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)

The GSTP1 gene encodes for an enzyme, glutathione S-transferase pi (GSTpi),involved in detoxification of carcinogens. An aminoacid substitution (I105V) in GSTP1 produces a variant enzyme with lower activity and less capability of effective detoxification. This variant GSTP*B allele has been associated with a propensity to develop several neoplasms. Because GSTP1 promoter hypermethylation and inactivation of GSTpi expression is a frequent alteration in prostate carcinoma, we hypothesized that this somatic epigenetic modification could obviate any reduced enzyme activity caused by the germ-line polymorphism. We tested for the GSTP1 genotype in a population of prostate cancer patients, and in a control group composed of patients with benign prostatic hyperplasia (BPH) and healthy blood donors. Tissue samples from the 105 prostate cancer cases (105 adenocarcinomas and 34 prostatic intraepithelial neoplasia lesions), and from 43 BPH patients were tested for GSTP1 hypermethylation by methylation-specific PCR. GSTpi protein expression was assessed by immunohistochemistry. No significant effect on prostate cancer risk was detectable for GSTP1 genotype compared with the control population (odds ratio, 1.02; 95% confidence interval, 0.59-1.75). Moreover, no association was found between this genotype and tumor or BPH methylation status. Patients with unmethylated carcinomas did not disclose significant differences in genotypic distribution compared with the control population. In adenocarcinoma, a strong association (P < 0.00001) between GSTP1 promoter hypermethylation and loss of GSTpi expression was observed; however, this trend was not retained in prostatic intraepithelial neoplasia or BPH lesions. Although the GSTP1 polymorphism is not associated with altered susceptibility to prostate cancer, somatic promoter hypermethylation is an effective, but not the only, cause of decreased GSTpi function.
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PMID:I105V polymorphism and promoter methylation of the GSTP1 gene in prostate adenocarcinoma. 1201 Aug 58

Human prostate cancer is characterized by an early and near-universal loss of expression of the phase 2 enzyme glutathione S-transferase-pi (GSTP1). We hypothesize that a mechanism-based prostate cancer preventive strategy could involve induction of phase 2 enzymes within the prostate to compensate for the loss of GSTP1 expression. NAD[P]H:(quinone-acceptor) oxidoreductase (quinone reductase or QR) enzymatic activity, a surrogate of phase 2 enzyme response, was measured after treating the human prostate cancer cell line LNCaP with known phase 2 enzyme-inducing agents from 10 distinct chemical classes. QR enzymatic activity was assayed in microtiter plates using the menadione-coupled reduction of tetrazolium dye. Degree of induction was expressed as fold-increase over control and corrected for toxicity. Compounds were also tested in LNCaP-5-aza-C, an LNCaP subline selected in 5-aza-cytidine that expresses GSTP1, and in the human liver cell line HepG2. LNCaP showed robust induction of QR enzymatic activity after treatment with a subset of the phase 2 enzyme-inducing agents. All Michael acceptors were effective at inducing QR activity in LNCaP. Some phenolic antioxidants, heavy metal salts, and quinones also significantly increased QR activity, although inducer potency varied widely within these classes of compounds. Some of the isothiocyanates, mercaptans, bifunctional inducers, and trivalent arsenicals also produced modest QR induction, but peroxides and dithiolethiones were inactive. LNCaP-5-aza-C and LNCaP responded similarly to all compounds, but the pattern of response for HepG2 differed significantly. The differences in QR responsiveness between the prostate cell lines and HepG2 suggest that prostate tissues may have a unique pattern of response to phase 2-inducing agents distinct from other tissue types. Our data suggest that measurement of QR induction in prostate cancer cell lines may help identify potential cancer chemopreventive agents effective in the prostate.
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PMID:Identification of potential prostate cancer preventive agents through induction of quinone reductase in vitro. 1222 31

