant DAOY p53 from novelly expressed wild-type p53. The second region that resulted in a gel shift by SSCP was shown to represent a p53 polymorphism demonstrating, as others have reported [20] , the need to confirm positive SSCP results by sequence analysis. Finally, viral transfer of wild-type p53 resulted in the down- regulation of the endogenous mutant transcript in DAOY cells.

DAOY is a cell line derived from a medulloblastoma [43] . This type of tumor accounts for up to 25% of all intracranial neoplasms in children and may develop in adults [16, 36] . While advances in surgery, radiation, and chemotherapy have resulted in longer survival, only

50% of patients survive 5 years [33] . Furthermore, it is known that many of the children that survive medulloblastoma will be damaged by the therapy they received [33] . Gene therapy offers a potential alternative to current treatment protocols. In human cancers where multiple genetic defects are involved in tumorigenesis it may not be possible to replace all defective genes. However, the replacement of critical genes such as wild-type p53 may be sufficient to suppress cell growth or induce cell death and potentially avoid the toxic side effects of conventional therapy [65] .

The HSV amplicon is an expression plasmid that can be packaged into HSV virions and is based upon the concept of HSV defective-interfering viruses [21, 22] . Since the defective HSV viral genome consists of multiple head to tail copies of the HSV amplicon genome, and approximately 150 kb of defective viral DNA is packaged, multiple repeats of the amplicon containing the eukaryotic gene are packaged into a single virion

[22] . Based upon the size of the p53 amplicon used, each dvHSV-p53 virion should have approximately 20 copies of the wild-type p53 gene [58] .

The expression of wild-type p53 in DAOY cells resulted in an apparent decreased expression of the endogenous mutant transcript. It is known that wild-type and mutant p53 can form complexes when they are contranslated [44a] . The mechanism or pathway through which wild-type p53 acts to down-regulate mutant p53 expression is not known. One study has reported that transfection of wild-type p53 resulted in transactivation of the p53 promoter through a mechanism that was not due to a direct interaction between p53 and the promoter [31, 32] . Downregulation of p53 expression is however more consistent with a protein that is involved in the regulation of cell growth. However, it is possible that p53 only downregulates itself in a cell that contains mutant p53 such as DAOY cells. Previous data also suggests that individual mutant p53 proteins may have different phenotypes [12] .

The lack of any direct interaction between p53 and its promoter would suggest that p53 acts through one or more intermediary agents. The results of p53 autoregulation could therefore be dependent upon cell specific responses. Several cellular targets of p53 have been identified, including mdm2 (murine double minute 2) [31, 32] and GADD45 (growth arrest DNA damage inducible gene) [53] . A new gene, WAF1 (Cipl) that is induced by wild-type but not mutant p53 has recently been cloned [10, 45] . The WAF1 gene product binds to cyclin complexes and inhibits the function of cyclin- dependent kinases thereby regulating progression through the cell cycle. Studies are in progress to determine if these genes are involved in regulation of p53 in DAOY cells.

With the defective HSV viral system presented in this study, it is now possible to examine the role of p53 not only in dividing brain tumor cells but also in the normal, non-dividing cells of the nervous system such as terminally differentiated neurons and quiescent glial cells, and in non-neuronal cells. New therapeutic modalities may be based upon the potential to reverse the neoplastic phenotype of a malignant cell with gene transfer. Through the use of mutant and antisense constructs, gene transfer studies should also prove valuable in elucidating pathways involved in the oncogenesis of primary brain tumors.

Experiment II: Materials and Methods:

Cell Lines. The medulloblastoma cell line DAOY was obtained from the American Type Culture Collection (ATCC HTB 166) as were African green monkey kidney (Vero) cells (ATCC CCL 81) , rabbit skin cells (ATCC CCL 68) and the osteosarcoma cell line, Saos-2 (ATCC HTB 85) . Cells were grown in Dulbecco's modified Eagle's medium (DME) supplemented with 10% fetal calf serum (FCS) , non-essential amino acids and 100 ug/ml penicillin/streptomycin.

(CMV) promoter was obtained from Dr. Arnold Levine

(Princeton University) . pHCl, an HSV amplicon containing the lacZ gene and two HSV recognition signals (origin of replication and cleavage/packaging signal) [37] was digested with Xbal/PvuII to release the HSV signals. These sequences were ligated to the

Xbal/Hindlll (blunted) fragment of pC53-SN3 to produce pCMV-p53.

