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 binding of human sex hormone-binding globulin (SHBG) to a human prostatic cancer cell line (LNCaP) and the results of that binding were examined. Membranes derived from LNCaP cells bound unliganded SHBG on two sets of sites whose affinities were: Ka1 = 3.1 +/- 1.6 x 10(10) M-1 and Ka2 = 8.7 +/- 4.3 x 10(6) M-1. Intact cells also bound SHBG, but even after 6 h, less than 10% of specifically bound SHBG was internalized. This observation speaks against a role for the membrane binding of SHBG in steroid transport across cell membranes. When LNCaP cells were prebound with SHBG, addition of dihydrotestosterone or estradiol resulted in a dose-dependent increase in intracellular cAMP. SHBG in the absence of steroids or dihydrotestosterone in the absence of SHBG was without effect. 2-Methoxyestradiol, a steroid metabolite without biological activity, but which binds to SHBG more tightly than does estradiol, was also without effect. These observations demonstrate a potentially important role for SHBG as a regulator of cell function. They also demonstrate an additional mode of action of steroid hormones, one that does not require that the steroid interact with a steroid receptor.
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PMID:Biologically active steroids activate receptor-bound human sex hormone-binding globulin to cause LNCaP cells to accumulate adenosine 3',5'-monophosphate. 216 70

2-Methoxyestradiol (2-ME), an endogenous metabolite of 17beta-estradiol, is present in human blood and urine. Here we show for the first time that 2-ME significantly inhibited the growth of normal prostate epithelial cells and androgen-dependent LNCaP and androgen-independent DU145 prostate cancer cells. This growth inhibition was accompanied by a twofold increase in the G(2)/M population, with a concomitant decrease in the G(1) population, as shown by cell-cycle analysis. 2-ME treatment affected the cell-cycle progression of prostate cancer cells specifically by blocking cells in the G(2) phase. Immunoblot analysis of the key cell-cycle regulatory proteins in the G(2)/M phase showed a 14-fold increase in the expression of p21 and an eightfold increase in the expression of p34 cell division cycle 2 (cdc2). We also found an accumulation of phosphorylated cdc2 after 2-ME treatment. Furthermore, Wee 1 kinase was detectable after 2-ME treatment. 2-ME treatment also led to an increase in the activity of caspase-3, followed by apoptosis, as shown by terminal deoxynucleotidyl transferase-mediated deoxyuridine 5-triphosphate-biotin nick end-labeling and fluorescein isothiocyanate-poly(ADP-ribose) polymerase assay. Estrogen receptor levels did not change after treatment with 2-ME. Examination of the signaling pathways that mediate 2-ME-induced apoptosis showed reduction in the level of p53 expression and its DNA-binding activity. Given the fact that p53 mutations are common in patients with metastatic prostate cancer, our finding that 2-ME-mediated growth inhibition of human prostate cancer cells occurred in a p53-independent manner has considerable clinical significance. These findings, combined with the limited toxicity of 2-ME, may have significant implications for alternative treatment of advanced prostate cancer.
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PMID:2-methoxyestradiol blocks cell-cycle progression at G(2)/M phase and inhibits growth of human prostate cancer cells. 1147 20

Prostate cancer is the most frequently diagnosed malignancy and the second most common cause of cancer-related death in men in the United States. Unfortunately, at the current time, no curative treatments are available for metastatic prostate cancer. As is the case for most solid tumors, the recruitment of blood vessels (angiogenesis) is key for the progression and metastasis of prostate cancer. Inhibition of this process is an attractive approach to treatment. Many antiangiogenic agents are currently in clinical development. The following discussion will outline the importance of angiogenesis in the metastasis and progression of prostate cancer, summarize the current surrogate markers of angiogenesis available for the drug development of antiangiogenic agents, and review examples of investigational agents that target tumor angiogenesis (e.g., TNP-470, Thalidomide, CC5013, Carboxyamido-triazole (CAI), Endostatin. SU5416, SU6668, Bevacizumab (Anti-VEGFrhuMAb), and 2-Methoxyestradiol).
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PMID:Inhibition of angiogenesis: treatment options for patients with metastatic prostate cancer. 1209 78