Evidence that somatic inactivation of GSTP1, encoding the human pi-class glutathione S-transferase, may initiate prostatic carcinogenesis is reviewed along with epidemiological evidence implicating several environment and lifestyle factors, including the diet and sexually transmitted diseases, as prostate cancer risk factors. An integrated model is presented featuring GSTPI function as a 'caretaker' gene during the pathogenesis of prostate cancer, in which the early loss of GSTPI activity renders prostate cells vulnerable to genome damage associated with chronic prostatic inflammation and repeated exposure to carcinogens. The model predicts that the critical prostate carcinogens will be those that are substrates for GSTP1 detoxification and are associated with high prostate cancer risk diet and lifestyle habits.
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PMID:The diet, prostate inflammation, and the development of prostate cancer. 1240 Sep 93

We determined whether the glutathione S-transferase GSTP1 Ile105 --> Val105 substitution is associated with response to androgen ablation therapy in patients with advanced prostate cancer. As response may be associated with tumor grade, Gleason score, clinical T stage and presence of metastases we also determined if GSTP1 genotypes were associated with these prognostic parameters. We speculated that GSTP1 Ile105/Ile105 would be linked with good response to androgen ablation therapy and, low/moderate tumor grade, 1/2 clinical T-stage, Gleason score < 6 and, no metastases. Genotype frequencies in cases and controls were not significantly different (P = 0.70) indicating that allelism in GSTP1 is not associated with susceptibility. There was no association between GSTP1 (Ile105/Ile105 versus Ile105/Val105 and Val105/Val105) and grade (P = 0.28, OR = 0.92), Gleason score (P = 0.84, OR = 0.94) or metastatic state (P = 0.68, OR = 0.88) though the frequency of GSTP1 Ile105/Ile105 was higher in cases with stage 1/2 tumors than those with stage 3/4 tumors (P = 0.03, OR = 1.89). GSTP1 Val105/Val105 was also associated with response to hormone ablation therapy. Thus, the GSTP1 Ile105/Ile105 frequency was significantly higher in 86/118 patients who demonstrated a good response than in those with poor response (P = 0.03, OR = 2.70). We speculate that the association of GSTP1 with response results from an effect of the gene product early in carcinogenesis.
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PMID:Glutathione S-transferase GSTP1 genotypes are associated with response to androgen ablation therapy in advanced prostate cancer. 1251 68

The methylation status of 7 genes was examined in four cell lines, 36 samples of benign prostatic hyperplasia (BPH), 20 samples of prostatic intraepithelial neoplasia (PIN) and 109 samples of prostate cancer (PCa), using methylation-specific PCR (MSP): the pi-class glutathione S-transferase (GSTP1), retinoic acid receptor beta 2(RARbeta2), androgen receptor (AR), death-associated protein kinase (DAPK), tissue inhibitor of metalloproteinase-3 (TIMP-3), O(6)-methylguanine DNA methyltransferase (MGMT), and hypermethylated in cancer-1 (HIC-1). The frequencies of methylation in PCa were 88% for GSTP1, 78% for RARbeta2, 36% for DAPK, 15% for AR, 6% for TIMP-3, and 2% for MGMT, whereas the values were 11% for AR and DAPK, 6% for TIMP-3, 3% for GSTP1, and 0 for RARbeta2 and MGMT in BPH. Aberrant methylation of the GSTP1 and RARbeta2 genes was detected in 30% and 20% of PIN, respectively. Most samples of BPH and PCa were positive for HIC-1 methylation. Regarding accumulation of methylated cancer-related genes, there were significant correlations between PCa and BPH as well as PIN and BPH. In the present study, a high frequency of aberrant promoter methylation of the GSTP1 and RARbeta2 genes was noted in PCa. Our findings suggest that methylation of cancer-related genes may be involved in carcinogenesis of the prostate.
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PMID:Altered methylation of multiple genes in carcinogenesis of the prostate. 1284 78

