Glucose deprivation induces chemoresistance in colorectal cancer cells by increasing ATF4 expression

Figure 6 Inhibition of activating transcription factor 4 activity reintroduces drug sensitivity in activating transcription factor 4-overexpressing colorectal cancer cells. A: After transfection with shATF4 or vector, ATF4-overexpressing cells were exposed to the indicated doses of LOHP or 5-FU for 48 h. Cell viabilities were determined by the CCK-8 assay; B: The apoptotic rates were much higher in the shATF4-transfected cells than in the control cells. Annexin V/7-AAD staining assay was performed to detect apoptosis; C and D: Inhibition of ATF4 decreased the MDR1 expression. The mRNA and protein levels of MDR1 in the ATF4-depleted cells were examined by qRT-PCR and Western blot, respectively, and β-actin was used as an internal controls. ^aP < 0.05, ^bP < 0.01, vehicle vs shATF4. GD: Glucose deprivation; CRC: Colorectal cancer.