Growth inhibition and apoptosis of human leukemia K562 cells induced by seleno-short-chain chitosan

In this article, the in vitro effects of seleno-short-chain chitosan (SSCC, molecular weight between 5,000 and 10,000 Da) on the proliferation of human leukemia K562 cells were investigated to illustrate the possible mechanisms involved. 3-[4,5-Dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assays showed that short-chain chitosan significantly suppressed the growth of K562 cells in a dose-dependent and time-dependent manner, although normal mouse embryonic fibroblasts NIH3T3 were viable after the same treatment. Cell growth inhibitory rate could reach 95% after exposure with more than 100 mu g/ml SSCC for 72 h. Flow cytometry analysis revealed that treatment of K562 cells with SSCC resulted in the accumulation of cells in the G(2)/M phase. The growth inhibition of K562 cells after treatment with SSCC was subsequently associated with the induction of apoptosis, as evidenced by (1) the typical apoptotic morphologic changes measured by a fluorescence microscope, (2) the internucleosomal DNA fragmentation into a ladder determined by agarose gel electrophoresis and (3) the occurrence of sub-G(0)/G(1), phase cells analyzed by flow cytometry. All these results indicated that SSCC may have therapeutic potential in human leukemia treatment. copyright 2008 Prous Science, S.A.U. or its licensors. All rights reserved.