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1.
Cancer Discov ; 5(10): 1049-57, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26216294

RESUMO

UNLABELLED: Oncogenic TRK fusions induce cancer cell proliferation and engage critical cancer-related downstream signaling pathways. These TRK fusions occur rarely, but in a diverse spectrum of tumor histologies. LOXO-101 is an orally administered inhibitor of the TRK kinase and is highly selective only for the TRK family of receptors. Preclinical models of LOXO-101 using TRK-fusion-bearing human-derived cancer cell lines demonstrate inhibition of the fusion oncoprotein and cellular proliferation in vitro, and tumor growth in vivo. The tumor of a 41-year-old woman with soft-tissue sarcoma metastatic to the lung was found to harbor an LMNA-NTRK1 gene fusion encoding a functional LMNA-TRKA fusion oncoprotein as determined by an in situ proximity ligation assay. In a phase I study of LOXO-101 (ClinicalTrials.gov no. NCT02122913), this patient's tumors underwent rapid and substantial tumor regression, with an accompanying improvement in pulmonary dyspnea, oxygen saturation, and plasma tumor markers. SIGNIFICANCE: TRK fusions have been deemed putative oncogenic drivers, but their clinical significance remained unclear. A patient with a metastatic soft-tissue sarcoma with an LMNA-NTRK1 fusion had rapid and substantial tumor regression with a novel, highly selective TRK inhibitor, LOXO-101, providing the first clinical evidence of benefit from inhibiting TRK fusions.


Assuntos
Antineoplásicos/uso terapêutico , Proteínas de Fusão Oncogênica/genética , Proteínas Oncogênicas/genética , Inibidores de Proteínas Quinases/uso terapêutico , Pirazóis/uso terapêutico , Pirimidinas/uso terapêutico , Sarcoma/tratamento farmacológico , Sarcoma/genética , Adulto , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Transformação Celular Neoplásica/genética , Relação Dose-Resposta a Droga , Feminino , Humanos , Lamina Tipo A/genética , Estadiamento de Neoplasias , Proteínas Oncogênicas/antagonistas & inibidores , Proteínas de Fusão Oncogênica/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Pirazóis/farmacologia , Pirimidinas/farmacologia , Sarcoma/diagnóstico , Tomografia Computadorizada por Raios X , Resultado do Tratamento
2.
Clin Lymphoma Myeloma Leuk ; 13(5): 584-91, 2013 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-23787123

RESUMO

INTRODUCTION: Omacetaxine mepesuccinate (omacetaxine) is a first-in-class cephalotaxine that has demonstrated efficacy in CML. In this analysis we evaluated omacetaxine in CML patients with resistance or intolerance to 2 or more tyrosine kinase inhibitors (TKIs). PATIENTS AND METHODS: Data were pooled from 2 phase II trials of subcutaneous omacetaxine, administered at 1.25 mg/m(2) twice daily for 14 consecutive days every 28 days until response, then for 7 days every 28 days as maintenance. Patients with resistance or intolerance to imatinib and at least 1 other approved TKI (dasatinib and/or nilotinib) were included; results for patients in chronic phase (CP) are reported here. Major cytogenetic response (MCyR) was the primary end point. RESULTS: Eighty-one patients with CML-CP (median age, 59 years; range, 26-83 years) were included in the analysis. All patients previously received imatinib, 69 (85%) previously received dasatinib, and 48 (59%) previously received nilotinib. Median omacetaxine exposure was 7.5 months (range, 0.03-38.6 months), with 13 patients ongoing. MCyR was reported in 16 patients (20%; one-sided 95% lower confidence limit, 12.8%), including 8 complete responses; median duration was 17.7 months (95% confidence interval, 4.1 months - not reached). Fifty-six patients (69%) achieved and/or maintained hematologic response for at least 8 weeks; median duration was 12.2 months (range, 8.4-26.2 months). Median failure-free and overall survival were 9.6 months and 34 months, respectively. Toxicity was mainly hematologic: the most common grade 3/4 adverse events were thrombocytopenia (67%), neutropenia (47%), and anemia (37%). CONCLUSION: Omacetaxine produced clinically meaningful responses with acceptable tolerability in patients with CML-CP previously treated with 2 or more TKIs.


