Abstract:Objective: To investigate the reversal effect of liver X receptor (LXR) agonist GW3965 on oxaliplatin (OXA) resistance in human colon cancer cells and its mechanism. Methods: OXA-resistant human colon cancer HCT116/L-OHP cells were established by stepwise exposure of human colon cancer HCT116 cells to increasing concentrations of OXA. The growth abilities and responses to OXA treatment between HCT116/L-OHP cells and their parent HCT116 cells were compared; the changes in OXA resistance and expressions of autophagy-related protein ATG-5, Beclin-1, p62 and LC3 in HCT-116/L-OHP cells after exposure to GW3965 for 48 h were determined. Results: The OXA-resistant HCT116/L-OHP cells were successfully established, as evidenced by the slightly decreased proliferative ability but significantly increased resistance to OXA in HCT116/L-OHP cells compared with their parent HCT116 cells (IC50: 244.99 μmol/L vs. 10.05 μmol/L, P<0.05), with a resistance index (RI) of 24.45. In HCT116/L-OHP cells after exposure to different concentrations (10, 20 and 30 μmol/L) of GW3965, the IC50 and RI to OXA were significantly decreased (all P<0.05), with a concentration-dependent manner (IC50: 199.49, 114.71 and 87.32 μmol/L; RI: 19.89, 11.40 and 8.69), and the reversal fold for the three concentrations was 1.23, 2.15 and 2.82 respectively; the expression levels of ATG-5 and Beclin-1 protein were significantly decreased, while the expression levels of p62 and LC3-II were significantly increased (all P<0.05), which all showed a concentration-dependent profile. Conclusion: LXR agonist GW3965 can reverse OXA resistance in human colon cancer cells, and the mechanism may be associated with its regulating the expression levels of the autophagy-related proteins.