6-Methoxydihydrosanguinarine synergizes with cisplatin to enhance lung cancer cell death via ROS-mediated autophagy, ER stress, and JNK activation.

6-Methoxydihydrosanguinarine is a natural alkaloid derived from medicinal plants that exhibits significant antitumor activity, making it a promising candidate for cancer therapy. However, the exact molecular mechanisms underlying its effects require further investigation. In this study, we investigated the cytotoxicity and underlying mechanisms of 6-Methoxydihydrosanguinarine in human non-small cell lung cancer (NSCLC) cells. Our findings reveal that reactive oxygen species (ROS) accumulation is the key driver of its antitumor activity. Mechanistically, 6-Methoxydihydrosanguinarine activates the JNK signaling pathway and induces endoplasmic reticulum (ER) stress, both of which can be reversed by the ROS scavenger N-acetylcysteine (NAC). Interestingly, 6-Methoxydihydrosanguinarine also activates autophagy, and inhibition of autophagy reverses the JNK and ER stress pathway activation induced by 6-Methoxydihydrosanguinarine. Notably, 6-Methoxydihydrosanguinarine synergistically enhances cisplatin-induced NSCLC cell death, and this synergistic effect is abolished by NAC, highlighting the critical role of ROS accumulation in their combined efficacy. This study systematically elucidates the molecular mechanisms of 6-Methoxydihydrosanguinarine against NSCLC, revealing that, in addition to the JNK and autophagy pathways, ER stress also mediates its antitumor effects. Moreover, our data establish a rationale for exploring 6-Methoxydihydrosanguinarine in NSCLC therapy and highlight its combination with cisplatin as a potentially effective strategy.