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

Tumor-directed gene therapy, such as "suicide gene" therapy, requires high levels of gene expression in a high percentage of tumor cells in vivo to be effective. Current vector strategies have been ineffective in achieving these goals. This report introduces the attenuated (thymidine kinase (TK)-negative) replication-competent vaccinia virus (VV) as a potential vector for tumor-directed gene therapy by studying the biodistribution of VV in animal tumor models. A TK-deleted recombinant VV (Western Reserve strain) expressing luciferase on a synthetic promoter was constructed. Luciferase activity was measured in vitro after transduction of a variety of human and murine tumor cell lines and in vivo after intraperitoneal (i.p.) delivery in C57BL/6 mice with 7-day i.p. tumors (10(6) MC-38 cells). Three other in vivo tumor models were examined for tumor-specific gene expression after intravenous delivery of VV (human melanoma in nude mice, adenocarcinoma liver metastasis in immunocompetent mice, and subcutaneous sarcoma in the rat). In addition, a replication-incompetent vaccinia (1 microg of psoralen and ultraviolet light, 365 nm, 4 minutes) was tested in vitro and in vivo and compared with active virus. Luciferase activity in i.p. tumors at 4 days after i.p. injection of VV was >7000-fold higher than lung, >3000-fold higher than liver, and >250-fold higher than ovary. In addition, intravenous injection of VV resulted in markedly higher tumor luciferase activity compared with any other organ in every model tested (up to 188,000-fold higher than liver and 77,000-fold higher than lung). Inactivation of the virus resulted in negligible gene expression in vivo. In summary, VV has a high transduction efficiency in tumor cells with high levels of gene expression. The results suggest a selective in vivo replication of TK-deleted VV in tumor cells. Replication competent, TK-deleted VV appears to be an ideal vector for testing the in vivo delivery of toxic genes to tumor cells.
 ...
PMID:Vaccinia as a vector for tumor-directed gene therapy: biodistribution of a thymidine kinase-deleted mutant. 1067 58

Homozygous deletions in the region of chromosome 9p21 are frequent in human melanoma. Mutations in the p16INK4A cyclin-dependent kinase inhibitor (CDI) gene at this locus have implicated the product of this gene as a tumor suppressor. Less attention has been focused on the homologous, closely linked p15INK4B gene. To facilitate study of the phenotypic effects of restoring expression of the latter in aggressive melanoma cells lacking INK4 expression, we inserted the cDNA encoding p15INK4B into an autonomously maintained plasmid under positive tetracycline control ('TET ON' system). Similarly regulated luciferase and herpes thymidine kinase sequences were used as controls. We demonstrate that this system enabled efficient, and reasonably uniform, induction of p15INK4B expression in a human melanoma cell line exposed to the tetracycline derivative, doxycycline. Flow cytometry showed that this induction resulted in substantial accumulation of cells in the G0/G1 phase of the cell cycle. This system will facilitate detailed analysis of the cell cycle inhibitory mechanisms of this CDI in human melanoma cells.
 ...
PMID:Positive tetracycline control of expression of p15INK4B from an Epstein-Barr autonomous plasmid in a human melanoma cell line. 1072 18

The cellular oncoprotein Ewing's sarcoma oncogene (EWS)/activating transcription factor 1 (ATF1) is a highly specific marker for malignant melanoma of soft parts (MMSP) and is a potent activator of several cAMP-inducible promoters, including the somatostatin promoter. Here we explored the potential for using the somatostatin promoter to direct toxic gene expression in MMSP cells. When introduced into MMSP cells, a somatostatin-herpes simplex virus thymidine kinase fusion gene confers strong and cell-specific sensitivity to the cytotoxic prodrug ganciclovir. Ganciclovir sensitivity requires the ATF-binding site present in the somatostatin promoter, indicating that toxic gene expression is caused by EWS/ATF1. We also tested the efficacy of recombinant adenoviruses adenoviruses for gene delivery and expression in two MMSP cell lines (DTC1 and Su-ccs-1). Surprisingly, several promoters (including somatostatin) that are strongly activated by EWS/ATF1 in transient assays are not activated in DTC1 and Su-ccs-1 cells when present in an adenovirus vector. In summary, our findings demonstrate the potential for using the somatostatin promoter for cytotoxic prodrug therapy for MMSP. However, first-generation adenovirus vectors cannot be used as promoter delivery vehicles for toxic gene expression in MMSP cells.
 ...
PMID:The cellular oncogene EWS/activating transcription factor 1 is unable to activate adenovirus-borne promoters: implications for cytotoxic prodrug therapy of malignant melanoma of soft parts. 1076 45