Assuntos
Inibidores da Angiogênese/administração & dosagem , Antineoplásicos Fitogênicos/administração & dosagem , Harringtoninas/administração & dosagem , Leucemia Mieloide de Fase Crônica/tratamento farmacológico , Adulto , Idoso , Idoso de 80 Anos ou mais , Inibidores da Angiogênese/efeitos adversos , Antineoplásicos Fitogênicos/efeitos adversos , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Benzamidas/administração & dosagem , Esquema de Medicação , Feminino , Harringtoninas/efeitos adversos , Mepesuccinato de Omacetaxina , Humanos , Mesilato de Imatinib , Infusões Subcutâneas , Leucemia Mieloide de Fase Crônica/mortalidade , Masculino , Pessoa de Meia-Idade , Piperazinas/administração & dosagem , Inibidores de Proteínas Quinases/administração & dosagem , Pirimidinas/administração & dosagem , Resultado do Tratamento
3.
Cancer Chemother Pharmacol ; 71(1): 35-41, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-23053254

RESUMO

PURPOSE: Omacetaxine mepesuccinate is a first-in-class cephalotaxine demonstrating clinical activity in chronic myeloid leukemia. A subcutaneous (SC) formulation demonstrated efficacy and safety in phase 1/2 trials in patients previously treated with ≥1 tyrosine kinase inhibitor. This study assessed pharmacokinetics and safety of SC omacetaxine in patients with advanced cancers. METHODS: Omacetaxine 1.25 mg/m(2) SC was administered BID, days 1-14 every 28 days for 2 cycles, until disease progression or unacceptable toxicity. Blood and urine were collected to measure omacetaxine concentrations and inactive metabolites. Adverse events, including QT interval prolongation, were recorded. Tumor response was assessed at cycle 2 completion. RESULTS: Pharmacokinetic parameters were estimated from cycle 1, day 1 data in 21 patients with solid tumors or hematologic malignancies and cycle 1, day 11 data in 10 patients. Omacetaxine was rapidly absorbed, with mean peak plasma concentrations observed within 1 h, and widely distributed, as evidenced by an apparent volume of distribution of 126.8 L/m(2). Plasma concentration versus time data demonstrated biexponential decay; mean steady-state terminal half-life was 7 h. Concentrations of inactive metabolites 4'-DMHHT and cephalotaxine were approximately 10 % of omacetaxine and undetectable in most patients, respectively. Urinary excretion of unchanged omacetaxine accounted for <15 % of the dose. Grade 3/4 drug-related adverse events included thrombocytopenia (48 %) and neutropenia (33 %). Two grade 2 increases in QTc interval (>470 ms) were observed and were not correlated with omacetaxine plasma concentration. No objective responses were observed. CONCLUSIONS: Omacetaxine is well absorbed after SC administration. Therapeutic plasma concentrations were achieved with 1.25 mg/m(2) BID, supporting clinical development of this dose and schedule.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Harringtoninas/administração & dosagem , Neoplasias Hematológicas/tratamento farmacológico , Neoplasias/tratamento farmacológico , Adulto , Idoso , Antineoplásicos Fitogênicos/efeitos adversos , Antineoplásicos Fitogênicos/farmacocinética , Feminino , Meia-Vida , Harringtoninas/efeitos adversos , Harringtoninas/sangue , Harringtoninas/farmacocinética , Neoplasias Hematológicas/patologia , Mepesuccinato de Omacetaxina , Humanos , Injeções Subcutâneas , Síndrome do QT Longo/induzido quimicamente , Masculino , Pessoa de Meia-Idade , Neoplasias/patologia , Neutropenia/induzido quimicamente , Trombocitopenia/induzido quimicamente , Distribuição Tecidual
4.
Blood ; 120(13): 2573-80, 2012 Sep 27.
Artigo em Inglês | MEDLINE | ID: mdl-22896000

