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)

Hormonal manipulation of cancer is no longer confined to the use of effective antiestrogen therapy for breast cancer or surgical or hormonal castration for prostate cancer. A broader acknowledgment of the potential of different hormonal ligands to evoke cell cycle arrest to prevent the progress of neoplastic transformation, and even to elicit active cell death, has expanded the concept of hormonal therapy. The use of retinoids and deltanoids in conjunction with antiestrogens and antiandrogens is progressing into clinical trials. The use of glucocorticoids in conjunction with cyclic AMP may enhance apotosis induction. The use of antiandrogens in conjunction with cytotoxic therapy may diminish the risk of bcl-2-mediated resistance in prostate cancer. Innovative use of sequential and synergistic hormonal manipulations based on an expanding understanding of transcriptional regulation promises to advance this science.
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PMID:Recent advances in hormonal therapy for cancer. 854 8

The secretion of prostate-specific antigen (PSA) by prostate cancer provides an important tool in the diagnosis and management of this disorder. While androgens are required for PSA synthesis, the neuroendocrine regulation of PSA secretion is less understood. Human prostate is extensively innervated with vasoactive intestinal peptide (VIP)-containing neurons, while both normal and malignant prostate cells contain VIP receptors. Therefore, we investigated the effects of VIP on PSA secretion by LNCaP prostate cancer cells. We found that 1-4-h VIP treatment produces 60-100% increases in PSA secretion by LNCaP cells. Increases in PSA secretion were seen with as little as 10(-10) M VIP with maximum effects at 10(-7) M. The predominant acute effect of VIP was to increase the secretion of stored PSA without increasing PSA mRNA. VIP's effect on PSA secretion involved the production of intracellular cAMP since all doses of VIP which increased secretion were associated with increased cyclic AMP and since dibutyryl-cyclic AMP treatment increased secretion similarly to VIP. These results suggest that VIP regulates PSA secretion by prostate cancer cells and also suggest a role for VIP to regulate PSA secretion by normal prostate epithelial cells.
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PMID:Vasoactive intestinal peptide stimulates prostate-specific antigen secretion by LNCaP prostate cancer cells. 888 83

Expression of aromatase P450 (P450arom), which catalyzes the formation of estrogens, is aberrantly increased in adipose fibroblasts surrounding breast carcinomas, giving rise to proliferation of malignant cells. Aromatase in human adipose tissue is primarily expressed in undifferentiated fibroblasts under the control of several distinct and alternatively used P450arom promoters. In tumor-free breast adipose tissue, P450arom is usually expressed at low levels via a distal promoter (I.4), whereas in the breast adipose tissue bearing a tumor, P450arom is increased through the activation of two proximal promoters, II and I.3. Because the in vivo activation of P450arom promoter II is a key event responsible for aberrantly high P450arom expression in breast tumors, we studied the molecular basis for the enhancement of P450arom promoter II using human adipose fibroblasts (HAFs) in primary culture treated with T47D breast cancer cell-conditioned medium (TCM) as a model system. Upon treatment with TCM, HAFs displayed a striking induction of P450arom mRNA levels via promoter II usage. This effect appeared to be specific for malignant breast epithelial cells, because conditioned media from breast cancer cell lines T47D and MCF-7 induced promoter II activity, whereas normal breast epithelial cells or liver or prostate cancer cell lines did not produce such an effect. Although treatment with a cyclic AMP analogue also caused a switch in the promoter use from I.4 to II in cultured HAFs, TCM-induced promoter II use was found to be mediated via a cyclic AMP-independent pathway. Use of serial deletion mutants of the promoter II 5'-flanking sequence revealed the presence of critical cis-acting elements in the -517/-278 bp region, which regulate the baseline activity. TCM caused a 5.7-fold induction of the -517-bp promoter II construct, whereas site-directed mutagenesis of a CCAAT/enhancer binding protein (C/EBP) binding site (-317/-304 bp) abolished both baseline and TCM-induced activities. Ectopic expressions of C/EBPalpha and C/EBPbeta, but not C/EBPdelta, significantly induced promoter II activity. Moreover, we demonstrated the presence of both C/EBPbeta and C/EBPdelta but not C/EBPalpha in a DNA-protein complex formed by the nuclear extract from TCM-treated HAFs and a probe containing this critical C/EBP binding element (-317/-304 bp). Finally, treatment of HAFs with TCM strikingly induced C/EBPbeta expression, whereas this did not affect the levels of C/EBPalpha or C/EBPdelta transcripts. In conclusion, malignant breast epithelial cells secrete factors, which induce aromatase expression in adipose fibroblasts via promoter II. This is, at least in part, mediated by a TCM-induced up-regulation and enhanced binding of C/EBPbeta to a promoter II regulatory element.
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PMID:Malignant breast epithelial cells stimulate aromatase expression via promoter II in human adipose fibroblasts: an epithelial-stromal interaction in breast tumors mediated by CCAAT/enhancer binding protein beta. 1128 Aug 6

