Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The most serious problem in current gene therapy is discrepancies between experimental data and actual clinical outcomes, which may be due to insufficient analyses and/or inappropriate animal models. We have explored suicide gene therapy by using various clinically relevant animal models and doubt the clinical use of maximal suicide gene expression, which has been generally recommended. To explore this subject further, we studied what expression level of suicide gene and what promoter led to the maximal clinical benefit in the case of hepatic metastatic cancer in mice. Therapeutic and adverse side effects of 4 adenoviral vectors that express herpes simplex virus thymidine kinase (HSV-tk) under different promoters were scrupulously investigated in 2 mouse models of hepatic metastasis of gastric cancer that possess clinical characteristics. Surprisingly, increases in HSV-tk expression beyond a certain point, achieved by the Rous sarcoma virus long terminal repeat promoter, not only enhanced the adverse side effects of lethal hepatotoxicity and ganciclovir-independent cytotoxicity but also failed to further increase therapeutic potential. Moreover, the carcinoembryonic antigen (CEA) tumor-specific promoter, the therapeutic potential of which had been underestimated, was much more useful-even in the case of low CEA-producing cancer-than had been previously reported. In conclusion, the optimal therapeutic expression level of a suicide gene is a novel concept and a crucial factor for successful cancer gene therapy. The present results, which contradict those of previous studies, alert researchers about possible problems with ongoing and future clinical trials that lack this concept.
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PMID:An optimal therapeutic expression level is crucial for suicide gene therapy for hepatic metastatic cancer in mice. 1250 Feb

The substantial advances made in recent years in the molecular biology of malignant urological tumors and the associated progressive analysis of these conditions at a molecular level have spurred research aimed at gene-based treatment. In the field of prostate cancer, while there have been many ground-breaking studies particularly in the United States, none has yet led to a revolutionary treatment for recurrent prostate cancer. Gene-based treatment is being applied seriously in clinical settings, especially in the United States, but so far without significant effect. Many researchers worldwide are devoting energy to the development of effective vectors. By adjusting the promoter, which has the function of directing the vector, we have developed organ-specific vectors for the treatment of prostate cancer. In the present study, which targeted prostate cancer with bone metastasis, we developed a suicide-gene therapy using an adenovirus vector with an organ-specific osteocalcin promoter. Clinical trials of this vector have already been conducted at the University of Virginia in the United States and have so far confirmed the safety of the therapy. In the present paper we present the results of this gene-therapy research from the basic to the clinical phase alongside an outline of related research at our institution. Gene therapy for cancer is now being targeted not only against the primary tumor but systemic cancers including distant metastases; systemic administration of adenovirus vectors with organ-specific promoters may become one of the most promising systemic anti-tumor therapies of the next-generation.
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PMID:[Gene therapy for prostate cancer]. 1251 50

The nitroreductase (NR)/CB1954 enzyme prodrug system has given promising results in preclinical studies and is currently being assessed in phase I clinical trials. It is well established that there is an immune component to the bystander effect observed with other systems such as thymidine kinase and cytosine deaminase; however, such an effect has not previously been described using NR. We have preliminary data suggesting an immune bystander effect with NR to further examine these effects and their potential enhancement by cytokines, an adenoviral vector containing CMV-NR, an internal ribosome entry site (IRES) and the gene for murine GM-CSF (mGM-CSF) was constructed. The NR-GM-CSF virus was validated in 2 experimental models and demonstrated increased therapeutic efficacy in the MC26 murine colorectal tumour model. These data illustrate that the combination of suicide gene therapy using NR and CB1954 with immune stimulation via GM-CSF gives an improved response compared to either modality alone and suggests that the immune component of this response may be beneficial in combating unresectable, metastatic disease and preventing tumour recurrence.
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PMID:Immune enhancement of nitroreductase-induced cytotoxicity: studies using a bicistronic adenovirus vector. 1253 26

