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: UMLS:C0376358 (prostate cancer)
59,338 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effects of nine potential cancer chemopreventive agents on cell growth or clonogenic survival were evaluated in normal human prostate epithelial cells, an immortalized but non-tumorigenic human prostate epithelial cell line (267B1), a human benign prostatic hyperplasia (BPH) cell line (BRF-55T), and a human prostate cancer cell line (267B1/Ki-ras). Of the nine agents tested, 9-cis retinoic acid, liarozole fumarate, phenylenebis(methylene)-selenocyanate (p-XSC), and L-selenomethionine demonstrated much stronger growth inhibitory effects on prostate cancer cells than on the normal prostate epithelial cells, suggesting that these agents may be useful as prostate cancer chemopreventive agents. 9-cis retinoic acid, genistein, liarozole fumarate, p-XSC, L-selenomethionine and vitamin E also showed much stronger growth inhibitory effects on BRF-55T cells than on the normal prostate epithelial cells, indicating that these agents may also be useful for the prevention and treatment of BPH. Difluoromethylornithine (DFMO), DHEA analogue 8354 (fluasterone), and oltipraz did not show strong inhibitory effects on the growth or survival of normal prostate epithelial cells, 267B1 or 267B1/Ki-ras cells, suggesting that these agents may not be effective as prostate cancer preventive or therapeutic agents.
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PMID:In vitro evaluation of chemopreventive agents using cultured human prostate epithelial cells. 1453 35

Taxotere is a cytotoxin effective in treating breast and prostate cancer. It stabilizes microtubules and causes catastrophic cell cycle arrest in G2/M. Taxanes also initiate apoptosis by activating signal pathways, such as the jun N-terminal kinase (JNK) pathway. Strategies aimed at potentiating cell death signaling may improve their efficacy while lessening the potential side effects. We reported that all-trans retinoic acid (ATRA) potentiated taxane-mediated cell death. Here we investigated whether ATRA potentiates cell death signaling through the JNK pathway. Activation of JNK by Taxotere 0.01, 0.1 and 1.0 microM was observed at 24 h in adherent cells and increased at 48 h. Taxotere 0.001 microM-induced JNK activation started after 48 h and increased at 72 h. The timing and intensity of PARP cleavage was similar to that of JNK activation. JNK activation and PARP cleavage induced by 30 nM Taxotere at 48 h were reversed by curcumin, PD169316 and SP600125, JNK inhibitors in order of progressive specificity. None of these inhibitors had an effect on p38 or ERK phosphorylation. All three inhibitors reversed Taxotere-induced phosphorylation of Bcl-2. ATRA induced JNK activation at 24, 48 and 72 h. Incubating cells with ATRA 0.01 microM for 3 days prior to Taxotere treatment potentiated Taxotere-induced JNK activation 24 and 48 h later, an effect sustained for 72 h. Cytotoxicities from 3-day ATRA 0.01 microM incubations were synergistic with subsequent 1-h Taxotere 0.01, 0.1 and 1.0 microM incubations in breast cancer cell lines MCF-7 and MDA-MB-231 and in prostate cancer cell lines LNCaP and PC-3, and additive in breast cancer cell line SK-Br-3. These data demonstrate the potentiation of Taxotere-induced cell death by ATRA pretreatment in breast and prostate cancer cells, and support a mechanism through accentuated and sustained JNK activation.
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PMID:All-trans retinoic acid potentiates Taxotere-induced cell death mediated by Jun N-terminal kinase in breast cancer cells. 1472 71

