MK-886 enhances tumour necrosis factor-α-induced differentiation and apoptosis

We investigated the role of the 5-lipoxygenase (5-LOX) pathway of arachidonic acid metabolism in tumour necrosis factor-α (TNF-α)-induced differentiation of human leukemic HL-60 cells using MK-886, an inhibitor of 5-LOX activating protein. MK-886 augmented cell cycle arrest and differentiation induced by TNF-α; however, both effects were probably 5-LOX-independent, because a general LOX inhibitor, NDGA, had no effect. Apoptosis was significantly elevated after combined TNF-α and MK-886 treatment, which could be partially associated with changes of Mcl-1 protein expression. NF-κB signalling or activation of JNKs were not modulated by MK-886. Thus, in addition to apoptosis, MK-886 can enhance TNF-α-induced differentiation.