Capsaicin: a potential therapeutic agent for human small cell lung cancer

Abstract

Capsaicin the major active ingredient of chili peppers can induce apoptosis in multiple human cancer cell lines in cell culture and animal models. The present study examines the anti‐neoplastic activity of capsaicin in human small cell lung cancer (SCLC). SCLC is characterized by rapid progression, early metastasis and low survival rates. Our study showed that capsaicin induced 5–6 fold increase in apoptosis in multiple human SCLC cell lines. Most interestingly, the apoptotic activity of capsaicin was only displayed in SCLC cells and not in normal human lung epithelial cells. Capsaicin also suppressed the invasion of human SCLC cells as determined by Boyden Chamber assays. The dietary administration of capsaicin decreased the growth of human SCLC tumors xenotransplanted in nude mice. The growth‐inhibitory activity of capsaicin was independent of TRPV1, which is known to be the classical receptor for capsaicin. In contrast, the growth‐inhibitory activity of capsaicin requires the TRPV6 receptor, and depletion of TRPV6 by siRNA ablated the growth‐inhibitory activity of capsaicin. Our findings suggest that capsaicin may have potential applications as a novel agent for management and therapy of human SCLCs. Funding for our study was supported by a COBRE Pilot Grant, CDDC Pilot Grant, an MU‐ADVANCE Fellowship, and the Flight Attendant Medical Research Institute YCSA Grant.