Chemically Induced Hypoxia Enhances miRNA Functions in Breast Cancer
Autor: | Bonita Shin, Mousumi Majumder, Reid Morgan Opperman, Sujit Maiti, Emma Gervin, Mackenzie Cullen, Riley Feser |
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Rok vydání: | 2020 |
Předmět: |
0301 basic medicine
Cancer Research Angiogenesis Hypoxia inducible factor 1-alpha (HIF-1α) Biology lcsh:RC254-282 Article 03 medical and health sciences Breast cancer 0302 clinical medicine SALL4 Prostaglandin E2 receptor 4 (EP4) medicine PTEN Epithelial–mesenchymal transition skin and connective tissue diseases Protein kinase B Migration PI3K/AKT/mTOR pathway PI3K/Akt lcsh:Neoplasms. Tumors. Oncology. Including cancer and carcinogens miR655 medicine.disease 030104 developmental biology Oncology miR526b Oxidative stress SKBR3 030220 oncology & carcinogenesis Cancer research biology.protein MicroRNA (miRNA) Cyclooxygenase-2 (COX-2) |
Zdroj: | Cancers Volume 12 Issue 8 Cancers, Vol 12, Iss 2008, p 2008 (2020) |
ISSN: | 2072-6694 |
Popis: | In aggressively growing tumors, hypoxia induces HIF-1&alpha expression promoting angiogenesis. Previously, we have shown that overexpression of oncogenic microRNAs (miRNAs, miRs) miR526b/miR655 in poorly metastatic breast cancer cell lines promotes aggressive cancer phenotypes in vitro and in vivo. Additionally, miR526b/miR655 expression is significantly higher in human breast tumors, and high miR526b/miR655 expression is associated with poor prognosis. However, the roles of miR526b/miR655 in hypoxia are unknown. To test the relationship between miR526b/miR655 and hypoxia, we used various in vitro, in silico, and in situ assays. In normoxia, miRNA-high aggressive breast cancer cell lines show higher HIF-1&alpha expression than miRNA-low poorly metastatic breast cancer cell lines. To test direct involvement of miR526b/miR655 in hypoxia, we analyzed miRNA-high cell lines (MCF7-miR526b, MCF7-miR655, MCF7-COX2, and SKBR3-miR526b) compared to controls (MCF7 and SKBR3). CoCl2-induced hypoxia in breast cancer further promotes HIF-1&alpha mRNA and protein expression while reducing VHL expression (a negative HIF-1&alpha regulator), especially in miRNA-high cell lines. Hypoxia enhances oxidative stress, epithelial to mesenchymal transition, cell migration, and vascular mimicry more prominently in MCF7-miR526b/MCF7-miR655 cell lines compared to MCF7 cells. Hypoxia promotes inflammatory and angiogenesis marker (COX-2, EP4, NF&kappa B1, VEGFA) expression in all miRNA-high cells. Hypoxia upregulates miR526b/miR655 expression in MCF7 cells, thus observed enhancement of hypoxia-induced functions in MCF7 could be attributed to miR526b/miR655 upregulation. In silico bioinformatics analysis shows miR526b/miR655 regulate PTEN (a negative regulator of HIF-1&alpha ) and NF&kappa B1 (positive regulator of COX-2 and EP4) expression by downregulation of transcription factors NR2C2, SALL4, and ZNF207. Hypoxia-enhanced functions in miRNA-high cells are inhibited by COX-2 inhibitor (Celecoxib), EP4 antagonist (ONO-AE3-208), and irreversible PI3K/Akt inhibitor (Wortmannin). This establishes that hypoxia enhances miRNA functions following the COX-2/EP4/PI3K/Akt pathways and this pathway can serve as a therapeutic target to abrogate hypoxia and miRNA induced functions in breast cancer. In situ, HIF-1&alpha expression is significantly higher in human breast tumors (n = 96) compared to non-cancerous control tissues (n = 20) and is positively correlated with miR526b/miR655 expression. In stratified tumor samples, HIF-1&alpha expression was significantly higher in ER-positive, PR-positive, and HER2-negative breast tumors. Data extracted from the TCGA database also show a strong correlation between HIF-1&alpha and miRNA-cluster expression in breast tumors. This study, for the first time, establishes the dynamic roles of miR526b/miR655 in hypoxia. |
Databáze: | OpenAIRE |
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