We show that mouse embryonic endothelial progenitor cells (eEPCs) home preferentially to hypoxic lung metastases when administered intravenously. This specificity is inversely related to the degree of perfusion and vascular density in the metastasis and directly related to local levels of hypoxia and VEGF. Ex vivo expanded eEPCs that were genetically modified with a suicide gene specifically and efficiently eradicated lung metastases with scant patent blood vessels. eEPCs do not express MHC I proteins, are resistant to natural killer cell-mediated cytolysis, and can contribute to tumor vessel formation also in nonsyngeneic mice. These results indicate that eEPCs can be used in an allogeneic setting to treat hypoxic metastases that are known to be resistant to conventional therapeutic regimes.
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PMID:Embryonic endothelial progenitor cells armed with a suicide gene target hypoxic lung metastases after intravenous delivery. 1514 46

The alphaviruses Semliki Forest virus (SFV) and Sindbis virus have recently been developed as prototype anti-cancer agents. These are RNA-containing enveloped viruses that code for only 9 proteins of unique sequence. The standard recombinant SFV vector system consists of suicide particles containing recombinant RNA. In addition, alphavirus vectors capable of limited multiplication in the host are also being developed. Several strategies are being adopted to construct prototype SFV vectors for cancer treatment. These include: 1) construction of both prophylactic and therapeutic vaccines to stimulate immunity to tumor-associated antigens, 2) use of apoptosis induction to destroy tumor cells, which includes both the use of the inherent apoptosis-inducing ability of the vector and the action of pro-apoptotic genes cloned into the vector, and 3) expression of cytokines and other immunoregulatory proteins by the vector that enhance anti-tumor immune responses and/or inhibit tumor cell growth. This includes the use of cytokines such as IL-12 that target angiogenesis. Sindbis virus appears to have a natural tropism for tumor cells that may allow targeting both of the wild-type virus and the vector. This approach may also be useful for targeting metastases. For SFV, neurovirulence and/or neurotropism, as well as other tissue damage, may preclude the use of unmodified replication competent wild-type virus in tumor treatment. However, it may be possible to use such a virus in animals that have been vaccinated, using a vector-derived vaccine.
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PMID:Alphaviruses and their derived vectors as anti-tumor agents. 1557 17

The incidence of prostate cancer has dramatically increased worldwide in the past decade, with mortality rates also increasing in many countries. Once prostate cancer is diagnosed, it is important to rapidly begin a treatment regimen that is either potentially curative or impedes disease progression. When the disease is confined to the prostate, it can be cured by radical prostatectomy or irradiation therapy. However, there are no curative therapies for locally advanced, recurrent, or metastatic diseases. Clearly, new therapies are needed for these patients. Gene therapy may provide additional therapeutic options with the potential to affect both localized and metastatic disease. Virus-mediated transduction of the herpes simplex virus thymidine kinase (HSV-tk) gene transfer, followed by a course of the prodrug ganciclovir (GCV), so-called suicide gene therapy, has been demonstrated by several investigators. The present in situ gene therapy clinical trial for human prostate cancer demonstrated safety, clinical efficacy, and biological effects of antitumor activity. HSV-tk clinical trials for prostate cancer are also ongoing in Japan, the Netherlands, and Mexico. Currently, numerous preclinical studies have reported immunomodulatory cytokine gene therapy, such as interleukin-2, interleukin-12, B7-1 (CD80), B7-2 (CD86) and granulocyte-macrophage colony-stimulating factor. Several clinical studies have been approved that potentially will show that these immunomodulatory gene therapies may generate an effective local and systemic antitumor activity and that should provide options for patients with prostate cancer. We review the multiple issues involved in current in situ gene therapy (gene/immunotherapy), its outcome, and future directions for patients with prostate cancer.
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PMID:In situ gene therapy for prostate cancer. 1563 15

A long-pursued goal in cancer treatment is to deliver a therapy specifically to metastases. As a result of the disseminated nature of the metastatic disease, carrying the therapeutic agent to the sites of tumor growth represents a major step for success. We hypothesized that tumor cells injected intravenously (i.v.) into an animal with metastases would respond to many of the factors driving the metastatic process, and would target metastases. Using a model of spontaneous metastases, we report here that i.v. injected tumor cells localized on metastatic lesions. Based on this fact, we used genetically transduced tumor cells for tumor targeting of anticancer agents such as a suicide gene or an oncolytic virus, with evident antitumoral effect and negligible systemic toxicity. Therefore, autologous tumor cells may be used as cellular vehicles for systemic delivery of anticancer therapies to metastatic tumors.
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PMID:Tumor cells as cellular vehicles to deliver gene therapies to metastatic tumors. 1565 Jul 63