Estrogens occurring naturally in the body are metabolized to catecholestrogens (2- and 4-hydroxyestradiol) by the cytochrome P450 enzymes. 2-Hydroxy catecholestrogens are further metabolized by catechol-O-methyltransferase to 2-methoxyestradiol, which is known to be protective against tumor formation. 2-Methoxyestradiol exhibits potent apoptotic activity against rapidly growing tumor cells. It also possesses antiangiogenic activity through a direct apoptotic effect on endothelial cells. Other molecular mechanisms, including microtubule stabilization by inhibition of the colchicine-binding site, have been reported. The exact mechanism of action of 2-methoxyestradiol is still unclear, but it has been shown to be effective in preventing tumor growth in a variety of cell lines. 2-Methoxyestradiol also possesses cardioprotective activity by inhibiting vascular smooth muscle cell growth in arteries. It has a lower binding affinity for estrogen receptor alpha compared with that of estradiol, and its affinity for estrogen receptor beta is even lower than that of estrogen receptor alpha, thus it has minimal estrogenic activity. 2-Methoxyestradiol is distinct because of its inability to engage estrogen receptors as an agonist, and its unique antiproliferative and apoptotic activities are mediated independently of estrogen receptors alpha and beta. A phase I clinical trial of 2-methoxyestradiol 200, 400, 600, 800, and 1,000 mg/day in 15 patients with breast cancer showed significant reduction in bone pain and analgesic intake in some patients, with no significant adverse effects. Another phase I study of 2-methoxyestradiol 200-1,000 mg/day in combination with docetaxel 35 mg/m2/week for 4-6 weeks performed in 15 patients with advanced refractory metastatic breast cancer showed no serious drug-related adverse effects. A phase II randomized, double-blind trial of 2-methoxyestradiol 400 and 1,200 mg/day in 33 patients with hormone-refractory prostate cancer showed that it was well tolerated and showed prostate specific antigen stabilizations and declines. We have started a phase I clinical trial to explore dosages greater than 1,000 mg/day.
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PMID:2-Methoxyestradiol, a promising anticancer agent. 1258 5

2-Methoxyestradiol (2-ME2) is a natural estrogen metabolite that, while devoid of estrogenic effects, has both antiangiogenic and antitumor effects. 2-ME2 is currently being evaluated in Phase I and Phase II clinical trials for the treatment of multiple types of cancer. Novel analogues of 2-ME2 were tested for activities that predict antiangiogenic and antitumor effects. Selected analogues were tested for inhibitory activity against endothelial cell proliferation and invasion. The results show that these analogues are effective inhibitors of endothelial cell activities that may predict antiangiogenic activity, and one analogue, 2-methoxy-14-dehydroestradiol (14-dehydro-2-ME2), was 6-15-fold more potent than the parental compound in these assays. The analogues were also evaluated for inhibition of proliferation and cytotoxicity against multiple tumor cell lines and found to be potent and effective. 14-Dehydro-2-ME2 was approximately 15-fold more potent than 2-ME2 against various tumor cell lines, and 2-methoxy-15-dehydroestradiol was particularly effective against DU 145 and PC3 prostate cancer cell lines. In vivo antitumor activity was observed for the three analogues tested in the murine xenograft MDA-MB-435 model; however, 2-ME2 provided no antitumor activity in this trial. The two most effective analogues, 14-dehydro-2-ME2 and 2-methoxyestradiol-15 alpha,16 alpha-acetonide, provided 29.4% and 26.7% inhibition of tumor burden, respectively. Mechanism of action studies indicate that the analogues cause mitotic spindle disruption, mitotic arrest, microtubule depolymerization, and inhibition of the assembly of purified tubulin similar to the effects of 2-ME2. Consistent with antimitotics that inhibit the dynamic instability of tubulin and initiate apoptosis, these novel 2-ME2 analogues cause Bcl-2 phosphorylation and activation of mitogen-activated protein kinase signaling pathways.
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PMID:Novel 2-methoxyestradiol analogues with antitumor activity. 1267 Sep 2

