[MiR-9 regulates the expression of CBX7 in human glioma].
OBJECTIVE
To detect the expression of CBX7 in human glioma and investigate the potential regulatory effect of abnormally expressed microRNAs on CBX7 expression.


METHODS
Semi-quantitative reverse transcription polymerase chain reaction (RT-PCR) and Western blot were applied to detect the expression pattern of CBX7 in 2 human normal brain tissues, 9 glioma tissues, and 3 glioma cell lines. Miranda algorithm and Ensemble Machine Learning algorithm were combined to predict miRNAs that target human CBX7. The expression of miR-9 in those tissues and cell lines were detected by real-time PCR. After miR-9 overexpression in 293ET and miR-9 knock-down in T98G, luciferase assay and Western blot were used to confirm the effect of miR-9 on CBX7 expression. MTT assay and flow cytometry were applied to detect the effect of miR-9 knock-down on T98G cells.


RESULTS
No obvious difference in the CBX7 mRNA level between normal and tumor tissues was observed, while the protein level of CBX7 was abrogated or markedly reduced in glioma tissues and cell lines. Several miRNAs including miR-9 may target CBX7 by bioinformatics prediction. MiR-9 was up-regulated in glioma tissues and cell lines. In 293ET cell, luciferase activity of CBX7-3'UTR reporter was decreased to 24% after miR-9 overexpression. After miR-9 knock-down in T98G cell, the luciferase activity was increased by 1.8 fold and there was no change of CBX7 mRNA, while the protein level of endogenous CBX7 was significantly increased. The number of survival T98G cells increased and cells in G1 phase decreased after miR-9 knock-down.


CONCLUSIONS
In human glioma, CBX7 is down-regulated by the inhibition of miR-9 at posttranscriptional level.
Chao
Teng-Fei
TF
National Laboratory of Medical Molecular Biology, Institute of Basic Medical Sciences, CAMS and PUMC, Beijing 100005, China.
Zhang
Yu
Y
Yan
Xing-Qi
XQ
Yin
Bin
B
Gong
Yan-Hua
YH
Yuan
Jian-Gang
JG
Qiang
Bo-Qin
BQ
Peng
Xiao-Zhong
XZ
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000465:Algorithms; D015153:Blotting, Western; D001921:Brain / Q000378:metabolism; D002460:Cell Line; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D002648:Child; D005260:Female; D005434:Flow Cytometry; D005910:Glioma / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D035683:MicroRNAs / Q000235:genetics / Q000502:physiology*; D008875:Middle Aged; D063150:Polycomb Repressive Complex 1; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D055815:Young Adult
C503627:CBX7 protein, human; C541874:MIRN92 microRNA, human; D035683:MicroRNAs; D012097:Repressor Proteins; D063150:Polycomb Repressive Complex 1