A recombinant MVMp of the fibrotropic strain of minute virus of mice (MVMp) expressing the chloramphenicol acetyltransferase reporter gene was used to infect a series of biologically relevant cultured cells, normal or tumor-derived, including normal melanocytes versus melanoma cells, normal mammary epithelial cells versus breast adenocarcinoma cells, and normal neurons or astrocytes versus glioma cells. As a reference cell system we used normal human fibroblasts versus the SV40-transformed fibroblast cell line NB324K. After infection, we observed good expression of the reporter gene in the different tumor cell types, but only poor expression if any in the corresponding normal cells. We also constructed a recombinant MVMp expressing the green fluorescent protein reporter gene and assessed by flow cytometry the efficiency of gene transduction into the different target cells. At a multiplicity of infection of 30, we observed substantial transduction of the gene into most of the tumor cell types tested, but only marginal transduction into normal cells under the same experimental conditions. Finally, we demonstrated that a recombinant MVMp expressing the herpes simplex virus thymidine kinase gene can, in vitro, cause efficient killing of most tumor cell types in the presence of ganciclovir, whilst affecting normal proliferating cells only marginally if at all. However, in the same experimental condition, breast tumor cells appeared to be resistant to GCV-mediated cytotoxicity, possibly because these cells are not susceptible to the bystander effect. Our data suggest that MVMp-based vectors could prove useful as selective vehicles for anticancer gene therapy, particularly for in vivo delivery of cytotoxic effector genes into tumor cells.
 ...
PMID:Tumor-selective gene transduction and cell killing with an oncotropic autonomous parvovirus-based vector. 1082 6

Adenoviral transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by administration of gancyclovir (GCV) was used to treat B 16 melanoma of C 57 BL/6 mice. B 16 murine melanoma cells transduced in vitro by a recombinant replication-defective adenovirus containing the HSV-tk gene [Ad(HSV-tk)] were highly sensitive to cell killing by GCV, and the IC50 was 0.1 microgram/ml. A significant "bystander effect" was observed when Ad(HSV-tk)-infected and -uninfected B 16 cells were mixed. Direct tumoral injection of Ad (HSV-tk) into established B 16 melanoma in C 57 BL/6 mice and subsequent treatment for 6 d with GCV resulted in the growth regression and necrosis of tumor nodules, and the tumor size was approximately reduced to one-twenty fifth of that of control animals. Finally, the safety of this treatment approach was demonstrated by limited dissemination of virus using sensitive RT-PCR. HSV-tk mRNA was detected only in the tumor nodule. These data indicated that gene therapy using Ad(HSV-tk)/GCV may function as an effective and safe alternative for treatment of melanoma in vivo.
 ...
PMID:[Gene therapy using recombinant adenovirus carrying herpes simplex-thymidine kinase gene to treat mouse B 16 melanoma in vivo]. 1103 21

Introduction of the herpes simplex type I thymidine kinase (HSV-TK) gene into tumor tissue, followed by ganciclovir, initiates a phosphorylation cascade that induces formation of a toxic ganciclovir triphosphate. Animal trials suggest that this ganciclovir triphosphate has antitumor activity. Here we report application of the HSV-TK transfection approach using a retroviral construct. Sixteen patients (median age 61.5 years) with refractory carcinoma (13 melanoma, 1 breast cancer, 1 nonsmall-cell lung cancer, and 1 osteogenic sarcoma) received intratumoral injection of HSV-TK retroviral vector at escalating doses (0.2x10(7) cfu per injection x 5 daily doses) and we evaluated them for toxicity and activity. We observed grade III pain associated with cellulitis in one patient following injection. Analysis of blood samples drawn between 3 and 28 weeks from 14 patients for replication-competent retrovirus by PCR analysis of the amphotrophic envelope revealed no replication-competent retrovirus. We injected 21 lesions. We identified no tumor responses of the injected lesions. Of 13 patients with advanced melanoma, 6 survived over one year. Thus, injection of retroviral delivered HSV-TK in patients with refractory cancer was well-tolerated.
 ...
PMID:Toxicity assessment of intratumoral injection of the herpes simplex type I thymidine kinase gene delivered by retrovirus in patients with refractory cancer. 1148 88

We report here the generation of recombinant vesicular stomatitis virus (VSV) able to produce the suicide gene product thymidine kinase (TK) or cytokine interleukin 4 (IL-4). In vitro cells infected with the engineered viruses expressed remarkably high levels of biologically active TK or IL-4 and showed no defects in replication compared to the wild-type virus. Recombinant viruses retained their ability to induce potent apoptosis in a variety of cancer cells, while normal cells were evidently more resistant to infection and were completely protected by interferon. Significantly, following direct intratumoral inoculation, VSV expressing either TK or IL-4 exhibited considerably more oncolytic activity against syngeneic breast or melanoma tumors in murine models than did the wild-type virus or control recombinant viruses expressing green fluorescent protein (GFP). Complete regression of a number of tumors was achieved, and increased granulocyte-infiltrating activity with concomitant, antitumor cytotoxic T-cell responses was observed. Aside from discovering greater oncolytic activity following direct intratumoral inoculation, however, we also established that VSV expressing IL-4 or TK, but not GFP, was able to exert enhanced antitumor activity against metastatic disease. Following intravenous administration of the recombinant viruses, immunocompetent BALB/c mice inoculated with mammary adenocarcinoma exhibited prolonged survival against lethal lung metastasis. Our data demonstrate the validity of developing novel types of engineered VSV for recombinant protein production and as a gene therapy vector for the treatment of malignant and other disease.
 ...
PMID:Genetically engineered vesicular stomatitis virus in gene therapy: application for treatment of malignant disease. 1175 78

