The somatostatin analogue (SA) Octreotide has been used as a therapeutic reagent for somatostatin receptor type 2a (SSTR2a)-positive cancers. The purpose of this study is to detect SSTR2a in human prostate carcinomas and to elucidate the effects of SA on SSTR2a-positive prostate carcinoma cells to determine the potential of this drug as a new therapeutic method for advanced prostate carcinoma. Immunohistochemical study of SSTR2a was performed on 95 prostate carcinoma cases, and the results showed expression of SSTR2a in 14 of the 95 cases (14.74%); the histological grade (Gleason) and capsular invasion of the prostate carcinoma were directly related to SSTR2a expression. Among the ten cases of lymph node metastasis, SSTR2a expression was markedly higher. In vitro studies were performed using SSTR2a-positive prostate cancer cells, DU145 and PC3. Migration and invasion abilities of DU145 and PC3 cells were inhibited by SA in a dose-dependent manner. This inhibition was reversed by Rho-kinase inhibitor Y-27632. Morphological changes of the prostate cancer cells treated with SA and Y27632 corroborate the migration and invasion assays, although SA had no effect on proliferation of DU145 and PC3 cells. In conclusion, the somatostatin analogue may be beneficial for patients with advanced prostate carcinoma or to protect from distal metastasis if they are positive for SSTR2a.

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