TY - JOUR
T1 - MiR-200b restoration and DNA methyltransferase inhibitor block lung metastasis of mesenchymal-phenotype hepatocellular carcinoma
AU - Ding, W.
AU - Dang, H.
AU - You, H.
AU - Steinway, S.
AU - Takahashi, Y.
AU - Wang, H. G.
AU - Liao, J.
AU - Stiles, B.
AU - Albert, R.
AU - Rountree, C. B.
N1 - Funding Information:
We thank Dr Yvette Liu, from the El-Deiry Laboratory, The Penn State Hershey Cancer Institute, for assisting with luciferase bioluminescence image collection. We thank Dr K Morishita, Department of Medical Sciences, University of Miyazaki, for providing us with pEGFP-C1-Zeb1 construct. We acknowledge Drs Kent Vrana and Willard Freeman of the Functional Genomics Core (The Pennsylvania State University College of Medicine). Important Functional Genomics Core Facility instrumentation purchases were made possible through Tobacco Settlement Funds and through a Penn State Cancer Institute contract with the Department of the Navy. This publication was made possible by generous support from the National Institute of Health, R03DK088013 (CBR); the American Cancer Society, Research Scholar Award, RSG-10-073-01-TBG (CBR); The Department of the Navy, Penn State Center for Pharmacogenetics Pilot Projects (CBR) and the Four Diamonds Foundation (CBR).
Funding Information:
Dr CB Rountree declares a small research grant (less than $10,000), which does not include direct salary support, from Bayer Pharmaceuticals. The remaining authors declare no conflict of interest.
PY - 2012
Y1 - 2012
N2 - Epithelial-to-mesenchymal transition (EMT) is associated with poor prognosis and metastasis in hepatocellular carcinoma. We have previously demonstrated an in vivo model of liver cancer in which mesenchymal cells post-EMT demonstrate a high rate of invasive growth and metastasis. Here, we investigate the role of microRNA 200 (miR-200) family members and epigenetic modifications on the maintenance of mesenchymal/metastatic phenotype after EMT. Mesenchymal cells post-EMT demonstrates high levels of E-box repressors Zeb1 and Zeb2 and downregulation of four miR-200 family members (miR-200a, miR-200b, miR-200c and miR-429). In addition, DNA sequencing after bisulfite modification demonstrates that several CpG sites within the E-cadherin promoter are methylated in mesenchymal cells. In mesenchymal cells, forced expression of miR-200b results in a significant increase in E-cadherin and a reduction in cell migration/invasion. Despite these mesenchymal-to-epithelial transition (MET) changes in vitro, there is no significant change in metastatic potential after miR-200b upregulation in vivo. After the mesenchymal cells were treated with combination of DNA methyltransferase (DNMT) inhibitor and upregulation of miR-200b, invasive phenotype was significantly reduced and metastatic potential was eliminated. Direct targeting of E-cadherin with short hairpin RNA does not restore metastatic potential after DNMT inhibition and miR-200b re-expression. In addition, restoration of E-cadherin alone was unable to block metastatic potential in primary mesenchymal cells. In conclusion, targeting mesenchymal liver cancer cells with miR-200b and DNMT inhibitor reduces metastatic potential irrespective of E-cadherin expression. Thus, the broader differentiation and MET effects of DNMT inhibition and miR-200b must be considered in terms of rescuing metastatic potential.
AB - Epithelial-to-mesenchymal transition (EMT) is associated with poor prognosis and metastasis in hepatocellular carcinoma. We have previously demonstrated an in vivo model of liver cancer in which mesenchymal cells post-EMT demonstrate a high rate of invasive growth and metastasis. Here, we investigate the role of microRNA 200 (miR-200) family members and epigenetic modifications on the maintenance of mesenchymal/metastatic phenotype after EMT. Mesenchymal cells post-EMT demonstrates high levels of E-box repressors Zeb1 and Zeb2 and downregulation of four miR-200 family members (miR-200a, miR-200b, miR-200c and miR-429). In addition, DNA sequencing after bisulfite modification demonstrates that several CpG sites within the E-cadherin promoter are methylated in mesenchymal cells. In mesenchymal cells, forced expression of miR-200b results in a significant increase in E-cadherin and a reduction in cell migration/invasion. Despite these mesenchymal-to-epithelial transition (MET) changes in vitro, there is no significant change in metastatic potential after miR-200b upregulation in vivo. After the mesenchymal cells were treated with combination of DNA methyltransferase (DNMT) inhibitor and upregulation of miR-200b, invasive phenotype was significantly reduced and metastatic potential was eliminated. Direct targeting of E-cadherin with short hairpin RNA does not restore metastatic potential after DNMT inhibition and miR-200b re-expression. In addition, restoration of E-cadherin alone was unable to block metastatic potential in primary mesenchymal cells. In conclusion, targeting mesenchymal liver cancer cells with miR-200b and DNMT inhibitor reduces metastatic potential irrespective of E-cadherin expression. Thus, the broader differentiation and MET effects of DNMT inhibition and miR-200b must be considered in terms of rescuing metastatic potential.
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U2 - 10.1038/oncsis.2012.15
DO - 10.1038/oncsis.2012.15
M3 - Article
C2 - 23552699
AN - SCOPUS:84868293073
SN - 2157-9024
VL - 1
JO - Oncogenesis
JF - Oncogenesis
IS - 6
M1 - e15
ER -