Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.1.21 (thymidine kinase)
7,561 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Four patients affected by glioblastoma recurrence were treated with a gene therapy-immunotherapy protocol consisting of intratumoral injections of culture cells producing a retroviral vector which expresses human interleukin-2 and the herpes simplex virus thymidine kinase genes. Seven to 14 days after implantation, the patients were treated with ganciclovir at standard doses. Anatomopathological and immunohistochemical data confirm the efficacy of transduction. From the clinical point of view, gene therapy combined with immunotherapy demonstrated safety and a short-range but clearcut oncolytic effect.
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PMID:Gene stereotactic neurosurgery for recurrent malignant gliomas. 971 24

Gene-based therapeutic strategies for cancer mainly include augmentation of immunotherapeutic and chemotherapeutic approaches. In this study we report the design and functional assay of a novel bicistronic Moloney-based retroviral vector expressing human interleukin-2 (IL-2) and herpesvirus thymidine kinase (tk) through a cap-dependent translation and an internal ribosome entry site (IRES)-regulated translation, respectively. This construct has the potential for allowing combination of cytokine and suicide gene therapy, especially in areas such as the brain, composed of post-mitotic cells refractory to transduction by type C retroviral vectors. Accordingly, human glioma cells were used as targets for gene transfer after selecting a packaging cell clone that produced a reasonable titer of recombinant virus and expressed high levels of IL-2 and tk transcripts. Although transduction efficiency was reduced in glioma cells as compared with murine NIH 3T3 cells, transgene expression was effectively achieved. Transduced glioma cells were sensitive to ganciclovir and secreted around 1000 U/ml IL-2 in the culture supernatants. Simultaneous production of IL-2 and tk in vivo by genetically treated tumor cells would hopefully potentiate the effect of gangiclovir-induced metabolic suicide, possibly by boosting the immune response associated with tumor debulking or by amplifying the bystander response.
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PMID:Production and characterization of a bicistronic Moloney-based retroviral vector expressing human interleukin 2 and herpes simplex virus thymidine kinase for gene therapy of cancer. 981 72

Inherited medullary thyroid carcinomas (MTC) are aggressive and resistant to conventional chemo- and radiotherapies. We evaluated a novel strategy for treatment of MTC, combining "suicide" and interleukin-2 (IL-2) gene therapies. Tumors were produced in Wag/Rij rats by orthotopic injection of the rMTC 6-23 cell line, and/or derivatives expressing the herpes simplex virus 1 thymidine kinase (HSV1-TK) gene (rMTC-TK). Ganciclovir, a nucleoside analog selectively transformed to a toxic metabolite by HSV1-TK, totally eradicated rMTC-TK tumors in 60% of the animals. 1:1 rMTC and rMTC-TK mixed tumors were also strongly inhibited by ganciclovir (P < 0.05), indicating the occurrence of an efficient "bystander" effect in vivo. Double labelling of rMTC cell membranes and apoptotic nuclei revealed that, as with the TK+ cells, some TK- cells died by apoptosis. A 1:1 mixture of rMTC and rMTC-TK cells was administered to produce established tumors and then rMTC cells, transfected to express the IL-2 gene (rMTC-IL2), were inoculated. Combined ganciclovir and IL-2 treatment improved the inhibition of tumor growth compared to that following ganciclovir alone (86% compared to 54%, P < 0.05). This treatment also significantly enhanced macrophage activation and tumor infiltration by CD8+ and CD4+ T lymphocytes. These results open an avenue for combining suicide and immunoregulatory gene therapies for MTC management in man.
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PMID:Treatment of medullary thyroid carcinoma by combined expression of suicide and interleukin-2 genes. 1041 62

This study investigated the therapeutic effects of a rat glioma cell line, C6, that was engineered to secrete mouse GM-CSF (mGM-CSF) on intracerebral (i.c.) brain tumors. Significant antitumor immunity was induced in rats when the live or irradiated mGM-CSF-secreting tumor vaccine was implanted i.c. The antitumor activity was effective on small tumors and, to a lesser extent, on large tumors or tumors existing in vivo for a longer duration. Immunohistochemical analysis revealed cellular infiltrates (granulocytes, macrophages, and CD4+ and CD8+ T cells) at both the vaccine site and the tumor site, indicating that immune responses were similarly activated when tumor vaccine was inoculated in the brain, as at the subcutis. Additional studies demonstrated that the therapeutic effects of tumor vaccines on the large tumors or the long-existing tumors were enhanced by strategies such as increasing the dosage of tumor vaccines, using combined vaccines consisting of mGM-CSF and human interleukin-2, or combining tumor vaccine with herpes simplex virus thymidine kinase/ganciclovir treatment. All of the modified strategies yielded synergistic therapeutic effects on the large tumor burdens. The data presented herein suggest that cytokine gene therapy is highly promising for the treatment of i.c. gliomas.
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PMID:Regression of orthotopic brain tumors by cytokine-assisted tumor vaccines primed in the brain. 1041 48

