TP53 and colonic neoplasm: To test the involvement of JNK phosphorylation in MSM-induced apoptosis, HCT-116 p53 +/+ and HCT-116 p53 −/− colon cancer cells were pre-incubated with JNK inhibitor SP600125 (25 μM) for one hour before incubation with MSM (500 mM) for 24 h.