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

We have isolated cis-diamminedichloroplatinum(II) (CDDP)-resistant variants, C/CDP-1 and C/CDP-2, from a Chinese hamster ovary (CHO) cell line after a stepwise exposure to increasing concentrations of CDDP, and a CDDP-sensitive revertant, R-1, from C/CDP-2 after continuous incubation for 5 months in the absence of CDDP, C/CDP-1 and C/CDP-2 showed 7- and 10-fold higher resistance to CDDP, respectively, compared to CHO cells. C/CDP-2 was cross-resistant to carboplatin, L-phenylalanine mustard (melphalan), and CdSO4, but not to other anticancer agents. Alkaline elution of DNA showed an increased amount of DNA interstrand cross-linking formation in CHO cells, but not in C/CDP-2 cells, when CHO and C/CDP-2 cells were cultured with CDDP. By contrast, alkaline elution of DNA showed increased formation of DNA cross-links when nuclei of C/CDP-2 cells were treated with CDDP. The activity of glutathione S-transferase (GST) of C/CDP-1 and C/CDP-2 was 4- and 6-fold higher than that of CHO cells, respectively. The cellular level of GST activity of R-1 was almost similar to that of CHO cells. Northern blotting analysis revealed that GST-pi mRNA in both C/CDP-1 and C/CDP-2 cell lines was increased more than 5-fold over that of CHO and R-1 cells. There is no apparent gene amplification of GST-pi gene in CDDP-resistant cell lines. Immunoblot assays showed a specific increase of GST-pi in C/CDP-1 and C/CDP-2, but no increase in GST-mu and GST-alpha. We also compared CDDP-resistant properties of a resistant variant, P/CDP-5, derived from human prostate cancer PC-3 cell line, with those of C/CDP-1 and C/CDP-2 cells and found no increased GST activity in P/CDP-5 cells. Multiple mechanisms might be considered for acquisition of CDDP resistance in various cell lines in culture.
 ...
PMID:Increased expression of glutathione S-transferase gene in cis-diamminedichloroplatinum(II)-resistant variants of a Chinese hamster ovary cell line. 247 74

The major groups of enzymes involved in activating and detoxifying therapeutic drugs, not least several anti-cancer drugs, include the cytochromes P450 (P450s), epoxide hydrolase, and glutathione S-transferases (GSTs). The expression of these enzymes in malignant tumours is one possible mechanism of anti-cancer drug resistance. This study has investigated the presence, cellular localization, and distribution of drug-metabolizing enzymes in prostate cancer. The P450 subfamilies CYP1A, CYP2C, and CYP3A were present in 63, 25, and 61 per cent of tumours, respectively. Epoxide hydrolase was identified in 96 per cent of tumours. GST-alpha and GST-mu were expressed in 29 and 41 per cent of tumours, respectively, while there was no immunoreactivity for the pi form of GST. The absence of GST-pi in prostate cancer contrasts with the frequent expression of GST-pi observed in other types of malignant tumour. In non-neoplastic prostatic epithelium, there was expression of CYP1A, CYP2C, epoxide hydrolase, and the different forms of GST, while there was no apparent immunoreactivity for CYP3A.
 ...
PMID:The immunohistochemical localization of drug-metabolizing enzymes in prostate cancer. 749 Jun 81

Hereditary peculiarities in individual responses to environmental chemicals are a common occurrence in human populations. Genetic variation in glutathione S-transferase, CYP1A2, N-acetyltransferase, and paraoxonase exemplify the relationship of metabolic variation to individual susceptibility to cancer and other toxicants of environmental origin. Heritable receptor protein variants, a subset of proteins of enormous pharmacogenetic potential that have not thus far been extensively explored from the pharmacogenetic standpoint, are also considered. Examples of interest that are considered include receptor variants associated with retinoic acid resistance in acute promyelocytic leukemia, with paradoxical responses to antiandrogens in prostate cancer, and with retinitis pigmentosa. Additional heritable protein variants of pharmacogenetic interest that result in antibiotic-induced deafness, glucocorticoid-remediable aldosteronism and hypertension, the long-QT syndrome, and beryllium-induced lung disease are also discussed. These traits demonstrate how knowledge of the molecular basis and mechanism of the variant response may contribute to its prevention in sensitive persons as well as to improved therapy for genetically conditioned disorders that arise from environmental chemicals.
 ...
PMID:Influence of heredity on human sensitivity to environmental chemicals. 778 56

