ATF4 and colon carcinoma: The induction of KRT16, FAM129A and HKDC1 transcripts in HCT116 colon carcinoma cells was tested by RT-qPCR after the treatment with mitochondrial respiratory chain complex I inhibitor Piericidin A or complex III inhibitor Myxothiazol under the previously optimized conditions that result in the induction of ATF4 but do not activate p53 [18].