Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0025202 (melanoma)
 69,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The retrovirus-mediated transfer of the herpes simplex virus-thymidine kinase (HSV-tk) gene into tumor cells renders them sensitive to the cytocidal effect of the antiviral drug ganciclovir. This method has shown promising results as a treatment for experimental brain tumors. These experiments indicate that a major mechanism for the effectiveness of HSV-tk retroviral gene therapy may be the bystander tumoricidal effect. The bystander effect was hypothesized to explain tumor eradication, given that the efficacy of in vivo gene transfer to tumor cells was less than 100%. We demonstrate, in this report, that the bystander tumoricidal effect is a major contributor to the tumoricidal effect of ganciclovir in cell culture experiments using the mouse K1735 C19 cerebral melanoma line, thereby expanding the observation of the bystander phenomenon to a broader range of tumor types. The bystander effect was studied in vitro by coculturing wild-type C19 melanoma cells with HSV-tk-expressing C19 (C19-STK) cells. A maximal tumoricidal effect was seen when only 1 in 10 tumor cells expressed the HSV-tk gene. This suggests that in effect, 1 tumor cell with the HSV-tk gene, when given ganciclovir, will destroy 10 neighboring or bystander cells. The destruction of bystander cells does not appear to be mediated by a soluble factor(s) released into the media but, rather, requires close cell proximity or cell contact. In addition, HSV-tk-expressing C19 cells can exert an antitumoral effect not only on wild-type C19 cells but also on cells from a variety of different tumor cell lines, including a human glioblastoma multiforme cell line, indicating that the bystander effect is not a cell line-specific phenomenon. Finally, we observed that the bystander tumoricidal effect could be harnessed directly without using retrovirus-producing cells to increase survival in the mouse C19 brain tumor model. The potential implications of our findings in treating human brain tumors are discussed.
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PMID:Bystander tumoricidal effect in the treatment of experimental brain tumors. 788 54

To study the immunotherapeutic potential of interleukin-4 (IL-4) delivered in vivo via a recombinant vaccinia virus, a thymidine kinase-negative (TK-) vaccinia virus that expressed the murine IL-4 gene (VV1/IL-4) was constructed. When mice were inoculated with 10(7) plaque-forming units (pfu) of VV1/IL-4 subcutaneously (s.c.), 10(5) pfu/cm2 were found in skin, and smaller numbers in liver and kidney between 1 and 7 days after infection; few viral pfu were found in spleen and lung, or in any organ after intravenous infection. This suggested that recombinant vaccinia viruses might be most efficient at delivery of cytokine genes to the skin. Because IL-4 has recently been found to have potent anti-tumor activity, the effect of recombinant virus infection on the development of s.c. tumors was studied. A single s.c. inoculation with VV1/IL-4 delayed the development of NCTC 2472 tumors, but when VV1/IL-4 was inoculated s.c. weekly for 8 weeks, tumor development was completely prevented in 93% of mice. Similarly, the development of M-3 melanoma tumors was also prevented by weekly s.c. inoculations of VV1/IL-4. About 40% of mice treated with control VV2/beta gal by the same regimen also failed to develop tumors. Weekly virus treatment did not prevent NCTC 2472 tumor development in athymic nu/nu mice, suggesting that mature T cells are required for expression of VV1/IL-4 induced antitumor activity. Thus, recombinant vaccinia viruses may be especially well suited for convenient therapeutic delivery of immunomodulator genes to skin-related sites.
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PMID:In vivo delivery of interleukin-4 by a recombinant vaccinia virus prevents tumor development in mice. 798 7

