High Mobility Group A1 Chromatin Keys: Unlocking the Genome During MPN Progression.

Patients with chronic, indolent myeloproliferative neoplasms (MPNs) are at risk for transformation to highly lethal leukemia, although targetable mechanisms driving progression remain elusive. We discovered that the High Mobility Group A1 (HMGA1) gene is up-regulated with MPN progression in patients and required for evolution into myelofibrosis (MF) or acute myeloid leukemia (AML) in preclinical models. HMGA1 encodes the HMGA1 epigenetic regulators that modulate the chromatin state during embryogenesis and tissue regeneration. While HMGA1 is silenced in most differentiated cells, it becomes aberrantly re-expressed in JAK2 mutant (JAK2-V617F) MPN, with the highest levels after transformation to secondary MF or AML. Here, we review recent work highlighting HMGA1 function in MPN progression. Though underlying mechanisms continue to emerge, increasing evidence suggests that HMGA1 functions as a "chromatin key" required to "unlock" regions of the genome involved in clonal expansion and progression in MPN. Together, these findings illuminate HMGA1 as a driver of MPN progression and a promising therapeutic target.