Targeting SIRT2-mediated mitophagy to enhance ferroptosis: a novel mechanism of berberine action in non-small cell lung cancer

INTRODUCTION: Berberine (BBR), a natural isoquinoline alkaloid, has been shown to specifically bind to sirtuin 2 (SIRT2) and exhibit anticancer activity. This study aimed to elucidate the therapeutic mechanisms of BBR in non-small cell lung cancer (NSCLC). MATERIAL AND METHODS: A murine xenograft tumor model of NSCLC was established. Hematoxylin and eosin (H&E) staining and immunohistochemistry were employed to evaluate the therapeutic efficacy of BBR in vivo. In vitro, H1975 cells were treated with BBR to assess cell viability and migration. H1975 cells were transfected with lentivirus carrying sh-SIRT2 constructs to knock down SIRT2 expression. Ferroptosis was evaluated by measuring malondialdehyde (MDA), glutathione (GSH), and iron (Fe2+) levels. Protein expression levels of SIRT2, ferroptosis markers, and mitophagy markers were analyzed by Western blotting. Mitophagy was also assessed by the colocalization of TOMM20 and LAMP1 using immunofluorescence. RESULTS: BBR inhibited NSCLC progression both in vivo and in vitro, accompanied by upregulated SIRT2 expression. Mechanistically, BBR induced mitophagy and ferroptosis, as evidenced by increased Fe2+ and MDA levels, decreased GSH content, downregulation of GPX4 and SLC7A11, increased protein levels of PINK1 and Parkin, and increased fluorescence colocalization of TOMM20 and LAMP1. Silencing of SIRT2 attenuated BBR-induced suppression of H1975 cell viability and promotion of ferroptosis in a mitophagy-dependent manner. Treatment with a mitophagy activator reversed the effects of sh-SIRT2 and restored the therapeutic efficacy of BBR. CONCLUSIONS: The SIRT2/mitophagy/ferroptosis axis represents a key mechanism underlying the anti-NSCLC activity of BBR.