Monoclonal Antibodies, Iππnunocytochemistry, and X-gal Cytochemistry. Anti-p53 antibody PAblδOl (Ab-2; Oncogene Science, Uniondale, NY) recognizes both human wild-type and mutant p53 proteins [4] . Anti-p53 antibody PAbl620 (Ab-5, Oncogene Science) specifically reacts with wild-type p53 [77] . Immunocytochemistry for mdm2 was done using the mouse monoclonal antibody 2A10 which recognizes an epitope in the central portion of the protein [76] . Studies of the cell cycle were done using monoclonal antibodies against cyclin E (clone HE67, PharMingen, San Diego, CA) , cyclin A (clone BF663, PharMingen, San Diego, CA) and Ki67 (clone Ki67; Becton-Dickinson, San Jose, CA) .

Cells were cytospun and fixed in cold methanol :acetone (1:1), then sequentially incubated with 0.1% hydrogen peroxide for 10 minutes to destroy endogenous peroxidase activity and 10% normal horse serum as a blocking serum for 30 minutes. After washing with PBS slides were incubated with PAblδOl (200 ng/ml) , PAbl620, antibody HE67, antibody BF683 or antibody Ki67

(5 μg/ml) , antibody 2A10 (1:1000) , or 5 μg/ml of an isotype-matched control mouse antibody (PharMingen, San Diego, CA) for 1 hour. Slides were washed and incubated with biotinylated horse anti-mouse IgG (1:500) (Vector, Burlingame, CA) , followed by- extensive washes and incubation with avidin-biotin peroxidase complexes at 1:25 dilution. Diaminobenzidine (0.05%) was used as the final chromogen and hematoxylin as the nuclear counterstain. For X-gal cytochemistry cells were fixed in 2% formaldehyde/0.2% gluteraldehyde in PBS and incubated as previously described [37] .

Propagation of Defective Viral Vectors and Isolation of Viral DNA. Rabbit skin cells were transfected with pCMV-p53 or pHCl (containing the lacZ gene) using the calcium phosphate method [28] followed by glycerol shock [49] . After an overnight incubation at 37°C in 5% C0₂, cells were superinfected with helper virus, a temperature-sensitive HSV1 (tsK) strain [26] (originally obtained from Dr. J. Subak-Sharpe, Institute of Virology, Glasgow, Scotland) at a multiplicity of infection (MOD of 0.1 plaque forming units per cell. Viral stocks were harvested when all of the cells showed cytopathic effects (usually 2-3 days after superinfection) . Cells were pelleted at 1000 x g for 10 minutes, and resuspended in 150 mM NaCl/ 20 mM Tris, pH 7.5. Suspensions were frozen to -70°C, thawed to 37°C three times, then sonicated five times for 30 seconds each. Cellular debris was removed by centrifugation at 1000 x g for 10 minutes and the supernatant stored at -85°C. Virus was serially passaged in Vero cells at a 1:3 dilution. The defective virus (dv) propagated from the pCMV-p53 amplicon was designated dv-p53, and from pHCl, dv-lacZ.

Deteradnation of Helper and Defective Viral Titers and Infection of Cells. Concentrations of tsK helper virus in the viral stocks was determined by standard viral plaque assay in Vero cells at 31°C. ^• Titers of dv-p53 were obtained by immunocytochemical detection of novel p53 expression in Saos-2 cells which express no p53 protein [11] . Titer was quantified as one defective vector per stained cell when reacted with PAblδOl or PAbl620 (both yielding the same titer) . The titer of dv-lacZ was obtained by X-gal cytochemistry. Reversion assays with this helper virus have shown that there are fewer than 10^"5 wild-type revertants per ml of viral stock [37] . This figure may be as low as <10^"7. For an average stock of 10^"5-i0^"~ viral particles per ml this represents less than 1 revertant per 10 μl. This volume is larger than that used in prior in vivo studies [37] .

Infections of cells were done at 37°C. Virus was diluted in PBS with 1% FCS . After a 1.5 hour incubation, the viral solution was removed and fresh DME was added to the cells.

