title: Cooperation of Gata3, c-Myc and Notch in malignant transformation of double positive thymocytes.
abstract: Gata transcription factors are critical regulators of proliferation and differentiation implicated in various human cancers, but specific genes activated by Gata proteins remain to be identified. We previously reported that enforced expression of Gata3 during T cell development in CD2-Gata3 transgenic mice induced CD4(+)CD8(+) double-positive (DP) T cell lymphoma. Here, we show that the presence of the DO11.10 T-cell receptor transgene, which directs DP cells towards the CD4 lineage, resulted in enhanced lymphoma development and a dramatic increase in thymocyte cell size in CD2-Gata3 transgenic mice. CD2-Gata3 DP cells expressed high levels of the proto-oncogene c-Myc but the Notch1 signaling pathway, which is known to induce c-Myc, was not activated. Gene expression profiling showed that in CD2-Gata3 lymphoma cells transcription of c-Myc and its target genes was further increased. A substantial fraction of CD2-Gata3 lymphomas had trisomy of chromosome 15, leading to an increased c-Myc gene dose. Interestingly, most lymphomas showed high expression of the Notch targets Deltex1 and Hes1, often due to activating Notch1 PEST domain mutations. Therefore, we conclude that enforced Gata3 expression converts DP thymocytes into a pre-malignant state, characterized by high c-Myc expression, whereby subsequent induction of Notch1 signaling cooperates to establish malignant transformation. The finding that Gata3 regulates c-Myc expression levels, in a direct or indirect fashion, may explain the parallel phenotypes of mice with overexpression or deficiency of either of the two transcription factors.
authors.affiliation: Department of Immunology, Erasmus MC Rotterdam, The Netherlands.
authors.forename: Jan Piet
authors.initials: JP
authors.lastname: van Hamburg
authors.forename: Marjolein J W
authors.initials: MJ
authors.lastname: de Bruijn
authors.forename: Gemma M
authors.initials: GM
authors.lastname: Dingjan
authors.forename: H Berna
authors.initials: HB
authors.lastname: Beverloo
authors.forename: Hans
authors.initials: H
authors.lastname: Diepstraten
authors.forename: Kam-Wing
authors.initials: KW
authors.lastname: Ling
authors.forename: Rudi W
authors.initials: RW
authors.lastname: Hendriks
mesh_terms: D000375:Aging; D000818:Animals; D018801:CD2 Antigens / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000378:metabolism / Q000473:pathology; D019070:Cell Lineage; D048429:Cell Size; D002471:Cell Transformation, Neoplastic / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D002869:Chromosome Aberrations; D033481:Chromosomes, Mammalian; D005091:Exons / Q000235:genetics; D005434:Flow Cytometry; D050990:GATA3 Transcription Factor / Q000378:metabolism*; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D008223:Lymphoma / Q000235:genetics / Q000473:pathology; D051379:Mice; D008822:Mice, Transgenic; D009154:Mutation / Q000235:genetics; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc / Q000378:metabolism*; D051881:Receptor, Notch1 / Q000235:genetics / Q000378:metabolism*; D012641:Selection, Genetic; D013601:T-Lymphocytes / Q000473:pathology*
chemical_list: D018801:CD2 Antigens; D050990:GATA3 Transcription Factor; C494748:Gata3 protein, mouse; C000715470:MAS1 protein, human; D000090063:Proto-Oncogene Mas; D016271:Proto-Oncogene Proteins c-myc; D051881:Receptor, Notch1