The browser you are using is not supported by this website. All versions of Internet Explorer are no longer supported, either by us or Microsoft (read more here: https://www.microsoft.com/en-us/microsoft-365/windows/end-of-ie-support).

Please use a modern browser to fully experience our website, such as the newest versions of Edge, Chrome, Firefox or Safari etc.

ETS1 mediates MEK1/2-dependent overexpression of cancerous inhibitor of protein phosphatase 2A (CIP2A) in human cancer cells.

På svenska

Author

  • Anchit Khanna
  • Juha Okkeri
  • Turker Bilgen
  • Timo Tiirikka
  • Mauno Vihinen
  • Tapio Visakorpi
  • Jukka Westermarck

Summary, in English

EGFR-MEK-ERK signaling pathway has an established role in promoting malignant growth and disease progression in human cancers. Therefore identification of transcriptional targets mediating the oncogenic effects of the EGFR-MEK-ERK pathway would be highly relevant. Cancerous inhibitor of protein phosphatase 2A (CIP2A) is a recently characterized human oncoprotein. CIP2A promotes malignant cell growth and is over expressed at high frequency (40-80%) in most of the human cancer types. However, the mechanisms inducing its expression in cancer still remain largely unexplored. Here we present systematic analysis of contribution of potential gene regulatory mechanisms for high CIP2A expression in cancer. Our data shows that evolutionary conserved CpG islands at the proximal CIP2A promoter are not methylated both in normal and cancer cells. Furthermore, sequencing of the active CIP2A promoter region from altogether seven normal and malignant cell types did not reveal any sequence alterations that would increase CIP2A expression specifically in cancer cells. However, treatment of cancer cells with various signaling pathway inhibitors revealed that CIP2A mRNA expression was sensitive to inhibition of EGFR activity as well as inhibition or activation of MEK-ERK pathway. Moreover, MEK1/2-specific siRNAs decreased CIP2A protein expression. Series of CIP2A promoter-luciferase constructs were created to identify proximal -27 to -107 promoter region responsible for MEK-dependent stimulation of CIP2A expression. Additional mutagenesis and chromatin immunoprecipitation experiments revealed ETS1 as the transcription factor mediating stimulation of CIP2A expression through EGFR-MEK pathway. Thus, ETS1 is probably mediating high CIP2A expression in human cancers with increased EGFR-MEK1/2-ERK pathway activity. These results also suggest that in addition to its established role in invasion and angiogenesis, ETS1 may support malignant cellular growth via regulation of CIP2A expression and protein phosphatase 2A inhibition.

Publishing year

2011

Language

English

Publication/Series

PLoS ONE

Volume

6

Issue

3

Document type

Journal article

Publisher

Public Library of Science (PLoS)

Topic

  • Medical Genetics

Keywords

  • Aryl Hydrocarbon Hydroxylases: antagonists & inhibitors
  • Aryl Hydrocarbon Hydroxylases: genetics
  • MAP Kinase Kinase 1: metabolism
  • MAP Kinase Kinase 2: metabolism
  • Proto-Oncogene Protein c-ets-1: physiology
  • Steroid Hydroxylases: antagonists & inhibitors
  • Steroid Hydroxylases: genetics

Status

Published

ISBN/ISSN/Other

  • ISSN: 1932-6203