One approach to gene therapy of cancer is based on the insertion of a suicide gene into tumor cells and subsequent activation of the suicide mechanism. We used the herpes simplex virus thymidine kinase (HSVtk) gene followed by ganciclovir (GCV) treatment. The goal of our experiments was to determine the effectiveness of HSVtk gene therapy in malignant melanoma. B16BL6 murine melanoma cells retrovirally transduced with the HSVtk gene became sensitive to low concentrations of GCV. Analysis by RT-PCR showed HSVtk expression in transduced B16BL6tk+ cells. Apoptotic cell death was found in B16BL6tk+ cells treated with GCV (20 microM). The sensitivity of B16BL6tk+ cells to GCV was also examined in vivo. Tumors inoculated subcutaneously into C57BL6 mice regressed rapidly when treated with GCV (50 mg/kg twice a day) and disappeared completely after 14 days treatment. The mice remained in remission for 5 months. A bystander effect through which nontransduced B16BL6 cells were also inhibited by GCV administration when cocultured with B16BL6tk+ cells was expected. However, only slight killing of nontransduced cells was observed in vitro. Analysis of the bystander effect in vivo showed complete regression of tumors inoculated with a mixture of cells mostly consisting of B16BL6tk+ cells. A distant bystander effect was also examined. There was no regression of wild-type tumors raised at a distant site from primary B16BL6tk+ tumors. The failure of a more effective bystander effect indicates the need for further investigation of the possible use of combined gene therapy to treat melanoma.
 ...
PMID:The efficacy of retroviral herpes simplex virus thymidine kinase gene transfer and ganciclovir treatment on the inhibition of melanoma growth in vitro and in vivo. 1182 Jul 24

In the accompanying study, we show how retroviral tropism can be redirected by insertion of short peptide ligands at multiple locations in envelope. Here we use this approach to selectively target and destroy human cancer cells. Many cancer cells overexpress specific cell surface receptors. We have generated Moloney murine leukemia virus (MLV) envelope derivatives bearing short peptide ligands for gastrin-releasing protein (GRP) and human epidermal growth factor receptors. Pseudotyped viruses containing these chimeric envelope derivatives selectively transduce human cancer cell lines that overexpress the cognate receptor. A retrovirus targeting the GRP receptor can deliver the thymidine kinase gene to human melanoma and breast cancer cells, which are killed by the subsequent addition of ganciclovir. Collectively, our results demonstrate that short peptide ligands inserted at appropriate locations in MLV envelope can selectively target retroviruses to human cancer cells and deliver a therapeutically relevant gene.
 ...
PMID:Selective targeting and inducible destruction of human cancer cells by retroviruses with envelope proteins bearing short peptide ligands. 1188 81

There are at least two hurdles confronting the use of the adenovirus (Ad)-mediated herpes simplex virus thymidine kinase (HSVtk)/ganciclovir (GCV) system for the treatment of cancer. One is inefficient Ad vector-mediated gene transfer into tumor cells lacking the primary receptor, i.e., the coxsackievirus and adenovirus receptor (CAR). The other is hepatotoxicity due to unwanted vector spread into the liver, even when Ad vectors are injected intratumorally. Herein, we present an attractive strategy for overcoming such limitations based on use of a fiber-modified Ad vector containing an RGD peptide motif in the fiber knob. HSVtk-expressing Ad vectors containing mutant fiber (AdRGD-tk) or wild-type fiber (Ad-tk) were injected intratumorally into CAR-negative B16 melanoma cells inoculated into mice, after which GCV was injected intraperitoneally for 10 days. AdRGD-tk showed approximately 25 times more antitumor activity than Ad-tk. Histopathological studies suggested that liver damage in mice injected with AdRGD-tk was significantly lower than that in mice injected with Ad-tk. Intratumoral administration of luciferase-expressing Ad vectors containing the mutant fiber (AdRGD-L2) resulted in nearly 40 times more luciferase production in the tumor, but 8 times less production in the liver than the conventional Ad vectors (Ad-L2). These results indicate that combination of fiber-modified vectors and a HSVtk/GCV system is a potentially useful and safe approach for the treatment of tumors lacking CAR expression, and that fiber-modified vectors could be of great utility for gene therapy and gene transfer experiments.
 ...
PMID:Enhanced antitumor effect and reduced vector dissemination with fiber-modified adenovirus vectors expressing herpes simplex virus thymidine kinase. 1189 39


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>