RESUMO

Chronic myeloid leukemia (CML) patients with the BCR-ABL T315I mutation do not benefit from therapy with currently approved tyrosine kinase inhibitors. Omacetaxine mepesuccinate is a protein synthesis inhibitor that has demonstrated activity in cells harboring the T315I mutation. This phase 2 trial assessed the efficacy of omacetaxine in CML patients with T315I and tyrosine kinase inhibitor failure. Patients received subcutaneous omacetaxine 1.25 mg/m(2) twice daily, days 1-14, every 28 days until hematologic response or a maximum of 6 cycles, and then days 1-7 every 28 days as maintenance. Results for patients treated in chronic phase are reported here. Patients (n = 62) received a median of 7 (range, 1-41) cycles. Complete hematologic response was achieved in 48 patients (77%; 95% lower confidence limit, 65%); median response duration was 9.1 months. Fourteen patients (23%; 95% lower confidence limit, 13%) achieved major cytogenetic response, including complete cytogenetic response in 10 (16%). Median progression free-survival was 7.7 months. Grade 3/4 hematologic toxicity included thrombocytopenia (76%), neutropenia (44%), and anemia (39%) and was typically manageable by dose reduction. Nonhematologic adverse events were mostly grade 1/2 and included infection (42%), diarrhea (40%), and nausea (34%). Omacetaxine may provide a safe and effective treatment for CML patients with T315I mutation. This study is registered at www.clinicaltrials.gov as NCT00375219.


Assuntos
Antineoplásicos Fitogênicos/administração & dosagem , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Proteínas de Fusão bcr-abl/genética , Harringtoninas/administração & dosagem , Leucemia Mieloide de Fase Crônica/tratamento farmacológico , Mutação/genética , Inibidores de Proteínas Quinases/efeitos adversos , Adulto , Idoso , Idoso de 80 Anos ou mais , Relação Dose-Resposta a Droga , Feminino , Seguimentos , Proteínas de Fusão bcr-abl/antagonistas & inibidores , Mepesuccinato de Omacetaxina , Humanos , Injeções Subcutâneas , Leucemia Mieloide de Fase Crônica/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Prospectivos , Terapia de Salvação , Taxa de Sobrevida
5.
Blood ; 118(18): 5000-10, 2011 Nov 03.
Artigo em Inglês | MEDLINE | ID: mdl-21881044

RESUMO

Although current antiplatelet therapies provide potent antithrombotic effects, their efficacy is limited by a heightened risk of bleeding and failure to affect vascular remodeling after injury. New lines of research suggest that thrombosis and hemorrhage may be uncoupled at the interface of pathways controlling thrombosis and inflammation. Here, as one remarkable example, studies using a novel and highly selective pharmacologic inhibitor of the spleen tyrosine kinase Syk [PRT060318; 2-((1R,2S)-2-aminocyclohexylamino)-4-(m-tolylamino)pyrimidine-5-carboxamide] coupled with genetic experiments, demonstrate that Syk inhibition ameliorates both the acute and chronic responses to vascular injury without affecting hemostasis. Specifically, lack of Syk (murine radiation chimeras) attenuated shear-induced thrombus formation ex vivo, and PRT060318 strongly inhibited arterial thrombosis in vivo in multiple animal species while having minimal impact on bleeding. Furthermore, leukocyte-platelet-dependent responses to vascular injury, including inflammatory cell recruitment and neointima formation, were markedly inhibited by PRT060318. Thus, Syk controls acute and long-term responses to arterial vascular injury. The therapeutic potential of Syk may be exemplary of a new class of antiatherothrombotic agents that target the interface between thrombosis and inflammation.


Assuntos
Peptídeos e Proteínas de Sinalização Intracelular/fisiologia , Proteínas Tirosina Quinases/fisiologia , Lesões do Sistema Vascular/fisiopatologia , Cicatrização/genética , Animais , Cicloexilaminas/farmacologia , Cicloexilaminas/uso terapêutico , Modelos Animais de Doenças , Avaliação Pré-Clínica de Medicamentos , Feminino , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Camundongos , Camundongos Knockout , Agregação Plaquetária/efeitos dos fármacos , Inibidores da Agregação Plaquetária/farmacologia , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Proteínas Tirosina Quinases/genética , Pirimidinas/farmacologia , Pirimidinas/uso terapêutico , Suínos , Quinase Syk , Trombose/tratamento farmacológico , Trombose/genética , Trombose/patologia , Lesões do Sistema Vascular/genética , Lesões do Sistema Vascular/reabilitação
6.
Blood ; 117(7): 2241-6, 2011 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-21088136

