Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0376358 (prostate cancer)
 59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In an extended phase I/II study we evaluated 36 prostate cancer patients with local recurrence after radiotherapy who received single or repeated cycles of replication-deficient adenoviral vector (ADV)-mediated herpes simplex virus-thymidine kinase (HSV-tk) plus ganciclovir (GCV) in situ gene therapy with respect to serum PSA levels, alterations in immune cells, and numbers of apoptotic cells in needle biopsies. An initial cycle of HSV-tk plus GCV gene therapy caused a significant prolongation of the mean serum PSA-doubling time (PSADT) from 15.9 to 42.5 months (p = 0.0271) and in 28 of the injected patients (77.8%) there was a mean PSA reduction (PSAR) of 28%. It took a mean of 8.5 months for the PSA to return to the initial PSA (TR-PSA) value. A repeated cycle of gene therapy failed to significantly extend PSADT but did result in significant increases in PSAR (29.4%) and TR-PSA (10.5 months). Moderately increased serum adenovirus antibody titers were generally observed 2 weeks after initial vector injection. Also at this time there was a statistically significant increase in the mean percent of CD8(+) T cells positive for the HLA-DR marker of activation in peripheral blood (p = 0.0088). Studies using prostate biopsies obtained at the same time point demonstrated that vector DNA was detectable by PCR in most samples yet all patients remained positive for prostate cancer in at least one biopsy core. Further analysis demonstrated a correlation between the level of CD8(+) cells and the number of apoptotic cells in biopsies containing cancer cells (p = 0.042). We conclude that repeated cycles of in situ HSV-tk plus GCV gene therapy can be administered to prostate cancer patients who failed radiotherapy and have a localized recurrence. Biological responses to this experimental therapy including increases in PSADT, PSAR, and TR-PSA, and activated CD8(+) T cells present in the peripheral blood, were demonstrated. Interestingly, the density of CD8(+) cells in posttreatment biopsies correlated with the number of apoptotic cells.
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PMID:Prostate-specific antigen response and systemic T cell activation after in situ gene therapy in prostate cancer patients failing radiotherapy. 1168 37

Viral gene therapy against malignant tumors holds great promise for tumors that are susceptible to the oncolytic activity of viruses. One advantage of oncolytic viral therapy is that it can potentially be combined with other therapies, such as radiotherapy, to obtain an enhanced tumor response. In the case of prostate cancer, herpes simplex virus-mediated therapies have been shown to be highly effective in animal models; however, studies of the efficacy of combined viral and radiation therapy have not yet been reported. In this study, we have combined G207, a multimutated HSV type 1 vector, with external beam radiation therapy of prostate tumors grown subcutaneously in mice. We examined both the human LNCaP tumor in athymic mice and the mouse transgenic TRAMP tumor in either athymic mice or its syngeneic host, C57BL/6 mice. Virus was delivered either intravenously, in the case of LNCaP, or intratumorally, in the case of TRAMP. We found that individually, either G207 or radiation was effective in delaying tumor growth in these models. However, delivering the treatments simultaneously did not produce an enhanced effect.
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PMID:Ionizing radiation does not alter the antitumor activity of herpes simplex virus vector G207 in subcutaneous tumor models of human and murine prostate cancer. 1168 57

We are developing assays to image tissue-specific reporter gene expression in living mice by using optical methods and positron emission tomography. Approaches for imaging reporter gene expression depend on robust levels of mRNA and reporter protein. Attempts to image reporter gene expression driven by weak promoters are often hampered by the poor transcriptional activity of such promoters. Most tissue-specific promoters are weak relative to stronger but constitutively expressing viral promoters. In this study, we have validated methods to enhance the transcriptional activity of the prostate-specific antigen promoter for imaging by using a two-step transcriptional amplification (TSTA) system. We used the TSTA system to amplify expression of firefly luciferase (fl) and mutant herpes simplex virus type 1 thymidine kinase (HSV1-sr39tk) in a prostate cancer cell line (LNCaP). We demonstrate approximately 50-fold (fl) and approximately 12-fold (HSV1-sr39tk) enhancement by using the two-step approach. The TSTA system is observed to retain tissue selectivity. A cooled charge-coupled device optical imaging system was used to visualize the amplified fl expression in living mice implanted with LNCaP cells transfected ex vivo. These imaging experiments reveal a approximately 5-fold gain in imaging signal by using the TSTA system over the one-step system. The TSTA approach will be a valuable and generalizable tool to amplify and noninvasively image reporter gene expression in living animals by using tissue-specific promoters. The approaches validated should have important implications for study of gene therapy vectors, cell trafficking, transgenic models, as well as studying development of eukaryotic organisms.
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PMID:Two-step transcriptional amplification as a method for imaging reporter gene expression using weak promoters. 1173 53