The use of retroviral-mediated gene transfer to introduce a DNA label into T cells (TIL) being used in the immunotherapy of patients with malignant melanoma finally opened the door to the clinical application of gene therapy for a wide variety of inherited and acquired diseases. The gene therapy trial for ADA deficiency SCID has demonstrated that long term stable expression of exogenous genes can be achieved in human T lymphocytes using retroviral vectors for ex vivo treatment and that significant immune reconstitution can be achieved in these patients following periodic infusions with ADA gene-corrected autologous T cells. Newer clinical applications include the insertion of genes into CD34 enriched stem cell populations, the testing of autologous tumor vaccines employing cytokine gene-modified tumor cells and the direct transfer of the herpes thymidine kinase gene into brain tumors in situ in order to render those tumors sensitive to treatment with the ordinarily non-cytotoxic drug ganciclovir.
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PMID:Strategies for gene therapy. 829 Mar 10

Twelve x-ray-induced transcripts (xips), differentially expressed 8- to 230-fold in x-irradiated versus unirradiated radioresistant human melanoma (U1-Mel) cells, were isolated as cDNA clones (xip1 through xip12) after four rounds of differential hybridization. Northern analyses revealed rare, medium, and abundant xips, ranging in size from 1.2 to 10 kb. All transcripts were transiently expressed and induced by low, but not by high (> 600 cGy), doses of radiation. Three transcripts (xip4, -7, and -12) were induced only by ionizing radiation, and many (i.e., xip1, -2, -3, -5, -6, -8, -9, -10, and -11) were also induced by UV irradiation or phorbol 12-myristate 13-acetate. Heat shock did not induce any of the xips, but it decreased basal levels of xip4, -7, -11, and -12. Three xip cDNA clones were identified as encoding thymidine kinase, DT diaphorase, and tissue-type plasminogen activator. The remaining nine cDNA clones showed little homology to known genes. Three clones contained regions homologous to c-fes/fps protooncogene, recombination activating gene 1, or the human angiogenesis factor gene. X-ray-inducible genes may function in damaged cells to regulate DNA repair, apoptosis, mutagenesis, and carcinogenesis.
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PMID:Isolation of x-ray-inducible transcripts from radioresistant human melanoma cells. 834 36

Malignant brain tumors are responsible for significant morbidity and mortality in both pediatric and adult populations. These common tumors present an enormous therapeutic challenge due to their poor outcome despite radical surgery, high dose radiotherapy and chemotherapy. Survival of patients from the time of diagnosis is measured in months and recurrence after treatment is associated with a life expectancy of weeks. In an attempt to improve this grim prognosis of patients with malignant brain tumors (both primary tumors and secondary metastasis from systemic cancer such as melanoma, lung and breast cancer), we have developed a novel approach to the therapy of brain tumors. This approach makes use of recombinant DNA technology to transfer a sensitivity gene into a brain tumor. This is achieved by direct injection of the tumor with a cell line actively producing a retroviral vector carrying a gene conferring drug sensitivity to the tumor. A retroviral vector is a mouse retrovirus genetically engineered to replace its own genes with a new gene. Such vectors are capable of "infecting" mammalian cells and stably incorporate their new genetic material into the genome of the infected host. The producer cell is an NIH 3T3 cell that has been genetically engineered to continually produce retroviral vectors. The new gene is incorporated into the genome of the tumor cells and expresses the protein which is encoded by the new gene. This protein (the herpes simplex virus enzyme thymidine kinase, HS-tk) sensitizes the tumor cells to an antiviral drug (ganciclovir, GCV) which is a natural substrate for HS-tk. The enzymatic process induced by GCV leads to death of the cell expressing the herpes TK activity, i.e., death of the tumor cells. Since the HS-tk enzyme which is normally present in mammalian cells has very low affinity for GCV, systemic toxicity related to this mechanism is not observed. This type of in vivo gene transfer has several unique features. First, these retroviral-vectors will only integrate and express their genes in cells which are actively synthesizing DNA. Therefore, surrounding non-proliferating normal brain tissue should not acquire the HS-tk gene and will remain insensitive to GCV. Second, all of the transduced tumor cells (and retroviral vector producing cells) will be killed by the host immune response and/or GCV treatment eliminating potential concern about insertional mutagenesis giving rise to malignant cells. This is the first clinical attempt to treat malignant tumors in human beings by in-vivo genetic manipulation of the tumor's genome.
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PMID:Gene therapy for the treatment of brain tumors using intra-tumoral transduction with the thymidine kinase gene and intravenous ganciclovir. 838 92