Introduction of the herpes simplex virus thymidine kinase (HSV-TK) gene into mammalian cells confers specific sensitivity to killing by the anti-herpes drug ganciclovir (GCV). This gene has therefore been used in a number of cancer gene therapy protocols as a therapeutic gene. However, the therapeutic efficacy of HSV-TK/GCV in cancer gene therapy experiments can be augmented by additional therapeutic genes. We have cloned a retroviral plasmid, pCC1, containing a fusion gene of HSV-TK and Sh-ble driven by an internal simian virus 40 early promoter. This gene encodes a fusion protein that confers GCV sensitivity and Zeocin resistance when introduced into mammalian cells. A multiple cloning site (MCS) allows the introduction of a second therapeutic gene under the transcriptional control of the Moloney murine leukemia virus 5' long terminal repeat. We have generated packaging cell lines electroporated with pCC1 or pCC1 rtIL-2 S (rat interleukin-2 gene cloned in the sense direction in the MCS), the supernatants of which transfer GCV sensitivity only, or both GCV sensitivity and rtIL-2 production, respectively to rat ovarian cancer cells. This plasmid may be useful for the study of combination suicide gene therapy strategies.
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PMID:Cloning and characterization of a retroviral plasmid, pCC1, for combination suicide gene therapy. 1072 73

Current treatment of osteosarcoma produces disappointing outcomes, and innovative therapies must be investigated. We have used retroviral vectors to transfer the herpes simplex virus thymidine kinase (HSVtk) and interleukin-2 genes to human osteosarcoma cells. Each gene was stably transduced and expressed; the HSVtk gene effectively conferred ganciclovir (GCV) susceptibility to transduced cells. A strong bystander effect was observed in vitro, whereby nontransduced tumor cells in proximity to transduced cells acquired susceptibility to GCV killing. Human osteosarcoma cells were used to develop a series of experiments in athymic nude mice to treat experimental osteosarcoma. Subcutaneously implanted mixtures of tumor cells and HSVtk vector producer cells developed into tumors that completely regressed upon administration of GCV. Subcutaneously implanted mixtures of transduced and wild-type cells showed a potent bystander effect upon administration of GCV, with complete tumor ablation when as little as 10% of the cells were HSVtk+. A significant (P < .05) antitumoral response was seen against primary tumors composed of unmodified cells when a secondary tumor of transduced cells was implanted at a distance of 1 cm, suggesting a diffusible bystander factor. The presence of interleukin-2-transduced cells improved the efficacy of treatment. A significant (P < .03) antitumoral response was seen in the treatment of established osteosarcomas by the injection of HSVtk vector producer cells.
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PMID:Bystander-mediated regression of osteosarcoma via retroviral transfer of the herpes simplex virus thymidine kinase and human interleukin-2 genes. 1077 Jun 26

Normally, thyroid cancer is a disease with a good prognosis, but about 30% of the tumours dedifferentiate and may finally develop into highly malignant anaplastic thyroid carcinomas with a mean survival time of less than 8 months. Due to the loss of thyroid-specific functions associated with dedifferentiation, these tumours are inaccessible to standard therapeutic procedures such as radioiodide therapy and thyroxine-mediated thyrotrophin suppression. Medullary thyroid carcinomas are also highly aggressive. Here, therapy is limited to surgery, and no alternative is left if patients do not respond to this standard procedure. Obviously, new approaches would be desirable. Several novel approaches are currently being tested for the treatment of thyroid cancer. Many of them utilise methods of gene therapy, but follow different strategies: (1) reintroduction of the tumour suppressor p53 into a background lacking functional p53; (2) suicide gene therapy with ganciclovir and a transduced gene for herpes simplex virus thymidine kinase controlled by the thyroglobulin promoter; (3) strengthening of the antitumour immune response by expression of an adenovirus-delivered interleukin-2 (IL-2) gene; (4) induction of an immune response by DNA vaccination against the tumour marker calcitonin; (5) transduction of the thyroid sodium/iodide transporter gene to make tissues that do not accumulate iodide treatable by radioiodide therapy; (6) blocking of the expression of the oncogene c-myc by antisense oligonucleotides. While these approaches are still tested in vitro or in animal models, first results from pilot studies concerning other novel treatment modalities are available: (7) radioimmunotherapy exploits the carcinoembryonic antigen expressed on medullary thyroid carcinomas to target a radiolabelled antibody to the tumour; and (8) retinoic acid is used for a redifferentiation therapy in the case of thyroid cancer. Hopefully, one or the other of these novel strategies may probably extend after some time the current therapeutic repertoire for thyroid cancers and provide a perspective for otherwise untreatable patients.
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PMID:Innovative strategies for the treatment of thyroid cancer. 1087 26