Prolonged increase of cyclic adenosine-monophosphate (cAMP) level in the culture medium of a well differentiated human prostatic cancer cell (LNCaP) inhibits cellular growth and stimulates PSA secretion. The differentiation of the cells tested was documented by their responsiveness to androgens and the ability to synthesize cellular markers of differentiation (PSA). The raise in cAMP level was produced by dibutyryl cyclic AMP (DBcAMP) or by agents acting at distinct levels in the pathway of cAMP generation (forskolin) or degradation (IBMX). Each of these three agents in a range of concentrations between 10-4-10-6 M had an inhibitory effect on the growth which is dose and time-dependent. The inhibition was reversible as demonstrated by complete restoration of cell growth soon after the withdrawal of the substances from the culture medium. When cAMP levels in culture medium was raised, an increase in PSA content was observed. However, the effects of cAMP on PSA content was not due to increase in PSA synthesis, since simultaneous measurement of secreted and cellular PSA indicated that the principal effect of the cyclic nucleotide was to enhance the secretion of stored PSA. Furthermore the inhibition of cellular growth by cAMP suggests new approaches in prostatic carcinoma therapy.
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PMID:Effects of cyclic adenosine-monophosphate on growth and PSA secretion of human prostate cancer cell line. 1129 58

Neuroendocrine differentiation of prostate epithelial cells is usually associated with an increased aggressivity and invasiveness of prostate tumors and a poor prognosis. However, the molecular mechanisms involved in this process remain poorly understood. We have investigated the possible expression of voltage-gated calcium channels in human prostate cancer epithelial LNCaP cells and their modulation during neuroendocrine differentiation. A small proportion of undifferentiated LNCaP cells displayed a voltage-dependent calcium current. This proportion and the calcium current density were significantly increased during neuroendocrine differentiation induced by long-term treatments with cyclic AMP permeant analogs or with a steroid-reduced culture medium. Biophysical and pharmacological properties of this calcium current suggest that it is carried by low-voltage activated T-type calcium channels. Reverse transcriptase-PCR experiments demonstrated that only a single type of LVA calcium channel mRNA, an alpha(1H) calcium channel mRNA, is expressed in LNCaP cells. Quantitative real-time reverse transcriptase-PCR revealed that alpha(1H) mRNA was overexpressed during neuroendocrine differentiation. Finally, we show that this calcium channel promotes basal calcium entry at resting membrane potential and may facilitate neurite lengthening. This voltage-dependent calcium channel could be involved in the stimulation of mitogenic factor secretion and could therefore be a target for future therapeutic strategies.
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PMID:Overexpression of an alpha 1H (Cav3.2) T-type calcium channel during neuroendocrine differentiation of human prostate cancer cells. 1179 14

Androgens play an important role in the development and physiology of the normal prostate as well as in prostate cancer cell proliferation. Comparison of the mRNA expression profiles of control and R1881-treated cultures of LNCaP human prostate cancer cells using cDNA subtraction led to the identification of a novel transcription factor that we named Androgen-Induced bZIP (AIbZIP) protein. AIbZIP is a 395 aa protein with homology to cyclic AMP-responsive element binding protein/activating transcription factor transcription factors. It contains an NH(2)-terminal activation domain, a central bZIP domain, and a COOH-terminal transmembrane domain. The AIbZIP gene is localized on chromosome 1q21.3 and consists of 10 exons. A major 1.7-kb transcript was detected exclusively in the prostate as well as in breast and prostate cancer cell lines. Androgens up-regulate AIbZIP mRNA and protein levels in a dose-dependent manner. The kinetics of AIbZIP mRNA up-regulation and the results of experiments with cycloheximide suggest that AIbZIP may be a delayed response gene. Immunoreactive AIbZIP protein was primarily detected in the cytoplasm of prostatic luminal epithelial cells. Similarly, full-length AIbZIP-green fluorescent protein fusion proteins were localized in the cytoplasm of LNCaP cells, whereas a truncated form of AIbZIP lacking the putative transmembrane domain was exclusively nuclear. Examination of AIbZIP protein and mRNA expression in a series of transurethral resection of the prostate and needle biopsy specimens indicated that AIbZIP is expressed at higher levels in cancerous prostate cells compared with noncancerous prostate cells. The highly tissue-specific expression profile, androgen regulation, chromosomal localization, and expression profile of AIbZIP in prostate tumors suggest that AIbZIP may play an important role in prostate cancer and in androgen receptor signaling in prostate cells. Future studies will confirm a possible relationship between AIbZIP and prostate cancer.
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PMID:AIbZIP, a novel bZIP gene located on chromosome 1q21.3 that is highly expressed in prostate tumors and of which the expression is up-regulated by androgens in LNCaP human prostate cancer cells. 1183 May 26

