title: Modification by heme oxygenase inhibitor, tin protoporphyrin, of cellular differentiation of human myeloid leukemia K562 cell line.
abstract: Human myeloid leukemia K562 cells can be induced to differentiate to mature cells bidirectionally, i.e., hemin induces erythroid differentiation, while 12-O-tetradecanoylphorbol 13-acetate (TPA) induces differentiation to monocytes. TPA is also a potent inducer of heme oxygenase (HO), which catabolizes heme to biliverdin. We show here that TPA suppresses hemin-induced erythroid differentiation of K562 cells, while retinoids augment it. Further, an HO inhibitor, tin protoporphyrin (SnPP), suppresses TPA-induced K562 cell differentiation to monocytes. It was also found that co-treatment of K562 cells with SnPP and TPA induces erythroid differentiation of K562 cells, though SnPP alone or TPA alone does not induce erythroid differentiation, suggesting a role of HO in the directional switch of differentiation.
mesh_terms: D002454:Cell Differentiation / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006419:Heme Oxygenase (Decyclizing) / Q000037:antagonists & inhibitors*; D006801:Humans; D020014:K562 Cells; D008665:Metalloporphyrins / Q000494:pharmacology*; D011524:Protoporphyrins / Q000494:pharmacology*; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology