LAUSR

Bevacizumab (BV) has an inhibitory effect on tumor growth including lung adenocarcinoma. However, its efficacy is greatly affected by drug resistance. Astragaloside IV (AST-IV) is effective in combination with other drugs is effective to treat cancer. This study aimed to investigate the effect of AST-IV on enhancing the sensibility of lung adenocarcinoma cells to BV. A549 cells were treated by different concentrations of BV and AST-IV. Cell viability, cell cycle, and apoptosis were detected by thiazolyl blue tetrazolium bromide (MTT) and flow cytometry, respectively. Quantitative reverse transcription-polymerase chain reaction (qRT-PCR) and western blotting were performed to detect the expression levels of autophagy- and apoptosis-related proteins, protein kinase B (AKT), and mammalian target of rapamycin (mTOR). The results showed that BV or AST-IV could inhibit the viability and promote the apoptosis of A549 cells in a concentration-dependent manner. Moreover, BV or AST-IV inhibited Bcl-2 expression and increased the expressions of Bax and Cleaved caspase-3, and promoted apoptosis. BV and AST-IV in combination acted synergistically on viability and apoptosis of A549 cells. However, BV alone down-regulated P62 expression, LC3I/LC3II level, the number of cells arrested at S phase and the phosphorylation levels of AKT and mTOR, but upregulated the number of cells arrested at G0/G1 phase and Beclin1 expression, whereas AST-IV alone could reverse the effect of BV on autophagy-related proteins, the phosphorylation levels of AKT and mTOR. This paper demonstrates that AST-IV enhances the effect of BV on inhibiting proliferation and promoting apoptosis of lung adenocarcinoma cells through inhibiting autophagy pathway.