Regenerating gene 4 promotes chemoresistance of colorectal cancer by affecting lipid droplet synthesis and assembly

Figure 2 Effects of regenerating gene 4 on chemoresistance and droplet formation of DLD-1 cells. A: After treatment with cisplatin (DDP) or 5-fluorouracil (5-FU), the viability was measured in DLD-1 cells, DLD-1 cells treated with recombinant human regenerating gene 4 (REG4) (rhREG4), DLD-1 cells transfected with full-length (FL)-REG4 plasmid, and DLD-1 cells treated with anti-REG4 antibody; B: The lipid droplet level was measured in DLD-1 cells, DLD-1 cells treated with rhREG4, DLD-1 cells transfected with FL-REG4 plasmid, and DLD-1 cells treated with anti-REG4 antibody; C: REG4 expression was detected in DLD-1, chemoresistant DLD-1 cells to DDP and 5-FU by western blot, proteins related to de novo synthesis or assembly pathway of lipid droplets were also detected in DLD-1 cells and DLD-1 cells transfected with FL-REG4; D: Nile red staining was used to detect the level of lipid droplets in DLD-1 cells and DLD-1 cells transfected with FL-REG4 after treatment with high glucose (HG), acetyl-CoA carboxylase 1 (ACC1) inhibitor and ATP-citrate lyase (ACLY) inhibitor; E: Tetrazolium salt assay was used to detect half maximal inhibitory concentration of DLD-1 cells for 5-FU and DDP when treated with HG, ACC1 and ACLY inhibitors, alone or in combination with the above conditions. ^aP < 0.001; ^bP < 0.01. Ab: Anti-REG4 antibody; REG4: Regenerating gene 4; rhREG4: Recombinant human regenerating gene 4; ACC1: Acetyl-CoA carboxylase 1; ACCY: ATP-citrate lyase; AC-H3: Acetyl-acetyl-histone 3; H4: Histone 4; ACC1: Acetyl-CoA carboxylase 1; HDAC: Si histone deacetylase; ING5: Inhibitor of growth protein 5; SREBP1: Sterol-regulatory element binding protein 1; ACAT: A-cholesterol acyltransferase; ADRP: Adipocyte differentiation-related protein; CIDE: Cell-death-inducing DFF45-like effector; TIP: Tail-interacting protein; DDP: Cisplatin; 5-FU: 5-fluorouracil; HG: High glucose.