Gap junctions composed of Cx43 regulate the cytotoxicity of oxaliplatin. (A-C) Clonogenic survival, LDH release and intracellular ROS of COLO320 cells exposed to oxaliplatin (100 µM, 24 h), at low or high density cell culture and co-incubated with or without Gap26 and RA. n=4–6; *P<0.05, compared with control group; #P<0.05, compared with oxaliplatin group at high-density cell culture. Cx43, connexin43; LDH, lactate dehydrogenase; ROS, reactive oxygen species; DMSO, dimethyl sulfoxide; RA, retinoic acid.