To enhance the NK population induced by Herpes Simplex virus thymidine kinase (HSV-tk) gene transduction and ganciclovir (GCV) treatment, adenovirus-mediated (Ad) expression of IL-12 was added to Ad.HSV-tk + GCV as combination gene therapy. This approach resulted in improved local and systemic growth suppression in a metastatic model of mouse prostate cancer (RM-1). In vitro assay of tumor infiltrating lymphocytes noted superior lysis of both RM-1 and Yac-1 targets with combination therapy, but in vivo depletion of NK cells only negatively impacted on systemic growth inhibition. TUNEL assay of primary tumors noted induction of apoptosis between two and four times higher than controls lasting for 6-8 days post-vector injection. After demonstrating that Ad.HSV-tk/GCV and Ad.mIL-12-induced IFN-gamma independently up-regulated expression of FasL and Fas, respectively, studies examined tumor cell-mediated death through Fas/FasL-induced apoptosis as a mechanism of primary tumor growth suppression. In vitro, combination therapy at low vector doses resulted in synergistic growth suppression, which could be negated by the addition of anti-FasL antibody. In vivo co-inoculation of an adenovirus expressing soluble Fas resulted in combination therapy-treated tumors, which were three times larger than expected, and a reduction in apoptosis to baseline levels. In FasL knockout mice, combination therapy maintained the superior results experienced in wild-type mice, indicating that tumor cell, not host cell FasL, was responsible for Fas transactivation. Therefore, the combination of Ad.HSV-tk/GCV + Ad.mIL-12 results in enhanced local growth control via apoptosis due to tumor cell expression of Fas and FasL and improved anti-metastatic activity secondary to a strong NK response.
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PMID:A novel bystander effect involving tumor cell-derived Fas and FasL interactions following Ad.HSV-tk and Ad.mIL-12 gene therapies in experimental prostate cancer. 1194 76

The herpes simplex virus (HSV) thymidine kinase gene (tk) forms the basis of a widely used strategy for suicide gene therapy. A library of HSV thymidine kinase enzyme (TK) active site mutants having different affinities for guanosine analog prodrugs was developed. We sought to determine the optimal combination of tk variant and prodrug specifically for prostate cancer gene therapy, using in vitro and in vivo studies of adenovirally infected CL1, DU-145, and LNCaP tumor lines carrying wild-type tk, tk30, tk75, and sr39tk mutants expressed by a strong, constitutive cytomegalovirus promoter and treated with ganciclovir and acyclovir. In vitro experiments involving prostate cancer (CaP) cell line infection were carried out with a broad range of prodrug concentrations, and cell killing was determined by limiting dilution (colony-forming), MTT, and propidium iodide assays. In vivo studies based on CL1-GFP xenograft experiments were carried out to examine the ability of each TK variant to prevent tumor formation and to inhibit tumor growth and development of metastases in established orthotopic and subcutaneous tumors in SCID mice. Both in vitro and in vivo studies suggest improved killing with the sr39tk variant. Thus, the results suggest that the use of sr39tk in future trials of prostate cancer tk suicide gene therapy may be beneficial.
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PMID:Optimizing prostate cancer suicide gene therapy using herpes simplex virus thymidine kinase active site variants. 1197 45

Viral-mediated transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene has been demonstrated by several investigators to confer sensitivity to nucleoside analogs such as ganciclovir (GCV) in a variety of tumor cells including brain, prostate, bladder, kidney, ovary, head and neck, lung, pancreas, and liver cancers. Fourteen suicide gene clinical protocols using adenovirus vectors have been conducted, including four in prostate cancer. Two additional protocols for prostate cancer are in preparation in Japan and the Netherlands. A study conducted at Baylor College of Medicine was the first to demonstrate the safety of HSV-tk plus GCV therapy for human prostate cancer and the anticancer activity of gene therapy in this disease. However, it is still in the early stage of its development, with a number of problems to be overcome. Systemic delivery, specific introduction, and specific expression of the target gene are the major issues to be managed in order to establish a clinically relevant treatment strategy.
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PMID:Suicide gene therapy for urogenital cancer: current outcome and prospects. 1200 45

