Histone demethylase retinoblastoma binding protein 2 is overexpressed in hepatocellular carcinoma and negatively regulated by hsa-miR-212.
BACKGROUND
The H3K4 demethylase retinoblastoma binding protein 2 (RBP2) is involved in the pathogenesis of gastric cancer, but its role and regulation in hepatocellular carcinoma (HCC) is unknown. We determined the function of RBP2 and its regulation in HCC in vitro and in human tissues.


METHODS
We analyzed gene expression in 20 specimens each of human HCC and normal liver tissue by quantitative real-time PCR and immunohistochemistry. Proliferation was analyzed by foci formation and senescence by β-galactosidase staining. Promoter activity was detected by luciferase reporter assay.


RESULTS
The expression of RBP2 was stronger in cancerous than non-cancerous tissues, but that of its binding microRNA, Homo sapiens miR-212 (hsa-miR-212), showed an opposite pattern. SiRNA knockdown of RBP2 significantly upregulated cyclin-dependent kinase inhibitors (CDKIs), with suppression of HCC cell proliferation and induction of senescence. Overexpression of hsa-miR-212 suppressed RBP2 expression, with inhibited cell proliferation and induced cellular senescence, which coincided with upregulated CDKIs; with low hsa-miR-212 expression, CDKIs were downregulated in HCC tissue. Inhibition of hsa-miR-212 expression upregulated RBP2 expression. Luciferase reporter assay detected the direct binding of hsa-miR-212 to the RBP2 3' UTR.


CONCLUSIONS
RBP2 is overexpressed in HCC and negatively regulated by hsa-miR-212. The hsa-miR-212-RBP2-CDKI pathway may be important in the pathogenesis of HCC.
Department of Microbiology/Key Laboratory for Experimental Teratology of Chinese Ministry of Education, Shandong University School of Medicine, Jinan, PR China.
Xiuming
X
Liang
Jiping
J
Zeng
Lixiang
L
Wang
Ming
M
Fang
Qing
Q
Wang
Min
M
Zhao
Xia
X
Xu
Zhifang
Z
Liu
Wenjuan
W
Li
Shili
S
Liu
Han
H
Yu
Jihui
J
Jia
Chunyan
C
Chen
D000328:Adult; D000368:Aged; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D008099:Liver; D008297:Male; D035683:MicroRNAs / Q000235:genetics*; D008875:Middle Aged; D060888:Real-Time Polymerase Chain Reaction; D056485:Retinoblastoma-Binding Protein 2 / Q000235:genetics / Q000378:metabolism*
D035683:MicroRNAs; D056485:Retinoblastoma-Binding Protein 2