RESUMO
Human fatty acid synthase (hFAS) is a complex, multifunctional enzyme that is solely responsible for the de novo synthesis of long chain fatty acids. hFAS is highly expressed in a number of cancers, with low expression observed in most normal tissues. Although normal tissues tend to obtain fatty acids from the diet, tumor tissues rely on de novo fatty acid synthesis, making hFAS an attractive metabolic target for the treatment of cancer. We describe here the identification of GSK2194069, a potent and specific inhibitor of the ß-ketoacyl reductase (KR) activity of hFAS; the characterization of its enzymatic and cellular mechanism of action; and its inhibition of human tumor cell growth. We also present the design of a new protein construct suitable for crystallography, which resulted in what is to our knowledge the first co-crystal structure of the human KR domain and includes a bound inhibitor.
Assuntos
3-Oxoacil-(Proteína Carreadora de Acil) Redutase/metabolismo , Inibidores Enzimáticos/metabolismo , Ácido Graxo Sintases/antagonistas & inibidores , Pirrolidinas/metabolismo , Pirrolidinas/farmacologia , Triazóis/metabolismo , Triazóis/farmacologia , 3-Oxoacil-(Proteína Carreadora de Acil) Redutase/química , Domínio Catalítico , Linhagem Celular Tumoral , Ácido Graxo Sintases/química , Humanos , Modelos Moleculares , Conformação Proteica , Difração de Raios XRESUMO
A series of 1,2,4-triazolo[1,5-a]pyrimidin-7(3H)-ones with excellent enzyme inhibition, improved isoform selectivity, and excellent inhibition of downstream phosphorylation of AKT has been identified. Several compounds in the series demonstrated potent (â¼ 0.100 µM IC(50)) growth inhibition in a PTEN deficient cancer cell line.
Assuntos
Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/química , Antineoplásicos/síntese química , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Humanos , PTEN Fosfo-Hidrolase/deficiência , Isoformas de Proteínas/antagonistas & inibidores , Pirimidinas , Relação Estrutura-Atividade , Especificidade por SubstratoRESUMO
A series of PI3K-beta selective inhibitors, imidazo[1,2-a]-pyrimidin-5(1H)-ones, has been rationally designed based on the docking model of the more potent R enantiomer of TGX-221, identified by a chiral separation, in a PI3K-beta homology model. Synthesis and SAR of this novel chemotype are described. Several compounds in the series demonstrated potent growth inhibition in a PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage independent conditions.
Assuntos
Antineoplásicos/síntese química , Imidazóis/síntese química , Inibidores de Fosfoinositídeo-3 Quinase , Inibidores de Proteínas Quinases/síntese química , Pirimidinonas/síntese química , Antineoplásicos/farmacologia , Sítios de Ligação , Neoplasias da Mama , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Deleção de Genes , Humanos , Imidazóis/farmacologia , Isoenzimas/antagonistas & inibidores , Isoenzimas/metabolismo , Cinética , Modelos Moleculares , PTEN Fosfo-Hidrolase/deficiência , PTEN Fosfo-Hidrolase/genética , Fosfatidilinositol 3-Quinase/metabolismo , Ligação Proteica , Inibidores de Proteínas Quinases/farmacologia , Pirimidinonas/farmacologia , Relação Estrutura-AtividadeRESUMO
A novel thiazolopyrimidinone series of PI3K-beta selective inhibitors has been identified. This chemotype has provided an excellent tool compound, 18, that showed potent growth inhibition in the PTEN-deficient breast cancer cell line MDA-MB-468 under anchorage-independent conditions, and it also demonstrated pharmacodynamic effects and efficacy in a PTEN-deficient prostate cancer PC-3 xenograft mouse model.
RESUMO
BACKGROUND: Aurora kinases play critical roles in mitosis and are being evaluated as therapeutic targets in cancer. GSK1070916 is a potent, selective, ATP competitive inhibitor of Aurora kinase B and C. Translation of predictive biomarkers to the clinic can benefit patients by identifying the tumors that are more likely to respond to therapies, especially novel inhibitors such as GSK1070916. METHODS: 59 Hematological cancer-derived cell lines were used as models for response where in vitro sensitivity to GSK1070916 was based on both time and degree of cell death. The response data was analyzed along with karyotype, transcriptomics and somatic mutation profiles to determine predictors of response. RESULTS: 20 cell lines were sensitive and 39 were resistant to treatment with GSK1070916. High chromosome number was more prevalent in resistant cell lines (p-value = 0.0098, Fisher Exact Test). Greater resistance was also found in cell lines harboring polyploid subpopulations (p-value = 0.00014, Unpaired t-test). A review of NOTCH1 mutations in T-ALL cell lines showed an association between NOTCH1 mutation status and chromosome number (p-value = 0.0066, Fisher Exact Test). CONCLUSIONS: High chromosome number associated with resistance to the inhibition of Aurora B and C suggests cells with a mechanism to bypass the high ploidy checkpoint are resistant to GSK1070916. High chromosome number, a hallmark trait of many late stage hematological malignancies, varies in prevalence among hematological malignancy subtypes. The high frequency and relative ease of measurement make high chromosome number a viable negative predictive marker for GSK1070916.