Prostate cancer is the second most common cause of death related to cancer in Western society. 2-Methoxyestradiol (2-ME), an endogenous metabolite of estradiol-17beta, inhibits tumor angiogenesis while also exerting potent cytotoxic effects on various cancer cells. 2-ME has been shown to activate the p38 MAPK and JNK pathways and to induce apoptosis in cells, although the underlying molecular mechanisms for this are unknown. Here we report that the expression of Smad7, an adaptor molecule required to activate p38 MAPK in the transforming growth factor beta signaling pathway, is also required for 2-ME-induced p38 activation and apoptosis in human prostate cancer cells (PC-3U). PC-3U/AS-S7 cells stably transfected with an antisense Smad7 construct, or PC-3U cells transiently transfected with short interfering RNA for Smad7, were protected against 2-ME-induced apoptosis. 2-ME-induced apoptosis was found to involve p38 MAPK and JNK, because simultaneous treatments with 2-ME and a specific p38 inhibitor (SB203580) or an inhibitor of JNK (L-JNK1) prevented 2-ME-induced apoptosis. Most interestingly, Smad7 was shown by both antisense and short interfering RNA techniques to affect levels of beta-catenin, which has been implicated previously in the regulation of apoptosis. Moreover, Smad7 was found to be important for the basal expression of Bim, a pro-apoptotic Bcl-2 family member, and for 2-ME-induced expression of Bim. These results suggest that expression of Smad7 is crucial for 2-ME-induced apoptosis in human prostate cancer cells.
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PMID:2-Methoxyestradiol-induced apoptosis in prostate cancer cells requires Smad7. 1570 59

2-Methoxyestradiol (2-ME) has potent antiproliferative effects on cancer cells. Its utility alone or in combination with other therapies for treating prostate cancer, however, has not been fully explored. Androgen-dependent and independent human prostate cancer cells were examined in vivo for their response to combination therapy. Efficacy was assessed by terminal deoxynucleotide transferase-mediated dUTP nick-end labeling assay and measuring microvessel density (MVD) in excised tumors. Animals harboring hormone-dependent tumors treated with 2-ME alone, androgen deprivation therapy alone, or the combination of the two had a 3.1-fold, 5.3-fold, and 10.1-fold increase in apoptosis, respectively. For hormone-independent tumors, treatment with 2-ME resulted in a 2.43-fold increase in apoptosis and a 73% decrease in MVD. 2-ME was most effective against hormone-dependent tumors in vivo and combination therapy resulted in a significant increase in efficacy compared to no treatment controls and trended toward greater efficacy than either 2-ME or androgen deprivation alone. Combination therapy should be investigated further as an additional therapeutic option for early prostate cancer.
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PMID:Effects of hormone deprivation and 2-methoxyestradiol combination therapy on hormone-dependent prostate cancer in vivo. 1622 6

2-Methoxyestradiol (2-ME) is an endogenous metabolite of estradiol with promise for cancer chemotherapy, including advanced prostate cancer. We have focused on events related to cell cycle arrest (G1 and G2/M) and induction of apoptosis in human prostate cancer cells. Treatment with 2-ME increased cyclin B1 protein and its associated kinase activity followed by later inhibition of cyclin A-dependent kinase activity and induction of apoptosis. Similar results were obtained with paclitaxel (taxol), a clinically relevant agent used to treat advanced prostate cancer. Cyclin-dependent kinase inhibitors prevented 2-ME and paclitaxel-mediated increase in cyclin B1-dependent kinase activity and blocked induction of apoptosis. Reduction of X-linked inhibitor of apoptosis (XIAP) protein by 2-ME and paclitaxel correlated with increased apoptosis. Lower doses of 2-ME and paclitaxel resulted in G1 (but not G2/M) cell cycle arrest in the p53 wild type LNCaP cell line, but with minimal induction of apoptosis. We suggest that 2-ME and paclitaxel-mediated induction of apoptosis in prostate cancer cells requires activation of cyclin B1-dependent kinase that arrests cells in G2/M and subsequently leads to the induction of apoptotic cell death.
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PMID:2-Methoxyestradiol and paclitaxel have similar effects on the cell cycle and induction of apoptosis in prostate cancer cells. 1635 31

