Betulinic Acid and Betulin Suppress Melanoma Growth by Modulating Apoptosis and Autophagy via PI3K/AKT/mTOR and MAPK Pathways

Malignant melanoma (MM) is a highly invasive and metastatic form of skin cancer. Betulinic acid (BA) and betulin (BE) possess pharmacological activities such as heat-clearing, detoxification, and anti-tumor effects, with BA showing potent selective cytotoxicity against melanoma cells. However, their underlying mechanisms in MM treatment remain unclear. Herein, this study systematically evaluated the anti-melanoma effects of BA and BE via integrated network pharmacology, in vitro and in vivo assays. Network pharmacology analysis revealed that BA and BE exerted anti-MM effects mainly by regulating apoptosis, angiogenesis and autophagy through the PI3K/AKT and MAPK signaling pathways. In vitro, both BA and BE inhibited colony formation and migration of B16-F10 cells, induced apoptosis by enhancing DNA damage and upregulating apoptotic protein expression, increased autophagic activity, and reduced ATP production and mitochondrial membrane potential (ΔΨm). These effects were closely associated with the inhibition of the PI3K/AKT/mTOR and MAPK pathways. Notably, BA showed stronger inhibitory effects than BE on the migration, invasion and tube formation of HUVECs. In vivo assays further confirmed that BA significantly suppressed melanoma growth in C57BL/6J mice by blocking the PI3K/AKT/mTOR and MAPK pathways. Collectively, BA and BE inhibit B16-F10 cell proliferation through the regulation of apoptosis and autophagy, with BA showing particularly promising potential as a candidate agent for MM therapy.