351. IGF2 mRNA binding protein-2 is a tumor promoter that drives cancer proliferation through its client mRNAs IGF2 and HMGA1.
- Author
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Dai N, Ji F, Wright J, Minichiello L, Sadreyev R, and Avruch J
- Subjects
- Adaptor Proteins, Signal Transducing genetics, Adaptor Proteins, Signal Transducing metabolism, Animals, Binding Sites, Cell Line, Tumor, Cell Proliferation, Embryo, Mammalian, Fibroblasts cytology, Fibroblasts metabolism, HMGA1a Protein metabolism, HeLa Cells, Humans, Insulin-Like Growth Factor II metabolism, Mice, Phosphorylation, Primary Cell Culture, Protein Binding, RNA, Messenger metabolism, RNA-Binding Proteins metabolism, Signal Transduction, TOR Serine-Threonine Kinases genetics, TOR Serine-Threonine Kinases metabolism, Gene Expression Regulation, Neoplastic, HMGA1a Protein genetics, Insulin-Like Growth Factor II genetics, RNA, Messenger genetics, RNA-Binding Proteins genetics
- Abstract
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.
- Published
- 2017
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