title: Increased phosphorylation of histone H3 at serine 10 is involved in Epstein-Barr virus latent membrane protein-1-induced carcinogenesis of nasopharyngeal carcinoma.
abstract: BACKGROUND
  Increased histone H3 phosphorylation is an essential regulatory mechanism for neoplastic cell transformation. We aimed to explore the role of histone H3 phosphorylation at serine10 (p-H3Ser10) in Epstein-Barr virus (EBV) latent membrane protein-1 (LMP1)-induced carcinogenesis of nasopharyngeal carcinoma (NPC).
  
  
  METHODS
  The expression of p-H3Ser10 was detected by the immunohistochemical analysis in NPC, chronic nasopharyngitis and normal nasopharynx tissues, and its correlation with LMP1 was analyzed in NPC tissues and cell lines. Using the small interfering RNA (siRNA)-H3 and histone H3 mutant (S10A), the effect of histone H3 Ser10 motif on LMP1-induced CNE1 cell proliferation, transformation and activator protein-1 (AP-1) activation were evaluated by CCK-8, focus-forming and reporter gene assay respectively. Mitogen- and stress-activated kinase 1 (MSK1) kinase activity and phosphorylation were detected by in vitro kinase assay and western blot. Using MSK1 inhibitor H89 or siRNA-MSK1, the regulatory role of MSK1 on histone H3 phosphorylation and AP-1 activation were analyzed.
  
  
  RESULTS
  Immunohistochemical analysis revealed that the expression of p-H3Ser10 was significantly higher in the poorly differentiated NPC tissues than that in chronic nasopharyngitis (p <0.05) and normal nasopharynx tissues (p <0.001). Moreover, high level of p-H3Ser10 was positively correlated with the expression of LMP1 in NPC tissues (χ2=6.700, p =0.01; C=0.350) and cell lines. The knockdown and mutant (S10A) of histone H3 suppressed LMP1-induced CNE1 cell proliferation, foci formation and AP-1 activation. In addition, LMP1 could increase MSK1 kinase activity and phosphorylation. MSK1 inhibitor H89 or knockdown of MSK1 by siRNA blocked LMP1-induced phosphorylation of histone H3 at Ser10 and AP-1 activation.
  
  
  CONCLUSIONS
  EBV-LMP1 can induce phosphorylation of histone H3 at Ser10 via MSK1. Increased phosphorylation of histone H3 at Ser10 is likely a crucial regulatory mechanism involved in LMP1-induced carcinogenesis of NPC.
authors.affiliation: Department of Pathophysiology, Basic Medical College of Zhengzhou University, No,100 of Science Road, Zhengzhou, 450001, China.
authors.forename: Binbin
authors.initials: B
authors.lastname: Li
authors.forename: Guoliang
authors.initials: G
authors.lastname: Huang
authors.forename: Xiangning
authors.initials: X
authors.lastname: Zhang
authors.forename: Rong
authors.initials: R
authors.lastname: Li
authors.forename: Jian
authors.initials: J
authors.lastname: Wang
authors.forename: Ziming
authors.initials: Z
authors.lastname: Dong
authors.forename: Zhiwei
authors.initials: Z
authors.lastname: He
mesh_terms: D000328:Adult; D002277:Carcinoma; D002460:Cell Line; D002472:Cell Transformation, Viral / Q000235:genetics; D005260:Female; D015870:Gene Expression; D006657:Histones / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged; D000077274:Nasopharyngeal Carcinoma; D009303:Nasopharyngeal Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000821:virology*; D010766:Phosphorylation; D038744:Ribosomal Protein S6 Kinases, 90-kDa / Q000378:metabolism; D012694:Serine / Q000378:metabolism; D014763:Viral Matrix Proteins / Q000235:genetics / Q000378:metabolism*
chemical_list: C037662:EBV-associated membrane antigen, Epstein-Barr virus; D006657:Histones; D014763:Viral Matrix Proteins; D012694:Serine; D038744:Ribosomal Protein S6 Kinases, 90-kDa; C116919:mitogen and stress-activated protein kinase 1