RESUMEN
BACKGROUND/AIM: Bruton's tyrosine kinase (BTK)-mediated B-cell-receptor signaling drives lymphomagenesis of diffuse large B-cell lymphoma (DLBCL). We investigated the clinicopathological significance of BTK positivity in DLBCL according to known molecules related to resistance to BTK inhibitors [BCL2 apoptosis regulator (BCL2)/MYC proto-oncogene, bHLH transcription factor (MYC)]. PATIENTS AND METHODS: We evaluated BTK expression immunohistochemically in 106 DLBCLs considering their BCL2/MYC status. RESULTS: Considering the whole cohort, BTK was expressed in 65.1%, including 70.4% (50/71) of non-germinal center B-cell-like (non-GCB) subtype; BCL2 expression was detected in 60.4%, MYC expression in 15.1%, MYC translocation in 4.2% (4/96) and MYC gain/amplification in 7.6% (8/105). Overall and in the non-GCB cohort, BTK positively correlated with high international prognostic index (both p=0.005) and stage (p=0.006 and p=0.002), and with BCL2 intensity (p=0.005 and p=0.026, respectively); MYC gain/amplification total cohort (p=0.038). Moreover, high risk, defined as co-expression of BTK and either or both BCL2/MYC, independently predicted shorter progression-free survival in patients treated with rituximab plus cyclophosphamide, doxorubicin, vincristine and prednisone (R-CHOP) (all R-CHOP-treated patients: hazard ratio=2.565, p=0.044; R-CHOP-treated non-GCB subgroup: HR=3.833, p=0.019). CONCLUSION: BTK expression may be utilized to stratify risk in patients with DLBCL.
Asunto(s)
Agammaglobulinemia Tirosina Quinasa/análisis , Biomarcadores de Tumor/análisis , Linfoma de Células B Grandes Difuso/enzimología , Adolescente , Adulto , Agammaglobulinemia Tirosina Quinasa/antagonistas & inhibidores , Anciano , Anciano de 80 o más Años , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapéutico , Biomarcadores de Tumor/genética , Resistencia a Antineoplásicos , Femenino , Amplificación de Genes , Humanos , Inmunohistoquímica , Hibridación Fluorescente in Situ , Linfoma de Células B Grandes Difuso/tratamiento farmacológico , Linfoma de Células B Grandes Difuso/mortalidad , Linfoma de Células B Grandes Difuso/patología , Masculino , Persona de Mediana Edad , Valor Predictivo de las Pruebas , Supervivencia sin Progresión , Inhibidores de Proteínas Quinasas/uso terapéutico , Proto-Oncogenes Mas , Proteínas Proto-Oncogénicas c-bcl-2/análisis , Proteínas Proto-Oncogénicas c-myc/genética , Estudios Retrospectivos , Medición de Riesgo , Factores de Riesgo , Translocación Genética , Adulto JovenRESUMEN
Bruton's tyrosine kinase, an essential mediator of B cell receptor (BCR) signalling, has been validated as an effective therapeutic target in oncology. Development of chemical sensors capable of precise detection of its expression and function is of great importance for cancer diagnosis and therapy. Here, a dual-purpose probe, IB-4, was developed with excellent inhibitory activity (IC50 = 35 nM), and has been demonstrated to be suitable for simultaneous imaging endogenous BTK activity and studying its target engagement in live cells for the first time. The unique turn-on design endows the probe with excellent sensitivity and selectivity toward BTK under both in vitro and in situ settings, and can be further extended to other irreversible inhibitors for protein characterization, quantification and inhibition studies.
Asunto(s)
Agammaglobulinemia Tirosina Quinasa/análisis , Colorantes Fluorescentes/química , Western Blotting/métodos , Línea Celular , Supervivencia Celular , Humanos , Células Jurkat , Simulación del Acoplamiento Molecular , Imagen Óptica/métodos , Proteínas Recombinantes/análisisRESUMEN
Bruton's tyrosine kinase (BTK), a critical component of B cell receptor signaling, has recently been implicated in regulation of the peripheral innate immune response. However, the role of BTK in microglia, the resident innate immune cells of the central nervous system, and its involvement in the pathobiology of neurodegenerative disease has not been explored. Here we found that BTK is a key regulator of microglial phagocytosis. Using potent BTK inhibitors and small interfering RNA (siRNA) against BTK, we observed that blockade of BTK activity decreased activation of phospholipase gamma 2, a recently identified genetic risk factor in Alzheimer's disease (AD), and reduced phagocytosis in rodent microglia and human monocyte-derived macrophages. Inhibition of BTK signaling also decreased microglial uptake of synaptosomes but did not have major impacts on other key microglial functions such as migration and cytokine release. Similarly, blocking BTK function ex vivo in acute brain slices reduced microglial phagocytosis and maintained numbers of resting microglia. In brain tissues from the 5xFAD mouse model of AD, levels of microglial BTK were elevated while in two gene expression datasets of post-mortem AD patient brain tissues, upregulation of BTK transcript was observed. Our study provides novel insights into the role of BTK in regulating microglial phagocytosis and uptake of synaptic structures and suggests that inhibiting microglial BTK may improve cognition in AD by preventing microglial activation and synaptic loss. Graphical Abstract Microglial-mediated synapse loss has been implicated in AD pathogenesis. Inhibition of BTK decreases activation of PLCγ2, a genetic risk factor in AD, and reduces microglial phagocytosis and uptake of synaptic structures. As such BTK inhibition may represent a therapeutic route to prevent microglial activation and synapse loss in AD.
