BCR-ABL but Not JAK2 V617F Inhibits Erythropoiesis through the Ras Signal by Inducing p21CIP1/WAF1

Masahiro Tokunaga,Sachiko Ezoe,Hirokazu Tanaka,Yusuke Satoh,Kentaro Fukushima,Keiko Matsui,Masaru Shibata,Akira Tanimura,Kenji Oritani,Itaru Matsumura,Yuzuru Kanakura

doi:10.1074/jbc.m110.118653

Masahiro Tokunaga, Sachiko Ezoe + Show 9 more

Open Access

https://doi.org/10.1074/jbc.m110.118653

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Abstract

BCR-ABL is a causative tyrosine kinase (TK) of chronic myelogenous leukemia (CML). In CML patients, although myeloid cells are remarkably proliferating, erythroid cells are rather decreased and anemia is commonly observed. This phenotype is quite different from that observed in polycythemia vera (PV) caused by JAK2 V617F, whereas both oncogenic TKs activate common downstream molecules at the level of hematopoietic stem cells (HSCs). To clarify this mechanism, we investigated the effects of BCR-ABL and JAK2 V617F on erythropoiesis. Enforced expression of BCR-ABL but not of JAK2 V617F in murine LSK (Lineage(-)Sca-1(hi)CD117(hi)) cells inhibited the development of erythroid cells. Among several signaling molecules downstream of BCR-ABL, an active mutant of N-Ras (N-RasE12) but not of STAT5 or phosphatidylinositol 3-kinase (PI3-K) inhibited erythropoiesis, while N-RasE12 enhanced the development of myeloid cells. BCR-ABL activated Ras signal more intensely than JAK2 V617F, and inhibition of Ras by manumycin A, a farnesyltransferase inhibitor, ameliorated erythroid colony formation of CML cells. As for the mechanisms of Ras-induced suppression of erythropoiesis, we found that GATA-1, an erythroid-specific transcription factor, blocked Ras-mediated mitogenic signaling at the level of MEK through the direct interaction. Furthermore, enforced expression of N-RasE12 in LSK cells derived from p53-, p16(INK4a)/p19(ARF)-, and p21(CIP1/WAF1)-null/wild-type mice revealed that suppressed erythroid cell growth by N-RasE12 was restored only by p21(CIP1/WAF1) deficiency, indicating that a cyclin-dependent kinase (CDK) inhibitor, p21(CIP1/WAF1), plays crucial roles in Ras-induced suppression of erythropoiesis. These data would, at least partly, explain why respective oncogenic TKs cause different disease phenotypes.

Highlights

Sports, and Culture and Technology of Japan. □S The on-line version of this article contains supplemental Table S1 and Methods. 1 To whom correspondence should be addressed
The activated Ras is considered to be essential for the pathogenesis of chronic myelogenous leukemia (CML), and is speculated to principally determine the disease phenotype of CML, that is, prominent proliferation of myeloid cells accompanied by the suppressed erythropoiesis
We showed that a cyclin-dependent kinase (CDK) inhibitor, p21CIP1/WAF1, plays crucial roles in Ras-induced suppression of erythropoiesis using p21CIP1/WAF1deficient hematopoietic cells

Summary

Introduction

Culture and Technology of Japan. □S The on-line version of this article (available at http://www.jbc.org) contains supplemental Table S1 and Methods. 1 To whom correspondence should be addressed. We found that BCR-ABL but not JAK2 V617F, and among their downstream molecules, Ras but not STAT5 or PI3-K suppress erythropoiesis from murine LSK cells.

Results

Conclusion