RESUMO
Chronic myeloid leukemia (CML) is a pathological condition associated with the uncontrolled proliferation of white blood cells and respective loss of function. Imatinib was the first drug that could effectively treat this condition, but its use is hindered by the development of mutations of the BCR-ABL protein, which are the cause of resistance. Therefore, dasatinib and afatinib present similarities that can be explored to discover new molecules capable of overcoming the effects of imatinib. Afatinib exhibited electronic and docking behavior, indicating that a replacement with some minor modifications could design a new potential inhibitor. The amide group in each candidate is clearly of pharmacophoric importance, and it needs to concentrate a negative region. Sulfur group presents a good pharmacophoric profile, which was shown by dasatinib results, adding to the influence of the Met318 residue in the target protein active site configuration. This behavior suggests that the sulfur atom and other fragments that have an affinity for the methionine sidechain may provide a significant positive effect when present in TKI molecules such as afatinib or dasatinib.
Assuntos
Afatinib/química , Dasatinibe/química , Proteínas de Fusão bcr-abl/química , Afatinib/metabolismo , Afatinib/farmacologia , Antineoplásicos/química , Antineoplásicos/metabolismo , Domínio Catalítico , Dasatinibe/metabolismo , Dasatinibe/farmacologia , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Proteínas de Fusão bcr-abl/genética , Proteínas de Fusão bcr-abl/metabolismo , Humanos , Mesilato de Imatinib/química , Mesilato de Imatinib/metabolismo , Mesilato de Imatinib/farmacologia , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Metionina/química , Simulação de Acoplamento Molecular , Mutação , Teoria Quântica , Enxofre/químicaRESUMO
Drug resistance is a serious problem in cancer, viral, bacterial, fungal and parasitic diseases. Examination of crystal structures of protein-drug complexes is often not enough to explain why a certain mutation leads to drug resistance. As an example, the crystal structure of the kinase inhibitor dasatinib bound to the Abl1 kinase shows a hydrogen bond between the drug and residue Thr315 and very few contacts between the drug and residues Val299 and Phe317, yet mutations in those residues lead to drug resistance. In the first case, it is tempting to suggest that the loss of a hydrogen bond leads to drug resistance, whereas in the other two cases it is not known why mutations lead to drug resistance in the first place. We carried out extensive molecular dynamics (MD) simulations and free energy calculations to explain drug resistance to dasatinib from a molecular point of view and show that resistance is due to a multitude of subtle effects. Importantly, our calculations could reproduce the experimental values for the binding energies upon mutations in all three cases and shed light on their origin.
Assuntos
Dasatinibe/farmacologia , Resistência a Medicamentos/efeitos dos fármacos , Inibidores de Proteínas Quinases/farmacologia , Proteínas Proto-Oncogênicas c-abl/antagonistas & inibidores , Dasatinibe/química , Humanos , Ligação de Hidrogênio , Simulação de Dinâmica Molecular , Inibidores de Proteínas Quinases/química , Proteínas Proto-Oncogênicas c-abl/metabolismo , TermodinâmicaRESUMO
BACKGROUND: Isocitrate dehydrogenase 1 (IDH1) is a dimeric enzyme responsible for supplying the cell's nicotinamide adenine dinucleotide phosphate (NADPH) reserves via dehydrogenation of isocitrate (ICT) and reduction of NADP+. Mutations in position R132 trigger cancer by enabling IDH1 to produce D-2-hydroxyglutarate (2-HG) and reduce inhibition by ICT. Mutant IDH1 can be found as a homodimer or a heterodimer. OBJECTIVE: We propose a novel strategy to inhibit IDH1 R132 variants as a means not to decrease the concentration of 2-HG but to provoke a cytotoxic effect, as the cell malignancy at this point no longer depends on 2-HG. We aim to inhibit the activity of the mutant heterodimer to block the wild-type subunit. Limiting the NADPH reserves in a cancerous cell will enhance its susceptibility to the oxidative stress provoked by chemotherapy. METHODS: We performed a virtual screening using all US FDA-approved drugs to replicate the loss of inhibition of mutant IDH1 by ICT. We characterized our results based on molecular interactions and correlated them with the described phenotypes. RESULTS: We replicated the loss of inhibition by ICT in mutant IDH1. We identified 20 drugs with the potential to inhibit the heterodimeric isoform. Six of them are used in cancer treatment. CONCLUSIONS: We present 20 FDA-approved drugs with the potential to inhibit IDH1 wild-type activity in mutated cells. We believe this work may provide important insights into current and new approaches to dealing with IDH1 mutations. In addition, it may be used as a basis for additional studies centered on drugs presenting differential sensitivities to different IDH1 isoforms.