Hypermethylation of regulatory sequences at the locus of the pi-class glutathione S-transferase gene GSTP1 was detected in 20 of 20 human prostatic carcinoma tissue specimens studied but not in normal tissues or prostatic tissues exhibiting benign hyperplasia. In addition, a striking decrease in GSTP1 expression was found to accompany human prostatic carcinogenesis. Immunohistochemical staining with anti-GSTP1 antibodies failed to detect the enzyme in 88 of 91 prostatic carcinomas analyzed. In vitro, GSTP1 expression was limited to human prostatic cancer cell lines containing GSTP1 alleles with hypomethylated promoter sequences; a human prostatic cancer cell line containing only hypermethylated GSTP1 promoter sequences did not express GSTP1 mRNA or polypeptides. Methylation of cytidine nucleotides in GSTP1 regulatory sequences constitutes the most common genomic alteration yet described for human prostate cancer.
 ...
PMID:Cytidine methylation of regulatory sequences near the pi-class glutathione S-transferase gene accompanies human prostatic carcinogenesis. 797 32

Metastatic prostate adenocarcinoma is unresponsive to alkylator chemotherapy with virtually no prolonged remissions. Glutathione (GSH) and glutathione S-transferase (GST) have been reported to play a role in tumor resistance to alkylator therapy; however, there are no baseline studies that have investigated and compared GSH and GST in human prostate cell lines and tissues. Thus, we determined the GSH content and GST activity in benign prostate, in primary and metastatic prostate adenocarcinoma tissues, in immortal adenocarcinoma cell lines, and in primary cell cultures derived from both benign prostate and primary prostatic carcinoma tissue. The GSH content was higher in the immortal cell lines than in the fresh tissues and primary cultures. Conversely, the GST activity was significantly higher in the tissues and primary cultures than in the cell lines. The GSH content and GST activity of the primary cultured prostatic cells were similar to those of the prostate tissues. The differences between the immortal prostate cancer cell lines and prostate tissue are of sufficient magnitude to suggest that in vitro results with cell lines may not extrapolate to prostate cancer in vivo. The GSH content and GST activity in a prostate specific antigen-secreting human prostate tumor xenograft, LuCaP23, maintained in nude mice were similar to those of human prostate tissue and primary cultures. Both the xenograft and primary cultures from patients with prostate cancer may be more appropriate models than established cell lines for investigating techniques to increase the effectiveness of alkylators in prostate cancer.
 ...
PMID:Glutathione and glutathione S-transferase in benign and malignant prostate cell lines and prostate tissues. 853 73

Two variant glutathione S-transferase cDNAs have been described at the GSTP1 locus, which differ by a single base pair (A-G) substitution at nucleotide 313 of the GSTP1 cDNA. This results in an amino acid substitution which alters the function of the enzyme. In this study, a novel PCR assay has been developed which demonstrates that these two variant cDNAs represent distinct GSTP1 alleles (GSTP1a and GSTP1b). In a study of individuals with different forms of cancer, the GSTP1b allele is found to be strongly associated with bladder cancer and testicular cancer. In controls 6.5% of individuals were homozygous for the GSTP1b allele. In bladder cancer cases, this rose to 19.7% [n = 71, odds ratio 3.6 (1.4-9.2), P = 0.006] and in testicular cancer to 18.7% [n = 155, odds ratio 3.3 (1.5-7.7), P = 0.002]. In addition, in prostate cancer a highly significant decrease in the frequency of the GSTP1a homozygotes was observed [control 51.0% versus 27.8% cancer cases, n = 36, odds ratio 0.4 (0.02-3.3), P = 0.008]. Increases in the frequency of GSTP1b homozygotes was also observed in lung cancer and chronic obstructive pulmonary disease. However, these were not statistically significant. No change in breast or colon cancer allele frequencies was observed.
 ...
PMID:Identification of genetic polymorphisms at the glutathione S-transferase Pi locus and association with susceptibility to bladder, testicular and prostate cancer. 911 Nov 93

The antioxidant enzymes catalase, glutathione reductase (GR), glutathione S-transferase (GST), glutathione peroxidase (GPx), and superoxide dismutase (SOD) were determined in the androgen-response LNCaP and androgen-nonresponsive PC-3 and DU 145 cells as well as in prostatic epithelial cell cultures of benign and malignant human prostatic tissue. There were no differences between the enzyme activities of the human primary cell cultures from cancerous tissue and their normal counterparts. The enzyme activities of the three permanent cell lines were either higher (SOD, catalase, GR) or lower (GST, GPx) than in the primary cell cultures. In LNCaP cells catalase and GR were significantly higher, GST, in contrast, was significantly lower than in PC-3 and DU 145 cells. GST in PC-3 and DU 145 cells, and SOD in all the three cell lines showed no significant differences. Catalase, GPx and GR values were significantly different in the three permanent cell lines. The different enzymatic equipment of the prostate cancer cell lines provides the basis for experimental testing of new concepts of cancer treatment with the help of systematic modulations of the antioxidant defence systems in prostate cancer.
 ...
PMID:Antioxidant enzymes in malignant prostate cell lines and in primary cultured prostatic cells. 916 5

