Rutecarpine Suppresses Non‐Small Cell Lung Cancer Progression Through Activating the <scp>STING</scp> Pathway and Elevating <scp>CD8</scp>+ T Cells

Globally, non-small cell lung cancer (NSCLC) is the primary cause of cancer-related deaths. Rutecarpine (RUT), a quinazolinocarboline alkaloid that is naturally occurring and present in Chinese medicinal herbs, has been shown to have anticancer properties in several cancer cell lines. However, the specific antitumor mechanisms of RUT in NSCLC remain unclear. This study demonstrates that RUT induces apoptosis and significantly reduces the viability of NSCLC cell lines. This effect is achieved by stimulating intracellular ROS production, leading to mitochondrial dysfunction. The decreased cell viability observed with RUT treatment is attributed to the elimination of ROS and apoptosis through the suppression of ROS by N-acetylcysteine (NAC). Furthermore, RUT therapy elevated the production of CXCL10 and CCL5 in NSCLC cell lines and markedly activated the STING pathway in NSCLC cells. Mechanistically, RUT substantially decreased the levels of PD-L1 protein in NSCLC cells. Notably, in vivo experiments demonstrated that RUT significantly inhibits mouse NSCLC tumor growth in mice, exhibiting anti-tumor activity by elevating CD8⁺ T cells. These findings strongly support RUT as a promising anti-cancer drug for NSCLC.