RREB1 repressed miR-143/145 modulates KRAS signaling through downregulation of multiple targets

O. A. Kent, K. Fox-Talbot, M. K. Halushka

Research output: Contribution to journalArticlepeer-review

Abstract

A lack of expression of miR-143 and miR-145 has been demonstrated to be a frequent feature of colorectal tumors. Activating KRAS mutations have been reported in 30-60% of colorectal cancers and an inverse correlation between Kras and miR-143/145 expression has been observed. Previously, we have demonstrated that oncogenic Kras leads to repression of the miR-143/145 cluster in pancreatic cancer and is dependent on the Ras responsive element (RRE) binding protein (RREB1), which negatively regulates miR-143/145 expression. In the present study, we have found that RREB1 is overexpressed in colorectal adenocarcinoma tumors and cell lines, and the expression of the miR-143/145 primary transcript is inversely related to RREB1 expression. In colorectal cancer cell lines, the miR-143/145 cluster is repressed by RREB1 downstream of constitutively active KRAS. RREB1 is activated by the MAPK pathway and negatively represses the miR-143/145 promoter through interaction with two RREs. In addition, overexpression of miR-143 or miR-145 in HCT116 cells abrogates signaling through the MAPK, PI3K and JNK pathways by downregulation of both KRAS and RREB1 in addition to downregulation of a cohort of genes in the MAPK signaling cascade. These results establish a complex network of regulation through which the miR-143/145 cluster is able to modulate KRAS signaling in colorectal cancer.

Original languageEnglish (US)
Pages (from-to)2576-2585
Number of pages10
JournalOncogene
Volume32
Issue number20
DOIs
StatePublished - May 16 2013

Keywords

  • Colorectal
  • KRAS
  • RREB1
  • miR-143
  • miR-145
  • miRNA

ASJC Scopus subject areas

  • Molecular Biology
  • Genetics
  • Cancer Research

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