Somatic inactivation of the glutathione S-transferase-pi gene (GSTP1) via CpG island hypermethylation occurs early during prostate carcinogenesis, present in approximately 70% of high-grade prostatic intraepithelial neoplasia (high-grade PIN) lesions and more than 90% of adenocarcinomas. Recently, there has been a resurgence of the concept that foci of prostatic atrophy (referred to as proliferative inflammatory atrophy or PIA) may be precursor lesions for the development of prostate cancer and/or high-grade PIN. Many of the cells within PIA lesions contain elevated levels of GSTP1, glutathione S-transferase-alpha (GSTA1), and cyclooxygenase-II proteins, suggesting a stress response. Because not all PIA cells are positive for GSTP1 protein, we hypothesized that some of the cells within these regions acquire GSTP1 CpG island hypermethylation, increasing the chance of progression to high-grade PIN and/or adenocarcinoma. Separate regions (n =199) from 27 formalin-fixed paraffin-embedded prostates were microdissected by laser-capture microdissection (Arcturus PixCell II). These regions included normal epithelium (n = 48), hyperplasticepithelium from benign prostatic hyperplasia nodules (n = 22), PIA (n = 64), high-grade PIN (n = 32), and adenocarcinoma (n = 33). Genomic DNA was isolated and assessed for GSTP1 CpG island hypermethylation by methylation-specific polymerase chain reaction. GSTP1 CpG island hypermethylation was not detected in normal epithelium (0 of 48) or in hyperplastic epithelium (0 of 22), but was found in 4 of 64 (6.3%) PIA lesions. The difference in the frequency of GSTP1 CpG island hypermethylation between normal or hyperplastic epithelium and PIA was statistically significant (P = 0.049). Similar to studies using nonmicrodissected cases, hypermethylation was found in 22 of 32 (68.8%) high-grade PIN lesions and in 30 of 33 (90.9%) adenocarcinoma lesions. Unlike normal or hyperplastic epithelium, GSTP1 CpG island hypermethylation can be detected in some PIA lesions. These data support the hypothesis that atrophic epithelium in a subset of PIA lesions may lead to high-grade PIN and/or adenocarcinoma. Because these atrophic lesions are so prevalent and extensive, even though only a small subset contains this somatic DNA alteration, the clinical impact may be substantial.
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PMID:Hypermethylation of the human glutathione S-transferase-pi gene (GSTP1) CpG island is present in a subset of proliferative inflammatory atrophy lesions but not in normal or hyperplastic epithelium of the prostate: a detailed study using laser-capture microdissection. 1293 33

Hypermethylation of the 5' promoter region of the glutathione S-transferase pi gene (GSTP1) occurs at a very high frequency in prostate adenocarcinoma. We compared the results of blinded histologic review of sextant biopsy samples from 72 excised prostates with those obtained using a quantitative methylation-specific polymerase chain reaction assay (QMSP) for GSTP1. Formal surgical pathologic review of the resected prostates was used to determine the number of patients with (n = 61) and without (n = 11) prostate cancer. Histology alone detected prostate carcinoma with 64% sensitivity (95% confidence interval [CI] = 51% to 76%) and 100% specificity (95% CI = 72% to 100%), whereas the combination of histology and GSTP1 QMSP at an assay threshold greater than 10 detected prostate carcinoma with 75% sensitivity (95% CI = 63% to 86%) and 100% specificity (95% CI = 72% to 100%), an 11% improvement (95% CI = 5% to 22%) in sensitivity over histology alone. The combination of histology and GSTP1 QMSP at an assay threshold greater than 5 detected prostate adenocarcinoma with 79% sensitivity (95% CI = 68% to 89%), a 15% improvement (95% CI = 7% to 26%) over histology alone. Thus, GSTP1 QMSP improved the sensitivity of histologic review of random needle biopsies for prostate cancer diagnosis. Further studies should determine whether detection of GSTP1 hypermethylation in a biopsy sample with normal histology indicates the need for an early repeat biopsy at the same site.
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PMID:Quantitative GSTP1 methylation and the detection of prostate adenocarcinoma in sextant biopsies. 1460 96

The molecular genetics of prostate cancer, the second most common cause of cancer-related death in men, is poorly understood. Inherited factors are believed to account for 42% of the risk of prostate cancer, and although multiple chromosomal loci of susceptibility have been identified, the target genes for these loci have not been well defined. Its heterogeneous nature suggests that the predisposition to prostate cancer may involve multiple genes and variable phenotypic expression. Genes that have been found to play a role in progression of prostate cancer include GSTP1 and PTEN, as well as the androgen receptor (AR) gene. Evidence suggests that the AR signaling pathway can be activated by other ligands when androgen levels are low. Recent findings have also implicated Kruppel-like factor 6 (KFL6), E-cadherin, the p40 subunit of eukaryotic translation initiation factor (eIF3-p40), and Elongin C, but confirmatory evidence is required to clarify the roles of these factors. Technologic advances, such as complementary DNA and tissue microarrays, have facilitated identification of genetic alterations and investigations of their function, but improved tools for searching and analyzing genes are still needed.
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PMID:The molecular genetics of prostate cancer. 1460 12

