MicroRNA-362 induces cell proliferation and apoptosis resistance in gastric cancer by activation of NF-κB signaling.
BACKGROUND
According to cancer-related microRNA (miRNA) expression microarray research available in public databases, miR-362 expression is elevated in gastric cancer. However, the expression and biological role of miR-362 in gastric progression remain unclear.


METHODS
miR-362 expression levels in gastric cancer tissues and cell lines were determined using real-time PCR. The roles of miR-362, in promoting gastric cancer cell proliferation and apoptosis resistance, were assessed by different biological assays, such as colony assay, flow cytometry and TUNEL assay. The effect of miR-362 on NF-κB activation was investigated using the luciferase reporter assay, fluorescent immunostaining.


RESULTS
MiR-362 overexpression induced cell proliferation, colony formation, and resistance to cisplatin-induced apoptosis in BGC-823 and SGC-7901 gastric cancer cells. MiR-362 increased NF-κB activity and relative mRNA expression of NF-κB-regulated genes, and induced nuclear translocation of p65. Expression of the tumor suppressor CYLD was inhibited by miR-362 in gastric cancer cells; miR-362 levels were inversely correlated with CYLD expression in gastric cancer tissue. MiR-362 downregulated CYLD expression by binding its 3' untranslated region. NF-κB activation was mechanistically associated with siRNA-mediated downregulation of CYLD. MiR-362 inhibitor reversed all the effects of miR-362.


CONCLUSIONS
The results suggest that miR-362 plays an important role in repressing the tumor suppressor CYLD and present a novel mechanism of miRNA-mediated NF-κB activation in gastric cancer.
Jin-tang
JT
Xia
Lian-zhou
LZ
Chen
Wei-hua
WH
Jian
Ke-Bing
KB
Wang
Yong-zhen
YZ
Yang
Wei-ling
WL
He
Yu-long
YL
He
Department of General Surgery, The third Affiliated Hospital, Guangzhou Medical University, #63 Duobao Road, Guangzhou, Guangdong 510150, China. drchende@gzmc.edu.cn.
De
D
Chen
Wen
W
Li
D020413:3' Untranslated Regions / Q000235:genetics; D017209:Apoptosis / Q000235:genetics*; D001483:Base Sequence; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D000074749:Deubiquitinating Enzyme CYLD; D015536:Down-Regulation / Q000235:genetics; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000378:metabolism*; D015398:Signal Transduction / Q000235:genetics*; D013274:Stomach Neoplasms / Q000235:genetics* / Q000473:pathology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism; D015854:Up-Regulation / Q000235:genetics
D020413:3' Untranslated Regions; C581582:MIRN362 microRNA, human; D035683:MicroRNAs; D016328:NF-kappa B; D025521:Tumor Suppressor Proteins; C409984:CYLD protein, human; D000074749:Deubiquitinating Enzyme CYLD