Nonspecific esterases of leukemia cell lines: evidence for activation of myeloid-associated zymogens in HL-60 by phorbol esters.

Myeloid leukemia cell line HL-60 contains fluoride-sensitive, myeloid-associated isoenzymes of nonspecific esterase that increase in activity when cultures are treated with phorbol ester. These isoenzymes are not detectable in B-lymphoblast cell line KLM-2, either in control or in phorbol-ester-treated cultures. No increased de novo synthesis of the isoenzymes is detectable in HL-60 treated with phorbol ester. The data suggest stimulated conversion of a preformed, myeloid-associated zymogen in HL-60.