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 presence of interleukin-2 (IL-2) and its receptors (Ralpha, Rbeta, Rgamma), and their relationship with the products of bcl-2 and bax genes was studied in normal prostates, benign prostatic hyperplasia (BPH), and prostatic cancer (PC) by ELISA, Western blot, and immunohistochemistry. A comparative semiquantitative immunohistochemical study was also performed. For all the antibodies assayed, immunoreactions were found in the epithelium and some stromal cells in the three types of specimens studied. These immunoreactions were much more higher in PC samples than in normal prostates. In BPH, immunoreactions were similar to that of normal prostates (bax), similar to that of PC (IL-2 and its three receptors), or intermediate between that of normal prostates and that of PC (bcl-2). Immunoexpressions of IL-2 and its receptors were found in the epithelial basal cells and some stromal cell of normal prostates and might be related to the control of the proliferation-apoptosis equilibrium. The increased expressions of IL-2 and its receptors in the epithelium of prostates in BPH, associated with increased bcl-2 expression which would account for the decrease in the apoptosis index that has been reported in this disorder. The increased expression of both bcl-2 and bax in PC might be involved in the higher apoptosis index reported in PC specimens. Since IL-2 administration seems to have an anti-tumour effect, the increased expression of this interleukin in BPH and PC could be interpreted as an attempt to hinder cell proliferation which would only be efficient at high doses.
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PMID:IL-2, its receptors, and bcl-2 and bax genes in normal, hyperplastic and carcinomatous human prostates: immunohistochemical comparative analysis. 1101 84

Androgen-independent prostate cancer cells are remarkably resistant to therapeutic agents that work by triggering apoptosis via the caspase cascade. The recent sequencing of the entire genome of one of the most radiation-resistant organisms known, Deinococcus radiodurans, yields some insight into how prostate cancer cells might mount such resistance to apoptosis. Rather than being attributable to any one mechanism, the extreme radiation resistance of D. radiodurans appears to reflect the expression of a large number of different systems capable of preventing, repairing, or tolerating DNA damage and a very high degree of redundancy in these systems. Many molecular alterations that may influence the threshold for apoptosis have already been described in advanced prostate cancer; changes in bcl-2, p53, and the androgen receptor have been the most extensively studied. Current information is consistent with the concept that individual prostate cancer cells express multiple antiapoptotic mechanisms. This conclusion implies that it will not be possible to enhance cellular sensitivity to therapeutics that activate apoptosis by disabling just one target in a pathway, because other proteins are likely to be available to assume its function. Likewise, even elimination of a whole pathway may have little effect on sensitivity because cellular viability is protected by so many different mechanisms. However, where molecular changes have a phenotypic consequence, they offer a window of opportunity for the development of novel therapeutic strategies. One such example is a recently identified small organic compound that can inhibit p53 function and thus protect normal tissues against radiation-induced apoptosis without impairing killing of p53-deficient tumor cells.
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PMID:Resistance to apoptosis in prostate cancer cells. 1106 78

Genistein, a naturally occurring isoflavone found chiefly in soy products, reportedly has antiprostate cancer effects, but the mechanisms underlying these effects are unknown. We studied the antiproliferative and apoptosis-inducing effects of genistein in the androgen-sensitive human prostate cancer cell line LNCaP. Viable cell number was assessed by the 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide assay; cell-cycle progression and apoptosis were evaluated by flow cytometry; apoptosis was also assessed by a histone enzyme-linked immunosorbent assay; and the expression of several cell-cycle- and apoptosis-related genes and their gene products was determined by northern blot analysis, western blot analysis, and/or assays based on polymerase chain reaction. Physiologic concentrations of genistein (< or = 20 microM) decreased LNCaP viable cell number in a dose-dependent manner, induced a G(1) cell-cycle block, decreased prostate-specific antigen mRNA expression, and increased p27(KIP1) and p21(WAF1) (mRNA and protein) but had no effect on apoptosis or the mRNA expression of the apoptosis- and cell-cycle-related markers bcl-2, bax, Rb, and proliferating cell nuclear antigen. Higher concentrations of genistein (> 20 microM) did induce apoptosis. We conclude that genistein (at physiologic concentrations) exerts potent antiproliferative effects on LNCaP cells by inducing a G(1) cell-cycle block. The antiproliferative effects of genistein may be mediated by increased levels of p27(KIP1) and p21(WAF1), which are negative cell-cycle regulators that act as cyclin-dependent kinase inhibitors and that have been recently linked with prostate carcinogenesis. These findings may provide insights into the mechanisms underlying the apparent antiprostate cancer effects of soy consumption observed in epidemiologic studies.
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PMID:Low-dose genistein induces cyclin-dependent kinase inhibitors and G(1) cell-cycle arrest in human prostate cancer cells. 1107 6

