[Effect of crocidolite fibers on the cathepsin B-like enzyme activity in HL-60 cells].

In a previous study, we found that crocidolite (an asbestos fiber) had an inhibitory effect on the differentiation process of HL-60 cells induced by dimethyl sulfoxide (DMSO). Here we describe the cathepsin B-like enzyme HL-60 cells and the changes of its activity during cell differentiation with or without crocidolite treatment. The cathepsin B-like enzyme in HL-60 cell extracts had almost the same characteristics and the already known cathepsin B as for the pH optima and the effects of proteinase inhibitors. The cathepsin B-like enzyme activity increased according to the cell differentiation induced by DMSO, however, its activity was depressed by crocidolite treatment.