It has been shown that expression of the RIalpha subunit of cyclic AMP (cAMP)-dependent protein kinase is enhanced in human cancer cell lines, primary tumors, and cells after transformation. Using an antisense strategy, we have shown that RIalpha has a role in neoplastic cell growth in vitro and in vivo. In the present study, we have investigated the sequence- and target-specific effects of exogenous RIalpha antisense oligodeoxynucleotides (ODNs) and endogenous antisense gene on tumor growth, apoptosis, and cAMP signaling in androgen-insensitive prostate cancer cells, both in vitro and in nude mice. Here, we show that an RIalpha antisense, RNA/DNA mixed backbone ODN exerts a reduction in RIalpha expression at both the mRNA and protein levels, up-regulation of both the RIIbeta subunit of cAMP-dependent protein kinase or protein kinase A and c-AMP-phosphodiesterase IV expression, and inhibition of cell growth. Growth inhibition was accompanied by changes in cell morphology and the appearance of apoptotic nuclei. In addition, Bcl-2 hyperphosphorylation; increase in the proapoptotic proteins Bax, Bak, and Bad; and Bad hypophosphorylation occurred in the antisense-treated cells. These effects of exogenously supplied antisense ODN mirrored those induced by endogenous antisense gene overexpression. The RIalpha antisense ODNs, which differed in sequence or chemical modification, promoted a sequence- and target-specific reduction in RIalpha protein levels and inhibited tumor growth in nude mice. These results demonstrate that in a sequence-specific manner, RIalpha antisense, via efficient depletion of the growth stimulatory molecule RIalpha, induces growth inhibition, apoptosis, and phenotypic (cell morphology) changes, providing an innovative approach to combat hormone-insensitive prostate cancer cell growth.
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PMID:Protein kinase A RIalpha antisense inhibition of PC3M prostate cancer cell growth: Bcl-2 hyperphosphorylation, Bax up-regulation, and Bad-hypophosphorylation. 1183 45

25-Hydroxyvitamin D-1alpha-hydroxylase (lalpha-OHase) is expressed in prostate cells. The expression suggests that local production of 1,25-dihydroxyvitamin D could provide an important cell growth regulatory mechanism. However, there is differential expression of 1alpha-OHase activity among the primary cultures of prostate cells derived from cancerous, benign prostatic hypertrophy and normal tissue, and among noncancerous (PZHPV-7) and various cancer cell lines (PC-3, DU145). No activity was found in cancer cell line LNCaP. The observed marked decrease in 1alpha-OHase activity in prostate cancer cells suggests some defect of the 1alpha-OHase in these cells. Using luciferase reporter gene assay, we observed a step-wise decrease in the basal promoter activity in two truncated promoter fragments, AN2 (-1,100 bp) and AN5 (-394 bp), with the highest basal activities found in PZHPV-7 and with loss of promoter activity in LNCaP. In order to understand the mechanism underlying the differential promoter activities among different prostate cells, we investigated the possible role of phosphorylation of cyclic AMP response element binding protein (CREB) on the regulation of 1alpha-OHase promoter activity in the four prostate cell lines. First we compared the levels of CREB phosphorylation among PZHPV-7, DU145, PC-3 and LNCaP cells by Western blot analysis using antibody against phosphorylated CREB. We observed that CREB was phosphorylated to a greater extent in PZHPV-7 than in DU145 cells. No significant phosphorylation of CREB was found in PC-3 and LNCaP cells. Next, we utilized activators and inhibitors of protein kinase A (PKA), protein kinase C (PKC), mitogen-activated protein kinase kinase (MAPKK) and calcium/calmodulin-dependent protein kinase II (CaMKII) to determine which kinases might be involved in phosphorylating the CREB in PZHPV-7 cells. We demonstrated that forskolin (an activator of PKA) increased the AN2 basal promoter activity 50%, whereas H-89 (an inhibitor of PKA) inhibited the basal and forskolin-stimulated AN2 promoter activity 40% and 70%, respectively. We also showed that PD98059 (an inhibitor of MAPKK) decreased the AN2 promoter activity 70%. Phorbol 12-myristate 13-acetate (an activator of PKC), GF109203 (an inhibitor of PKC) and KN-93 (an inhibitor of CaMKII) had no effect on AN2 promoter activity in PZHPV-7 cells. Thus, our results suggest that differential phosphorylation of CREB through PKA and MAPK pathways may be involved in the regulation of 1alpha-OHase promoter activity.
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PMID:Vitamin D autocrine system and prostate cancer. 1289 25

