[Astragalus polysaccharide inhibits autophagy and regulates expression of autophagy-related proteins in lung cancer A549 cells induced by xanthine oxidase].

Objective To investigate the effects of Astragalus polysaccharide (APS) on autophagy and expression of microtubule-associated protein 1 light chain 3B (LC3B), mammalian target of rapamycin (mTOR) and beclin1 in xanthine oxidase (XOD)-induced autophagic model of non-small cell lung cancer A549 cells. Methods A549 cells were divided into five groups: control group, model group, 100, 200 and 400 μg/mL APS-treated group. Except for control group, all groups were administered XOD for 24 hours to establish autophagic models. Morphology of autophagosome was detected by transmission electron microscopy (TEM) and the number was counted by monodansylcadaverine (MDC) staining. The expression levels of LC3B, beclin1 and mTOR were detected by Western blot analysis. Results Compared with the control group, the number of autophagosome in the model group increased; the expression of LC3B and beclin1 significantly increased; while the expression of mTOR significantly decreased. Compared with the model group, the number of autophagosome decreased remarkably; the expression of LC3B and beclin1 severely decreased, and the expression of mTOR obviously increased in 200 or 400 μg/mL APS-treated group. Conclusion APS reduces the level of autophagy, down-regulates the expression of LC3B and beclin1, and increases mTOR expression in the autophagic model of A549 cells induced by XOD.