Clinically achievable concentrations of 12-O-tetradecanoylphorbol-13-acetate (TPA; 0.16-0.32 nM) and all-trans-retinoic acid (ATRA; 0.5-1 micro M) had a synergistic inhibitory effect on the growth of cultured LNCaP prostate cancer cells, and apoptosis was markedly stimulated. In additional studies, NCr immunodeficient mice received s.c. injection with LNCaP cells in Matrigel. After 4-6 weeks, mice with well-established tumors received i.p. injection with vehicle, TPA (0.16 nmol/g body weight), ATRA (0.5 nmol/g body weight), or TPA+ATRA in vehicle once a day for 46 days. Tumor growth occurred in all of the vehicle-treated control mice. The percentage of animals with some tumor regression after 21 days of treatment was 0% for the control group, 31% for the ATRA group, 62% for the TPA group, and 100% for the TPA+ATRA group (13 mice/group). Although treatment of the mice with TPA or TPA+ATRA continued to inhibit tumor growth for the duration of the 46-day study, treatment of the mice with ATRA alone did not inhibit tumor growth beyond 28 days of daily injections (6 mice/group). Mechanistic studies indicated that treatment of the mice with TPA or TPA+ATRA for 46 days increased apoptosis in the tumors, and treatment with TPA+ATRA also decreased the mitotic index. Because the dose of TPA used in this study was effective and resulted in clinically achievable blood levels, clinical trials with TPA alone or in combination with ATRA in patients with prostate cancer may be warranted.
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PMID:Inhibitory effect of 12-O-tetradecanoylphorbol-13-acetate alone or in combination with all-trans-retinoic acid on the growth of LNCaP prostate tumors in immunodeficient mice. 1499 44

A variety of tumor suppressor genes are down-regulated by hypermethylation during carcinogenesis. Using methylated CpG amplification-representation difference analysis, we identified a DNA fragment corresponding to the Tazarotene-induced gene 1 (TIG1) promoter-associated CpG island as one of the genes hypermethylated in the leukemia cell line K562. Because TIG1 has been proposed to act as a tumor suppressor, we tested the hypothesis that cytosine methylation of the TIG1 promoter suppresses its expression and causes a loss of responsiveness to retinoic acid in some neoplastic cells. We examined TIG1 methylation and expression status in 53 human cancer cell lines and 74 primary tumors, including leukemia and head and neck, breast, colon, skin, brain, lung, and prostate cancer. Loss of TIG1 expression was strongly associated with TIG1 promoter hypermethylation (P < 0.001). There was no correlation between TIG1 promoter methylation and that of retinoid acid receptor beta2 (RARbeta2), another retinoic-induced putative tumor suppressor gene (P = 0.78). Treatment with the DNA methyltransferase inhibitor 5-aza-2'-deoxycytidine for 5 days restored TIG1 expression in all eight silenced cell lines tested. TIG1 expression was also inducible by treatment with 1 micro M all-trans-retinoic acid for 3 days except in densely methylated cell lines. Treatment of the K562 leukemia cells with demethylating agent combined with all-trans-retinoic acid induced apoptosis. These findings indicate that silencing of TIG1 promoter by hypermethylation is common in human cancers and may contribute to the loss of retinoic acid responsiveness in some neoplastic cells.
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PMID:Hypermethylation and silencing of the putative tumor suppressor Tazarotene-induced gene 1 in human cancers. 1505 93

Nonsteroidal signaling via the androgen receptor (AR) plays an im-portant role in hormone-refractory prostate cancer. Previously, we have reported that the pleiotropic cytokine, interleukin (IL)-6, inhibited dihydrotestosterone-mediated expression of prostate-specific antigen in LNCaP cells (Jia et al., Mol Can Res 2003;1:385-92). In the present study, we explored the mechanisms involved in this inhibition and considered possible effects on AR nuclear translocation, recruitment of transcription cofactors, and the signaling pathways that may mediate this inhibitory effect. IL-6 neither induced nuclear localization of the AR nor inhibited dihydrotestosterone-induced nuclear translocation of the receptor. IL-6 did not affect AR or p160 coactivator recruitment to the transcription initiation complex on the prostate-specific antigen enhancer and promoter. Moreover, it did not lead to the recruitment of the corepressor silencing mediator of retinoic acid and thyroid hormone receptor (SMRT) or histone deacetylase 1 (HDAC1) at the same sites. IL-6 did, however, prevent the recruitment of the secondary coactivator, p300, to the complex and partially inhibited histone H3 acetylation at the same loci. Furthermore, inhibition by IL-6 was not mediated by the mitogen-activated protein kinase or the Akt pathways and was partially abrogated by signal transducers and activators of transcription-3 knock-down using small interfering RNA. Our results show that IL-6 modulates androgen action through the differential recruitment of cofactors to target genes. These findings may account for the pleiotropic actions of IL-6 in malignant prostate cells.
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PMID:Androgen receptor signaling: mechanism of interleukin-6 inhibition. 1505 19

