Somatostatin receptors in prostate tissues and derived cell cultures, and the in vitro growth inhibitory effect of BIM-23014 analog.

We investigated somatostatin receptors (SSTRs) in surgical specimens of prostate cancer and benign prostate hyperplasia (BPH), a normal immortalized epithelial cell line (PNT1), epithelial cancer cell lines, and stromal cells in short-term culture derived from normal and BPH biopsies. Cross-linking studies with 125I-Tyr11-SRIF-14 (125I-SRIF) and the SRIF analog 125I-BIM-23104 identified one major 57-kDa band both in surgical specimens and in epithelial and stromal cells cultures. In membrane-enriched fractions and whole stromal cells from a normal prostate and from one BPH, a single type of SSTR was characterized (Kd = 6.10(-9) and 10(-8) M, respectively, Bmax = 1.6 pmol per mg of proteins). mRNA for SSTR1 was detected in all epithelial and stromal cells tested except for PNT1, while SSTR2 mRNA was detected in one BPH stromal cell culture. BIM-23104 had no effect on the in vitro growth of the epithelial cells tested. Conversely, 10(-10) M BIM-23104 induced >50% growth inhibition of stromal cells after 6 days in culture. These results may have implications for therapeutic strategies using SRIF analogs in BPH and prostate cancer.