Asunto(s)
Agammaglobulinemia Tirosina Quinasa/antagonistas & inhibidores , Enfermedad de Alzheimer/tratamiento farmacológico , Microglía/efectos de los fármacos , Proteínas del Tejido Nervioso/antagonistas & inhibidores , Fagocitosis/efectos de los fármacos , Inhibidores de Proteínas Quinasas/farmacología , Acrilamidas/farmacología , Adenina/análogos & derivados , Agammaglobulinemia Tirosina Quinasa/análisis , Agammaglobulinemia Tirosina Quinasa/biosíntesis , Agammaglobulinemia Tirosina Quinasa/genética , Enfermedad de Alzheimer/enzimología , Animales , Encéfalo/enzimología , Línea Celular , Movimiento Celular/efectos de los fármacos , Citocinas/metabolismo , Conjuntos de Datos como Asunto , Inducción Enzimática/efectos de los fármacos , Perfilación de la Expresión Génica , Humanos , Ratones , Ratones Endogámicos C57BL , Microglía/enzimología , Microglía/fisiología , Microglía/ultraestructura , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Piperidinas , Inhibidores de Proteínas Quinasas/uso terapéutico , Pirazoles/farmacología , Pirimidinas/farmacología , Interferencia de ARN , ARN Interferente Pequeño/farmacología , Ratas , Ratas Sprague-DawleyRESUMEN
Ibrutinib has shown significant activity in patients with relapsed or refractory mantle cell lymphoma (RR-MCL). We report the long-term outcome and safety profile of a single-centre, single arm, open-label, phase 2 study of RR-MCL treated with IR. Overall, the median follow-up time was 47 months (range 1-52 months), median duration on treatment was 16 months (range 1-53 months) and median number of treatment cycles was 17 (range 1-56). Twenty-nine patients (58%) achieved complete remission and of these, 12 patients continue on study. Thirty-eight patients discontinued treatment, 14 due to disease progression (2 transformed). Patients with blastoid morphology, high risk MCL International Prognostic Index score and high Ki67% had inferior survival. The commonest grade 1-2 toxicities were fatigue, diarrhoea, nausea, arthralgias and myalgias. None had long term toxicities. Median progression-free survival was 43 months. Eighteen patients (36%) died (14 deaths were MCL-related). The median overall survival has not been reached. Treatment with IR can provide durable remissions in a subset of patients with RR-MCL, especially those with low Ki67%. The possible benefit of adding other therapies in combination with IR in RR-MCL is under exploration.
Asunto(s)
Linfoma de Células del Manto/tratamiento farmacológico , Pirazoles/uso terapéutico , Pirimidinas/uso terapéutico , Rituximab/uso terapéutico , Terapia Recuperativa/métodos , Adenina/análogos & derivados , Agammaglobulinemia Tirosina Quinasa/análisis , Estudios de Seguimiento , Humanos , Antígeno Ki-67/análisis , Linfoma de Células del Manto/mortalidad , Piperidinas , Pronóstico , Recurrencia , Inducción de Remisión , Terapia Recuperativa/efectos adversos , Análisis de SupervivenciaRESUMEN
As a key regulator of the B-cell receptor signaling pathway, Bruton's tyrosine kinase (Btk) has emerged as an important therapeutic target for various malignancies and autoimmune disorders. However, data on the expression profiles of Btk are lacking. Here, we report the discovery of a new, selective Btk probe and of a sandwich-type ELISA quantification method to detect endogenous Btk in live cells. We achieved selective labeling of Btk in vivo and quantified Btk levels in seven types of human lymphoma cell lines. This quantification method provides a powerful tool to study Btk in live cells that may also be useful in clinical settings.
Asunto(s)
Agammaglobulinemia Tirosina Quinasa/análisis , Ensayo de Inmunoadsorción Enzimática/métodos , Colorantes Fluorescentes/química , Línea Celular Tumoral , Colorantes Fluorescentes/síntesis química , Humanos , Linfoma/enzimologíaRESUMEN
Mice lacking secreted IgM (sIgM -/-) antibodies display abnormal splenic B cell development, which results in increased marginal zone and decreased follicular B cell numbers. However, the mechanism by which sIgM exhibit this effect is unknown. Here, we demonstrate that B cells in sIgM -/- mice display increased B cell receptor (BCR) signaling as judged by increased levels of phosphorylated Bruton's tyrosine kinase (pBtk), phosphorylated Spleen tyrosine kinase (pSyk), and nuclear receptor Nur77. Low dosage treatment with the pBtk inhibitor Ibrutinib reversed the altered B cell development in the spleen of sIgM -/- mice, suggesting that sIgM regulate splenic B cell differentiation by decreasing BCR signaling. Mechanistically, we show that B cells, which express BCRs specific to hen egg lysozyme (HEL) display diminished responsiveness to HEL stimulation in presence of soluble anti-HEL IgM antibodies. Our data identify sIgM as negative regulators of BCR signaling and suggest that they can act as decoy receptors for self-antigens that are recognized by membrane bound BCRs.