RESUMO

Heparin-induced thrombocytopenia (HIT) is a major cause of morbidity and mortality resulting from the associated thrombosis. Extensive studies using our transgenic mouse model of HIT have shown that antibodies reactive with heparin-platelet factor 4 complexes lead to FcγRIIA-mediated platelet activation in vitro as well as thrombocytopenia and thrombosis in vivo. We tested PRT-060318 (PRT318), a novel selective inhibitor of the tyrosine kinase Syk, as an approach to HIT treatment. PRT318 completely inhibited HIT immune complex-induced aggregation of both human and transgenic HIT mouse platelets. Transgenic HIT model mice were treated with KKO, a mouse monoclonal HIT-like antibody, and heparin. The experimental group received orally dosed PRT318, whereas the control group received vehicle. Nadir platelet counts of PRT318-treated mice were significantly higher than those of control mice. When examined with a novel thrombosis visualization technique, mice treated with PRT318 had significantly reduced thrombosis. The Syk inhibitor PRT318 thus prevented both HIT immune complex-induced thrombocytopenia and thrombosis in vivo, demonstrating its activity in HIT.


Assuntos
Heparina/efeitos adversos , Peptídeos e Proteínas de Sinalização Intracelular/antagonistas & inibidores , Inibidores de Proteínas Quinases/farmacologia , Proteínas Tirosina Quinases/antagonistas & inibidores , Trombocitopenia/prevenção & controle , Trombose/prevenção & controle , Animais , Complexo Antígeno-Anticorpo/sangue , Complexo Antígeno-Anticorpo/efeitos dos fármacos , Plaquetas/efeitos dos fármacos , Plaquetas/enzimologia , Plaquetas/imunologia , Humanos , Técnicas In Vitro , Peptídeos e Proteínas de Sinalização Intracelular/sangue , Camundongos , Camundongos Transgênicos , Ativação Plaquetária/efeitos dos fármacos , Ativação Plaquetária/imunologia , Proteínas Tirosina Quinases/sangue , Receptores de IgG/antagonistas & inibidores , Quinase Syk , Trombocitopenia/induzido quimicamente , Trombocitopenia/imunologia , Trombose/induzido quimicamente , Trombose/imunologia
7.
Blood Cells Mol Dis ; 36(2): 228-31, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16473533

RESUMO

Platelet aggregation is a dynamic entity, capable of directing its own growth and stability via the activation of signaling cascades that lead to the expression and secretion of various secondary agonists. Recent data using proteomics and genomics strategies have established that signaling pathways during platelet aggregation are triggered by two homophilic adhesion molecules, CD84 and CD150 (SLAM), and by a novel EGF-containing receptor, PEAR1, which are tyrosine-phosphorylated in a platelet-aggregation-dependent fashion (N. Nanda, P. Andre, M. Bao et al., Platelet aggregation induces platelet aggregate stability via SLAM family receptor signaling, Blood 106 (2005) 3028-3034, N. Nanda, M. Bao, H. Lin et al., Platelet Endothelial Aggregation Receptor 1 (PEAR1), a novel epidermal growth factor repeat-containing transmembrane receptor, participates in platelet contact-induced activation, J. Biol. Chem. 280 (2005) 24680-24689). Analysis of SLAM-deficient mice revealed an overall defect in platelet aggregation in vitro and a delayed arterial thrombotic process in vivo. The data indicate that these aggregation co-receptors may function in a "platelet synapse" and may be novel targets for antithrombotic drug discovery.


Assuntos
Sistemas de Liberação de Medicamentos , Fibrinolíticos/farmacologia , Agregação Plaquetária , Receptores de Superfície Celular/fisiologia , Animais , Antígenos CD/fisiologia , Fibrinolíticos/uso terapêutico , Humanos , Receptores de Superfície Celular/antagonistas & inibidores , Transdução de Sinais , Família de Moléculas de Sinalização da Ativação Linfocitária , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária
8.
Blood ; 106(9): 3028-34, 2005 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-16037392

RESUMO

Platelet aggregation is a dynamic entity, capable of directing its own growth and stability via the activation of signaling cascades that lead to the expression and secretion of various secondary agonists. Here we show that the signaling pathways triggered during platelet aggregation include an intrinsic pro-thrombotic activity mediated by 2 homophilic adhesion molecules, CD84 and CD150 (SLAM [signaling lymphocyte activation molecule]), which are tyrosine phosphorylated in a platelet aggregation-dependent fashion. The 2 CD84/SLAM adapter proteins, SAP (SLAM-associated protein) and EAT-2 (EWS-activated transcript-2), were found in platelets; only SAP, however, was found to immunoprecipitate with tyrosine-phosphorylated SLAM. The immobilized extracellular domain of CD84 promoted microaggregate formation, while SAP-deficient platelets demonstrated defective spreading on immobilized CD84, demonstrating a functional role in platelets for SLAM family interactions. Finally, analysis of SLAM-deficient mice revealed an overall defect in platelet aggregation in vitro and a delayed arterial thrombotic process in vivo. The data indicate that signaling of the adhesion molecules in the SLAM family, activated by proximity during aggregation, further stabilize platelet-platelet interactions in thrombosis.