Generation of an efficient graft-versus-leukemia (GVL) effect in patients with hematological malignancies who relapse after allogeneic bone marrow transplantation depends in part upon the number of infused T lymphocytes. Currently, a GVL reaction cannot be achieved without inducing concomitant graft-versus-host disease (GVHD); thus, one strategy is to try to modulate this GVL/GVHD ratio. We engineered human T lymphocytes with herpes simplex virus-thymidine kinase and neomycin resistance genes, with an LXSN-derived vector that confers a ganciclovir-specific sensitivity to the transduced T cells. We analyzed proliferation, interleukin-2 production, alloreactivity in a mixed lymphocyte culture, and clonogenicity during the different stages of retroviral infection and G418 selection. Our results confirm that a sufficient number of transduced T lymphocytes can be obtained after selection for clinical studies. Their proliferative activity, alloresponsiveness, and ability to produce and respond to interleukin-2 were retained. Compared with control populations, their clonogenicity, as assessed by limiting dilution assays, was reduced after retroviral infection and G418 selection by 1.6 and 2.9 logs, respectively, with both viral supernatant incubation and coculture procedures. This study shows that infection and selection with the thymidine kinase-neomycin resistance gene retroviral vector significantly reduces the number of functional T lymphocytes. This finding should be taken into account when establishing the dose of T lymphocytes necessary to trigger a modulated GVL/GVHD effect.
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PMID:T-lymphocyte function after retroviral-mediated thymidine kinase gene transfer and G418 selection. 1088 24

Infusions of donor peripheral blood T cells can induce durable remissions of Epstein-Barr virus (EBV) lymphomas complicating marrow grafts, but they contain alloreactive T cells capable of inducing graft-versus-host disease. EBV-specific T-cell lines or clones avoid this problem but require 30 to 40 days of culture to establish. To accelerate the generation of EBV-specific T cells, we tested whether retroviral vectors, which only integrate in dividing cells, could be used to transduce and select antigen-reactive T cells early after sensitization to autologous EBV-transformed B cells. T cells were transduced with a dicistronic retroviral vector, NIT, which encodes low-affinity nerve growth factor receptor as an immunoselectable marker and herpes simplex virus thymidine kinase as a suicide gene, at different time points after sensitization. EBV-specific cytotoxic T lymphocyte precursor (CTLp) frequencies in purified NIT(+) T-cell fractions transduced on day 8 of culture were comparable to those of EBV-specific T-cell lines cultured for 30 days or more. Alloreactive CTLp frequencies were markedly reduced in the NIT(+) fraction relative to the untransduced T-cell population. NIT(+) fractions transduced on day 8 possessed more CD4(+) T cells than the cell lines at day 30 and exhibited the same selective pattern of reactivity against immunodominant antigens presented by specific HLA alleles. In contrast, T cells transduced with NIT 5 days after stimulation with mitogen and interleukin-2 were relatively depleted of T cells specific for autologous EBV-transformed cells. Thus, retroviral vectors may be used for rapid selection of viral antigen-reactive T cells depleted of alloreactive T cells.
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PMID:Rapid selection of antigen-specific T lymphocytes by retroviral transduction. 1089 38

Immunotherapy in combination with suicide gene therapy for breast cancer was tested using a metastatic animal model. Subcutaneous injection of the nonimmunogenic breast cancer cell line 4T1 in BALB/C mice gave rise to tumors in 100% of mice with both micrometastases and macrometastases in the lung. We used the herpes simplex virus thymidine kinase (HSV-TK) gene along with the cytokine genes granulocyte-macrophage colony-stimulating factor (GM-CSF) and interleukin-2 (IL-2) to determine their effect on tumor regression and inhibition of lung metastasis. Adenoviral (AV) vectors carrying these transgenes, in separate constructs, were used in this study. Intratumoral administration of AV-TK followed by 10 days of ganciclovir treatment resulted in a delay in tumor growth and, in some cases, in a low to moderate reduction in tumor volume. Inclusion of either GM-CSF or IL-2 gene with HSV-TK resulted in a slightly greater reduction in tumor volume, although these data were not significantly different from those obtained for TK treatment alone. However, when both cytokine genes were combined with TK, a substantial reduction in tumor growth was observed compared with HSV-TK alone (P < .02). Tumor weight data also exhibited superior efficacy of TK/GM-CSF/IL-2 treatment when compared with animals treated with TK gene only (P < .01). More importantly, TK/GM-CSF/IL-2 combination gene therapy induced a significant reduction in lung metastasis compared with any other treatment groups in the 4T1 model (P < .001 between TK GM-CSF/IL-2 versus TK only). Surgical excision of primary tumors after TK/GM-CSF/IL-2 plus ganciclovir treatment resulted in anti-metastatic activity that was similar to that observed for animals in which no surgery was performed. Survival analysis showed a significant difference between animals treated with AV-TK/GM-CSF/IL-2 and animals treated with TK only at 35 days after virus injection (P < .01). Immunophenotypic data suggest infiltration of lymphocytes within the tumor microenvironment in TK- and cytokine gene-treated animals. Thus, the overall data presented here demonstrate that TK gene therapy in combination with GM-CSF and IL-2 gene-mediated immunotherapy strategies have important implications in the treatment of breast cancer.
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PMID:Efficacy of herpes simplex virus thymidine kinase in combination with cytokine gene therapy in an experimental metastatic breast cancer model. 1091 12


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