Kawano Takeshi, Horiguchi-Yamada Junko, Iwase Satsuki, Furukawa Yusuke, Kano Yasuhiko, Yamada Hisashi
Department of Molecular Genetics, Institute of DNA Medicine, Jikei University School of Medicine, Minato-ku, Tokyo, Japan.
Mol Cell Biochem. 2004 Mar;258(1-2):25-33. doi: 10.1023/b:mcbi.0000012830.96393.b9.
K562 cells contain a Bcr-Abl chimeric gene and differentiate into various lineages in response to different inducers. We studied the role of the mitogen-activated protein kinase (MAPK) kinase 1 (MEK1)/extracellular signal-regulated kinase (ERK) pathway during the erythroid differentiation of K562 cells induced by tyrosine kinase inhibitors (herbimycin A or STI571), using genetically modified cells (constitutively MEK1-activated K562: K562/MEK1, and inducible ERK-inactivated K562: K562/CL100). Basal expression of glycophorin A was markedly reduced in K562/MEK1 cells compared with that in parental cells, while it was augmented in K562/CL100 cells. Herbimycin A and STI571 differentiated K562 cells accompanying with the transient down-regulated ERK. Moreover, the erythroid differentiation was markedly suppressed in K562/MEK1 cells, and early down-regulation of ERK activity was not observed in these cells. In contrast, the induction of ERK-specific phosphatase in K562/CL100 cells potentiated erythroid differentiation. Once the phosphatase was induced, the initial ERK activity became repressed and its early down-regulation by the inhibition of Bcr-Abl was marked and prolonged. These results demonstrate that the erythroid differentiation of K562 cells induced by herbimycin A or STI571 requires the down-regulation of MEK1/ ERK pathway.
K562细胞含有Bcr-Abl嵌合基因，并能响应不同诱导剂分化为各种谱系。我们使用基因改造细胞（组成型MEK1激活的K562：K562/MEK1，以及可诱导的ERK失活的K562：K562/CL100），研究了丝裂原活化蛋白激酶（MAPK）激酶1（MEK1）/细胞外信号调节激酶（ERK）途径在酪氨酸激酶抑制剂（除草霉素A或STI571）诱导的K562细胞红系分化过程中的作用。与亲本细胞相比，K562/MEK1细胞中血型糖蛋白A的基础表达明显降低，而在K562/CL100细胞中则增加。除草霉素A和STI571使K562细胞分化，同时ERK短暂下调。此外，K562/MEK1细胞中的红系分化明显受到抑制，且在这些细胞中未观察到ERK活性的早期下调。相反，K562/CL100细胞中ERK特异性磷酸酶的诱导增强了红系分化。一旦诱导了磷酸酶，初始的ERK活性就会受到抑制，并且其通过抑制Bcr-Abl引起的早期下调明显且持续时间延长。这些结果表明，除草霉素A或STI571诱导的K562细胞红系分化需要MEK1/ERK途径的下调。
