Antidepressants Fluoxetine Mediates Endoplasmic Reticulum Stress and Autophagy of Non-Small Cell Lung Cancer Cells Through ATF4-AKT-mTOR Signaling Pathway.

Abstract

Cancer patients often suffer the depression with worse quality of life and prognosis. Therefore, studying how antidepressants affect the cancer is of great significance. Recent years witnessed the reports that antidepressants have the antiproliferation effect, However, in lung cancer it’s still unclear about the specific molecular target. This study mainly focused on how fluoxetine influenced different types of cells and discovered the molecular basis of its inhibitory effect in lung cancer. The specific antiproliferation effect and autophagy induced by fluoxetine on lung cancer cell were shown in CCK8 and immunofluorescence. The RNA sequence hinted that the endoplasmic reticulum (ER) stress-related protein and mTOR pathway were enriched after fluoxetine treating. Western blot results revealed that the ER stress pathway was activated by fluoxetine, including PERK, ATF4, and CHOP, while the AKT/mTOR pathway was inhibited. In addition, the transfection of ATF4 siRNA further discovered that ER stress participated in the inhibition of AKT/mTOR pathway and the induction of antiproliferation and autophagy in the fluoxetine-treated cells. More importantly, fluoxetine was demonstrated to play cytotoxic activity in cancer cells without affecting normal cells. Our results showed that fluoxetine triggered the ATF4-AKT-mTOR signaling pathway to induce cell cycle arrest and autophagy restraining cancer cells’ growth in lung cancer. This study found fluoxetine unaffected the proliferation of normal lung epithelial cells, providing safe clinical therapeutic strategies for lung cancer patients with depression.