Format

Send to

Choose Destination
J Pathol. 2013 May;230(1):28-38. doi: 10.1002/path.4178. Epub 2013 Mar 21.

miR-29a inhibition normalizes HuR over-expression and aberrant AU-rich mRNA stability in invasive cancer.

Author information

1
Molecular Biomedicine Programme, King Faisal Specialist Hospital and Research Centre, Riyadh, Saudi Arabia.

Abstract

The activities of RNA-binding proteins are perturbed in several pathological conditions, including cancer. These proteins include tristetraprolin (TTP, ZFP36) and HuR (ELAVL1), which respectively promote the decay or stability of adenylate-uridylate-rich (AU-rich) mRNAs. Here, we demonstrated that increased stabilization and subsequent over-expression of HuR mRNA were coupled to TTP deficiency. These findings were observed in breast cancer cell lines with an invasive phenotype and were further confirmed in ZFP36-knockout mouse fibroblasts. We show that TTP-HuR imbalance correlated with increased expression of AU-rich element (ARE) mRNAs that code for cancer invasion genes. The microRNA miR-29a was abundant in invasive breast cancer cells when compared to non-tumourigenic cell types. When normal breast cells were treated with miR-29a, HuR mRNA and protein expression were up-regulated. MiR-29a recognized a seed target in the TTP 3' UTR and a cell-permeable miR-29a inhibitor increased TTP activity towards HuR 3' UTR. This led to HuR mRNA destabilization and restoration of the aberrant TTP-HuR axis. Subsequently, the cancer invasion factors uPA, MMP-1 and MMP-13, and cell invasiveness, were decreased. The TTP:HuR mRNA ratios were also perturbed in samples from invasive breast cancer patients when compared with normal tissues, and were associated with invasion gene expression. This study demonstrates that an aberrant ARE-mediated pathway in invasive cancer can be normalized by targeting the aberrant and functionally coupled TTP-HuR axis, indicating a potential therapeutic approach.

PMID:
23401122
PMCID:
PMC3732382
DOI:
10.1002/path.4178
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for Wiley Icon for PubMed Central
Loading ...
Support Center