bq-123 and Prostatic-Neoplasms

To investigate the anti-tumor effect of the endothelin A receptor antagonist BQ123 on human prostate cancer cell line PC-3M in vitro by observing its impact on the proliferation and apoptosis of human prostate cancer cells.. The inhibiting effect of BQ123 on the proliferation of PC-3M cells was observed by MTT assay, erosion trace test and Transwell chamber chemotaxis assay, and its induction of their apoptosis determined by Annexin V-FITC/PI staining and cytometry.. BQ123 exhibited increased inhibition of PC-3M cells in a time-dependent manner, with inhibition rates of 22.32%, 44.88% and 64.47% at 24 h, 48 h and 72 h, respectively (P < 0.05). The migration distances of the PC-3M cells in the BQ123 group were (103.42 +/- 75.63) microm, (243.75 +/- 121.53) microm and (422.07 +/- 36.01) microm at 12 h, 24 h and 48 h, obviously lower than (162.93 +/- 19.87) microm, (317.19 +/- 43.19) microm and (692.74 +/- 40.84) microm in the control group (P < 0.05). The number of the PC-3M cells that invaded the inferior chamber in the BQ123 group was (79.2 +/- 9.58), significantly decreased as compared with (92.6 +/- 5.94) in the control (P < 0.05). The apoptosis rate of PC-3M exposed to BQ123 was (15.03 +/- 0.93)%, significantly higher than (9.38 +/- 1.37)% in the control (P < 0.05). The ratio of PC-3M cells in different cycles showed no significant differences.. BQ123 inhibits the proliferation of PC-3M cells and induces their apoptosis in vitro, which may give a new idea on the studies of prostate cancer therapies.

Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Endothelin A Receptor Antagonists; Humans; Male; Peptides, Cyclic; Prostatic Neoplasms

2-Methoxyestradiol (2ME2) is an antitumoral and antiangiogenic compound that inhibits hypoxia-inducible factor (HIF)-1, a key regulator of the hypoxic response that promotes tumor progression. HIF-1alpha, the regulated subunit of HIF-1, is overexpressed in premalignant, cancerous and metastatic lesions of prostate. Endothelin (ET)-1 is a HIF target gene and one that plays an important role during prostate bone metastasis via its interaction with endothelin A (ET(A)) receptor. We reasoned that 2ME2 combined with an ET(A) receptor antagonist would induce potent cytotoxic effects in prostate cancer cells.. PC-3 and LNCaP cells were grown alone or cocultured with human osteoblasts. The cells were treated with 2ME2, with an ET(A) receptor antagonist (BQ-123) or with combinations of both compounds. The cells were then evaluated for cytotoxicity, HIF-1alpha protein expression and HIF-1 transcriptional activity.. The combination of 2ME2 with BQ-123 induced synergistic cytotoxic effects in prostate cancer cells and in their cocultures with osteoblasts. No synergism was observed when 2ME2 was combined with the ET(B) selective antagonist, BQ-788. These results correlated with inhibition of HIF-1alpha protein expression, HIF-1 transcriptional activity, and PSA mRNA expression.. The ET(A) receptor antagonist was capable of potentiating the cytotoxic effects of 2ME2 in prostate cancer cells. These effects were apparently mediated through the inhibition of the HIF-1 pathway. Our in vitro data strengthen the rationale for using 2ME2 in combination with ET(A) receptor antagonists for the treatment of metastatic prostate cancer.

