title: The histone H2A isoform Hist2h2ac is a novel regulator of proliferation and epithelial-mesenchymal transition in mammary epithelial and in breast cancer cells.
abstract: Proliferation and differentiation are controlled through chromatin remodelling. Therefore, there is an enormous biological significance and clinical value in understanding how specific signalling pathways are affected by histone replacement in the nucleosome. In this work, mass spectrometry was used to screen HC11 mammary epithelial cells for changes in histone levels throughout cell differentiation. The canonical histone isoform Histone H2A type 2-C (Hist2h2ac) was found only in undifferentiated/proliferating cells. Hist2h2ac mRNA was induced by EGF, specifically in the CD24+/CD29hi/DC44hi cell subpopulation. Hist2h2ac mRNA was increased by MEK1/2or PI3-K activation in HC11 and EpH4 mammary epithelial cells, and in MC4-L2 and T47-D breast cancer cells. Hist2h2ac silencing inhibited EGF-induced Zeb-1 expression and E-cadherin down-regulation, and this effect was reverted by Hist2h2ac re-expression. Notably, silencing of Hist2h2ac increased EGFR, ERBB2, and ERK1/2activation but did not allow EGF-induced proliferation. HIST2H2AC was expressed in all breast cancer molecular subtypes and found altered in 17% breast cancers, being 16.8% of the cases related to HIST2H2AC gene amplification and/or mRNA upregulation. In summary, this is the first study that identifies a canonical histone isoform -Hist2h2ac-downstream of the EGFR pathway, regulating oncogenic signalling and thereby contributing to deregulation of target genes.
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal; Cancer Biology and Epigenetics Group, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
authors.forename: Fátima Liliana
authors.initials: FL
authors.lastname: Monteiro
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal; Institute for Biomedicine -iBiMED, Department of Medical Sciences, University of Aveiro, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Vitorino
authors.affiliation: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signalling, University of Houston, Houston, TX 77204, USA.
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Cardoso
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Hugo
authors.initials: H
authors.lastname: Laranjeira
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Joana
authors.initials: J
authors.lastname: Simões
authors.affiliation: Department of Pathology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal.
authors.forename: Margarida
authors.initials: M
authors.lastname: Caldas
authors.affiliation: Cancer Biology and Epigenetics Group, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal; Department of Pathology, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal; Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar (ICBAS) - University of Porto, 4050-313 Porto, Portugal.
authors.forename: Rui
authors.initials: R
authors.lastname: Henrique
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal.
authors.forename: Francisco
authors.initials: F
authors.lastname: Amado
authors.affiliation: Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signalling, University of Houston, Houston, TX 77204, USA; Science for Life Laboratory, Division of Proteomics, School of Biotechnology, KTH - Royal Institute of Technology, 171 21 Solna, Sweden; Department of Biosciences, Karolinska Institutet, Huddinge, Sweden.
authors.forename: Cecilia
authors.initials: C
authors.lastname: Williams
authors.affiliation: Cancer Biology and Epigenetics Group, Portuguese Oncology Institute of Porto, 4200-072 Porto, Portugal; Department of Pathology and Molecular Immunology, Institute of Biomedical Sciences Abel Salazar (ICBAS) - University of Porto, 4050-313 Porto, Portugal.
authors.forename: Carmen
authors.initials: C
authors.lastname: Jerónimo
authors.affiliation: Mass Spectrometry Centre, Organic Chemistry and Natural Products Unit, Dep. of Chemistry, Universidade de Aveiro, Campus de Santiago, 3810-193, Aveiro, Portugal; Institute for Biomedicine -iBiMED, Department of Medical Sciences, University of Aveiro, Portugal. Electronic address: luisa.helguero@ua.pt.
authors.forename: Luisa A
authors.initials: LA
authors.lastname: Helguero
mesh_terms: D001940:Breast / Q000166:cytology; D001943:Breast Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D002454:Cell Differentiation / Q000502:physiology; D049109:Cell Proliferation / Q000502:physiology; D004847:Epithelial Cells / Q000473:pathology; D058750:Epithelial-Mesenchymal Transition; D005260:Female; D006657:Histones / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D013058:Mass Spectrometry; D020033:Protein Isoforms; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism
chemical_list: D006657:Histones; D020033:Protein Isoforms; D012333:RNA, Messenger
keywords: Breast cancer; Epidermal growth factor; Epithelial mesenchymal transition; Hist2h2ac; Histone H2A variants; Mammary epithelial cells