Adenovirus-mediated suicide gene therapy may hold promise in the treatment of human cancer. We have developed a novel approach that utilizes a lytic, replication-competent adenovirus (Ad5-CD/TKrep) to deliver a cytosine deaminase/herpes simplex virus-1 thymidine kinase fusion gene to tumors. The cytosine deaminase and herpes simplex virus-1 thymidine kinase suicide genes render malignant cells sensitive to specific pharmacological agents and, importantly, sensitize them to radiation. The Phase I study described here represents the first gene therapy trial in which a replication-competent virus was used to deliver a therapeutic gene to humans. The indication is local recurrence of prostate cancer after definitive radiation therapy. An escalating dose (10(10), 10(11), and 10(12) viral particles) of the Ad5-CD/TKrep virus was injected intraprostatically under transrectal ultrasound guidance into 16 patients in four cohorts. Two days later, patients were given 5-fluorocytosine and ganciclovir prodrug therapy for 1 (cohorts 1-3) or 2 (cohort 4) weeks. There were no dose-limiting toxicities, and the maximum tolerated dose of the Ad5-CD/TKrep vector was not defined. Ninety-four percent of the adverse events observed were mild or moderate (grade 1/2) in nature. Seven of 16 (44%) patients demonstrated a >or=25% decrease in serum prostate-specific antigen, and 3 of 16 (19%) patients demonstrated a >or=50% decrease in serum prostate-specific antigen. Transgene expression and tumor destruction at the injection site were confirmed by sextant needle biopsy of the prostate at 2 weeks. Two patients were negative for adenocarcinoma at 1 year follow-up. Although Ad5-CD/TKrep viral DNA could be detected in blood as far out as day 76, no infectious adenovirus was detected in patient serum or urine. Together, the results demonstrate that intraprostatic administration of the replication-competent Ad5-CD/TKrep virus followed by 2 weeks of 5-fluorocytosine and ganciclovir prodrug therapy can be safely applied to humans and is showing signs of biological activity.
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PMID:Phase I study of replication-competent adenovirus-mediated double suicide gene therapy for the treatment of locally recurrent prostate cancer. 1220 48

To enhance the efficacy of suicide gene therapy for prostate cancer under androgen deprivation, we designed a promoter system that consists of the prostate-specific membrane antigen (PSMA) promoter / enhancer (PEPM) and Cre-loxP DNA recombination system. We constructed two kinds of plasmids. One plasmid contains a Cre recombinase (Cre) under the control of PEPM and the other expresses CMV-lox-luciferase / herpes simplex virus thymidine kinase (TK). In PSMA-positive LNCaP cells, the promoter activity of the PEPM-Cre plus CMV-lox-luciferase demonstrated 800-fold greater activity compared with that of the PSMA promoter alone. However, no enhancement of the promoter activity was observed in the PSMA-negative cells. Furthermore, in contrast to prostate specific antigen promoter / enhancer (PP), the promoter activity of PEPM did not decrease when the LNCaP cells were cultured in charcoal-stripped fetal bovine serum (CFBS). In an in vitro gene therapy model with LNCaP cells, the cell growth inhibition in the presence of ganciclovir (GCV) was more evident in the cells transfected with the PEPM-Cre plus CMV-lox-TK than in the cells with the PP-TK, and the difference in efficacy between the two plasmids was more remarkable when the cells were maintained in CFBS medium. The therapeutic effect of PEPM-Cre plus CMV-lox-TK was also observed in xenografted LNCaP cells on nude mice when the plasmids were directly injected into tumors and GCV was administered intraperitoneally. These findings indicate that the combination of the PSMA promoter / enhancer and the Cre-loxP system can enhance the PSMA promoter activity even under androgen ablation conditions and can exert its anti-tumor effect both in vitro and in vivo.
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PMID:Development of gene therapy using prostate-specific membrane antigen promoter/enhancer with Cre Recombinase/LoxP system for prostate cancer cells under androgen ablation condition. 1241 46