Results and Discussion:

Overexpression of Wild-type p53 Leads to Increased Expression of mdm2. DAOY cells infected with dv-p53 were studied by immunocytochemistry using a panel of well characterized antibodies to p53 and mdm.2 proteins.

For these studies cells were infected with virus at a

MOI of 1.5 which resulted in infection of 90-95% of the cells. After wt p53 gene transfer, DAOY cells showed a marked increase in immunostaining with the anti-mdm2 monoclonal antibody 2A10 suggesting an increase in the level of expression of mdm2 proteins in these cells

(Figure 10B) while transfer of dv-lacZ did not alter the expression of mdm2. Cells arrest in G_x after wild-type p53 gene transfer.

Figure 11A shows the reactivity of DAOY cells with an antibody against cyclin E, a marker for cells in late G_λ and early S phase. Figure 11B shows the reactivity of DAOY cells with an antibody against cyclin A, a marker for cells in mid-S phase and G₂. The positive staining pattern obtained prior to wt p53 gene transfer indicates passage of DAOY cells through the cell cycle. Twenty four hours after wt p53 gene transfer there is loss of reactivity against cyclin E (Figure 11C) and cyclin A (Figure 11D) but there is no change in reactivity with Ki67 (not shown) . These findings demonstrate that after wt p53 gene transfer the DAOY cells arrest in G- . Although multiple genetic defects appear to be involved in tumorigenesis, the replacement of critical genes may suffice no suppress cell growth or indu e cell death [22] . The tumor suppressor gene p53 acts as a transcriptional activator as well as a negative growth regulator that suppresses transformation [17, 18, 44] . p53 is also involved in progression of the cell through the cell cycle and the process of programmed cell death or apoptosis [39, 56, 67] . Allelic losses and point mutations of p53 are found in numerous cancers including brain tumors [20, 30, 41, 47, 63] , and overexpression of mutant p53 proteins is one of the most commonly detected abnormalities in human cancer [41] . In addition to somatic alterations, p53 germline mutations are the underlying genetic alteration associated with the development of tumors in patients with the Li-Fraumeni syndrome [42] . Mutations of p53 usually occur within highly conserved domains [30] and result in abrogation of gene function [18, δO] .

p53 gene transfer using AAV-p53 vector. SAOS-2, a p53 null, osteogenic sarcoma cell-line, are not reactive with antibodies against wild type and mutant p53 protein (Figure 12A) . Sixteen hours after p53 gene transfer using AAV-p53 there is the development of strong nuclear reactivity using an antibody against wild type p53 indicating novel expression of p53 indicating novel expression of p53 protein (Figure 12B) .

In vivo gene transfer into mammalian tumor cells. In order to determine if gene transfer with an adeno- associated viral vector can be accomplished in a model of leptomeningeal disease, leptomeningeal (LM) xenografts of a human medulloblastoma cell line (DAOY' were established in nude rats. An AAV vector containing the bacterial lacZ marker gene (AAV-lacZ) was made and residual helper adenovirus was eliminated. AAV-lacZ was injected into a cerebral ventricle 12 days after xenograft implantation and the animals were sacrificed 2 days later. Sections of the brain and spinal cord were studied by histochemistry for expression of LacZ and mutant p53. DAOY tumor cells implanted into the subarachnoid space of nude rats im unoreacted with an antibody against p53 demonstrates the typical nuclear immunostaining seen in cells that cverexpress mutant p53 (Figure 13A) .

In a consecutive section, four days after one injection of AAV-lacZ viral vector, lacZ expression was observed in tumor xenograft cells infiltrating the leptomeninges but not in underlying normal brain (Figure 13B) . LacZ positive cells were found in the subarachnoid space distant from the ventricular injection site. No evidence of inflammation or acute toxicity was noted in AAV-lacZ injected animals. Therefore gene transfer into leptomeningeal xenografts is achieved using AAV viral vector. In addition, there is no associated acute toxicity. In these studies, defective HSV vector and defective AAV vector were used to replace wt p53 in DAOY cells which express mutant p53 [21, 58, 74] and SAOS-2 cells which are null for p53. The results demonstrated that wt p53 gene transfer results in the production of functionally active wt p53 protein by examining alterations in the expression of mdm2 proteins and effects on cell cycle progression.

