Docetaxel in combination with octreotide shows synergistic apoptotic effect by increasing SSTR2 and SSTR5 expression levels in prostate and breast cancer cell lines

Published on Thursday, 12 May 2016


PURPOSE: Docetaxel (DTX) is widely used for the treatment of metastatic prostate and breast cancers. Despite the clinical success of DTX, drug-related cumulative toxicity restricts its clinical use in cancer therapy. Thus, there is an urgent need for new therapeutic options. Octreotide (OCT) is a synthetic somatostatin analog that induces apoptosis in different cancer cell lines in vitro. In this study, we investigated the possible synergistic apoptotic effects of DTX in combination with OCT in prostate and breast cancer cell lines.

METHODS: The XTT cell viability assay was used to determine cytotoxicity. Apoptosis was evaluated by Cell Death Detection ELISA(Plus) Kit. The expression levels of apoptotic proteins were assessed by human apoptosis antibody array. Levels of SSTR2 and SSTR5 proteins were determined by western blot analysis.

RESULTS: DTX and OCT combination induced apoptosis in both breast and prostate cancer cells in a concentration- and time-dependent manner. Moreover, combination treatment resulted in inhibition of anti-apoptotic proteins such as Bcl-2 and Bcl-xL and induction of pro-apoptotic proteins Bax, Cytochrome c and IAPs in all of the tested cancer cell lines. SSTR2 and SSTR5 protein levels were induced as compared to any agent alone.

CONCLUSIONS: These results indicate that this combination treatment is a significant inducer of apoptosis in a synergistic manner in breast and prostate cancer cells. This strong synergism helps to lower the dose of DTX in both types of cancers, thus letting DTX to be used for longer periods by delaying resistance development and lesser side effects.



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See also:

- Somatostatin in oncology, the overlooked evidences;

- Somatostatin in oncology, the overlooked evidences in the "Some additional publications about hGH/GH-GHRH/GHRF/GRF" section;

- Evaluation of the safety and efficacy of the first-line treatment with somatostatin combined with melatonin, retinoids, vitamin D3, and low doses of cyclophosphamide in 20 cases of breast cancer: a preliminary report;

- The Di Bella Method (DBM) improved survival, objective response and performance status in a retrospective observational clinical study on 122 cases of breast cancer;

- Complete objective response to biological therapy of plurifocal breast carcinoma;

- The Di Bella Method (DBM) in the treatment of prostate cancer: a preliminary retrospective study of 16 patients and a review of the literature.