We report here the use of the 5' flanking region of the murine tyrosinase gene to direct expression of the herpes simplex virus thymidine kinase (tk) gene specifically to murine melanoma cells, whilst not permitting expression in a range of other cell types. Expression of the herpes simplex virus tk gene from the tyrosinase promoter in melanoma cells rendered them sensitive to killing by ganciclovir (100% cell death of a tk-expressing B16 clone after 12 days in culture at 1 microgram/ml ganciclovir). We also observed a substantial bystander killing effect when expressing cells were mixed with nontransfected parental B16 cells. When transfected murine melanoma cells expressing tk were injected into syngeneic mice both their tumorigenicity and experimental metastatic potential were abrogated completely when the mice were treated with ganciclovir (27 of 28 mice treated with water developed progressively growing tumors versus 1 of 30 in the ganciclovir-treated group). Direct injection of the tk gene under control of the tyrosinase promoter into established tumors in mice, followed by treatment with ganciclovir, led to significant reductions in resultant tumor size relative to the size of tumor developing in mice treated with water (median tumor weight, 1.65 g versus 2.75 g). Therefore, direct transfer of recombinant genes by injection of DNA can significantly reduce established tumor burden in vivo.
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PMID:Use of tissue-specific expression of the herpes simplex virus thymidine kinase gene to inhibit growth of established murine melanomas following direct intratumoral injection of DNA. 839 31

A recombinant retrovirus encoding E. coli nitroreductase (NTR) was used to infect mammalian cells. NIH3T3 cells expressing NTR were killed by the prodrug CB1954, which NTR converts to a bifunctional alkylating agent. Admixed, unmodified NIH3T3 cells could also be killed. In contrast to the Herpes simplex virus (HSV) thymidine kinase (TK)/ganciclovir(GCV) enzyme/prodrug system, NTR/CB1954 cell killing was effective in non-cycling cells. Co-operative killing was observed when cells expressing both NTR and TK were treated with a combination of CB1954 and GCV. NTR expression in human melanoma, ovarian carcinoma or mesothelioma cells also rendered them sensitive to CB1954 killing. These data suggest that delivery of the NTR gene to human tumours, followed by treatment with CB1954, may provide a novel tumour gene therapy approach.
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PMID:Expression of the bacterial nitroreductase enzyme in mammalian cells renders them selectively sensitive to killing by the prodrug CB1954. 865 70

The aim of the study was to use a virus-free system to transfer the Herpes Simplex Virus-thymidine kinase (HSV-TK) gene in mice bearing melanoma tumours. B16 F1 murine melanoma cells were injected subcutaneously. On days 11 and 14, an intratumoral injection of either naked plasmid containing the HSV-TK gene (pAG0) or pAG0-lipofectamine complexes was given. Ganciclovir (120 mg/kg/day) was given for 5 days starting on day 14. Tumour weight reduction (40-50%) was observed in treated animals versus different control groups. Moreover, histopathological analysis on tumours showed large areas of cavitary necrosis (85%) in treated groups compared to controls (10%). Using a simple and safe method, the results presented here demonstrated that virus-free mediated delivery of the HSV-TK gene is efficient in vivo in murine malignant melanoma.
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PMID:Direct gene transfer of a plasmid carrying the herpes simplex virus-thymidine kinase gene (HSV-TK) in transplanted murine melanoma: in vivo study. 869 74

