[Apoptosis of Megakaryocytic Leukemia Cell Line Meg-01 Induced by TSP-1 Via CD36/Caspase-3].

ABSTRACT

OBJECTIVE: To investigate the effect of thrombospondin-1 (TSP-1) on apoptosis of human megakaryocytic leukemia cell line Meg-01 and its possible mechanism. METHODS: The expression of CD36 antigen in Meg-01 cells was detected by flow cytometry and immunocytochemistry. Meg-01 cells were cultured for 48 hours with TSP-1 and CD36 antibody FA6-152 at different concentrations. The early apoptosis and activity of caspase-3 were detected by flow cytometry. The effect of TSP-1 on the growth and differentiation of megakaryocytes was investigated by cell counting and CFU-MK culture. RESULTS: The flow cytometry and immunocytochemistry showed that CD36 antigen was expressed on the surface of Meg-01 cells. TSP-1 (5 µg/ml) inhibited the growth of Meg-01 cells, but had unobvious effect on M-07e cells. After addition of CD36 antibody FA6-152 (5, 10, and 25 µg/ml), the inhibition effect of TSP-1 was significantly reduced. TSP-1 (2.5, 5, and 7.5 µg/ml) increased the positive expression of Annexin V (P<0.01) and caspase-3 activity (P<0.01), which indicated that TSP-1 had a significant effect on inducing apoptosis. After addition of CD36 antibody FA6-152 (25 µg/ml), the apoptosis induced by TSP-1 in Meg-01 cells was significantly reduced. TSP-1 (5, 10, and 25 µg/ml) could significantly inhibit the formation of CFU-MK in mouse bone marrow cells, while ß-TG could not. CD36 antibody FA6-152 (25 µg/ml) could significantly reduce the inhibition of TSP-1 on CFU-MK. CONCLUSION: TSP-1 may induce apoptosis of megakaryocytic leukemia cell line Meg-01 cells via CD36/caspase-3, which provides a potential new drug development and treatment target for clinical treatment of megakaryocytic leukemia.