Abstract

The aim of the present study was to investigate the molecular mechanism of nifuroxazide (NFZ) in the induction of apoptosis of NCI‑H1299 human non‑small cell lung cancer (NSCLC) cells through the reactive oxygen species (ROS)/Ca²⁺/protein kinase R‑like ER kinase (PERK)-activating transcription factor 4 (ATF4)‑DNA damage inducible transcript 3 (CHOP) signaling pathway. Morphological changes of cells were observed by microscopy, and the apoptosis and intracellular ROS levels of cells were observed by inverted fluorescence microscopy. Cell viability after the addition of the PERK inhibitor, GSK2606414, were detected by Cell Counting Kit‑8 assay. Annexin V‑FITC was used to detect cell apoptosis, Brite 670 was used to detect intracellular ROS and Fura Red AM was used to detect Ca²⁺ content. Western blotting was used to detect PERK, phosphorylated (P)‑PERK, ATF4, CHOP, P‑Janus kinase 2 and P‑signal transducer and activator of transcription 3 expression levels. Compared with the dimethyl sulfoxide control group, NFZ inhibited the survival activity in the H1299 NSCLC cell line, in a time‑ and dose‑dependent manner. However, GSK2606414 inhibited the NFZ‑induced apoptosis of H1299 cells. GSK2606414 also inhibited the increase in ROS and Ca²⁺ in H1299 cells induced by NFZ. Western blotting results demonstrated that NFZ significantly increased the expression levels of P‑PERK, ATF4 and CHOP, whereas GSK2606414 significantly reduced the NFZ‑induced increase in these protein expression levels. In conclusion, NFZ may induce the apoptosis of H1299 NSCLC cells through the ROS/Ca2+/PERK‑ATF4‑CHOP signaling pathway.