Insulin Substrate Receptor (IRS) proteins in normal and malignant hematopoiesis

The insulin receptor substrate (IRS) proteins are a family of cytoplasmic proteins that integrate and coordinate the transmission of signals from the extracellular to the intracellular environment via transmembrane receptors, thus regulating cell growth, metabolism, survival and proliferation. The PI3K/AKT/mTOR and MAPK signaling pathways are the best-characterized downstream signaling pathways activated by IRS signaling (canonical pathways). However, novel signaling axes involving IRS proteins (noncanonical pathways) have recently been identified in solid tumor and hematologic neoplasm models. Insulin receptor substrate-1 (IRS1) and insulin receptor substrate-2 (IRS2) are the best-characterized IRS proteins in hematologic-related processes. IRS2 binds to important cellular receptors involved in normal hematopoiesis (EPOR, MPL and IGF1R). Moreover, the identification of IRS1/ABL1 and IRS2/JAK2V617F interactions and their functional consequences has opened a new frontier for investigating the roles of the IRS protein family in malignant hematopoiesis. Insulin receptor substrate-4 (IRS4) is absent in normal hematopoietic tissues but may be expressed under abnormal conditions. Moreover, insulin receptor substrate-5 (DOK4) and insulin receptor substrate-6 (DOK5) are linked to lymphocyte regulation. An improved understanding of the signaling pathways mediated by IRS proteins in hematopoiesis-related processes, along with the increased development of agonists and antagonists of these signaling axes, may generate new therapeutic approaches for hematological diseases. The scope of this review is to recapitulate and review the evidence for the functions of IRS proteins in normal and malignant hematopoiesis.

Leucemia mieloide crónica en crisis: blástica bases moleculares y diagnóstico / Chronic myelogenous leukemia in blastic crisis: molecular basis and diagnostic

La leucemia mieloide crónica es una enfermedad con comportamiento bifásico o trifásico, 90 por ciento de los pacientes debuta en fase crónica, 50 por ciento asintomáticos al diagnóstico. Un porcentaje con enfermedad crónica desarrollan en tiempo variable una enfermedad más agresiva definida por un período intermedio y crisis blástica. Se diagnostica al encontrar más del 20 por ciento de blastos en médula ósea, 30 por ciento en sangre periférica o enfermedad extramedular. El pronóstico es pobre, al lograr respuesta completa, con una mediana de sobrevida de 3-12 meses, independiente del fenotipo. El 50 por ciento de los pacientes tendrán una mieloide, 25 por ciento linfoide y 25 por ciento fenotipo indiferenciado. Un grupo de expertos clínicos de Bogotá, Colombia, revisaron la mejor evidencia sobre diagnóstico y tratamiento. La información se obtuvo de búsquedas estructuradas y varios registros de experimentos clínicos en curso. Presentamos conclusiones y recomendaciones para la toma de decisiones basadas en la mejor evidencia.