miR-29a suppresses tristetraprolin, which is a regulator of epithelial polarity and metastasis.

IMBA Vienna, Institute for Molecular Pathology, Dr Bohrgasse 3-5, 1030 Vienna, Austria.
EMBO Reports (Impact Factor: 7.86). 03/2009; 10(4):400-5. DOI: 10.1038/embor.2009.9
Source: PubMed

ABSTRACT Several microRNAs (miRNAs) have recently been described as crucial regulators of epithelial-to-mesenchymal transition (EMT) and metastasis. By comparing the expression profiles of miRNAs, we found upregulation of miR-29a in mesenchymal, metastatic RasXT cells relative to epithelial EpRas cells. Overexpression of miR-29a suppressed the expression of tristetraprolin (TTP), a protein involved in the degradation of messenger RNAs with AU-rich 3'-untranslated regions, and led to EMT and metastasis in cooperation with oncogenic Ras signalling. We also observed enhanced miR-29a and reduced TTP levels in breast cancer patient samples, indicating relevance for human disease. Previously, miR-29 family members were shown to have tumour-suppressive effects in haematopoietic, cholangiocytic and lung tumours. Therefore, miRNAs can act as either oncogenes or tumour suppressors, depending on the context.

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