Capsaicin Induces Apoptosis of Colon Cancer SW480 Cells Through TRPV1 / 中国实验方剂学杂志

ABSTRACT

Objective:To investigate the effects of capsaicin on colon cancer SW480 cells and the underlying molecular mechanism through the transient receptor potential vanilloid 1（TRPV1）. Method:Capsaicin groups with different concentrations and a blank group were set up. The cell viability was detected by cell counting kit-8 （CCK-8） after SW480 cells were treated with capsaicin（50，100，200，300，400，500，600，800，1 000 μmol·L^-1） for 12，24，and 48 h to select the concentration of capsaicin which can effectively inhibit proliferation. The cell cycle and apoptosis were detected by flow cytometry after SW480 cells were treated with capsaicin （200，400，800 μmol·L^-1） for 24 h. The protein expression levels of TRPV1，p53，p-p53，B-cell lymphoma-2（Bcl-2），Bcl-2-associated X protein（Bax），cleaved cysteinyl aspartate-specific protease-3（cleaved Caspase-3），cleaved Caspase-8，and cleaved poly adenosine diphosphate ribose polymerase （PARP） were detected by Western blot after SW480 cells were treated with capsaicin （200，400 μmol·L^-1） for 24 h．In addition，the apoptosis was detected after SW480 cells were treated with TRPV1 microRNA（mRNA） and capsaicin（200 μmol·L^-1）. Western blot analysis was used to detect the protein expression levels of the above proteins. Result:As compared with the blank group，capsaicin（≥200 μmol·L^-1）significantly inhibited the cell viability of SW480 cells（<italic>P</italic><0.01） in dose- and time-dependent manners. The cell cycle was arrested in G₂/M phase by 200 and 400 μmol·L^-1 capsaicin treatment，and arrested in G₁ phase by 800 μmol·L^-1 capsaicin treatment （<italic>P</italic><0.05）. Flow cytometry showed that capsaicin （200， 400， 800 μmol·L^-1） significantly promoted apoptosis of SW480 cells simultaneously（<italic>P</italic><0.05，<italic>P</italic><0.01）. Western blot showed that capsaicin （200，400 μmol·L^-1） significantly up-regulated the protein levels of apoptosis-related proteins（p53，p-p53，Bax，cleaved Caspase-3，cleaved Caspase-8，and cleaved PARP） （<italic>P</italic><0.05，<italic>P</italic><0.01），and significantly down-regulated Bcl-2（<italic>P</italic><0.01）. In addition，siRNA-mediated knockdown of TRPV1 significantly attenuated capsaicin-induced apoptosis and the protein levels of apoptosis-related proteins in SW480 cells（<italic>P</italic><0.05，<italic>P</italic><0.01）. Conclusion:Capsaicin can inhibit cell proliferation，arrest cell cycle，and induce apoptosis of SW480 cells，and the possible mechanism may be related to TRPV1 activation.