Lentivirus-mediated RNA interference targeting enhancer of zeste homolog 2 inhibits hepatocellular carcinoma growth through down-regulation of stathmin.
Enhancer of zeste homolog 2 (EZH2) has been shown to be overexpressed in hepatocellular (HCC). We investigated the potential role of EZH2 in HCC tumorigenesis and examined the usefulness of RNA interference (RNAi) targeting EZH2 as a form of HCC treatment. Lentivirus-mediated RNAi was employed to knock-down EZH2 expression in human hepatoma cells to study the function of EZH2 in tumorigenesis and evaluate the treatment efficacy. Lentivirus-mediated RNAi effectively reduced EZH2 expression. Suppression of EZH2 in HCC cells significantly reduced their growth rate in vitro and markedly diminished their tumorigenicity in vivo. Moreover, in a mice model of established large-sized HCC, we showed that intratumor injection of lentiviral (Lenti)-shRNA (short hairpin RNA) or siRNA (small interfering RNA) targeting EZH2 produced significant tumor regression. To understand its molecular mechanism of action, we employed proteomic profiling technique and found that stathmin 1 is the downstream target of EZH2, as Lenti-shEZH2 treatment decreased stathmin protein expression, and ectopic overexpression of stathmin prevented Lenti-shEZH2 mediated tumor growth inhibition.


CONCLUSIONS
Results from our study suggested for the first time that EZH2 plays a key role in HCC tumorigenesis, and is a novel therapeutic target for HCC.
Chen
Yangchao
Y
Stanley Ho Center for Emerging Infectious Diseases, Hong Kong, China.
Lin
Marie C
MC
Yao
Hong
H
Wang
Hua
H
Zhang
Ai-Qun
AQ
Yu
Jun
J
Hui
Chee-kin
CK
Lau
George K
GK
He
Ming-liang
ML
Sung
Joseph
J
Kung
Hsiang-fu
HF
D006528:Carcinoma, Hepatocellular / Q000473:pathology*; D018929:Cell Culture Techniques; D002455:Cell Division / Q000235:genetics*; D003001:Cloning, Molecular; D004268:DNA-Binding Proteins / Q000235:genetics*; D004742:Enhancer Elements, Genetic; D000071221:Enhancer of Zeste Homolog 2 Protein; D015967:Gene Expression Regulation, Viral; D006801:Humans; D016086:Lentivirus / Q000235:genetics*; D008099:Liver / Q000473:pathology / Q000502:physiology*; D008113:Liver Neoplasms / Q000473:pathology*; D063151:Polycomb Repressive Complex 2; D011401:Promoter Regions, Genetic; D034622:RNA Interference / Q000502:physiology*; D012367:RNA, Viral / Q000235:genetics; D015183:Restriction Mapping; D050777:Stathmin / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics*
D004268:DNA-Binding Proteins; D012367:RNA, Viral; D050777:Stathmin; D014157:Transcription Factors; C498409:EZH2 protein, human; D000071221:Enhancer of Zeste Homolog 2 Protein; D063151:Polycomb Repressive Complex 2