Journal Article

Targeting Bcr–Abl by combining allosteric with ATP-binding-site inhibitors

Strauss, André, Sim, Taebo, Dierks, Christine, Guo, Gui-Rong, Grzesiek, Stephan, Gray, Nathanael S., Adrián, Francisco J., Wojciechowski, Amy, Bursulaya, Badry, Zhang, Jianming, Engen, John R., Iacob, Roxana E., Sun, Fangxian, Liu, Yi, Azam, Mohammad, Li, Allen G., Vajpai, Navratna, Okram, Barun, Choi, Yongmun, Deng, Xianming, Ding, Qiang, Daley, George Q., Cowan-Jacob, Sandra W., Tuntland, Tove, Manley, Paul W., Liu, Guoxun, Powers, John, Fendrich, Gabriele, Warmuth, Markus, Jahnke, Wolfgang

2010

Overview

In an effort to find new pharmacological modalities to overcome resistance to ATP-binding-site inhibitors of Bcr–Abl, we recently reported the discovery of GNF-2, a selective allosteric Bcr–Abl inhibitor. Here, using solution NMR, X-ray crystallography, mutagenesis and hydrogen exchange mass spectrometry, we show that GNF-2 binds to the myristate-binding site of Abl, leading to changes in the structural dynamics of the ATP-binding site. GNF-5, an analogue of GNF-2 with improved pharmacokinetic properties, when used in combination with the ATP-competitive inhibitors imatinib or nilotinib, suppressed the emergence of resistance mutations in vitro , displayed additive inhibitory activity in biochemical and cellular assays against T315I mutant human Bcr–Abl and displayed in vivo efficacy against this recalcitrant mutant in a murine bone-marrow transplantation model. These results show that therapeutically relevant inhibition of Bcr–Abl activity can be achieved with inhibitors that bind to the myristate-binding site and that combining allosteric and ATP-competitive inhibitors can overcome resistance to either agent alone. Targeting Bcr–Abl tumours The success of Bcr–Abl tyrosine kinase inhibitors such as imatinib (Gleevec) in treating chronic myelogenous leukaemia (CML) has generated intense interest in the potential of targeting signal transduction mechanisms to create new anticancer drugs. But the picture is complicated by the emergence of inhibitor-resistant kinase alleles. One way to overcome these resistant mutants is to design new ATP-competitive inhibitors, as demonstrated by the second-generation Bcr–Abl inhibitors nilotinib and dasatinib. Zhang et al . have pursued an alternative approach by developing inhibitors that can regulate kinase activity by binding outside of the ATP-binding site. They now demonstrate that GNF-2, a selective allosteric Bcr–Abl inhibitor, binds to the myristate-binding site of the Abl protein. When GNF-5, an analogue of GNF-2 with improved pharmacokinetic properties, was used in combination with imatinib or nilotinib, the emergence of drug-resistance mutations was suppressed in vitro . In addition, the combination of the two classes of small molecules displayed efficacy in vivo against the recalcitrant T315I Bcr–Abl mutant in a murine bone-marrow transplantation model. These results indicate that the combination of allosteric and ATP-competitive inhibitors can overcome resistance to either agent alone. GNF-2 is a recently discovered, selective allosteric Bcr–Abl inhibitor. Solution NMR, X-ray crystallography, mutagenesis and hydrogen exchange mass spectrometry are now used to show that GNF-2 binds to the myristate-binding site of Abl, leading to changes in the structural dynamics of the ATP-binding site. The results show that the combination of allosteric and ATP-competitive inhibitors can overcome resistance to either agent alone.

• Publisher: Nature Publishing Group UK,Nature Publishing Group
• Subject: 631/250/1904 / 631/45/535 / 631/92/436 / 692/700/565/1436/1437 / Alleles / Analysis / Animals / Antineoplastic agents / Antineoplastic Agents - chemistry / Antineoplastic Agents - metabolism / Antineoplastic Agents - pharmacology / Antineoplastic Combined Chemotherapy Protocols / ATP / ATPases / Benzamides / Binding proteins / Binding Sites / Biochemistry / Biological and medical sciences / Bone marrow / Bone Marrow Transplantation / Cell Line, Tumor / Cellular signal transduction / Chromosome abnormalities / Chronic myeloid leukemia / Competition / Crystal structure / Crystallization / Crystallography / Dasatinib / Diagnosis / Disease Models, Animal / Drug resistance / Drug resistance in microorganisms / Drug Resistance, Neoplasm - drug effects / Drug therapy / E coli / Enzymes / Female / Fundamental and applied biological sciences. Psychology / Fusion Proteins, bcr-abl - chemistry / Fusion Proteins, bcr-abl - genetics / Fusion Proteins, bcr-abl - metabolism / Gene mutations / Genetic aspects / Health aspects / Humanities and Social Sciences / Humans / Hydrogen / Imatinib Mesylate / Inhibitors / Inhibitory Concentration 50 / Kinases / Leukemia / Leukemia, Myelogenous, Chronic, BCR-ABL Positive - drug therapy / Leukemia, Myelogenous, Chronic, BCR-ABL Positive - enzymology / Leukemia, Myelogenous, Chronic, BCR-ABL Positive - metabolism / Male / Mass Spectrometry / Mice / Models, Molecular / Molecular and cellular biology / multidisciplinary / Mutation - genetics / Nilotinib / Nuclear magnetic resonance spectroscopy / Observations / Pharmacokinetics / Phenols (Class of compounds) / Physiological aspects / Piperazines - chemistry / Piperazines - pharmacology / Protein binding / Protein Structure, Tertiary / Proteins / Pyrimidines - chemistry / Pyrimidines - metabolism / Pyrimidines - pharmacology / Science / Spectroscopy / Studies / Surgery / Transplantation, Heterologous / Tumors / Tyrosine / X-ray crystallography