[Effect of HMBA on differentiation and apoptosis of HL-60 and U937 cells and its mechanism].

OBJECTIVES:To explore the effect of hexamethylene bisacetamide (HMBA) on the differentiation and apoptosis of HL-60 and U937 cells, and its mechanism. METHODS:Flow cytometry was used to evaluate the expressions of cellular surface antigen CD(11b), CD(14), apoptotic marker Annexin V, cell cycle distribution and endocytic antigen cyclin D, cyclin E and p27. Changes of c-myc, Rb, Bcl-2 gene mRNA levels were detected by RT-PCR. RESULTS:After 72 hours of HMBA treatment, CD(11b) expressions increased significantly, apoptosis increased under high-dose HMBA, cells were arrested in G(0)/G(1) phase and reduced cyclin E, increased cyclin D and p27 were significant in a dose-dependent manner in HL-60 and U937 cells. RT-PCR showed that c-myc and bcl-2 mRNA was significantly down-regulated and Rb mRNA up-regulated in HL-60 and U937 cells. CONCLUSION:HMBA can induce the differentiation of HL-60 and U937 cells, while apoptosis of these cell is induced only by high dose of HMBA. The possible mechanism of HMBA inducing differentiation might be related to the changes of cell cycle regulators and certain proliferation and differentiation related genes.