The mdm2 gene codes for a protein that complexes with p53 protein resulting in the inhibition of p53 function

[45] . Wild- ype p53 and mdm2 are involved in an autoregulatory feedback loop in which p53 up-regulates mdm.2 at the level of transcription and mdm2 protein in turn inhibits p53 function by complexing with p53 protein [81] . The expression of the mdm2 gene is therefore regulated by the level of p53 protein in the cell.

Increases in the cellular levels of wt p53 occur in response to DNA damage from a variety of agents including ionizing radiation [82] and ultraviolet light [83, 84] . In some cells, this results in cell cycle arrest in G [39, 85] while in other cells, perhaps related to the amount of DNA damage, this results in the induction of apoptosis [86,87] . Results demonstrating increased immunoreactive mdm2 protein and -_L arrest after wt p53 gene transfer are therefore consistent with restoration of functional wt p53. Although wt p53 can induce cell cycle arrest in neoplastic cells [88, 89] , this appears to be independent of the function leading to apoptosis [23, 67] . In fact, transduction of wt p53 leads to apoptosis in a small percentage of cells.

After transfer of wt p53, the over-expression of wt p53 proteins in DAOY cells produced a change in the immunocytochemical staining pattern of the endogenous mutant p53 proteins. The altered staining pattern observed after gene transfer could be due to the ability of p53 to undergo conformational changes that result in altered antibody recognition [90] . Wild-type and mutant p53 form complexes when they are co- translated but do not form complexes if mixed post- translationally [44a] .

Alternatively, the decreased nuclear staining of mutant p53 could be consistent with decreased expression of the mutant transcript secondary to the overexpression of wt p53. Although not addressed by the current experiments, this conclusion is supported by several studies demonstrating that wt p53 can down-regulate the activity of a variety of promoters including an autoregulatory effect on its own promoter [91-94] . The mechanism or pathway through which two systems that are well suited to this purpose p53 would act to down- regulate mutant p53 expression has not been elucidated. Over-expression of wt p53 may lead to a down-regulation of transcription by modification of the nuclear environment through sequestration of transcription factors [95] . Others studies have indicated that the human p53 promoter may contain upstream negative regulatory elements similar to those reported for murine p53 [96, 97] and that p53 levels are regulated post-transcriptionally, perhaps at the level of mRNA stability [98] .

As the pathways of oncogenesis are elucidated, the appropriate targets of gene therapy will be found. Gene therapy may offer alternatives to current treatment protocols and could avoid the toxic side effects of the presently available brain tumor therapies. However, the development of efficient and safe gene transfer methods is important . There are several viral vector systems currently in use, the more common being retroviruses, recombinant adenoviruses, and the defective HSV viruses. Each have their own benefits and drawbacks including the retention of potentially toxic viral genes [99] . Newer and potentially safer vector systems such as the adeno- associated viral vector [100-102] and non-viral mediated gene transfer [103-104] are under study. The present results, along with those of others demonstrating pnenotypic correction af er gene transfer [102] , should encourage continued research in this field.

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Claims

What is claimed is:

1. A defective Herpes Simplex Virus (dvHSV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) an origin of DNA replication, (c) a cleavage/packaging function signal, and (d) regulatory elements, such that the defective Herpes Simplex Virus (dvHSV-p53) is incapable of autonomous replication.

2. The dvHSV-p53 of claim 1, wherein the origin of DNA replication is HSV ori.

3. The dvHSV-p53 of claim 1, wherein the cleavage/packaging function signal is HSVa.

4. The dvHSV-p53 of claim 1, wherein the regulatory elements are selected from a group consisting of a CMV, herpes simplex virus type I, I.E. 4/5 protein, the herpes simplex virus type I thymidine kinase, the pseudorabies virus thymidine kinase, the pseudorabies virus immediate early gene, the pseudorabies virus glycoprotein X or the pseudorabies virus glycoprotein 92.

5. The dvHSV-p53 of claim 4, wherein there are a plurality of regulatory elements.

6. A pharmaceutical composition comprising the dvHSV- p53 of claim 1 and a pharmaceutically acceptable carrier.

7. A defective Adeno-Associated Virus (dvAAV-p53) incapable of autonomous replication, comprising (a) an expressible foreign DNA sequence encoding p53, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals, such that the defective Adeno-Associated Virus (dvAAV-p53) is incapable of autonomous replication.

