Activation and proliferation of cancer stem cells exert an important role in the invasion, metastasis, and recurrence of malignant tumors, including lung cancer. Therefore, exploring molecular targets related to self-renewal and mobility of lung cancer stem cells has important clinical significance. In our present study, we aimed to explore the effects of miR-138-5p on lung cancer stem-like cells and associated regulatory mechanism. In our present study, enhanced self-renewal capacity and elevated expression of cancer stem cells markers CD133, CD44, aldehyde dehydrogenase 1 of lung cancer stem-like cells derived from A549 cells were firstly verified. Then, obviously enhanced autophagy was found in lung cancer stem-like cells compared with parental cells A549. Besides, we found that enhanced autophagy induced by rapamycin promoted self-renewal and cell mobility of lung cancer stem-like cells and suppression of autophagy by 3-methyladenine exerted just opposite effects. In addition, miR-138-5p was found to be downregulated in lung cancer stem-like cells compared with that in parental cell A549. At the same time, overexpression of miR-138-5p by transfected with miR-138-5p mimic was found to effectively suppress self-renewal and invasion of lung cancer stem-like cells. Further study revealed that ATG7 was a target of miR-138-5p and overexpressed miR-138-5p suppressed ATG7-mediated autophagy. In addition, specific small interference RNA-ATG7 strengthened the inhibiting effect of miR-138-5p mimic on self-renewal and invasion of lung cancer stem-like cells. Taken together, we found that autophagy helped to maintain self-renewal and invasion ability of lung cancer stem-like cells and overexpressed miR-138-5p exerted anti-tumor effects by blocking the self-renewal and invasion of lung cancer stem-like cells through suppressing ATG7-mediated autophagy.
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