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Exp Hematol. 2016 Mar;44(3):177-88.e5. doi: 10.1016/j.exphem.2015.11.009. Epub 2015 Dec 15.

Ph-like ALL-related novel fusion kinase ATF7IP-PDGFRB exhibits high sensitivity to tyrosine kinase inhibitors in murine cells.

Author information

1
Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan; Department of Pediatrics and Adolescent Medicine, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan.
2
Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan.
3
Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan; Department of Industrial Chemistry, Faculty of Engineering, Tokyo University of Science, Shinjuku-ku, Tokyo, Japan.
4
Department of Pediatrics and Adolescent Medicine, Juntendo University Graduate School of Medicine, Bunkyo-ku, Tokyo, Japan.
5
Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan. Electronic address: kiyokawa-n@ncchd.go.jp.

Abstract

ATF7IP-PDGFRB is a novel PDGFRB-related fusion gene identified in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) with a signature similar to that of Ph1 ALL, so-called Ph-like ALL. When we introduced ATF7IP-PDGFRB, murine Ba/F3 cells acquired the ability to proliferate in an interleukin (IL)-3-independent manner. On the contrary, the expression of wild-type PDGFRB is not sufficient to acquire the ability for IL-3-independent proliferation in Ba/F3 cells. The introduction of ATF7IP-PDGFRB also induces a typical gene expression profile for Ph1-ALL in Ba/F3 cells. A series of biochemical and cell biological experiments revealed the constitutive activation of ATF7IP-PDGFRB as well as downstream signaling molecules, including AKT and MAPK. Although the phosphoinositide 3-kinase inhibitor led to cell death in both cells into which ATF7IP-PDGFRB had been introduced and IL-3-maintained Mock cells, MEK inhibitor selectively led to cell death into which ATF7IP-PDGFRB had been introduced. The introduction of tyrosine to phenylalanine mutations at binding sites of adaptor molecules important in the MAPK pathway located in the PDGFRB portion abolished ATF7IP-PDGFRB-mediated cell transformation, suggesting that MAPK-mediated signals are critical in ATF7IP-PDGFRB-mediated cell transformation. On treatment with tyrosine kinase inhibitors, ATF7IP-PDGFRB-expressing, but not Mock, Ba/F3 cells underwent rapid apoptosis accompanied by reduced phosphorylation of MAPK. Importantly, the sensitivity of ATF7IP-PDGFRB-expressing Ba/F3 cells to imatinib is significantly higher than that of BCR-ABL1-transformed Ba/F3 cells, as assessed by the IC50. Taken together, ATF7IP-PDGFRB has transforming potential via the constitutive activation of MAPK and participates in the pathogenesis of Ph-like ALL. Our observations suggest the therapeutic importance of tyrosine kinase inhibitors and possibly MEK inhibitor for a subset of BCP-ALL harboring PDGFRB-related fusion kinases.

PMID:
26703895
DOI:
10.1016/j.exphem.2015.11.009
[Indexed for MEDLINE]

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