Assuntos
Compostos Aza/farmacologia , Cromossomos Humanos/genética , Neoplasias Hematológicas/enzimologia , Neoplasias Hematológicas/genética , Indóis/farmacologia , Poliploidia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Aurora Quinase B , Aurora Quinases , Ciclo Celular/efeitos dos fármacos , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Diploide , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Neoplasias Hematológicas/patologia , Humanos , Mutação/genética , Fenótipo , Prognóstico , Proteínas Serina-Treonina Quinases/metabolismo , Receptores Notch/genéticaRESUMO
The Aurora kinases play critical roles in the regulation of mitosis and are frequently overexpressed or amplified in human tumors. Selective inhibitors may provide a new therapy for the treatment of tumors with Aurora kinase amplification. Herein we describe our lead optimization efforts within a 7-azaindole-based series culminating in the identification of GSK1070916 (17k). Key to the advancement of the series was the introduction of a 2-aryl group containing a basic amine onto the azaindole leading to significantly improved cellular activity. Compound 17k is a potent and selective ATP-competitive inhibitor of Aurora B and C with K(i)* values of 0.38 +/- 0.29 and 1.5 +/- 0.4 nM, respectively, and is >250-fold selective over Aurora A. Biochemical characterization revealed that compound 17k has an extremely slow dissociation half-life from Aurora B (>480 min), distinguishing it from clinical compounds 1 and 2. In vitro treatment of A549 human lung cancer cells with compound 17k results in a potent antiproliferative effect (EC(50) = 7 nM). Intraperitoneal administration of 17k in mice bearing human tumor xenografts leads to inhibition of histone H3 phosphorylation at serine 10 in human colon cancer (Colo205) and tumor regression in human leukemia (HL-60). Compound 17k is being progressed to human clinical trials.
Assuntos
Compostos Aza/síntese química , Indóis/síntese química , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Animais , Aurora Quinase A , Aurora Quinase B , Aurora Quinases , Compostos Aza/química , Compostos Aza/farmacologia , Linhagem Celular Tumoral , Ensaios de Seleção de Medicamentos Antitumorais , Histonas/metabolismo , Humanos , Indóis/química , Indóis/farmacologia , Camundongos , Transplante de Neoplasias , Fosforilação , Estereoisomerismo , Relação Estrutura-Atividade , Transplante HeterólogoRESUMO
Novel Aurora inhibitors were identified truncating clinical candidate GSK1070916. Many of these truncated compounds retained potent activity against Aurora B with good antiproliferative activity. Mechanistic studies suggested that these compounds, depending on the substitution pattern, may or may not exert their antiproliferative effects via inhibition of Aurora B. The SAR results from this investigation will be presented with an emphasis on the impact structural changes have on the cellular phenotype.
Assuntos
Compostos Aza/química , Indóis/química , Inibidores de Proteínas Quinases/farmacologia , Proteínas Serina-Treonina Quinases/antagonistas & inibidores , Aurora Quinase B , Aurora Quinases , Linhagem Celular Tumoral , Descoberta de Drogas , Citometria de Fluxo , Humanos , Inibidores de Proteínas Quinases/química , Relação Estrutura-AtividadeRESUMO
The protein kinases, Aurora A, B, and C have critical roles in the regulation of mitosis and are frequently overexpressed or amplified in human tumors. GSK1070916, is a novel ATP competitive inhibitor that is highly potent and selective for Aurora B/C kinases. Human tumor cells treated with GSK1070916 show dose-dependent inhibition of phosphorylation on serine 10 of Histone H3, a substrate specific for Aurora B kinase. Moreover, GSK1070916 inhibits the proliferation of tumor cells with EC(50) values of <10 nmol/L in over 100 cell lines spanning a broad range of tumor types. Although GSK1070916 has potent activity against proliferating cells, a dramatic shift in potency is observed in primary, nondividing, normal human vein endothelial cells, consistent with the proposed mechanism. We further determined that treated cells do not arrest in mitosis but instead fail to divide and become polyploid, ultimately leading to apoptosis. GSK1070916 shows dose-dependent inhibition of phosphorylation of an Aurora B-specific substrate in mice and consistent with its broad cellular activity, has antitumor effects in 10 human tumor xenograft models including breast, colon, lung, and two leukemia models. These results show that GSK1070916 is a potent Aurora B/C kinase inhibitor that has the potential for antitumor activity in a wide range of human cancers.