MAPK/ERK2 phosphorylates ERG at serine 283 in leukemic cells and promotes stem cell signatures and cell proliferation

• Published in: Leukemia 2016-07, Vol.30 (7), p.1552-1561
• Main Authors: Huang, Y, Thoms, J A I, Tursky, M L, Knezevic, K, Beck, D, Chandrakanthan, V, Suryani, S, Olivier, J, Boulton, A, Glaros, E N, Thomas, S R, Lock, R B, MacKenzie, K L, Bushweller, J H, Wong, J W H, Pimanda, J E
• Format: Article
• Language: English
• Subjects: 38/109; 38/39; 38/44; 38/70; 38/91; 631/337/458/1733; 631/45/612/822; 631/67/1990/283/1897; 631/67/1990/283/2125; 631/80/86; 82/81; Acute lymphoblastic leukemia; Acute lymphocytic leukemia; Acute myeloid leukemia; Antibodies; Avian erythroblastosis virus; Binding Sites; Cancer Research; Care and treatment; Cell growth; Cell Line, Tumor; Cell Proliferation; Critical Care Medicine; Development and progression; Extracellular signal-regulated kinase; Fourier transforms; Gene expression; Genetic aspects; Genetic transcription; Glycerol; Health aspects; Hematology; Hematopoietic Stem Cells; Homology; Humans; Intensive; Internal Medicine; Kinases; Leukemia; Leukemia - pathology; Leukemia, Myeloid, Acute - pathology; Liquid chromatography; Lymphatic leukemia; Lymphocytes T; MAP kinase; MAP Kinase Signaling System - physiology; Mass spectrometry; Mass spectroscopy; Medical research; Medicine; Medicine & Public Health; Oncogenes; Oncology; original-article; Phosphorylation; Post-translation; Precursor T-Cell Lymphoblastic Leukemia-Lymphoma - pathology; Progenitor cells; Properties; Protein kinase; Protein Processing, Post-Translational; Proteins; Research centers; Scientific imaging; Serine - metabolism; Stem cells; Transcription; Transcription factors; Transcriptional Regulator ERG - metabolism; Transcriptome; Viruses; Xenografts; Xenotransplantation
• ISSN: 0887-6924; 1476-5551
• DOI: 10.1038/leu.2016.55

Aberrant ERG (v-ets avian erythroblastosis virus E26 oncogene homolog) expression drives leukemic transformation in mice and high expression is associated with poor patient outcomes in acute myeloid leukemia (AML) and T-acute lymphoblastic leukemia (T-ALL). Protein phosphorylation regulates the activity of many ETS factors but little is known about ERG in leukemic cells. To characterize ERG phosphorylation in leukemic cells, we applied liquid chromatography coupled tandem mass spectrometry and identified five phosphorylated serines on endogenous ERG in T-ALL and AML cells. S283 was distinct as it was abundantly phosphorylated in leukemic cells but not in healthy hematopoietic stem and progenitor cells (HSPCs). Overexpression of a phosphoactive mutant (S283D) increased expansion and clonogenicity of primary HSPCs over and above wild-type ERG. Using a custom antibody, we screened a panel of primary leukemic xenografts and showed that ERG S283 phosphorylation was mediated by mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signaling and in turn regulated expression of components of this pathway. S283 phosphorylation facilitates ERG enrichment and transactivation at the ERG +85 HSPC enhancer that is active in AML and T-ALL with poor prognosis. Taken together, we have identified a specific post-translational modification in leukemic cells that promotes progenitor proliferation and is a potential target to modulate ERG-driven transcriptional programs in leukemia.