[Efficacy of diacetyl hexamethylene diamine in treatment of patients with high risk myelodysplastic syndrome].

The aim of this study was to investigate the efficacy of diacetyl hexamethylene diamine (CAHB) for patients with high risk myelodysplastic syndrome (MDS), and to explore the effect of CAHB on HL-60 cells in vitro and its possible mechanism. 8 patients with high risk MDS were treated with CAHB by continuous intravenous infusion for 10 days, and repeated once after an interval of 28 days. The count of the granulo- and mono-blasts in bone marrow (BM) aspirate was measured before and after treatment. HL-60 cells were treated with different concentrations of CAHB for 72 hours in vitro. The inhibitory effect of CAHB on proliferation of HL-60 cells in vitro was measured by MTT assay. Differentiation of HL-60 cells was detected by the changes of CD11b and CD14 expression on cell surface. Apoptosis of HL-60 cells was detected by double staining of Annexin V and PI. The cell cycle distribution change of HL-60 cells was analyzed by flow-cytometry. The results indicated that the granulo- and mono-blasts in BM decreased in all the 8 patients after CAHB treatment. The main side effect of CAHB on hematological system was thrombocytopenia. After being treated with 1, 2, 3, 4 mmol/L CAHB for 72 hours in vitro, the result of MTT assay showed the inhibitory effect of CAHB on the proliferation of HL-60 cells in dose-dependent manner. After being treated manner 1, 2, 3, 4 mmol/L CAHB for 72 hours, the CD11b positive HL-60 cells were 22.39+/-3.97%, 33.12+/-4.46%, 49.25+/-5.27%, 78.05+/-5.66%, respectively, which were significantly different from the control group (CD11b positive HL-60 cells was 5.89+/-2.94%) (p<0.01). The CD14 expression was negative in all the 5 groups. These results suggested that CAHB could induce HL-60 cells to differentiate into mature granulocytes, and the effect of CAHB appeared in dose-dependent manner. After being treated for 72 hours by 1, 2, 3, 4 mmol/L CAHB, the apoptotic cells (Annexin V(+)/PI(-) cells) increased mildly, which suggested that CAHB only weakly induces HL-60 cells to apoptosis at the concentration of 1 to 4 mmol/L. Along with the concentration increase of CAHB, the ratio of cells in G(0)/G(1) phase increased, and ratio of cells in S phase and G(2)/M phase decreased correspondingly, it indicated that CAHB could arrest HL-60 cells in G(0)/G(1) phase in a dose-dependent manner. It is concluded that induction of cell differentiation may be the primary effect of CAHB on MDS. Cell cycle arrest may be essential to the effect of CAHB as well. Side effect of CAHB on platelet count may correlated with its inhibitory effect on hematopoiesis.