miR-20b Modulates VEGFExpression by Targeting HIF-1aand STAT3 in MCF-7 BreastCancer Cells

Antonio Russo, Nicolo' Gebbia, Valeria Amodeo, Viviana Bazan, Gaspare Gulotta, Rita Ferla, Eliana Gulotta, Aleco D'Andrea, Nicola Gebbia, Valeria Amodeo, Antonio Russo, Sandra Cascio, Viviana Bazan, Eva Surmacz, Aleco D'Andrea, Rita Ferla, Sandra Cascio

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195 Citazioni (Scopus)


MicroRNAs (miRNAs) are small non-coding RNAs that regulate the expression of different genes, including genes involved in cancer progression. A functional link between hypoxia, a key feature of the tumor microenvironment, and miRNA expression has been documented. We investigated whether and how miR-20b can regulate the expression of vascular endothelial growth factor (VEGF) in MCF-7 breast cancer cells under normoxic and hypoxia-mimicking conditions (CoCl2 exposure). Using immunoblotting, ELISA, and quantitative real-time PCR, we demonstrated that miR-20b decreased VEGF protein levels at 4 and 24 h following CoCl2 treatment, and VEGF mRNA at 4 h of treatment. In addition, miR-20b reduced VEGF protein expression in untreated cells. Next, we investigated the molecular mechanism by which pre-miR-20b can affect VEGF transcription, focusing on hypoxia inducible factor 1 (HIF-1) and signal transducer and activator of transcription 3 (STAT3), transcriptional inducers of VEGF and putative targets of miR-20b. Downregulation of VEGF mRNA by miR-20b under a 4 h of CoCl2 treatment was associated with reduced levels of nuclear HIF-1 subunit and STAT3. Chromatin immunoprecipitation (ChIP) assays revealed that HIF-1, but not STAT3, was recruited to the VEGF promoter following the 4 h of CoCl2 treatment. This effect was inhibited by transfection of cells with pre-miR-20b. In addition, using siRNA knockdown, we demonstrated that the presence of STAT3 is necessary for CoCl2-mediated HIF-1 nuclear accumulation and recruitment on VEGF promoter. In summary, this report demonstrates, for the first time, that the VEGF expression in breast cancer cells is mediated by HIF-1 and STAT3 in a miR-20b-dependent manner.
Lingua originaleEnglish
pagine (da-a)242-249
Numero di pagine8
RivistaJournal of Cellular Physiology
Stato di pubblicazionePublished - 2010

All Science Journal Classification (ASJC) codes

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  • ???subjectarea.asjc.1300.1308???
  • ???subjectarea.asjc.1300.1307???


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