FLT3/ITD regulates leukaemia cell adhesion through α4β1 integrin and Pyk2 signalling

Akira Katsumi, Hitoshi Kiyoi, Akihiro Abe, Ryohei Tanizaki, Toshihiro Iwasaki, Miki Kobayashi, Tadashi Matsushita, Kozo Kaibuchi, Takeshi Senga, Tetsuhito Kojima, Takayuki Kohno, Michinari Hamaguchi, Tomoki Naoe

Research output: Contribution to journalArticlepeer-review

17 Citations (Scopus)


Internal tandem duplication of FMS-like receptor tyrosine kinase 3 (FLT3/ITD) within its juxtamembrane domain is a frequent mutation in adult acute myeloid leukaemia (AML). This mutation causes constitutive activation of FLT3 and is associated with poor prognosis. The high relapse rate of FLT3/ITD-positive AML might be partly because of insufficient eradication of slow-cycling leukaemic stem cells in the bone marrow microenvironment. β1 integrin mediates haematopoietic stem and progenitor cell homing along with their retention in the bone marrow and also inhibits haematopoietic proliferation and differentiation. Here, we demonstrate that inhibition of FLT3/ITD kinase activity by a FLT3 selective inhibitor named FI-700 decreases affinity of α4β1 integrin to soluble VCAM-1. α4β1 integrin deactivation by FI-700 is independent of Rap1, which is the critical regulator of integrin inside-out signalling. In addition, selective inhibition of FLT3/ITD induces Pyk2 dephosphorylation together with the inhibition of phosphatidylinositol-3-kinase (PI3K)/Akt pathway. Both wild-type and ITD-FLT3 proteins co-immunoprecipitated with β1 integrin and Pyk2 indicating the signal crosstalk between FLT3, β1 integrin and Pyk2. These results collectively indicated that the inhibition of FLT3 kinase might contribute not only to the induction of apoptosis, but also to the leukaemia cell detachment from the bone marrow microenvironment in the treatment of AML.

Original languageEnglish
Pages (from-to)191-198
Number of pages8
JournalEuropean Journal of Haematology
Issue number3
Publication statusPublished - 03-2011
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Hematology


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