8. The dvAAV-p53 of claim 7, wherein the regulatory elements are selected from the group consisting of a CMV, herpes simplex virus type I, I.E. 4/5, the herpes simplex virus type I thymidine kinase, the pseudorabies virus thymidine kinase, the pseudorabies virus immediate early gene, the pseudorabies virus glycoprotein X or the pseudorabies virus glycoprotein 92.

9. The dvAAV-p53 of claim 8, wherein there are a plurality of regulatory elements.

10. A pharmaceutical composition comprising the dvAAV- p53 of claim 7 and a pharmaceutically acceptable carrier.

11. An expressible Herpes Simplex Virus (HSV-p53) vector, comprising (a) an expressible foreign DNA sequence encoding p53 inserted into a non essential site, (b) an origin of DNA replication recognition signal, (c) a cleavage/packaging recognition function signal, and (d) regulatory elements.

12. The vector of claim 11, wherein the vector is a plasmid.

13. The vector of claim 12, wherein the plasmid is designated pHSV-p53 (ATCC Accession Number 69599) .

14. The HSV-p53 vector of claim 11, wherein the regulatory elements are selected from the group consisting of a CMV, herpes simplex virus type I, I.E. 4/5, the herpes simplex virus type I thymidine kinase, the pseudorabies virus thymidine kinase, the pseudorabies virus immediate early gene, the pseudorabies virus glycoprotein X or the pseudorabies virus glycoprotein 92.

15. The HSV-p53 of claim 14, wherein there are a plurality of regulatory elements.

16. The HSV-p53 vector of claim 11, wherein the HSV- p53 vector is replicated by a helper virus.

17. The HSV-p53 vector of claim 16, wherein the helper virus is an HSV helper virus.

18. The HSV-p53 of claim 17, wherein the HSV helper virus is an HSV1 mutant incapable of replication at physiologic temperatures.

19. An expressible Adeno-Associated Virus (AAV-p53) vector, comprising an (a) expressible foreign DNA sequence encoding p53 inserted into a non essential site, (b) regulatory elements, and (c) flanking terminal repeats containing at least an origin of DNA replication and packaging function signals.

20. The AAV-p53 vector of claim 19, wherein the vector is a plasmid.

21. The plasmid of claim 20, wherein the plasmid is designated pAAV-CMV-p53 (ATCC Accession Number

69600) .

22. The AAV-p53 vector of claim 20, wherein the regulatory elements are selected from the group consisting of a CMV, herpes simplex virus type I, I.E. 4/5, the herpes simplex virus type I thymidine kinase, the pseudorabies virus thymidine kinase, the pseudorabies virus immediate early gene, the pseudorabies virus glycoprotein X or the pseudorabies virus glycoprotein 92.

23. The AAV-p53 vector of claim 22, wherein there are a plurality of regulatory elements.

24. The AAV-p52 vector of claim 19, wherein the AAV- p53 vector is replicated by a helper virus.

25. The AAV-p53 vector of claim 24, wherein the helper functions are provided by an AAV helper virus and an adenovirus.

26. The AAV-p53 vector of claim 25, wherein the AAV helper virus is an pAdδ .

27. A method of treating a subject with cancer, which comprises administering an effective amount of claim 1 or 7, so as to thereby treat the subject with cancer.

28. The method of claim 27, wherein the cancer is bladder, breast, prostate, lung, colon, soft tissue sarcomas, osteosarcomas or neuronal cancer.

29. The method of claim 27, wherein the subject is a mammal .

30. The method of claim 29, wherein the mammal is selected from the group consisting of a human, monkey, dog, rabbit or rodent.

31. The method of claim 27, wherein the administration is in a method including, but not limited to topical, oral, aerosol, intravenous, intratumoral, intramuscular, intratracheal, subcutaneous administration, or by colonoscopy.

32. A method of overexpressing p53 in a cell of a subject with cancer, which comprises contacting the ceil with an effective amount of claim 1 or 7, so as to thereby overexpress p53 in the cell of a subject with the cancer.

33. A method of increasing the level of mdm2 protein in a cell, which comprises contacting the cell with an effective amount of claim 1, so as to thereby increase the level of mdm2 in the cell.