Gene therapy of cancer offers the possibility of a targeted treatment that destroys tumors and metastases, but not normal tissues. In gene-directed enzyme prodrug therapy (GDEPT), or suicide gene therapy, the gene encoding an enzyme is delivered to tumor cells, followed by administration of a prodrug, which is converted locally to a cytotoxin by the enzyme. The producer cells as well as surrounding bystanders are subsequently killed. Promising results have meant that suicide gene therapy has reached multicenter phase III clinical trials. This review will discuss the development, efficiency, mode of action and pharmacokinetics of seven GDEPT systems in vitro and in vivo. We will review the latest data of those systems in clinical trials (herpes simplex virus thymidine kinase/gancyclovir, bacterial cytosine deaminase/5-fluorocytosine, bacterial nitroreductase/CB1954 and cytochrome P450/cyclophosphamide), as well as the development of more recent and experimental systems which are not yet in clinical trials (P450 reductase/tirapazamine, carboxypeptidase/CMDA, horseradish peroxidase/indole-3-acetic acid or paracetamol and others).
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PMID:From bench to bedside for gene-directed enzyme prodrug therapy of cancer. 1574 71

A 51-year-old man with left renal tumor and multiple lung metastases was admitted to our hospital for treatment. Left nephrectomy was performed, and pathological diagnosis was renal cell carcinoma (clear cell carcinoma, G2, pT3a). Initially, Interferon-alpha (IFN-alpha) therapy was started for lung metastases. About 40 days after surgery, head magnetic resonance imaging revealed brain metastases, and therefore gamma knife radiosurgery(GKS) was performed. Since chest computed tomography showed no change in lung metastases, we tried a combination of interleukin-2 (IL-2) and IFN-alpha therapy to elininate those metastases. As a result, neither lung nor brain metastases could be detected at the 4th month follow-up examination. At 5 months after the IL-2 and IFN-alpha therapy, the patient attempted suicide. Therefore, the IL-2 and IFN-alpha therapy was stopped and an antidepressant was prescribed. Now 11 months after withdrawal of the IL-2 and IFN-alpha, the patient's mental condition remains stable. No recurrence of the cancer has been detected by CT.
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PMID:[Synergetic responses after administration of interleukin-2 and Interferon-alpha combined with gamma knife radiosurgery in a patient with multiple lung and brain metastases: a case report]. 1605 Apr 76

Viral gene therapy has exceptional potential as a specifically tailored cancer treatment. However, enthusiasm for cancer gene therapy has varied over the years, partly owing to safety concerns after the death of a young volunteer in a clinical trial for a genetic disease. Since this singular tragedy, results from numerous clinical trials over the past 10 years have restored the excellent safety profile of adenoviral vectors. These vectors have been extensively studied in phase I and II trials as intraprostatically administered agents for patients with locally recurrent and high-risk local prostate cancer. Promising therapeutic responses have been reported in several studies with both oncolytic and suicide gene therapy strategies. The additional benefit of combining gene therapy with radiation therapy has also been realized; replicating adenoviruses inhibit DNA repair pathways, resulting in a synergistic sensitization to radiation. Other, nonreplicating suicide gene therapy strategies are also significantly enhanced with radiation. Combined radiation/gene therapy is currently being studied in phase I and II clinical trials and will likely be the first adenoviral gene therapy mechanism to become available to urologists in the clinic. Systemic gene therapy for metastatic disease is also a major goal of the field, and clinical trials are currently under way for hormone-resistant metastatic prostate cancer. Second- and third-generation "re-targeted" viral vectors, currently being developed in the laboratory, are likely to further improve these systemic trials.
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PMID:Adenoviral gene therapy, radiation, and prostate cancer. 1698 30


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