Topics: 2-Methoxyestradiol; Adenocarcinoma; Antineoplastic Agents; Cell Line, Tumor; Cell Survival; Coculture Techniques; Dose-Response Relationship, Drug; Drug Screening Assays, Antitumor; Drug Synergism; Endothelin Receptor Antagonists; Estradiol; Gene Expression Regulation, Neoplastic; Humans; Hypoxia-Inducible Factor 1, alpha Subunit; Male; Osteoblasts; Peptides, Cyclic; Prostate-Specific Antigen; Prostatic Neoplasms; RNA, Messenger

To study the expression of ET receptor and the apoptosis after intervened with ET receptor antagonist in androgen-independent prostate cancer.. PC3, an androgen-independent prostate cancer cell line, was used. The expression of ETA and ETB receptor in PC3 was measured through RT-PCR. After intervened with selective ETA and ETB receptor antagonist, the apoptosis in PC3 was studied through flow cytometry and electron microscope.. Clear signal was obtained in PC3 for ETA receptor mRNA transcript, while the signal for ETB receptor mRNA transcript was very weak. The expression of ETA receptor mRNA was obviously reduced and the apoptosis of PC3 cell was observed after intervened with selective ETA receptor antagonist. There was no change after intervened with selective ETB receptor antagonist.. ET-1 exerts its effects through the ETA receptor subtype and ETB receptor is silenced in PC3. The expression of ETA was reduced and the apoptosis was observed in PC3 when ETA receptor was blocked. It was dose-dependent.

Topics: Androgens; Apoptosis; Endothelin A Receptor Antagonists; Endothelin B Receptor Antagonists; Endothelin-1; Humans; In Vitro Techniques; Male; Neoplasms, Hormone-Dependent; Oligopeptides; Peptides, Cyclic; Piperidines; Prostatic Neoplasms; Receptor, Endothelin A; Receptor, Endothelin B

The objective of the present study was to characterize the binding and functional properties of endothelin (ET) receptor subtypes in the human prostate. Human prostatic tissue was obtained from male subjects undergoing radical prostatectomy for low-volume prostate cancer. The optimal assay conditions for characterizing human prostatic ET-1 binding sites on slide-mounted tissue sections were defined. Maximal specific 125I-ET-1 binding was achieved after a 10-min preincubation, a 120-min incubation, and a washing procedure that consisted of a brief rinse and a 1-min wash. The mean equilibrium dissociation constant (Kd) and density (Bmax) of ET-1 binding sites determined from six saturation studies were 0.72 +/- 0.13 nM and 40.4 +/- 6.9 fmol/mg of wet weight, respectively. The mean Hill coefficient was 0.99 +/- 0.01, indicating that 125I-ET-1 identifies a single population of binding sites. The pharmacology of 125I-ET-1 binding sites was characterized using competitive binding experiments. The competition plots for ET-1 were best fit by a one-binding site model, whereas the plots for sarafotoxin 6C (S6C) and BQ123 were consistently best fit by a two-site model. The mean Ki value of ET-1 was 0.34 +/- 0.12 nM. The mean Ki values for the high and low affinity S6C binding sites were 0.50 +/- 0.09 nM and 0.84 +/- 0.28 microM, respectively. The mean Ki values for the high and low affinity BQ123 binding sites were 5.51 +/- 1.05 nM and 24.9 +/- 6.5 microM, respectively. The ratio of ETA to ETB binding sites was approximately 2:1. The ET receptor subtype mediating prostatic smooth muscle tension was investigated using agonist-antagonist competition studies. ET-1, a nonselective ET agonist, elicited a potent contraction of prostate smooth muscle. The pA2 of BQ123 for inhibiting ET-1-mediated contraction was 6.84. S6C, a selective ETB agonist, also elicited a potent contraction of prostate smooth muscle. BQ123 at concentractions between 0.1 and 10 microM did not shift the S6C dose-response curve. These functional studies suggest that both ETA and ETB receptors mediate the tension of prostate smooth muscle. Endogenous ETS may be involved in the pathophysiology of bladder outlet obstruction in men with benign prostatic hyperplasia. If this is the case, then ET antagonists may represent effective treatment for benign prostatic hyperplasia.

Topics: Binding, Competitive; Dose-Response Relationship, Drug; Endothelin Receptor Antagonists; Endothelins; Frozen Sections; Humans; Male; Muscle Contraction; Muscle, Smooth; Peptides, Cyclic; Prostate; Prostatic Neoplasms; Receptors, Endothelin; Tissue Embedding; Viper Venoms