The impact of bcl-2 proto-oncogene expression on the pathogenesis and progression of prostate cancer was examined in a transgenic mouse model. Probasin-bcl-2 transgenic mice were crossed with TRAMP (TRansgenic Adenocarcinoma Mouse Prostate) mice that express the SV40 early genes (T/t antigens) under probasin control. Prostate size, cell proliferation, apoptosis, and the incidence and latency of tumor formation were evaluated. The double transgenic, probasin-bcl-2 X TRAMP F1 (BxT) mice exhibited an increase in the wet weight of the prostate. This was associated with an increase in proliferation, attributable to T/t antigens, and a decrease in apoptosis attributable to bcl-2. The latency to tumor formation was also decreased in the BxT mice compared to the TRAMP mice. The incidence of metastases was identical in both the TRAMP and BxT mice. Lastly, the incidence of hormone-independent prostate cancer was reduced in the BxT mice compared to the TRAMP mice. Together, these results demonstrate that bcl-2 can facilitate multistep prostate carcinogenesis in vivo.
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PMID:Bcl-2 accelerates multistep prostate carcinogenesis in vivo. 1107 42

The templates required for inducing posttranscriptional gene silencing (PTGS) effects have been investigated in human prostate cancer LNCaP cells. Transfection of a mRNA-cDNA hybrid construct was found to result in a relatively long-term interference of specific gene expression. Androgen-stimulated expression of bcl-2 has been reported to increase the tumorigenic and metastatic potentials of human prostate cancer LNCaP cells, as well as their resistance to many apoptotic stimuli. The addition of bcl-2 antisense oligonucleotides, however, restored apoptosis. Our studies demonstrate gene silencing effects of the mRNA-cDNA transfection that is similar to those of PTGS/RNAi in this in vitro prostate cancer cell model. A potential RNA-directed RNA polymerase activity was also detected which is alpha-amanitin-sensitive. These findings indicate that a novel gene silencing system may exist in mammalian cells.
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PMID:A Novel mRNA-cDNA interference phenomenon for silencing bcl-2 expression in human LNCaP cells. 1123 5

A high-throughput screening assay was designed to select compounds that inhibit the growth of cultured mammalian cells. After screening more than 60,000 compounds, A-105972 was identified and selected for further testing. A-105972 is a small molecule that inhibits the growth of breast, central nervous system, colon, liver, lung, and prostate cancer cell lines, including multidrug-resistant cells. The cytotoxic IC50 values of A-105972 were between 20 and 200 nM, depending on the specific cell type. The potency of A-105972 is similar in cells expressing wild-type or mutant p53. A majority of cells treated with A-105972 were trapped in the G2-M phases, suggesting that A-105972 inhibits the progression of the cell cycle. Using [3H]A-105972, we found that A-105972 bound to purified tubulin. Unlabeled A-105972 competed with [3H]A-105972 binding with an IC50 value of 3.6 microL. Colchicine partially inhibited [3H]A-105972 binding with an IC50 value of approximately 90 microM, whereas paclitaxel and vinblastine had no significant effect. Tumor cells treated with A-105972 were observed to contain abnormal microtubule arrangement and apoptotic bodies. DNA ladder studies also indicated that A-105972 induced apoptosis. A-105972 caused a mobility shift of bcl-2 on SDS-PAGE, suggesting that A-105972 induced bcl-2 phosphorylation. A-105972 treatment increased the life span of mice inoculated with B16 melanoma, P388 leukemia, and Adriamycin-resistant P388. These results suggest that A-105972 is a small molecule that interacts with microtubules, arrests cells in G2-M phases, and induces apoptosis in both multidrug resistance-negative and multidrug resistance-positive cancer cells. A-105972 and its analogues may be useful for treating cell proliferative disorders such as cancer.
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PMID:Identification and characterization of A-105972, an antineoplastic agent. 1124 55

In this study, the potential interactions between dihydrotestosterone (DHT), a survival factor, and transforming growth factor-beta (TGF-beta), an apoptotic inducer, were examined in a derivative of the hormone-sensitive prostate cancer cell line LNCAP: The LNCaP TGF-beta receptor II cells, engineered to express TGF-beta receptor II, are sensitive to both DHT and TGF-beta. Surprisingly, when the LNCaP TGF-beta receptor II cells were treated with TGF-beta in the presence of physiological levels of DHT, both cell cycle arrest and apoptosis induction were significantly enhanced over TGF-beta alone. This effect temporally correlated with an increased expression of the cell cycle regulator p21 as well as the apoptotic executioner, procaspase-1, and a parallel down-regulation of the antiapoptotic protein, bcl-2. Expression of bax and caspase-3 proteins remained unchanged following treatment. Furthermore, apoptosis induction was suppressed by the caspase-1 inhibitor, z-YVAD, but not the caspase-3 inhibitor, z-DQMD, thus demonstrating the functional significance of increased procaspase-1 expression in TGF-beta-mediated apoptosis in prostate cancer cells. These results indicate that TGF-beta-mediated apoptosis can actually be enhanced by androgens through specific mechanisms involving cell cycle and apoptosis regulators and provide initial evidence on the ability of physiological levels of androgens to stimulate the intrinsic apoptotic potential of prostate cancer cells. Therefore, this study provides a molecular basis for the priming of prostate cancer cells for maximal apoptosis induction, during hormone- ablation therapy.
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PMID:Dihydrotestosterone enhances transforming growth factor-beta-induced apoptosis in hormone-sensitive prostate cancer cells. 1135 90

