Proteomic screening identifies calreticulin as a miR-27a direct target repressing MHC class I cell surface exposure in colorectal cancer
Open Access
- 25 February 2016
- journal article
- research article
- Published by Springer Science and Business Media LLC in Cell Death & Disease
- Vol. 7 (2), e2120
- https://doi.org/10.1038/cddis.2016.28
Abstract
Impairment of the immune response and aberrant expression of microRNAs are emerging hallmarks of tumour initiation/progression, in addition to driver gene mutations and epigenetic modifications. We performed a preliminary survey of independent adenoma and colorectal cancer (CRC) miRnoma data sets and, among the most dysregulated miRNAs, we selected miR-27a and disclosed that it is already upregulated in adenoma and further increases during the evolution to adenocarcinoma. To identify novel genes and pathways regulated by this miRNA, we employed a differential 2DE-DIGE proteome analysis. We showed that miR-27a modulates a group of proteins involved in MHC class I cell surface exposure and, mechanistically, demonstrated that calreticulin is a miR-27a direct target responsible for most downstream effects in epistasis experiments. In vitro miR-27a affected cell proliferation and angiogenesis; mouse xenografts of human CRC cell lines expressing different miR-27a levels confirmed the protein variations and recapitulated the cell growth and apoptosis effects. In vivo miR-27a inversely correlated with MHC class I molecules and calreticulin expression, CD8+ T cells infiltration and cytotoxic activity (LAMP-1 exposure and perforin release). Tumours with high miR-27a, low calreticulin and CD8+ T cells' infiltration were associated with distant metastasis and poor prognosis. Our data demonstrate that miR-27a acts as an oncomiRNA, represses MHC class I expression through calreticulin downregulation and affects tumour progression. These results may pave the way for better diagnosis, patient stratification and novel therapeutic approaches.Keywords
This publication has 39 references indexed in Scilit:
- Comprehensive molecular characterization of human colon and rectal cancerNature, 2012
- Colorectal-Cancer Incidence and Mortality with Screening Flexible SigmoidoscopyNew England Journal of Medicine, 2012
- Identifying Functional MicroRNAs in Macrophages with Polarized PhenotypesJournal of Biological Chemistry, 2012
- Hallmarks of Cancer: The Next GenerationCell, 2011
- Guidelines for the welfare and use of animals in cancer researchBritish Journal of Cancer, 2010
- Modes of Calreticulin Recruitment to the Major Histocompatibility Complex Class I Assembly PathwayJournal of Biological Chemistry, 2010
- miR-27a is a negative regulator of adipocyte differentiation via suppressing PPARγ expressionBiochemical and Biophysical Research Communications, 2010
- Calreticulin-dependent recycling in the early secretory pathway mediates optimal peptide loading of MHC class I moleculesThe EMBO Journal, 2009
- Cromoglycate drugs suppress eicosanoid generation in U937 cells by promoting the release of Anx-A1Biochemical Pharmacology, 2009
- A methodology for the combined in situ analyses of the precursor and mature forms of microRNAs and correlation with their putative targetsNature Protocols, 2009