We previously demonstrated significant therapeutic activities associated with adenoviral vector-mediated Herpes Simplex Virus/thymidine kinase (AdHSV-tk) with ganciclovir (GCV) in situ gene therapy in the RM-1 orthotopic mouse prostate cancer model and interleukin-12 (AdmIL-12) in situ gene therapy in the RM-9 orthotopic mouse prostate model for prostate cancer. In both protocols, local cytotoxicity and activities against pre-established lung metastases were demonstrated. To test whether combined AdHSV-tk+GCV+IL-12 gene therapy would lead to enhanced therapeutic effects when compared to either treatment alone, we used RM-9 mouse prostate cancer cells in both orthotopic and pre-established lung metastases models of prostate cancer. Combined treatment with a single injection of optimal doses of AdHSV-tk+GCV or AdmIL-12 led to significantly increased suppression of orthotopic tumor growth. IL-12 gene therapy alone was more effective than AdHSV-tk+GCV in suppressing spontaneous lymph node metastases and pre-established lung metastases but combination gene therapy did not result in additional anti-metastatic activities. Combination gene therapy also did not achieve significantly better animal survival compared to AdHSV-tk+GCV or AdmIL-12 alone. Analysis of localized antitumor activities demonstrated that AdHSV-tk+GCV therapy induced higher levels of necrosis compared to AdmIL-12 or combination therapy. However, both treatments alone and combination therapy produced similar increases in apoptotic index. To address the possible mechanisms of locally co-operative cytotoxic activities, we analyzed the systemic natural killer (NK) response and the numbers of tumor-infiltrating immune cells using quantitative immunohistochemical analysis. AdHSV-tk+GCV therapy alone led to detectable increases in iNOS-positive cells, CD4+and CD8+T-cells and moderately increased numbers of F4/80 (macrophage selective)-positive cells within treated tumors. In contrast, AdmIL-12 elicited a highly robust pattern of tumor infiltration for all four of these immune cells that was in general mimicked by combination therapy. Further analysis of the accumulation of transforming growth factor-beta1 (TGF-beta1) immunohistochemical staining demonstrated that AdHSV-tk+GCV treatment, but not AdmIL-12 treatment, produced cancer cell-associated increases in this cytokine relative to control Ad-beta-gal injections. Interestingly, local injection with AdHSV-tk+GCV induced significant splenocyte-derived NK cell cytolytic activities with maximal response 7 days following treatment, whereas AdmIL-12 injection produced significantly higher NK activity with maximal response 2 days following injection. The combined treatment produced a higher systemic NK response over the 14-day treatment period. Depletion of NK cells in vivo demonstrated that this immunocyte subpopulation was responsible for early locally cytotoxic activities induced by AdHSV-tk+GCV but not AdmIL-12 and that NK activities were largely responsible for activities against pre-established metastases generated by both gene therapy protocols. Prostate Cancer and Prostatic Diseases (2001) 4, 44-55
Prostate Cancer Prostatic Dis 2001
PMID:Combination gene therapy with adenoviral vector-mediated HSV-tk+GCV and IL-12 in an orthotopic mouse model for prostate cancer. 1249 62

Adenoviral vector delivery of the Herpes simplex virus thymidine kinase (HSV-tk) gene in combination with the prodrug ganciclovir (GCV) has been tested in phase I clinical trials for prostate cancer and found to exhibit a satisfactory toxicity profile. We have developed additional adenoviral vectors with differing promoters to optimize the expression profile and in the present study evaluate the potential systemic toxicity of these vectors. Four recombinant adenoviral vectors that express the HSV-tk gene were generated using three different promoters: CMV (leftward orientation); RSV (both rightward and leftward orientation); and the mouse caveolin-1 (cav-1) promoter (leftward orientation). Efficacy was determined in vitro by cytotoxicity assays in a mouse prostate cancer cell line, RM-9, and in vivo by treating orthotopic tumors. Potential toxicity was evaluated from liver histology and apoptotic cell counts and enzyme levels in the serum following intravenous adenoviral vector injection. Although there were differences in HSV-tk expression at the protein level among the four vectors there were no significant differences in in-vitro cytotoxicity studies with GCV or in vivo in tumor growth suppression of an orthotopic mouse prostate cancer model in GCV treated mice. Intravenous delivery of high doses of all adenoviral vectors lead to abnormalities in liver function as measured by specific serum markers and histological evaluation of liver tissue and increased levels of apoptosis in the liver. These abnormalities were most prevalent with the vector containing the CMV promoter and the rightward oriented RSV promoter. They were least prevalent in the vector regulated by the cav-1 promoter. Upregulation of specific chemokines, MIP-2 and MIP-1beta was correlated with apoptotic counts. Our results demonstrate that comprehensive toxicological analysis of adenoviral vectors provides internally consistent information that can differentiate vectors with comparable efficacy based on toxicity. In these studies vectors with the cav-1 promoter-driven and leftward RSV-driven HSV-tk gene demonstrated minimal toxicities with cytotoxic effectiveness comparable to more toxic vectors. Our studies further suggest that promoter selection can influence the toxic effects of an adenoviral gene therapy vector.
Prostate Cancer Prostatic Dis 2002
PMID:Gene therapy for prostate cancer: toxicological profile of four HSV-tk transducing adenoviral vectors regulated by different promoters. 1262 18


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