Sinensetin Induces Oxidative Stress‐Mediated Apoptosis in Non‐Small Cell Lung Cancer Cells by Suppressing Nrf2/ARE‐Dependent Antioxidant Defense

Non‐small cell lung cancer (NSCLC) cells frequently depend on Nrf2/ARE‐driven antioxidant programs to maintain redox balance and evade apoptosis. This study investigated whether sinensetin, a naturally occurring polymethoxylated flavone, reduces NSCLC cell survival by interfering with this cytoprotective pathway. A549 and H1299 NSCLC cells and normal BEAS‐2B bronchial epithelial cells were exposed to sinensetin. Cell viability was measured by MTT assay, apoptosis was quantified by Annexin V‐FITC/PI flow cytometry, and pathway‐ and apoptosis‐related proteins were analyzed by western blotting. Nrf2 distribution was evaluated by nuclear/cytoplasmic fractionation, ARE‐dependent transcription was assessed using a dual‐luciferase reporter system, and Nrf2 was silenced by shRNA. Intracellular ROS was measured by DCFH‐DA, antioxidant rescue was assessed with N‐acetyl‐ l ‐cysteine (NAC), Nrf2/ARE‐related proteins were examined in BEAS‐2B cells, and Nrf2 overexpression was used as a rescue approach in A549 cells. Sinensetin inhibited NSCLC cell growth, increased apoptosis, reduced total and nuclear Nrf2, decreased ARE reporter activity, and downregulated HO‐1 and NQO1. Sinensetin also increased intracellular ROS, whereas NAC partially reduced ROS accumulation, restored cell viability, and decreased apoptosis. BEAS‐2B cells showed comparatively modest Nrf2/ARE pathway changes. Nrf2 overexpression partially restored HO‐1 and NQO1, reduced apoptotic signaling, and attenuated sinensetin‐induced loss of viability and apoptosis. These results support a model in which sinensetin promotes oxidative stress‐mediated apoptosis in NSCLC cells, at least in part, through suppression of Nrf2/ARE‐dependent antioxidant defense.