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

Figure 5 Down-regulation of activating transcription factor 4 significantly reverses the glucose deprivation-induced resistance of colorectal cancer cells to chemotherapy. A: Depletion of ATF4 enhanced the sensitivity of CRC cells to chemical drugs. Vector and shATF4 stably transfected LoVo cells were treated with the indicated doses of the different drugs for 48 h. In vitro drug sensitivity was tested using the CCK-8 assay; B and C: The apoptotic rates were much higher in the ATF4-depleted cells than in the control cells. Hoechst 33258 nuclear staining and Annexin V/7-AAD staining assays were performed to detect apoptosis; D: Depletion of ATF4 by shRNA in CRC cells led to significantly reduced expression of MDR1. The mRNA and protein levels of MDR1 were detected by qRT-PCR and Western blot, respectively, and β-actin was used as an internal controls. ^aP < 0.05, ^bP < 0.01, ^cP < 0.001, vehicle GD vs shATF4-GD. GD: Glucose deprivation; CRC: Colorectal cancer.