Role of Autophagy in Cisplatin Resistance of Retinoblastoma Y79 Cells and Its Mechanism

Objective To investigate the role of autophagy in cisplatin resistance of retinoblastoma Y79 cells and its mechanism.

Methods The IC₅₀ of cells was detected by CCK-8 assay. Y79 cells were randomly divided into control group, Cisplatin group and cisplatin combined with autophagyroup). Western blot, cell autophagy staining kit (MDC method) and transmi inhibitor 3-methyladenine group(Cis+3-MA gssion electron microscopy were used to observe cell autophagy. CCK-8 assay was used to detect the inhibitory rate of cisplatin on Y79 cells. Annexin V/PI double staining was used to detect cells apoptosis. q-PCR was applied to detect drug-resistance-related genes transcription levels. The expression of CaMKK2, p-AMPK, mTORC1 and LC3Ⅱ were detected by Fluo-4 AM calcium ion fluorescent probe staining.

Results Autophagy of retinoblastoma Y79 cells was induced by cisplatin. Autophagy inhibitor 3-MA reduced the level of autophagy. Compared with cisplatin group, the cisplatin inhibition rate was increased, the apoptosis rate was increased and the drug-resistance-related gene transcription level was down-regulated in Cis+3-MA group. After adding cisplatin, the level of intracellular calcium was increased, the expressions of CaMKK2, p-AMPK and LC3Ⅱ were up-regulated and the expression of mTORC1 was down-regulated.

Conclusion Cisplatin-induced autophagy is protective for the drug resistance of retinoblastoma Y79 cells and the inhibition of autophagy could improve tumor cells resistance to cisplatin. Cisplatin could induce autophagy in Y79 cells by Ca²⁺ activation of CAMKK2/AMPK/mTORC1 pathway.