Assuntos
Plaquetas/metabolismo , Glicoproteínas/classificação , Glicoproteínas/metabolismo , Imunoglobulinas/classificação , Imunoglobulinas/metabolismo , Agregação Plaquetária/fisiologia , Transdução de Sinais , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Antígenos CD/metabolismo , Glicoproteínas/deficiência , Glicoproteínas/genética , Humanos , Imunoglobulinas/deficiência , Imunoglobulinas/genética , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Fosfotirosina/metabolismo , Receptores de Superfície Celular , Família de Moléculas de Sinalização da Ativação Linfocitária , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Trombose , Fatores de Transcrição/metabolismo
9.
J Biol Chem ; 280(26): 24680-9, 2005 Jul 01.
Artigo em Inglês | MEDLINE | ID: mdl-15851471

RESUMO

The present study was designed to identify novel membrane proteins that signal during platelet aggregation. Because one putative mechanism for signaling by a membrane protein involves phosphorylation, we used oligonucleotide-based microarray analyses and mass spectrometric proteomics techniques to specifically discover membrane proteins and also identify those proteins that become phosphorylated on tyrosine, threonine, or serine residues upon platelet aggregation. Surprisingly, both techniques converged to identify a novel membrane protein we have termed PEAR1 (platelet endothelial aggregation receptor 1). Sequence analysis of PEAR1 predicts a type-1 membrane protein, 15 extracellular epidermal growth factor-like repeats, and multiple cytoplasmic tyrosines. Analysis of the tissue distribution of PEAR1 showed that it was most highly expressed in platelets and endothelial cells. Upon platelet aggregation induced by physiological agonists, PEAR1 became phosphorylated on tyrosine (Tyr-925), and serine (Ser-953 and Ser-1029) residues. PEAR1 tyrosine phosphorylation was blocked by eptifibatide, an alpha(IIb)beta(3) antagonist, which inhibits platelet aggregation. Immune clustering of PEAR1 resulted in PEAR1 phosphorylation. Aggregation-induced PEAR1 tyrosine phosphorylation lead to the subsequent association with the ShcB adaptor protein. Platelet proximity induced by centrifugation also induced PEAR1 tyrosine phosphorylation, a reaction not inhibited by eptifibatide. These data suggest that PEAR1 is a novel platelet receptor that signals secondary to alpha(IIb)beta(3)-mediated platelet-platelet contacts.


Assuntos
Plaquetas/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Receptores de Superfície Celular/biossíntese , Receptores de Superfície Celular/fisiologia , Sequência de Aminoácidos , Animais , Biotina/química , Western Blotting , Células COS , Comunicação Celular , Linhagem Celular , Clonagem Molecular , Reagentes de Ligações Cruzadas/farmacologia , Citoplasma/metabolismo , DNA Complementar/metabolismo , Relação Dose-Resposta a Droga , Eletroforese em Gel de Poliacrilamida , Células Endoteliais/metabolismo , Eptifibatida , Citometria de Fluxo , Humanos , Imunoprecipitação , Espectrometria de Massas , Dados de Sequência Molecular , Análise de Sequência com Séries de Oligonucleotídeos , Peptídeos/química , Peptídeos/farmacologia , Peroxidase/química , Fosforilação , Ativação Plaquetária , Agregação Plaquetária , Complexo Glicoproteico GPIIb-IIIa de Plaquetas/química , Ligação Proteica , Estrutura Terciária de Proteína , RNA/metabolismo , RNA Mensageiro/metabolismo , Receptores de Superfície Celular/química , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Homologia de Sequência de Aminoácidos , Serina/química , Transdução de Sinais , Treonina/química , Distribuição Tecidual , Transfecção , Tirosina/química
10.
Mol Cell Neurosci ; 25(3): 493-503, 2004 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-15033177

