Betulinaldehyde exhibits effective anti-tumor effects in A549 cells by regulating intracellular autophagy

It is of great significance to find new effective drugs for an adjuvant therapy targeting lung cancer to improve the survival rate and prognosis of patients with the disease. Previous studies have confirmed that certain Chinese herbal extracts have clear anti-tumor effects, and in our preliminary study, betulinaldehyde was screened for its potential anti-tumor effects. The current study thus aimed to confirm the anti-tumor effect of betulinaldehyde, using in vitro experiments to explore its underlying molecular mechanism. It was found that betulinaldehyde treatment significantly inhibited the viability, proliferation, and migration of A549 cells in a dose-dependent manner. In addition, betulinaldehyde inhibited the activation of Akt, MAPK, and STAT3 signaling pathways in A549 cells in a time-dependent manner. More importantly, betulinaldehyde also decreased the expression level of SQSTM1 protein, increased the expression level of LC3 II, and increased the autophagy flux in A549 cells. The pretreatment of A549 cells with the autophagy inhibitor, 3-methyladenine, could partially negate the anti-tumor effects of betulinaldehyde. These findings suggest that betulinaldehyde could significantly inhibit the oncological activity of A549 cells by regulating the intracellular autophagy level, making it a potentially effective option for the adjuvant therapy used to treat lung cancer in the future.