MicroRNA-34a is a tumor suppressor in choriocarcinoma via regulation of Delta-like1

BMC Cancer

Research Article

Kevin KW Lam¹  Carmen ON Leung¹  Tian-Min Ye¹  Cheuk-Lun Lee²  William SB Yeung²  Philip CN Chiu²  Ronald TK Pang² 

[1] Department of Obstetrics and Gynaecology, The University of Hong Kong, Pokfulam Road, Hong Kong, China;Department of Obstetrics and Gynaecology, The University of Hong Kong, Pokfulam Road, Hong Kong, China;Center for Reproduction, Development and Growth, The University of Hong Kong, Pokfulam Road, Hong Kong, China;

关键词: miR-34a;    DLL1;    Choriocarcinoma;    Invasion;    Notch;   

DOI  :  10.1186/1471-2407-13-25

 received in 2012-07-19, accepted in 2013-01-10,  发布年份 2013

来源: Springer

【 摘 要 】

BackgroundChoriocarcinoma is a gestational trophoblastic tumor which causes high mortality if left untreated. MicroRNAs (miRNAs) are small non protein-coding RNAs which inhibit target gene expression. The role of miRNAs in choriocarcinoma, however, is not well understood. In this study, we examined the effect of miR-34a in choriocarcinoma.MethodsMiR-34a was either inhibited or ectopically expressed transiently in two choriocarcinoma cell lines (BeWo and JEG-3) respectively. Its actions on cell invasion, proliferation and colony formation at low cell density were examined. The miR-34a putative target Notch ligand Delta-like 1 (DLL1) was identified by adoption of different approaches including: in-silico analysis, functional luciferase assay and western blotting. Real-time quantitative polymerase chain reaction was used to quantify changes in the expression of matrix proteinase in the treated cells. To nullify the effect of miR-34a ectopic expression, we activated Notch signaling through force-expression of the Notch intracellular domain in the miR-34a force-expressed cells. In addition, we studied the importance of DLL1 in BeWo cell invasion through ligand stimulation and antibody inhibition. Furthermore, the induction in tumor formation of miR-34a-inhibited BeWo cells in SCID mice was investigated.ResultsTransient miR-34a force-expression significantly suppressed cell proliferation and invasion in BeWo and JEG-3 cells. In silicon miRNA target prediction, luciferase functional assays and Western blotting analysis demonstrated that miR-34a regulated DLL1 expression in both cell lines. Although force-expression of miR-34a suppressed the expression of DLL1 and NOTCH1, the extent of suppression was higher in DLL1 than NOTCH1 in both cell lines. MiR-34a-mediated DLL1 suppression led to reduced matrix metallopeptidase 9 and urokinase-type plasminogen activator expression. The effect of miR-34a on cell invasion was partially nullified by Notch signaling activation. DLL1 ligand stimulated while anti-DLL1 antibody treatment suppressed cell invasion. Mice inoculated with BeWo cells transfected with miR-34a inhibitor had significantly larger xenografts and stronger DLL1 expression than those with cells transfected with the control inhibitor.ConclusionsMiR-34a reduced cell proliferation and invasiveness, at least, partially through its inhibitory effect on DLL1.

【 授权许可】

Unknown   
© Pang et al.; licensee BioMed Central Ltd. 2013. This article is published under license to BioMed Central Ltd. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/2.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.