IGF2 mRNA binding protein-2 is a tumor promoter that drives cancer proliferation through its client mRNAs IGF2 and HMGA1
Ning Dai,
Fei Ji,
Jason Wright,
Liliana Minichiello,
Ruslan Sadreyev,
Joseph Avruch
Affiliations
Ning Dai
Department of Molecular Biology, Massachusetts General Hospital, Boston, United States; Diabetes unit, Medical Services, Massachusetts General Hospital, Boston, United States; Department of Medicine, Harvard Medical School, Boston, United States
Fei Ji
Department of Molecular Biology, Massachusetts General Hospital, Boston, United States; Department of Genetics, Harvard Medical School, Boston, United States
Jason Wright
Program in Medical and Population Genetics, Broad Institute of Harvard and MIT, Cambridge, United States
Liliana Minichiello
Department of Pharmacology, University of Oxford, Oxford, United Kingdom
Ruslan Sadreyev
Department of Molecular Biology, Massachusetts General Hospital, Boston, United States; Department of Pathology, Harvard Medical School, Boston, United States
Department of Molecular Biology, Massachusetts General Hospital, Boston, United States; Diabetes unit, Medical Services, Massachusetts General Hospital, Boston, United States; Department of Medicine, Harvard Medical School, Boston, United States
The gene encoding the Insulin-like Growth Factor 2 mRNA binding protein 2/IMP2 is amplified and overexpressed in many human cancers, accompanied by a poorer prognosis. Mice lacking IMP2 exhibit a longer lifespan and a reduced tumor burden at old age. Herein we show in a diverse array of human cancer cells that IMP2 overexpression stimulates and IMP2 elimination diminishes proliferation by 50–80%. In addition to its known ability to promote the abundance of Insulin-like Growth Factor 2/IGF2, we find that IMP2 strongly promotes IGF action, by binding and stabilizing the mRNA encoding the DNA binding protein HMGA1, a known oncogene. HMGA1 suppresses the abundance of IGF binding protein 2/IGFBP2 and Grb14, inhibitors of IGF action. IMP2 stabilization of HMGA1 mRNA plus IMP2 stimulated IGF2 production synergistically drive cancer cell proliferation and account for IMP2’s tumor promoting action. IMP2’s ability to promote proliferation and IGF action requires IMP2 phosphorylation by mTOR.