Apoptosis, a type of programmed cell death, is a decisive mechanism in cell processes such as homeostasis, development, and many diseases including cancer. In mammals, the mechanisms that trigger and control the process of apoptosis are complex, because it has been observed that many molecules might be involved, acting in distinct ways and depending on the cellular type. The process of apoptosis is characterized by specific biochemical and morphologic changes. However, important specific messengers such as Ca(2)+ act in active proliferation as well as in apoptosis. At present, there is convincing evidence that a sustained increase in intracellular Ca(2)+ can activate cytotoxic mechanisms in various cells and tissues. Several ionic channels located in the cytoplasmic membrane might participate in the entry of calcium into the cytosol during apoptosis. Among these ionic channels, the purinoreceptors P2X and the channels of capacitative entry of calcium have been described. Pro- and anti-apoptotic molecules such as bax and bcl-2, respectively, have also been shown to participate in the process. We have recently found the activation of a Ca(2)+-permeable, nonselective cation channel of 23 pS conductance in prostatic cancer (LNCaP) exclusively in cells previously induced to apoptosis. Our findings are discussed taking into account the different ion channels that might participate in programmed cell death in prostate cancer.
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PMID:Apoptosis and cell death channels in prostate cancer. 1139 81

Progression to androgen-independence remains the main obstacle to improving survival for patients with advanced prostate cancer. In this review, findings are summarized that have recently been demonstrated to establish novel therapeutic strategy targeting several genes playing functionally important roles after androgen withdrawal and during androgen-independent progression. The authors initially characterized changes in gene expression after androgen withdrawal in the androgen-dependent Shionogi and LNCaP tumor models using cDNA arrays. Based on these results, they focused on genes highly upregulated after androgen ablation (i.e. bcl-2, bcl-xL, TR.PM-2, IGFBP-5), which have anti-apoptotic or mitogenic activities, and thereby confer a resistance to androgen withdrawal as well as cytotoxic chemotherapy. The authors further demonstrated the efficacy of an antisense oligodeoxynucleotide (ODN) strategy for patients with advanced prostate cancer through the inhibition of target gene expression, resulting in a delay in the progression to androgen-independence by enhancing apoptotic cell death induced by androgen ablation and chemotherapy. The authors also showed the effectiveness of combined antisense ODN therapy and cytotoxic chemotherapy by achieving additive or synergistic effects. These findings provide a basic significance for the design of clinical studies using antisense ODN either alone or in combination with chemotherapeutic agents in patients with advanced prostate cancer.
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PMID:Novel therapeutic strategy for advanced prostate cancer using antisense oligodeoxynucleotides targeting anti-apoptotic genes upregulated after androgen withdrawal to delay androgen-independent progression and enhance chemosensitivity. 1144 54

An inverse association has been observed between dietary intake of lycopene and the risk of prostate cancer. We investigated the effects of lycopene supplementation in patients with prostate cancer. Twenty-six men with newly diagnosed, clinically localized (14 T(1) and 12 T(2)) prostate cancer were randomly assigned to receive 15 mg of lycopene (n = 15) twice daily or no supplementation (n = 11) for 3 weeks before radical prostatectomy. Biomarkers of differentiation and apoptosis were assessed by Western blot analysis on benign and malignant parts of the prostate gland. Prostatectomy specimens were entirely embedded, step-sectioned, and evaluated for pathological stage, Gleason score, volume of cancer, and extent of high-grade prostatic intraepithelial neoplasia. Plasma levels of lycopene, insulin-like growth factor-1 (IGF-1), IGF binding protein-3, and prostate-specific antigen were measured at baseline and after 3 weeks of supplementation or observation. Eleven (73%) subjects in the intervention group and two (18%) subjects in the control group had no involvement of surgical margins and/or extra-prostatic tissues with cancer (P = 0.02). Twelve (84%) subjects in the lycopene group and five (45%) subjects in the control group had tumors <4 ml in size (P = 0.22). Diffuse involvement of the prostate by high-grade prostatic intraepithelial neoplasia was present in 10 (67%) subjects in the intervention group and in 11 (100%) subjects in the control group (P = 0.05). Plasma prostate-specific antigen levels decreased by 18% in the intervention group, whereas they increased by 14% in the control group (P = 0.25). Expression of connexin 43 in cancerous prostate tissue was 0.63 +/- 0.19 absorbance in the lycopene group compared with 0.25 +/- 0.08 in the control group (P = 0.13). Expression of bcl-2 and bax did not differ significantly between the two study groups. IGF-1 levels decreased in both groups (P = 0.0002 and P = 0.0003, respectively). The results suggest that lycopene supplementation may decrease the growth of prostate cancer. However, no firm conclusions can be drawn at this time because of the small sample size.
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PMID:Phase II randomized clinical trial of lycopene supplementation before radical prostatectomy. 1148 52


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