Jon C. Aster, MD, PhD

Brigham And Women's Hospital

Academic Titles

Ramzi S. Cotran Professor, Pathology, Harvard Medical School

Research Program Affiliation

Member, Lymphoma and Myeloma

Member, Leukemia

Leadership Roles

Deputy Associate Director, Membership

Institutional Representative for BWH, Membership Committee

Co-Chair, Membership Committee

Deputy Associate Director, Membership, Executive Committee

Member, Clinical Science Coordinating Committee

Member, Center Scientific Council

Director, Specialized Histopathology

Research Abstract

My lab is focused on understanding the pathogenesis of Notch1-induced T-cell acute lymphoblastic leukemia/lymphoma (T-ALL). Notch1 (N1) is a member of a family of structurally-unique single-pass transmembrane receptors that regulate cellular differentiation through a novel type of signal transduction pathway. Normal N1 activation is triggered by ligand-dependent proteolytic cleavages that result in the release of the intracellular portion of N1 (ICN1), which then translocates to the nucleus and forms a transcription activation complex with the DNA-binding factor RBP-Jk/CSL and co-activators of the mastermind family. In 2004, we discovered frequent "gain-of-function" point mutations involving NOTCH1 in T-ALLs lacking the t(7;9). These mutations, depending on their location, either increase the rate of proteolysis and generation of ICN1, or enhance the stability of ICN1. ICN1 turns on a number of downstream targets, including c-Myc and components of the mTOR pathway, that support the growth and proliferation of T-ALL cells. Current activities include studies aimed at understanding in detail how Notch1 mutations act to increase ICN1 production and stability; the nature of the cross-talk between Notch1, mTOR, and other pathways that regulate cellular metabolism; the development of novel inhibitors that are selective for Notch1; and the identification and application of small molecules that act synergistically with Notch pathway inhibitors against tumor cells that depend on Notch signals.