2-Methoxyestradiol (2-ME(2)), a promising anticancer drug, induces growth arrest and apoptosis in various androgen-dependent (LNCaP) and -independent (DU145 and PC-3) prostate cancer cell lines. Moreover, flow cytometric analysis indicated a novel dual impact of 2-ME(2) on the cell division cycle of prostate cancer cells. Chronic exposure of high doses of 2-ME(2) enhance the accumulation of cells in S and G2/M phases, while cell numbers in the G1 phase were reduced significantly by this treatment. Because cyclin B1 overexpression, induction of cdc2 phosphorylation, and its regulatory proteins wee1 and phospho-cdc25C (interphase and mitotic forms) by 2-ME(2) treatment correlated with the induction of apoptosis, growth arrest at the G2/M phase, and accumulation of the S phase, we reasoned that cyclin B1 and cdc2 phosphorylation and its upstream regulatory molecular networks may be associated with the ultimate impacts of 2-ME(2). Because phosphorylation of cdc2 and upregulation of wee1 by 2-ME(2) can be abolished by both extracellular receptor kinase (ERK) inhibitor (U0126) and c-Jun N-terminal kinase (JNK) inhibitor (SP600125), our studies indicate that the 2-ME(2)-induced upregulation of wee1 and subsequent cdc2 phosphorylation are mediated through mitogen-activated protein kinase (MAPK)-ERK-JNK signaling pathways.
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PMID:Modulation of cell-cycle regulatory signaling network by 2-methoxyestradiol in prostate cancer cells is mediated through multiple signal transduction pathways. 1653 53

2-Methoxyestradiol (2ME2) is an endogenous estradiol metabolite that inhibits microtubule polymerization, tumor growth, and angiogenesis. Because prostate cancer is often treated with radiotherapy, and 2ME2 has shown efficacy as a single agent against human prostate carcinoma, we evaluated 2ME2 as a potential radiosensitizer in prostate cancer models. A dose-dependent decrease in mitogen-activated protein kinase phosphorylation was observed in human PC3 prostate cancer cells treated with 2ME2 for 18 h. This decrease correlated with in vitro radiosensitization measured by clonogenic assays, and these effects were blocked by the expression of constitutively active MEK. Male nude mice with subcutaneous PC3 xenografts in the hind leg were treated with 2ME2 (75 mg/kg) p.o. for 5 days, and 2 Gy radiation fractions were delivered each day at 4 h after drug treatment. A statistically significant super-additive effect between radiation and 2ME2 was observed in this subcutaneous model, using analysis of within-animal slopes. A PC-3M orthotopic model was also used, with bioluminescence imaging as an end point. PC-3M cells stably expressing the luciferase gene were surgically implanted into the prostates of male nude mice. Mice were given oral doses of 2ME2 (75 mg/kg), with radiation fractions (3 Gy) delivered 4 h later. Mice were then imaged weekly for 4 to 5 weeks with a Xenogen system. A significant super-additive effect was also observed in the orthotopic model. These data show that 2ME2 is an effective radiosensitizing agent against human prostate cancer xenografts, and that the mechanism may involve a decrease in mitogen-activated protein kinase phosphorylation by 2ME2.
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PMID:Radiosensitization and modulation of p44/42 mitogen-activated protein kinase by 2-Methoxyestradiol in prostate cancer models. 1780 47


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