Synthetic retinoid-related molecules, such as N-(4-hydroxyphenyl)retinamide (fenretinide) and 6-[3-(1-adamantyl)-4-hydroxyphenyl]-2-naphthalene carboxylic acid (CD437) induce apoptosis in a variety of malignant cells. The mechanism(s) of action of these compounds does not appear to involve retinoic acid receptors (RARs) and retinoid X receptors (RXRs), although some investigators disagree with this view. To clarify whether some retinoid-related molecules can induce apoptosis without involving RARs and/or RXRs, we used 4-[3-(1-heptyl-4,4-dimethyl-2-oxo-1,2,3,4-tetrahydroquinolin-6-yl)-3-oxo-E-propenyl] benzoic acid (AGN193198) that neither binds effectively to RARs and RXRs nor transactivates in RAR- and RXR-mediated reporter assays. AGN193198 potently induced apoptosis in prostate, breast, and gastrointestinal carcinoma cells and in leukemia cells. AGN193198 also abolished growth (by 50% at 130-332 nM) and induced apoptosis in primary cultures established from prostatic carcinoma (13 patients) and gastrointestinal carcinoma (1 patient). Apoptosis was induced rapidly, as indicated by mitochondrial depolarization and DNA fragmentation. Molecular events provoked by AGN193198 included activation of caspase-3, -8, -9, and -10 (by 4-6 h) and the production of BID/p15 (by 6 h). These findings show that caspase-mediated induction of apoptosis by AGN193198 is RAR/RXR-independent and suggest that this compound may be useful in the treatment of prostate cancer.
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PMID:A retinoid-related molecule that does not bind to classical retinoid receptors potently induces apoptosis in human prostate cancer cells through rapid caspase activation. 1512 74

Retinoic acid receptor beta2 (RARbeta2) is a tumor suppressor gene frequently hypermethylated in several human neoplasms. To further characterize this epigenetic alteration in prostate cancer progression, we examined tumor tissue from 118 patients with prostate carcinoma (PCa), 38 paired high-grade prostatic intraepithelial neoplasias (HGPIN), and non-neoplastic prostate tissue from 30 patients with benign prostate hyperplasia (BPH), using quantitative methylation-specific PCR. We found RARbeta2 hypermethylation in 97.5% of PCa, 94.7% of HGPIN, and 23.3% of BPH. Methylation levels were significantly higher in PCa compared with HGPIN and BPH (P < 0.00001). By establishing an empiric cutoff value, we were able to discriminate between neoplastic and non-neoplastic tissue, with 94.9% sensitivity and 100% specificity. Moreover, RARbeta2 methylation levels correlated with higher pathological stage (r = 0.30, P = 0.0009). This quantitative assay represents a novel and promising molecular marker that may augment current approaches for prostate cancer detection.
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PMID:Quantitative RARbeta2 hypermethylation: a promising prostate cancer marker. 1521 22

