The Study of Effect and Mechanism by Vitamin K2 on Human MDS Cell Line MUTZ-1.

The myelodysplastic syndromes (MDS) are characterized by hemopoietic insufficiency associated with cytopenias leading to serious morbidity and the additional risk of leukemic transformation. Vitamin K2(VK₂) is reported to induce apoptosis or differentiation of leukemic cell lines in vitro. For investigating the effects and mechanism of VK₂ on human MDS cell line MUTZ-1 in vitro,we observed the changes of morphologic features of MUTZ-1 cells by exposing to VK₂.The transmission electron microscope was used to observe the apoptosis of MUTZ-1 cells. Cellular proliferation was determined by the MTT assay. The flow cytometry was used to analysis apoptosis rate and the change of cell cycle. The expression of apoposis-related genes bcl-2, survivin and bax were detected by reverse transcriptase polymerase chain reaction(RT-PCR).The activity of caspase-3 was detected by chemiluminescence assay. After exposing to 10μmol L⁻¹ and higher concentration of VK₂, it could inhibit MUTZ-1 cells proliferation in a dose-and time-dependent manner(p<0.05). At concentration of 5μmol/l VK₂ treatment, it might accelerate cellular proliferation, but there’s no significant difference compared with control group. Apoptosis peak on FCM and positive Annexin-V FITC/PI on cell membrane showed that VK₂ induced apoptosis of MUTZ-1 cells in a dose-and-time-dependent manner, G₀/G₁ cell cycle arrest, significantly dow-regulated the expression of bcl-2 and survivin, but had no effect on the expression of bax.The activities of caspase-3 were significantly increased. Low concentration of VK₂ could facilitate cell proliferation. The higher concentration of VK₂ could induce apoptosis of MUTZ-1 cells. These results indicate that VK₂ induces MUTZ-1 cells apoptosis by activating caspase-3 pathway, the apoptosis related genes bcl-2, survivin down-regulated might play an important role in this process.