To date, several reports have been published about CpG island methylation of various genes in prostate cancer. However, most of these studies have focused on cancer tissue only or a single gene and data about concurrent methylation of multiple genes in prostate cancer or prostatic intraepithelial neoplasia (PIN) are limited. The aim of the present study was to determine the methylation profile of 11 tumour-related genes in prostate cancer and PIN. Seventy-one samples, including 37 prostate cancers, 14 PINs, and 20 normal prostates, were examined for the methylation status of 11 tumour-related genes using methylation-specific PCR. The mean number of genes methylated was significantly higher in prostate cancer and PIN than in non-neoplastic prostate (4.4, 3, and 0.2, respectively; p < 0.001). In prostate cancer, APC, GSTP1, MGMT, and RASSF1A were frequently methylated at a frequency of 56.8%, 86.5%, 75.7%, and 83.8%, respectively. These genes were methylated in more than 30% of PINs. Prostate cancers with high serum prostate-specific antigen (PSA) (more than 8 ng/ml) or a high Gleason score (GS) (3 + 4 or more) showed higher numbers of methylated genes than those with low serum PSA (8 or less) or low GS (3 + 3 or less) (5.4 versus 2.5 and 5.4 versus 3.1, respectively; p < 0.05). The methylation frequency of APC, RASSF1A, and RUNX3 was higher in prostate cancers with high serum PSA or with high GS than in those with low PSA or with low GS, respectively, the differences reaching statistical significance (p < 0.05). A strong association between MGMT methylation and loss of MGMT expression was demonstrated by immunohistochemistry. CpG island methylation is a frequent event, occurs early, and accumulates during multi-step prostatic carcinogenesis. High levels of CpG island hypermethylation might serve as a potential biological marker for aggressive prostate cancer.
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PMID:Aberrant CpG island hypermethylation of multiple genes in prostate cancer and prostatic intraepithelial neoplasia. 1474 6

Somatic hypermethylation of CpG island sequences at GSTP1, the gene encoding the pi-class glutathione S-transferase, appears to be characteristic of human prostatic carcinogenesis. To consider the potential utility of this epigenetic alteration as a biomarker for prostate cancer, we present here a comprehensive review of the literature describing somatic GSTP1 changes in DNA from prostate cells and tissues. GSTP1 CpG island hypermethylation has been detected in prostate cancer DNA using a variety of assay techniques, including (i) Southern blot analysis (SB), after treatment with (5-m)C-sensitive restriction endonucleases, (ii) the polymerase chain reaction, following treatment with (5-m)C-sensitive restriction endonucleases (RE-PCR), (iii) bisulfite genomic sequencing (BGS), and (iv) bisulfite modification followed by the polymerase chain reaction, using primers selective for target sequences containing (5-m)C (MSP). In the majority of the case series so far reported, GSTP1 CpG island hypermethylation was present in DNA from at least 90% of prostate cancer cases. When analyses have been carefully conducted, GSTP1 CpG island hypermethylation has not been found in DNA from normal prostate tissues, or from benign prostatic hyperplasia (BPH) tissues, though GSTP1 CpG island hypermethylation changes have been detected in DNA from candidate prostate cancer precursor lesions proliferative inflammatory atrophy (PIA) and prostatic intraepithelial neoplasia (PIN). Using PCR methods, GSTP1 CpG island hypermethylation has also been detected in urine, ejaculate, and plasma from men with prostate cancer. GSTP1 CpG island hypermethylation, a somatic epigenetic alteration, appears poised to serve as a molecular biomarker useful for prostate cancer screening, detection, and diagnosis.
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PMID:GSTP1 CpG island hypermethylation as a molecular biomarker for prostate cancer. 1475 84


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