Up-regulation of Nrf2 pathway and intervention of intracellular redox homeostasis in shikonin-induced A549 cell apoptosis / 中国药理学通报

ABSTRACT

Aim To investigate the roles of intracellu-lar reactive oxygen species ( ROS ) and Nrf2 pathway in shikonin-induced A549 cell apoptosis. Methods The cytotoxicity was analyzed by MTT assay. The ap-optosis of A549 cells was analyzed by both cellular morphological and biochemical methods. The relative changes of the redox marks ( ROS/GSH) were studied by fluorescence assay in the shikonin-treated A549 cells in accompany with the changes of the intracellular redox homeostasis by GSH/GSSG ratio. ROS inhibitor was also employed in the treatment to find the role of ROS in shikonin-induced A549 cell apoptosis. Real-time PCR analysis and ELISA assay were performed as well to determine the role of Nrf2 pathway in the shiko-nin-induced A549 cell apoptosis. Results The IC50 of shikonin on A549 cells was 3. 2 mg·L-1 . The cellu-lar redox homeostasis shifted toward oxidation signifi-cantly in shikonin treatment in a time-dependent man-ner. The expression of the Nrf2 pathway related genes was up-regulated by shikonin ( 3 . 2 mg · L-1 , 8 h ) . The expression of the anti-apoptotic genes was down-regulated , and proapoptotic genes were up-regulated by shikonin (3. 2 mg·L-1, 24h). Futhermore, the inhi-bition of intracellular ROS alleviated the cytotoxicity of shikonin in A549 cells. Conclusion The critical role of shikonin-induced redox imblance in A549 cell, coped with the secondary produced ROS and Nrf2 path-way antioxidants, result in A549 cell apoptosis.