Transglutaminase activity increases in HL60 cells induced to differentiate with retinoic acid and TPA but not with DMSO.

HL60 cells induced to differentiate into myeloid cells by retinoic acid exhibited a 300-fold increase in transglutaminase (TGase) activity which peaked on day 5. HL60 cells induced to differentiate into monocytes by a phorbol ester tetradecanoylphorbol-12-myristate-13-acetate (TPA) had a greater than 840-fold increase in TGase activity on day 7. In contrast, cells induced to differentiate along the myeloid pathway by dimethyl sulfoxide (DMSO) exhibited no increase in TGase activity. Elevation of TGase activity appears to be characteristic of monocyte differentiation and retinoic acid-induced myeloid differentiation but not of myeloid differentiation in response to DMSO.