Screening of synthetic retinoids for activity against prostate carcinoma cell lines has identified antagonists of retinoic acid receptors (RARs) as potent growth inhibitors (Hammond et al, 2001, Br J Cancer 85, 453-462). Here we report that 5 days of exposure to a high-affinity pan-RAR antagonist (AGN194310) abolished growth of prostate carcinoma cells from 14 out of 14 patients, with half-maximal inhibition between 200 and 800 nM. It had similar effects (at approximately 250 nM) on the prostate carcinoma lines LNCaP, DU-145 and PC-3. AGN194310 inhibited the growth of normal prostate epithelium cells less potently, by 50% at approximately 1 microM. The growth of tumour cells was also inhibited more than that of normal cells when RARbeta together with RARgamma, but not RARalpha alone, were antagonised. Treatment of LNCaP cells with AGN194310 arrested them in G1 of cell cycle within 12 h, with an accompanying rise in the level of p21(waf1). The cells underwent apoptosis within 3 days, as indicated by mitochondrial depolarisation, Annexin V binding and DNA fragmentation. Apoptosis was caspase-independent: caspases were neither cleaved nor activated, and DNA fragmentation was unaffected by the pan-caspase inhibitor Z-VAD-FMK. The ability of AGN 194310 to induce apoptosis of prostate cancer cells and its differential effect on malignant and normal prostate epithelial cells suggests that this compound may be useful in the treatment of prostate cancer.
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PMID:An antagonist of retinoic acid receptors more effectively inhibits growth of human prostate cancer cells than normal prostate epithelium. 1526 11

Heparin affin regulatory peptide (HARP), also known as pleiotrophin or heparin-binding growth-associated molecule, is an 18-kDa growth factor that has a high affinity for heparin. It constitutes with midkine and retinoic acid heparin-binding protein, a family of structurally related heparin-binding growth factors. A growing body of evidence indicates that HARP is involved in the control of cellular proliferation, migration and differentiation and plays a significant role in tumor growth and angiogenesis. HARP has a well described role in physiological as well as tumor angiogenesis, and is detected in various carcinomas, such as human breast and prostate cancer, neuroblastomas, gliomas, benign meningiomas, small cell lung cancer and mammary tumors, exhibiting a proto-oncogene function. It is also constitutively expressed in tumour cell lines and is involved in tumour growth and metastasis. Therefore, HARP appears to be a potential new target for the treatment or/and diagnosis of several types of cancer.
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PMID:Heparin affin regulatory peptide: a new target for tumour therapy? 1537 33

We previously showed that HIV-1 protease inhibitors (PIs) slowed the proliferation of human myeloid leukemia cells and enhanced their differentiation in the presence of all-trans-retinoic acid. In this study, we found that PIs, including ritonavir, saquinavir, and indinavir, inhibited the growth of DU145 and PC-3 androgen-independent prostate cancer cells as measured by a clonal proliferation assay. Recent studies showed that ritonavir inhibited cytochrome P450 3A4 enzyme (CYP3A4) in liver microsomes. The CYP3A4 is involved in drug metabolism and acquisition of drug resistance. To clarify the drug interaction between ritonavir and other anticancer drugs, we cultured DU145 cells with docetaxel either alone or in combination with ritonavir. Ritonavir enhanced the antiproliferative and proapoptotic effects of docetaxel in the hormonally independent DU145 prostate cancer cells in vitro as measured by the clonogenic soft agar assay and detection of the activated form of caspase-3 and cleavage of poly(ADP-ribose) polymerase using Western blot analysis. Real-time PCR showed that docetaxel induced the expression of CYP3A4 at the transcriptional level, and ritonavir (10(-5) mol/L) completely blocked this induction. An ELISA-based assay also showed that ritonavir inhibited DNA binding activity of nuclear factor kappaB (NFkappaB) in DU145 cells, which is a contributor to drug resistance in cancer cells. Furthermore, combination treatment of docetaxel and ritonavir dramatically inhibited the growth of DU145 cells present as tumor xenografts in BNX nude mice compared with either drug alone. Importantly, docetaxel induced expression of CYP3A4 in DU145 xenografts, and ritonavir completely blocked this induction. Ritonavir also inhibited NFkappaB DNA binding activity in DU145 xenografts. Extensive histologic analyses of the liver, spleen, kidneys, bone marrow, skin, and subcutaneous fat pads from these mice showed no abnormalities. In summary, combination therapy of ritonavir and anticancer drugs holds promise for the treatment of individuals with advanced, drug resistant cancers.
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PMID:HIV-1 protease inhibitor, ritonavir: a potent inhibitor of CYP3A4, enhanced the anticancer effects of docetaxel in androgen-independent prostate cancer cells in vitro and in vivo. 1549 66


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