Methylsulfonylmethane induces caspase-dependent apoptosis in acute myeloid leukemia cell lines

Background: Acute myeloid leukemia (AML) is a heterogeneous ailment in both biological and clinical concepts. Numerous efforts have been devoted to discover natural compounds for combating cancer, which showed great potential in cancer management. Methylsulfonylmethane (MSM), an organosulfur dietary supplement, is utilized for improving various clinical conditions, particularly osteoarthritis. MSM can exert antitumor activity in a wide range of cancers. Objectives: The molecular mechanisms of action underlying antileukemic activity of MSM remain unclear. In this regard, we aimed to investigate the anticancer properties of MSM on human AML cell lines (U937 and HL60) with focus on underlying cell death mechanism. Methods: Anticancer activity of the MSM was examined employing MTT assay, Annexin V-PE/7AAD staining, caspase3/7 activity test, and real-time qPCR. Both cell lines were treated with different concentrations (50–400 mM) of MSM for 24 h. Pretreatment of the cells with a caspase inhibitor (i.e., Z-VAD-fmk) was performed for the assessment of apoptosis induction. Results: The results of MTT assay revealed that in both cell lines, the MSM markedly reduced cell viability in comparison to the control cells. Additionally, findings of Annexin V-7AAD staining revealed that MSM induced apoptosis and activated caspase 3/7 in both cell lines markedly. Real-time quantitative PCR results also supported the induction of apoptosis in AML cells. MSM altered the expression levels of various apoptotic genes (BAX, BAD, and BIM). Conclusion: Overall, our results indicated that MSM could induce apoptosis in AML cell lines in a dose-dependent manner, which therefore could be utilized as an antileukemic agent.