CROCIDOLITE ASBESTOS SUPPRESSES THE DIFFERENTIATION OF HL-60 CELLS INDUCED BY DMSO

This study was undertaken to determine if the biological function of i nducers for cell differentiation is affected by asbestos fibers, which are sometimes deposited in human tissues. Protein kinase C activity, c-myc protein expression and cell surface CR3 expression were used as the markers of cell differentiation. The function of dimethylsulfoxide (DMSO), an inducer of cell differentiation, was suppressed by the co- culturing of crocidolite asbestos, because DMSO reacted with the hydro xyl radical released after the stimulation with crocidolite and spent itself. Superoxide dismutase (SOD) inhibited the effect of crocidolite , reacting rapidly with .O2- before the secondary release of .OH. Asbe stos fibers deposited in tissues may inhibit the function of inducers which stimulate immature cells to differentiate, because such inducers frequently are also radical scavengers.