title: Impairment of p53 acetylation by EWS-Fli1 chimeric protein in Ewing family tumors.
abstract: The chromosomal translocation t(11;22)(q24;q12) yields the EWS-Fli1 fusion gene, which contributes to the development of Ewing Family Tumors (EFTs). Previous studies have shown the ability of EWS-Fli1 chimeric protein to silence p53 activity. Here we demonstrate that the introduction of EWS-Fli1 significantly inhibited p300-mediated acetylation of p53 at Lys-382 and depletion of EWS-Fli1 protein by small interfering RNAs (siRNA) in EFTs cells facilitated it in response to DNA damage. Furthermore, the deacetylation of p53 by EWS-Fli1 suppressed its transcriptional activity and enhanced mdm2-mediated p53 degradation. On the other hand, immunoprecipitation study shows that N-terminal region of EWS-Fli1 associated with histone deacetylase 1 (HDAC1) to forms a complex with p53. Knockdown of HDAC1, but not HDAC2 or HDAC3 protein restored the expression of p53 Lys-382 in EFTs cells. Overexpression of HDAC1 also significantly inhibited p53 transcriptional activity. Pharmacologic inhibitor of HDAC, trichostatin A (TSA) promoted p53-p300 interaction and recruitment of p53 Lys-382 to promoter regions of its target genes p21 and Puma, consequently inducing apoptosis and stabilizing the acetylation of p53 at Lys-382 together with the upregulation of p21 and Puma, which were impaired in EFTs cells after the knockdown of p53 expression. Our data indicate EWS-Fli1 might deacetylate p53 to inhibit its transcriptional function and protein stability via the recruitment of HDAC1. These results might elucidate a novel molecular mechanism about the abrogation of p53 pathway by EWS-Fli1 in EFTs pathogenesis.
authors.affiliation: Department of Orthopaedic Surgery, The First Affiliated Hospital, China Medical University, Shenyang, People's Republic of China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.forename: Xu
authors.initials: X
authors.lastname: Li
authors.forename: Guangyu
authors.initials: G
authors.lastname: Fan
authors.forename: Jun-Ichi
authors.initials: J
authors.lastname: Fukushi
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Iwamoto
authors.forename: Yue
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D000107:Acetylation; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001859:Bone Neoplasms / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D050881:E1A-Associated p300 Protein / Q000378:metabolism; D056284:Histone Deacetylase 1 / Q000378:metabolism; D006801:Humans; D006877:Hydroxamic Acids / Q000494:pharmacology; D051379:Mice; D041681:NIH 3T3 Cells; D015514:Oncogene Proteins, Fusion / Q000235:genetics / Q000378:metabolism*; D051789:Proto-Oncogene Protein c-fli-1 / Q000235:genetics / Q000378:metabolism*; D051736:Proto-Oncogene Proteins c-mdm2 / Q000378:metabolism; D034802:RNA-Binding Protein EWS / Q000235:genetics / Q000378:metabolism*; D012512:Sarcoma, Ewing / Q000235:genetics / Q000378:metabolism*; D015533:Transcriptional Activation / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: C106031:EWS-FLI fusion protein; D006877:Hydroxamic Acids; D015514:Oncogene Proteins, Fusion; D051789:Proto-Oncogene Protein c-fli-1; D034802:RNA-Binding Protein EWS; C495901:TP53 protein, human; D016159:Tumor Suppressor Protein p53; C012589:trichostatin A; D050881:E1A-Associated p300 Protein; C494360:EP300 protein, human; C494361:Ep300 protein, mouse; D051736:Proto-Oncogene Proteins c-mdm2; D056284:Histone Deacetylase 1