RESUMO

Tissue transglutaminase (tTG) is a multifunctional enzyme that catalyzes peptide cross-linking and polyamination reactions, and also is a signal-transducing GTPase. tTG protein content and enzymatic activity are upregulated in the brain in Huntington's disease and in other neurological diseases and conditions. Since mouse models are currently being used to study the role of tTG in Huntington's disease and other neurodegenerative diseases, it is critical that the level of its expression in the mouse forebrain be determined. In contrast to human forebrain where tTG is abundant, tTG can only be detected in mouse forebrain by immunoblotting a GTP-binding-enriched protein fraction. tTG mRNA content and transamidating activity are approximately 70% lower in mouse than in human forebrain. However, tTG contributes to the majority of transglutaminase activity within mouse forebrain. Thus, although tTG is expressed at lower levels in mouse compared with human forebrain, it likely plays important roles in neuronal function.


Assuntos
Modelos Animais de Doenças , Doenças Neurodegenerativas/enzimologia , Transglutaminases/fisiologia , Idoso , Idoso de 80 Anos ou mais , Animais , Feminino , Humanos , Fígado/enzimologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Doenças Neurodegenerativas/genética , Prosencéfalo/enzimologia , Transglutaminases/biossíntese , Transglutaminases/deficiência , Transglutaminases/genética
11.
J Biol Chem ; 278(21): 18824-32, 2003 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-12606540

RESUMO

Altered chondrocyte differentiation, including development of chondrocyte hypertrophy, mediates osteoarthritis and pathologic articular cartilage matrix calcification. Similar changes in endochondral chondrocyte differentiation are essential for physiologic growth plate mineralization. In both articular and growth plate cartilages, chondrocyte hypertrophy is associated with up-regulated expression of certain protein-crosslinking enzymes (transglutaminases (TGs)) including the unique dual-functioning TG and GTPase TG2. Here, we tested if TG2 directly mediates the development of chondrocyte hypertrophic differentiation. To do so, we employed normal bovine chondrocytes and mouse knee chondrocytes from recently described TG2 knockout mice, which are phenotypically normal. We treated chondrocytes with the osteoarthritis mediator IL-1 beta, with the all-trans form of retinoic acid (ATRA), which promotes endochondral chondrocyte hypertrophy and pathologic calcification, and with C-type natriuretic peptide, an essential factor in endochondral development. IL-1 beta and ATRA induced TG transamidation activity and calcification in wild-type but not in TG2 (-/-) mouse knee chondrocytes. In addition, ATRA induced multiple features of hypertrophic differentiation (including type X collagen, alkaline phosphatase, and MMP-13), and these effects required TG2. Significantly, TG2 (-/-) chondrocytes lost the capacity for ATRA-induced expression of Cbfa1, a transcription factor necessary for ATRA-induced chondrocyte hypertrophy. Finally, C-type natriuretic peptide, which did not modulate TG activity, comparably promoted Cbfa1 expression and hypertrophy (without associated calcification) in TG2 (+/+) and TG2 (-/-) chondrocytes. Thus, distinct TG2-independent and TG2-dependent mechanisms promote Cbfa1 expression, articular chondrocyte hypertrophy, and calcification. TG2 is a potential site for intervention in pathologic calcification promoted by IL-1 beta and ATRA.


Assuntos
Cartilagem Articular/patologia , Condrócitos/patologia , Proteínas de Ligação ao GTP/fisiologia , Proteínas de Neoplasias , Transglutaminases/fisiologia , Fosfatase Alcalina/metabolismo , Animais , Calcinose/induzido quimicamente , Calcinose/patologia , Bovinos , Células Cultivadas , Colágeno Tipo X/genética , Colagenases/genética , Subunidade alfa 1 de Fator de Ligação ao Core , Extremidades , Proteínas de Ligação ao GTP/deficiência , Proteínas de Ligação ao GTP/genética , Expressão Gênica/efeitos dos fármacos , Hipertrofia , Interleucina-1/farmacologia , Metaloproteinase 13 da Matriz , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Peptídeo Natriurético Tipo C/farmacologia , Osteoartrite/induzido quimicamente , Osteoartrite/patologia , Proteína 2 Glutamina gama-Glutamiltransferase , Fatores de Transcrição/genética , Transglutaminases/deficiência , Transglutaminases/genética , Tretinoína/farmacologia
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