TY - JOUR
T1 - MiR-20a regulates FAS expression in osteosarcoma cells by modulating FAS promoter activity and can be therapeutically targeted to inhibit lung metastases
AU - Yang, Yuanzheng
AU - Huang, Gangxiong
AU - Zhou, Zhichao
AU - Fewell, Jason G.
AU - Kleinerman, Eugenie S.
N1 - Publisher Copyright:
© 2017 American Association for Cancer Research.
PY - 2018/1
Y1 - 2018/1
N2 - The metastatic potential of osteosarcoma cells is inversely correlated to cell surface FAS expression. Downregulation of FAS allows osteosarcoma cells to escape FAS ligand-mediated apoptosis when they enter a FAS ligand-positive microenvironment such as the lung. We have previously demonstrated that miR-20a, encoded by the miR-17-92 cluster, downregulates FAS expression in osteosarcoma. We further demonstrated an inverse correlation between FAS expression and miR-20a expression. However, the mechanism of FAS regulation by miR-20a was still unclear. The purpose of the current study was to evaluate the mechanism of FAS regulation by miR-20a in vitro and test the effect of targeting miR-20a in vivo. We investigated whether miR-20a's downregulation of FAS was mediated by binding to the 3′-untranslated region (3′-UTR) of FAS mRNA with the consequent induction of mRNA degradation or translational suppression. We identified and mutated two miR-20a binding sites on the FAS mRNA 3′-UTR. Using luciferase reporter assays, we demonstrated that miR-20a did not bind to either the wild-type or mutated FAS 3′-UTR. In contrast, overexpression of miR-20a resulted in downregulation of FAS promoter activity. Similarly, the inhibition of miR-20a increased FAS promoter activity. The critical region identified on the FAS promoter was between -240 bp and -150 bp. Delivery of anti-miR-20a in vivo using nanoparticles in mice with established osteosarcoma lung metastases resulted in upregulation of FAS and tumor growth inhibition. Taken together, our data suggest that miR-20a regulates FAS expression through the modulation of the FAS promoter and that targeting miR-20a using anti-miR-20a has therapeutic potential.
AB - The metastatic potential of osteosarcoma cells is inversely correlated to cell surface FAS expression. Downregulation of FAS allows osteosarcoma cells to escape FAS ligand-mediated apoptosis when they enter a FAS ligand-positive microenvironment such as the lung. We have previously demonstrated that miR-20a, encoded by the miR-17-92 cluster, downregulates FAS expression in osteosarcoma. We further demonstrated an inverse correlation between FAS expression and miR-20a expression. However, the mechanism of FAS regulation by miR-20a was still unclear. The purpose of the current study was to evaluate the mechanism of FAS regulation by miR-20a in vitro and test the effect of targeting miR-20a in vivo. We investigated whether miR-20a's downregulation of FAS was mediated by binding to the 3′-untranslated region (3′-UTR) of FAS mRNA with the consequent induction of mRNA degradation or translational suppression. We identified and mutated two miR-20a binding sites on the FAS mRNA 3′-UTR. Using luciferase reporter assays, we demonstrated that miR-20a did not bind to either the wild-type or mutated FAS 3′-UTR. In contrast, overexpression of miR-20a resulted in downregulation of FAS promoter activity. Similarly, the inhibition of miR-20a increased FAS promoter activity. The critical region identified on the FAS promoter was between -240 bp and -150 bp. Delivery of anti-miR-20a in vivo using nanoparticles in mice with established osteosarcoma lung metastases resulted in upregulation of FAS and tumor growth inhibition. Taken together, our data suggest that miR-20a regulates FAS expression through the modulation of the FAS promoter and that targeting miR-20a using anti-miR-20a has therapeutic potential.
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U2 - 10.1158/1535-7163.MCT-17-0042
DO - 10.1158/1535-7163.MCT-17-0042
M3 - Article
C2 - 29079708
AN - SCOPUS:85040030820
SN - 1535-7163
VL - 17
SP - 130
EP - 139
JO - Molecular cancer therapeutics
JF - Molecular cancer therapeutics
IS - 1
ER -