Published online 26 March 2008
Haematologica, Vol 93, Issue 5, 653-661 doi:10.3324/haematol.12212
Copyright © 2008 by Ferrata Storti Foundation

This Article Full Text Full Text (PDF) Puttini et al. - Supplementary Data Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Puttini, M. Articles by Gambacorti-Passerini, C. Search for Related Content PubMed PubMed Citation Articles by Puttini, M. Articles by Gambacorti-Passerini, C.

Chronic Myeloid Leukemia

Characterization of compound 584, an Abl kinase inhibitor with lasting effects

Miriam Puttini¹, Sara Redaelli¹, Loris Moretti², Stefania Brussolo³, Rosalind H Gunby¹, Luca Mologni¹, Edoardo Marchesi⁴, Loredana Cleris⁴, Arianna Donella-Deana⁵, Peter Drueckes⁶, Elisa Sala¹, Vittorio Lucchini³, Michael Kubbutat⁶, Franca Formelli⁴, Alfonso Zambon³, Leonardo Scapozza², Carlo Gambacorti-Passerini^1,7

¹ Department of Clinical Medicine, University of Milano-Bicocca, S. Gerardo Hospital, Monza, Italy
² Pharmaceutical Biochemistry Group, School of Pharmaceutical Sciences, University of Geneva, University of Lausanne, Geneva, Switzerland
³ Department of Environmental Sciences, University of Ca’ Foscari, Venezia, Italy
⁴ Department of Experimental Oncology, National Cancer Institute, Milan, Italy
⁵ Department of Biological Chemistry University of Padova, Padova, Italy
⁶ ProQinase GmbH, Freiburg, Germany and
⁷ Department of Oncology, McGill University, Montreal, Quebec, Canada

Correspondence: Leonardo Scapozza, PhD, School of Pharmaceutical Sciences, University of Geneva, Quai Ernest-Ansermet 30, 1211 Genève 4, Switzerland. E-mail: leonardo.scapozza{at}pharm.unige.ch

Background: Resistance to imatinib is an important clinical issue in the treatment of Philadelphia chromosome-positive leukemias which is being tackled by the development of new, more potent drugs, such as the dual Src/Abl tyrosine kinase inhibitors dasatinib and bosutinib and the imatinib analog nilotinib. In the current study we describe the design, synthesis and biological properties of an imatinib analog with a chlorine-substituted benzamide, namely compound 584 (cmp-584).

Design and Methods: To increase the potency, we rationally designed cmp-584, a compound with enhanced shape complementarity with the kinase domain of Abl. cmp-584 was synthesized and characterized in vitro against a panel of 67 serine/threonine and tyrosine kinases using radioactive and enzyme-linked immunosorbent kinase assays. We studied inhibitory cellular activity using Bcr/Abl-positive human cell lines, murine transfectants in proliferation experiments, and a murine xenotrans-planted model. Kinase assays on isolated Bcr/Abl protein were also performed. Finally, we used a wash-out approach on whole cells to study the binding kinetics of the inhibitor.

Results: cmp-584 showed potent anti-Abl activity both on recombinant protein (IC₅₀: 8 nM) and in cell-based assays (IC₅₀: 0.1–10 nM). The drug maintained inhibitory activity against platelet-derived growth factor receptors and c-KIT and was also active against Lyn (IC₅₀: 301 nM). No other kinase of the panel was inhibited at nanomolar doses. cmp-584 was 20- to 300-fold more active than imatinib in cells. This superior activity was evident in intact cells, in which full-length Bcr-Abl is present. In vivo experiments confirmed the activity of cmp-584. Wash-out experiments showed that short exposure to the drug impaired cell proliferation and Bcr-Abl phosphorylation for a substantially longer period of time than imatinib.

Conclusions: The present results suggest a slower off-rate (dissociation rate) of cmp-584 compared to imatinib as an explanation for the increased cellular activity of the former.

Key words: Abl, tyrosine kinase inhibitor, off-rate, imatinib analog.