Mechanism of dihydroartemisinin binding SERCA2b and inducing apoptosis in colorectal cell HCT-116 / 中国医科大学学报

ABSTRACT

Objective To investigate the binding sites of dihydroartemisinin(DHA)and sarcoplasmic/endoplasmic reticulum calcium ATPase(SERCA)and explore the mechanisms underlying apoptosis induction in HCT-116 colon cancer cells through the mitochondrial pathway.Methods HCT-116 cells were cultured in DHA concentrations of 0,10,20,40 μmol/L.After 24 h of culture,Western blot-ting assessed SERCA concentration,CCK-8 measured cell proliferation,Hoechst nuclear staining examined cell apoptosis,JC-1 probe evaluated mitochondrial membrane potential.LeDock molecular docking predicted DHA and SERCA binding sites.Synthetic SERCA2b mutated and non-mutated proteins at Ile315 and Thr316 sites were combined with small molecule DHA using biofilm interference tech-nology.Results Western blotting revealed a significant decrease in SERCA2 protein levels with increasing DHA concentration.CCK-8 demonstrated a statistically significant decrease in cell proliferation with increasing DHA concentration(P＜0.01).Hoechst nuclear staining illustrated DHA-induced rounding and pyknosis of HCT-116 cell nuclei compared to the control group.DHA gradually decreased mitochondrial membrane potential within the first 4 h of treatment,starting from 5 h,followed by a sustained reduction.Molecular docking predicted a hydrogen bond with Thr316 and a hydrophobic interaction with Ile315.Biofilm interference techniques indicated robust binding of DHA to non-mutated SERCA2b protein,while binding to the SERCA2b mutant protein at Ile315 and Thr316 sites was poor.Conclusion DHA directly binds to the Ile315 and Thr316 sites of SERCA2b,inducing apoptosis in colon cancer cells HCT-116 through the mitochondrial pathway.