To assess the efficacy of an in vivo adenoviral-mediated cytotoxic gene therapy, human melanomas were established in nude mice and transduced with herpes simplex virus-thymidine kinase (tk) followed by treatment with ganciclovir (GCV). In initial experiments, adenovirus (adv) containing the beta-galactosidase reporter gene was employed to determine melanoma cell infectivity in vitro. In comparison to murine melanoma cell lines B16 and K1735-M2, human A375-SM cells exhibited up to a 10-fold greater susceptibility to adenoviral transduction, similar to the degree of infectivity found for human epidermal HaCaT cells. In addition, human A375-SM melanoma cells exhibited a greater sensitivity in vitro to the cytotoxic effects of transduction with tk-adv and treatment with GCV, which was mediated by a strong bystander effect. In vivo, intratumoral injection of relatively large human melanomas (160 mm3) with 1.2 X 109 pfu of tk-adv, followed by intraperitoneal GCV treatment (60 mg/kg twice daily) over 4 days, typically resulted in a 50% reduction in melanoma growth rate compared to mock or untreated controls. Moreover, histometrical analysis employing a rigorous computerized imaging system revealed that the residual viable tumor area in the tk-adv/GCV-treated group was only one-fifth that of solvent controls. These data show that adv is a highly efficient in vivo gene delivery system to treat experimental human melanomas. In comparison to a previous murine melanoma study, human melanomas appeared to exhibit a greater sensitivity to this cytotoxic treatment in vivo, which may hold significant promise for development of effective gene therapy modalities to treat melanoma in humans.
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PMID:Adenoviral-mediated herpes simplex virus-thymidine kinase gene transfer in vivo for treatment of experimental human melanoma. 875 51

This protocol presents a new therapeutic approach to the treatment of patients with otherwise incurable malignant metastatic melanoma. Its objective is to define the safety of escalating doses of an anti-cancer treatment involving intratumoral injections of cells that produce recombinant retroviruses. The experimental treatment is based on the introduction into tumoral cells of a suicide gene coding for the herpes simple virus type 1 thymidine kinase (HSV1-TK). Cells that express HSV1-TK become sensitive to ganciclovir (GCV). GCV has no toxicity for normal cells, but kills cells expressing the HSV1-TK enzyme. Such toxicity is restricted to cells undergoing division. Introduction of the gene into tumoral cells is obtained through the intratumoral injection of murine fibroblasts modified by genetic engineering (M11 cells). These cells continuously produce recombinant defective retroviruses containing the HSV1-TK gene. Retroviruses can integrate their genes only when the cells they infect are undergoing division. Thus, after intratumoral injection of M11 cells, the tumoral cells, but not the quiescent cells of the healthy tissue surrounding them, express the HSV1-TK gene and can be destroyed by GCV. In addition, tumoral cells that do not express the gene, but which are located in the immediate vicinity of the transduced cells, are also destroyed through a "bystander effect," also restricted to cells undergoing division. It is therefore not necessary for all the tumoral cells to express HSV1-TK for all of them to be destroyed. Finally, preliminary data suggest that this localized tumoricidal activity may trigger a more general antineoplastic action, by facilitating a specific antitumoral immune response. The efficacy of the above therapeutic approach has been evidenced with animals in the treatment of brain tumors, of colic adenocarcinoma hepatic metastases and of malignant melanoma. A therapeutic trial on recurrent brain tumors or metastases has begun in the USA, using a similar approach. We propose a phase I-II clinical study of the treatment of metastatic malignant melanoma. The patients enrolled in the study must present a metastatic malignant melanoma that is no longer treatable by conventional therapy (life expectancy of patients < 12 months). Progressively increased doses of M11 cells (1 x 10(8), 2 x 10(8), 3 x 10(8) cells/cm3 of tumor) will be injected transcutaneously in the cutaneous, sub-cutaneous or ganglionary tumoral nodules. For a given dosage, four patients receiving the treatment will be studied. Four additional patients will be enrolled at the higher tolerated dosage. We will study the safety and the tumoricidal effect of the direct intratumoral injection of M11 cells followed by treatment with GCV at a constant, intravenous dosage of 10 mg/kg/d x 14 days.
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PMID:Gene therapy for metastatic malignant melanoma: evaluation of tolerance to intratumoral injection of cells producing recombinant retroviruses carrying the herpes simplex virus type 1 thymidine kinase gene, to be followed by ganciclovir administration. 878 75


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