Cancer-associated somatic genome alterations offer great promise as cancer biomarkers. Here we describe a new biomarker for human prostate cancer: extensive methylation of deoxycytidine nucleotides distributed throughout a 5' "CG island" region of the pi-class glutathione S-transferase gene (GSTP1). Using the PCR to amplify a GSTP1 promoter sequence fragment containing 12 recognition sites for HpaII and MspI, 52 of 57 (91%) prostatic carcinoma DNA specimens demonstrated extensive somatic increases in deoxycytidine methylation, detected as amplification of target GSTP1 promoter sequences following HpaII digestion, but not following MspI treatment. Using nested primer sets, a sensitive PCR assay for extensive GSTP1 CG island methylation changes was developed that was capable of detecting 200 pg of prostate cancer cell DNA among 1 microgram of normal leukocyte DNA. This GSTP1 CG island DNA methylation assay, which targets a somatic genome change present in most prostate cancer cells but not in normal cells, may serve as a new molecular diagnosis and staging tool to aid in prostate cancer detection and treatment.
 ...
PMID:CG island methylation changes near the GSTP1 gene in prostatic carcinoma cells detected using the polymerase chain reaction: a new prostate cancer biomarker. 918 79

Prostate intraepithelial neoplasia (PIN) is a purported prostate cancer precursor lesion and a candidate biomarker for efficacy assessment in prostate cancer chemoprevention trials. Loss of expression of the pi-class glutathione S-transferase enzyme GSTP1, which is associated with the hypermethylation of deoxycytidine residues in the 5'-regulatory CG island region of the GSTP1 gene, is a near-universal finding in human prostate cancer. GSTP1 expression was assessed by immunohistochemistry in 60 high-grade PIN samples adjacent to and distant from prostate adenocarcinoma. Whereas abundant enzyme polypeptide expression was evident in all normal prostatic tissues, all samples of high-grade PIN and adenocarcinoma were completely devoid of GSTP1. DNA from 10 high-grade PIN lesions was analyzed for GSTP1 CG island methylation changes using a PCR technique targeting a polymorphic (ATAAA)n repeat sequence in the promoter region of the GSTP1 gene. Somatic GSTP1 CG island methylation changes were detected in DNA from 7 of the 10 PIN lesions. Allele discrimination was possible for 5 of the 10 DNA samples: 2 of the 5 samples exhibited DNA methylation changes at both alleles; whereas 3 samples displayed no DNA methylation changes at either allele. GSTP1 CG island methylation changes were present in each of the five homozygous samples. Hypermethylation of the 5'-regulatory region of the GSTP1 gene may serve as an important molecular genetic biomarker for both prostate cancer and PIN. The finding of frequent GSTP1 methylation changes in PIN and prostate cancer supports a role for PIN lesions as a prostate cancer precursor and may provide insight to the molecular pathogenesis of prostate cancer.
 ...
PMID:CG island methylation changes near the GSTP1 gene in prostatic intraepithelial neoplasia. 964 98

Androgens are critical in the development and maintenance of the male reproductive system and important in the progression of prostate cancer. The effects of androgens are mediated through the androgen receptor (AR), which is a ligand-modulated transcription factor that belongs to the nuclear receptor superfamily. In addition to its ability to activate transcription from androgen response elements, AR can inhibit activator protein-1 (AP-1) activity, composed of Jun and Fos oncoproteins, in a ligand-dependent manner. Conversely, when activated, AP-1 can block AR activity. We found that CREB (cAMP response element-binding protein) binding protein (CBP) had a direct role in both of these activities of AR. CBP significantly increased the ability of endogenous AR in LNCaP cells to activate transcription from an AR-dependent reporter construct. On the other hand, repression of AR activity by treatment of LNCaP cells with an activator of AP-1 was largely relieved when CBP was ectopically expressed. AR and CBP can physically interact in vitro as was shown in glutathione S-transferase pulldown assays. Whereas both the N terminus and ligand-binding domain of AR can interact with CBP, a short region in the N terminus of CBP is required for these interactions. As opposed to the interaction of CBP with other nuclear receptors studied so far, CBP-AR interactions were not affected by ligand binding to AR in vitro. These data suggest that CBP is a coactivator for AR in vivo and that the transcriptional interference between AR and AP-1 is the result of competition for limiting amounts of CBP in the cell.
 ...
PMID:CREB binding protein is a coactivator for the androgen receptor and mediates cross-talk with AP-1. 982 53


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