Inhibition of microvesiculation sensitizes prostate cancer cells to chemotherapy and reduces docetaxel dose required to limit tumor growth in vivo

Jorfi, Samireh; Ansa-Addo, Ephraim A.; Kholia, Sharad; Stratton, Dan; Valley, Shaunelle; Lange, Sigrun; Inal, Jameel

Abstract

Microvesicles shed from cells carry constituents of the cell cytoplasm, including, of importance in multidrug resistance to cancer chemotherapy, drugs that the tumor cell attempts to efflux. To see whether such drugs could be used at lower concentrations with the same efficacy, it was first shown that microvesiculation of prostate cancer (PCa) cells, PC3, could be inhibited pharmacologically with calpeptin (calpain inhibitor) and by siRNA (CAPNS1). In cells treated with docetaxel (DTX), this inhibition resulted in a third-fold increase in intracellular concentrations of DTX. As a result, 20-fold lower concentrations of DTX (5 nM) could be used, in the presence of calpeptin (20μM) inducing the same degree of apoptosis after 48 h in PC3 cells, as 100 nM of DTX alone. Inhibition of microvesiculation similarly improved combination chemotherapy (DTX and methotrexate). In a mouse xenograft model of PCa, DTX (0.1 mg/kg) together with calpeptin (10 mg/kg), administered i.p., significantly reduced tumor volumes compared to DTX alone (0.1 mg/kg) and brought about the same reductions in tumor growth as 10 mg/kg of DTX alone. As well as further reducing vascularization, it also increased apoptosis and reduced proliferation of PC3 cells in tumor xenografts.

Citation

Jorfi, S., Ansa-Addo, E. A., Kholia, S., Stratton, D., Valley, S., Lange, S., & Inal, J. (2015). Inhibition of microvesiculation sensitizes prostate cancer cells to chemotherapy and reduces docetaxel dose required to limit tumor growth in vivo. Scientific reports, 5(1), Article 13006. https://doi.org/10.1038/srep13006

• Journal Article Type: Article
• Acceptance Date: Jul 9, 2015
• Online Publication Date: Aug 25, 2015
• Publication Date: 2015-10
• Deposit Date: Jul 4, 2018
• Publicly Available Date: Jul 13, 2018
• Journal: Scientific Reports
• Print ISSN: 2045-2322
• Publisher: Nature Publishing Group
• Peer Reviewed: Peer Reviewed
• Volume: 5
• Issue: 1
• Article Number: 13006
• DOI: https://doi.org/10.1038/srep13006
• Public URL: https://hull-repository.worktribe.com/output/910335
• Publisher URL: https://www.nature.com/articles/srep13006
• Contract Date: Jul 13, 2018