Fig 1: MSM induced extrinsic apoptosis pathway. (A) Fluorescein-conjugated annexin V (annexin V-FITC) vs. propidium iodide (PI) staining analysis showed apoptosis induction after treatment with 200 mM MSM for 48 h in NCCIT and NTERA-2 cells. (B) Western blotting of NCCIT and NTERA-2 cells with 100 and 200 mM MSM for 48 h showing the expression of TRAIL, DR4, DR5, TRADD, Casp8, Casp3, and C-Casp3 proteins. Expression levels were estimated by densitometry and normalized to β-actin. Data were in triplicate. (C) Real-time qPCR analysis showing illustrative expression of genes responsible for the extrinsic apoptosis pathway in NCCIT and NTERA-2 cells with 100 and 200 mM MSM for 48 h. Cp values were normalized to GAPDH mRNA. Controls were set at 100. *** p < 0.001 (ANOVA test). # p < 0.001 vs. control. (D) Human TRAIL assay shows Human TRAIL elevation by 200 mM MSM treatment for 48 h in NCCIT and NERA-2 cells. Controls were set to 100. *** p < 0.001 (Student’s t-test). (E) Caspase-Glo 3/7 assay showing the enhancement of caspase-3/7 activity by 200-mM MSM treatment for 48 h. Controls were set at 100. * p < 0.05 and ** p < 0.01 (Student’s t-test).