ATF4 and non-small cell lung carcinoma: PT treatment (20, 40, and 60 μM) significantly enhanced the expression of p-PERK, IRE1, ATF4, and CHOP in both NSCLC cell lines in a dose-dependent manner (P < 0.05, compared with the control group, Fig. 5), but the pro-ERS effect on normal bronchial epithelial cells was weaker than on NSCLS cells.