title: Alternative Splicing of EZH2 pre-mRNA by SF3B3 Contributes to the Tumorigenic Potential of Renal Cancer.
abstract: Purpose:Deregulation or mutation of theEZH2gene causes various tumors, including clear cell renal cell carcinoma (ccRCC). Although several splice variants of EZH2 have been identified, little is known about how EZH2 splicing is regulated or the contribution of alternative splicing to its protumorigenic functions.Experimental Design:We conducted RT-PCR, Western blot analysis, and IHC techniques to examine EZH2 and its alternative splicing transcript expression in renal cancer tissue and renal cancer cell lines. Proliferation, migration, clonogenicity, and tumorigenicity of renal cancer cells either exhibiting knockdown of EZH2 or its splicing factor SF3B3 were assessed by CCK8, Transwell assay, and murine xenograft experiments.Results:We found that the inclusion of alternative EZH2 exon 14 was significantly increased in ccRCC samples and renal cancer cell lines. In ccRCC lines, enforced expression of EZH2Δ14 inhibited, and EZH2 promoted, cell growth, migration, proliferation, and tumorigenicity in a xenograft model. Mechanistic studies demonstrated that EZH2Δ14 isoform functions as a dominant-negative inhibitor of full-length EZH2. Coexpression of EZH2Δ14 variant with full-length EZH2 not only abrogated DAB2IP and HOXA9 suppression but also inhibited EZH2-driven tumorigenesis. Strikingly, the splicing factor SF3B3 stimulates inclusion of exon14 and has pro-proliferative activity. Importantly, the upregulation of SF3B3 expression observed in clinical ccRCC samples parallels the increased inclusion of EZH2 exon14, and the SF3B3 level is associated with higher tumor stage and poor overall survival.Conclusions:These results suggest SF3B3 as a key regulator of EZH2 pre-mRNA splicing and SF3B3 may represent a novel prognostic factor and potential therapeutic target in ccRCC.Clin Cancer Res; 23(13); 3428-41. ©2016 AACR.
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Ke
authors.initials: K
authors.lastname: Chen
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.|Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.
authors.forename: Haibing
authors.initials: H
authors.lastname: Xiao
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Jin
authors.initials: J
authors.lastname: Zeng
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Gan
authors.initials: G
authors.lastname: Yu
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhou
authors.affiliation: College of Basic Medicine, Hubei University of Traditional Chinese Medicine, No.1 HUANGJIAHU Road, Hongshan District, Wuhan, China.
authors.forename: Chunhua
authors.initials: C
authors.lastname: Huang
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Yao
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Xiao
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Junhui
authors.initials: J
authors.lastname: Hu
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Wei
authors.initials: W
authors.lastname: Guan
authors.affiliation: Department of Molecular and Medical Pharmacology, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, California.
authors.forename: Lily
authors.initials: L
authors.lastname: Wu
authors.affiliation: Department of Urology, David Geffen School of Medicine at UCLA, Los Angeles, California.
authors.forename: Jiaoti
authors.initials: J
authors.lastname: Huang
authors.affiliation: The Wistar Institute, Philadelphia, Pennsylvania.
authors.forename: Qihong
authors.initials: Q
authors.lastname: Huang
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China. xuhua@hust.edu.cn.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xu
authors.affiliation: Department of Urology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, P.R. China.|Hubei Institute of Urology, Wuhan, P.R. China.
authors.forename: Zhangqun
authors.initials: Z
authors.lastname: Ye
mesh_terms: D017398:Alternative Splicing / Q000235:genetics; D000818:Animals; D063646:Carcinogenesis / Q000235:genetics*; D002292:Carcinoma, Renal Cell / Q000235:genetics* / Q000473:pathology; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000235:genetics; D049109:Cell Proliferation / Q000235:genetics; D000071221:Enhancer of Zeste Homolog 2 Protein / Q000235:genetics*; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D051379:Mice; D020033:Protein Isoforms / Q000235:genetics; D012322:RNA Precursors / Q000235:genetics; D000072260:RNA Splicing Factors / Q000235:genetics*; D023041:Xenograft Model Antitumor Assays
chemical_list: D020033:Protein Isoforms; D012322:RNA Precursors; D000072260:RNA Splicing Factors; C486349:SF3B3 protein, human; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein