Open Access Research article

Allosteric inhibition enhances the efficacy of ABL kinase inhibitors to target unmutated BCR-ABL and BCR-ABL-T315I

Afsar Ali Mian1, Anna Metodieva1, Susanne Badura1, Mamduh Khateb2, Nili Ruimi2, Yousef Najajreh3, Oliver Gerhard Ottmann1, Jamal Mahajna24 and Martin Ruthardt15*

Author affiliations

1 Department of Hematology, Goethe University, Frankfurt, Germany

2 Cancer Drug Discovery, Migal-Galilee Technology Center, Kiryat Shmona, Israel

3 Faculty of Pharmacy, Al-Quds University, Jerusalem-Abu Dies, Palestine

4 Departments of Nutritional Sciences, Tel Hai Academic College, Kiryat Shmona, Israel

5 Labor für Tumorstammzellbiologie, Med. Klinik II/Hämatologie, Klinikum der Goethe Universität Frankfurt, Theodor Stern Kai 7, 60590, Frankfurt, Germany

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Citation and License

BMC Cancer 2012, 12:411  doi:10.1186/1471-2407-12-411

Published: 17 September 2012

Abstract

Background

Chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive (Ph+) acute lymphatic leukemia (Ph + ALL) are caused by the t(9;22), which fuses BCR to ABL resulting in deregulated ABL-tyrosine kinase activity. The constitutively activated BCR/ABL-kinase “escapes” the auto-inhibition mechanisms of c-ABL, such as allosteric inhibition. The ABL-kinase inhibitors (AKIs) Imatinib, Nilotinib or Dasatinib, which target the ATP-binding site, are effective in Ph + leukemia. Another molecular therapy approach targeting BCR/ABL restores allosteric inhibition. Given the fact that all AKIs fail to inhibit BCR/ABL harboring the ‘gatekeeper’ mutation T315I, we investigated the effects of AKIs in combination with the allosteric inhibitor GNF2 in Ph + leukemia.

Methods

The efficacy of this approach on the leukemogenic potential of BCR/ABL was studied in Ba/F3 cells, primary murine bone marrow cells, and untransformed Rat-1 fibroblasts expressing BCR/ABL or BCR/ABL-T315I as well as in patient-derived long-term cultures (PDLTC) from Ph + ALL-patients.

Results

Here, we show that GNF-2 increased the effects of AKIs on unmutated BCR/ABL. Interestingly, the combination of Dasatinib and GNF-2 overcame resistance of BCR/ABL-T315I in all models used in a synergistic manner.

Conclusions

Our observations establish a new approach for the molecular targeting of BCR/ABL and its resistant mutants using a combination of AKIs and allosteric inhibitors.

Keywords:
Philadelphia chromosome; BCR/ABL; “gatekeeper” mutation T315I; Allosteric inhibition; Abl kinase inhibitors; Molecular therapy