Expression data of mouse hematopoietic cells, Nr4a1/3 wild type and double mutant. Mus musculus

We investigate the cellular and molecular mechanisms of tumor suppression by NR4A1 and NR4A3, and show a cell intrinsic essential function in maintenance of hematopoietic stem cell (HSC) homeostasis. In the absence of Nr4a1/3, HSC lost quiescence, became highly proliferative leukemia-stem cell (LSC) that transplanted AML to recipient mice. We further revealed that loss of NR4A1/3 leads to deregulated expression of the key cell cycle regulator Cdkn1c (P57), c-Myc oncogene, and glucose metabolic genes leading to enhanced aerobic glycolysis or ‘Warburg effect’ in LSCs. Reintroduction of Nr4a1 in LSCs restored HSC quiescence, and reversed Nr4a1/3 deficiency induced P57 suppression and c-Myc overexpression. Collectively, we identify an essential role of Nr4a1/3 in coordinately regulating cell cycle entry and glucose metabolism to prevent uncontrolled stem cell proliferation and AML transformation. These results have major implications for designing therapeutic strategies in AML. Overall design: To identify NR4A-dependent molecular signaling pathways that may control HSC homeostasis, we performed genome-wide transcript profiling of Lin-Sca1+ (LS) cells from WT and DKO mice. For Affymetrix analysis, we generated three independent pools of RNA from sorted LS cells from 10-20 WT or DKO (2- to 3-week-old) mice per sample.