Small interfering RNA-mediated Nrf2 gene knockdown enhances hirsutanols A-induced cytotoxicity in cancer cells / 南方医科大学学报

ABSTRACT

<p><b>OBJECTIVE</b>To investigate the effect of Nrf2 gene knockdown on hirsutanols A-induced cytotoxicity in cancer cells.</p><p><b>METHODS</b>The changes in the cell viability following treatment with different concentrations of hirsutanols A was detected by MTT assay, and the generation of reactive oxygen species (ROS) was assayed using flow cytometry. AnnexinV-FITC apoptosis kit was used to detect the cell apoptosis. Nrf2 protein expression in HepG2 and SW480 cells transfected with the siRNA targeting Nrf2 was analyzed with Western blotting.</p><p><b>RESULTS</b>At the concentrations of 1.25, 2.5, 5, 10, 20 and 40 µmol/L, hirsutanols A obviously inhibited the cell proliferation of human liver cancer HepG2 and colon cancer SW480 cells in a concentration-dependent manner. The levels of hydrogen peroxide increased rapidly after hirsutanols A treatment in both HepG2 (30 µmol/L) and SW480 (15 µmol/L) cells. Hirsutanols A also induced apoptosis of the two cells. Pretreatment with 5 mmol/L NAC totally inhibited apoptosis and ROS accumulation in the two cells induced by hirsutanols A. Transfection of HepG2 and SW480 cells with the siRNA caused a significant reduction in Nrf2 protein expression, which resulted in an increased sensitivity of the cells to hirsutanols A.</p><p><b>CONCLUSION</b>Hirsutanols A can induce apoptosis in HepG2 and SW480 cells by promoting ROS production and up-regulating Nrf2 expression. Nrf2 knockdown by siRNA can increase the sensitivity of the cancer cells to hirsutanols A in vitro.</p>