ATF4 and cancer: The expression analysis of ATF4, DDIT3 encoding DNA damage-inducible transcript 3 (CHOP), BAX, and Bcl-2 mRNA was performed both in HPF and A549 cells exposed to the investigated NCI 159456 compound (3–100 μM) or with 0.1% DMSO, as well as in cancer A549 cells under Th-induced ER stress and incubated with the NCI 159456 PERK inhibitor (3 and 50 μM).