著者

小磯 邦子 中島 修 松村 大輔 藤本 康之 橋本 祐一

出版者

公益社団法人日本薬学会

雑誌

藥學雜誌 = Journal of the Pharmaceutical Society of Japan (ISSN:00316903)

巻号頁・発行日

vol.120, no.1, pp.104-112, 2000-01-01

---

Human myeloid leukemia K562 cells can be induced to differentiate to mature cells bidirectionary, i.e., hemin induces erythroid differentiation, while 12-O-tetradecanoylphorbol 13-acetate (TPA) induces differentiation to monocytes. The differentiation-inducing activity of various hemin-related compounds suggested certain structural requirements for the activity : 1) the iron moiety of hemin is not essential, and 2) the propionic acid side chains of hemin play an important role in the differntiation and induction. In addition, we have examined the influence of some bioresponsemodifying factors on hemin/protoporphyrin IX-induced differentiation of K562 cell line. Retinoids and tubulindisruptors, themselves did not induce differentiation, enhanced hemin/protoporphyrin IX-induced differentiation of K562 cells. We also examined the possible involvement of peripheral-type benzodiazepine receptor (PBR) in hemin/protoporphyrin IX-induced differentiation on K562 cell lines. The PBR specific ligands modified hemin-induced differentiation. These results suggest a requirement for retinoids (or retinoids-like cofactors) for hemin/protoporphyrin IX-induced differentiation of K562 cells and the involvement of PBR in erythroid differentiation of K562 cell line. Further we showed that TPA suppresses hemin-induduced erythroid differentiation of K562 cells, while retinoids augment it. TPA is a potent inducer of heme oxygenase (HO), which catabolizes heme to biliverdin. An HO inhibitor, tin protoporphyrin (SnPP), suppresses TPA-induced K562 cell differentiation to monocytes. It was also found that cotreatment 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.