Osteocalcin and bone sialoprotein are the most abundant noncollagenous bone matrix proteins expressed by osteoblasts. Surprisingly, osteocalcin and bone sialoprotein are also expressed by malignant but not normal prostate epithelial cells. The purpose of this study is to investigate how osteocalcin and bone sialoprotein expression is regulated in prostate cancer cells. Our investigation revealed that (a) human osteocalcin and bone sialoprotein promoter activities in an androgen-independent prostate cancer cell line of LNCaP lineage, C4-2B, were markedly enhanced 7- to 12-fold in a concentration-dependent manner by conditioned medium collected from prostate cancer and bone stromal cells. (b) Deletion analysis of human osteocalcin and bone sialoprotein promoter regions identified cyclic AMP (cAMP)-responsive elements (CRE) as the critical determinants for conditioned medium-mediated osteocalcin and bone sialoprotein gene expression in prostate cancer cells. Consistent with these results, the protein kinase A (PKA) pathway activators forskolin and dibutyryl cAMP and the PKA pathway inhibitor H-89, respectively, increased or repressed human osteocalcin and bone sialoprotein promoter activities. (c) Electrophoretic mobility shift assay showed that conditioned medium-mediated stimulation of human osteocalcin and bone sialoprotein promoter activities occurs through increased interaction between CRE and CRE-binding protein. (d) Conditioned medium was found to induce human osteocalcin and bone sialoprotein promoter activities via increased CRE/CRE-binding protein interaction in a cell background-dependent manner, with marked stimulation in selected prostate cancer but not bone stromal cells. Collectively, these results suggest that osteocalcin and bone sialoprotein expression is coordinated and regulated through cAMP-dependent PKA signaling, which may define the molecular basis of the osteomimicry exhibited by prostate cancer cells.
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PMID:Human osteocalcin and bone sialoprotein mediating osteomimicry of prostate cancer cells: role of cAMP-dependent protein kinase A signaling pathway. 1578 44

Cyclic nucleotide levels are controlled through their synthesis from nucleotide triphosphates by cyclases and their degradation to 5'-monophosphates by phosphodiesterases (PDEs). Components controlling cyclic AMP-induced relaxation in the urinary tract include receptors, inhibitory and stimulatory G-proteins, isoforms of adenylyl cyclase and PDEs. The responsiveness of PDEs to a variety of physiological challenges is related to the presence of multiple families of isoenzymes with specific localization within tissues and within cells. At least 11 families of PDEs encode more than 50 PDE proteins produced in mammalian cells. In the urinary tract, characterization of PDE isoforms has lagged behind other systems and much of the literature was published prior to identification of PDE7, 8, 9, 10, 11. Specific PDE inhibitors regulate smooth muscle function in the bladder, urethra, prostate and ureter. The pharmacological potential of these inhibitors may include treatment of urge incontinence and the low compliance bladder, and treatment of prostate cancer. G-proteins also regulate cyclic AMP production. Changes in specific G- protein isoforms with aging, most prominently Gialpha2, cause decreased relaxation response in the aging bladder. As we have seen here with aging and certainly in other disease processes, levels of the components of adenylyl cyclase/phosphodiesterase/protein kinase can change and thus affect the relaxation response. By exploitation of differences in PDE expression in disease, such as the overexpression of PDEs in cancer, treatment options may present themselves.
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PMID:Regulation of cyclic nucleotides in the urinary tract. 1585 36


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