RESUMEN

The recurrent V617F mutation in JAK2 (JAK2V617F) has emerged as the primary contributor to the pathogenesis of myeloproliferative neoplasms (MPN). However, the lack of complete response in most patients treated with the JAK1/2 inhibitor, ruxolitinib, indicates the need for identifying pathways that cooperate with JAK2. Activated JAK2 was found to be associated with the insulin receptor substrate 2 (IRS2) in non-hematological cells. We identified JAK2/IRS2 binding in JAK2V617F HEL cells, but not in the JAK2WT U937 cell line. In HEL cells, IRS2 silencing decreased STAT5 phosphorylation, reduced cell viability and increased apoptosis; these effects were enhanced when IRS2 silencing was combined with ruxolitinib. In U937 cells, IRS2 silencing neither reduced cell viability nor induced apoptosis. IRS1/2 pharmacological inhibition in primary MPN samples reduced cell viability in JAK2V617F-positive but not JAK2WT specimens; combination with ruxolitinib had additive effects. IRS2 expression was significantly higher in CD34+ cells from essential thrombocythemia patients compared to healthy donors, and in JAK2V617F MPN patients when compared to JAK2WT. Our data indicate that IRS2 is a binding partner of JAK2V617F in MPN. IRS2 contributes to increased cell viability and reduced apoptosis in JAK2-mutated cells. Combined pharmacological inhibition of IRS2 and JAK2 may have a potential clinical application in MPN.

Asunto(s)

Apoptosis/efectos de los fármacos , Proteínas Sustrato del Receptor de Insulina/antagonistas & inhibidores , Janus Quinasa 2/genética , Mutación/genética , Trastornos Mieloproliferativos/patología , Pirazoles/farmacología , Adulto , Anciano , Anciano de 80 o más Años , Western Blotting , Estudios de Casos y Controles , Proliferación Celular/efectos de los fármacos , Femenino , Técnica del Anticuerpo Fluorescente , Estudios de Seguimiento , Silenciador del Gen , Humanos , Técnicas para Inmunoenzimas , Inmunoprecipitación , Proteínas Sustrato del Receptor de Insulina/genética , Proteínas Sustrato del Receptor de Insulina/metabolismo , Janus Quinasa 2/metabolismo , Masculino , Persona de Mediana Edad , Trastornos Mieloproliferativos/tratamiento farmacológico , Trastornos Mieloproliferativos/genética , Estadificación de Neoplasias , Nitrilos , Pronóstico , Pirimidinas , ARN Mensajero/genética , ARN Interferente Pequeño/genética , Reacción en Cadena en Tiempo Real de la Polimerasa , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Transducción de Señal , Células Tumorales Cultivadas , Ensayos Antitumor por Modelo de Xenoinjerto , Adulto Joven