Non-small-cell lung cancer (NSCLC) is an aggressive subtype of pulmonary carcinomas with high mortality. However, chemotherapy drug resistance and high recurrence rates hinder the curative effect of platinum-based first-line chemotherapy, which makes it urgent to develop new antitumor drugs for NSCLC. 9za, a new candidate drug synthesized by our research group, has been verified with potent antilung cancer activity in preliminary experiments. However, the underlying molecular mechanism of 9za remains largely vague. This work revealed that 9za could play important cytotoxic and proapoptotic roles in NSCLC cells. Moreover, 9za could induce autophagy and promote autophagy flux. Interestingly, the cytotoxic and proapoptotic roles were significantly dependent on 9za-induced cytoprotective autophagy. That is, the coadministration of 9za with an autophagy inhibitor such as chloroquine or 3-methyladenine exhibited increased cytotoxic and proapoptotic effects compared with 9za treatment alone. In addition, 9za exposure suppressed the phosphorylation of phosphoinositide-dependent protein kinase 1 (PDK1), protein kinase B (Akt), mammalian targets of rapamycin (mTOR), p70 S6 kinase, and 4E binding protein 1 by a dose-dependent way, manifesting that the Akt/mTOR axis was implicated in 9za-induced autophagy. In addition, the overexpression of PDK1 resulted in increased phosphorylation of PDK1 and Akt and blocking of 9za-mediated autophagy. These data showed that the PDK1/Akt/mTOR pathway was involved in Abbreviations: Akt, protein kinase B; ATG5, autophagy-related gene 5; BrdU, bromodeoxyuridine; CCK-8, cell counting kit-8; CQ, chloroquine; 4EBP1, 4E binding protein 1; LAMP1, lysosomal associated membrane protein 1; LC3, microtubule-associated protein 1 light chain 3; 3-MA, 3-methyladenine; mTOR, mammalian targets of rapamycin; NSCLC, non-small-cell lung cancer; PARP, poly (ADP-ribose) polymerase; PDK1, phosphoinositide-dependent protein kinase 1; PI, propidium iodide; p70S6K, p70 S6 kinase; RAPA, rapamycin; SQSTM1, sequestosome 1; Z-VADfmk, Z-Val-Ala-Asp-fluoromethylketone.
SUPPORTING INFORMATIONAdditional supporting information may be found online in the Supporting Information section at the end of the article.How to cite this article: Liu R, Chen Z, Yi X, et al. 9za plays cytotoxic and proapoptotic roles and induces cytoprotective autophagy through the PDK1/Akt/mTOR axis in non-smallcell lung cancer.