Abstract: AIM: To study the effects and mechanism of down-regulating lncRNA LINC00176 on cisplatin resistance and autophagy in lung cancer A549/DDP cells. METHODS: The qRT-PCR method was used to determine the expression changes of LINC00176 in normal bronchial epithelial 16HBE cells and lung cancer A549, A549/DDP, NCI-H1299 and SK-MES-1 cells. A549/DDP cells were divided into Control group, si-NC group, and si-LINC00176 group, si-LINC00176+ Anti-miR-NC group, and si-LINC00176+ Anti-miR-138-5p group. MTT experiment detected the half inhibitory concentration (IC50) of cisplatin on A549/DDP. Flow cytometry was used to measure cell apoptosis. Western blot was used to determine the protein expression of LC3-I, LC3-II, Beclin 1, C-Caspase-3. The luciferase reporter system was used to identify the targeting relationship between LINC00176 and miR-138-5p. RESULTS: The expression level of LINC00176 in A549, A549/DDP, NCI-H1299 and SK-MES-1 cells was higher than that in 16HBE cells (P<0.01). The expression level of LINC00176 in A549/DDP cells was significantly higher than that in A549 cells (P<0.01). Compared with the Control and si-NC groups, the IC50 of A549/DDP cells in the si-LINC00176 group was significantly reduced (P<0.01), the expression of LC3-II/LC3-I, Beclin 1 protein was significantly reduced (P<0.01), the apoptosis rate, and the expression of C-Caspase-3 protein and miR-138-5p were significantly increased (P<0.01). LINC00176 directly bound to miR-138-5p. Compared with the si-LINC00176+Anti-miR-NC group, the IC50 of A549/DDP cells in the si-LINC00176+Anti-miR-138-5p group was significantly increased (P<0.01), and the expression of LC3-II/LC3-I and Beclin 1 protein was significantly increased (P<0.01), the apoptosis rate and C-Caspase-3 protein expression were significantly reduced (P<0.01).CONCLUSION: Down-regulating lncRNA LINC00176 could inhibit cisplatin resistance, inhibit autophagy and induce apoptosis in lung cancer A549/DDP cells by targeting and up-regulating miR-138-5p.

Key words: lung cancer, cisplatin resistance, autophagy, LINC00176, miR-138-5p