The relationship between EZH2 expression and microRNA-31 in colorectal cancer and the role in evolution of the serrated pathway

Hiroyoshi Kurihara, Reo Maruyama, Kazuya Ishiguro, Shinichi Kanno, Itaru Yamamoto, Keisuke Ishigami, Kei Mitsuhashi, Hisayoshi Igarashi, Miki Ito, Tokuma Tanuma, Yasutaka Sukawa, Kenji Okita, Tadashi Hasegawa, Kohzoh Imai, Hiroyuki Yamamoto, Yasuhisa Shinomura, Katsuhiko Nosho

Research output: Contribution to journalArticlepeer-review

18 Citations (Scopus)

Abstract

Polycomb group protein enhancer of zeste homolog 2 (EZH2) is a methyltransferase that correlates with the regulation of invasion and metastasis and is overexpressed in human cancers such as colorectal cancer. MicroRNA-31 (miR-31) plays an oncogenic role and is associated with BRAF mutation and poor prognosis in colorectal cancer. EZH2 is functionally considered to suppress miR-31 expression in human cancers; however, no study has reported its relationship with colon cancer. We therefore evaluated EZH2 expression using immunohistochemistry and assessed miR-31 and epigenetic alterations using 301 colorectal carcinomas and 207 premalignant lesions. Functional analysis was performed to identify the association between EZH2 and miR-31 using cancer cell lines. In the current study, negative, weak, moderate, and strong EZH2 expressions were observed in 15%, 19%, 25%, and 41% of colorectal cancers, respectively. EZH2 was inversely associated with miR-31 (P < 0.0001), independent of clinicopathological and molecular features. In a multivariate stage-stratified analysis, high EZH2 expression was related to favorable prognosis (P = 0.0022). Regarding premalignant lesions, negative EZH2 expression was frequently detected in sessile serrated adenomas/polyps (SSA/Ps) (76%; P < 0.0001) compared with hyperplastic polyps, traditional serrated adenomas, and non-serrated adenomas (25-36%). Functional analysis demonstrated that the knockdown of EZH2 increased miR-31 expression. In conclusion, an inverse association was identified between EZH2 and miR-31 in colorectal cancers. Our data also showed that upregulation of EZH2 expression may be rare in SSA/Ps. These results suggest that EZH2 suppresses miR-31 in colorectal cancer and may correlate with differentiation and evolution of serrated pathway.

Original languageEnglish
Pages (from-to)12704-12717
Number of pages14
JournalOncotarget
Volume7
Issue number11
DOIs
Publication statusPublished - 2016 Mar 15

Keywords

  • CIMP
  • ChIP
  • EGFR
  • EZH2
  • H3K27me3

ASJC Scopus subject areas

  • Oncology

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