RESUMEN
Patients with common variable immunodeficiency (CVID) constitute a clinically and immunologically heterogeneous group characterized by B-cell dysfunction with hypogammaglobulinemia and defective immunoglobulin class switch of unknown etiology. Current classification systems are insufficient to achieve precise disease management. Characterization of signaling pathways essential for B-cell differentiation and class switch could provide new means to stratify patients. We evaluated constitutive and induced signaling by phospho-specific flow cytometry in 26 CVID patients and 18 healthy blood donors. Strong responses were induced both in CVID and healthy donor B cells upon activation. In contrast, constitutive phosphorylation levels of STAT3,-5,-6, Erk, PLC-γ and Syk were significantly increased in CVID B cells only. Hierarchical clustering revealed a subgroup of CVID patients with elevated constitutive phosphorylation of Syk and PLC-γ. All these patients had non-infectious complications, indicating that a distinct phosphorylation pattern of kinases in B cells identifies a clinically important subgroup of CVID patients.
Asunto(s)
Subgrupos de Linfocitos B/inmunología , Inmunodeficiencia Variable Común/inmunología , Fosforilación/inmunología , Fosfotransferasas/inmunología , Adulto , Anciano , Femenino , Humanos , Cambio de Clase de Inmunoglobulina/inmunología , Activación de Linfocitos/inmunología , Masculino , Persona de Mediana Edad , Receptores de Antígenos de Linfocitos B/inmunología , Transducción de Señal/inmunología , Adulto JovenRESUMEN
Double minute chromosomes (DMs) are extrachromosomal cytogenetic structures found in tumour cells. As hallmarks of gene amplification, DMs often carry oncogenes and drug-resistance genes and play important roles in malignant tumour progression and drug resistance. The mitogen-activated protein kinase (MAPK) signalling pathway is frequently dysregulated in human malignant tumours, which induces genomic instability, but it remains unclear whether a close relationship exists between MAPK signalling and DMs. In the present study, we focused on three major components of MAPK signalling, ERK1/2, JNK1/2/3 and p38, to investigate the relationship between MAPK and DM production in tumour cells. We found that the constitutive phosphorylation of ERK1/2, but not JNK1/2/3 and p38, was closely associated with DMs in tumour cells. Inhibition of ERK1/2 activation in DM-containing and ERK1/2 constitutively phosphorylated tumour cells was able to markedly decrease the number of DMs, as well as the degree of amplification and expression of DM-carried genes. The mechanism was found to be an increasing tendency of DM DNA to break, become enveloped into micronuclei (MNs) and excluded from the tumour cells during the S/G2 phases of the cell cycle, events that accompanied the reversion of malignant behaviour. Our study reveals a linkage between ERK1/2 activation and DM stability in tumour cells.