Inhibition of c-FLIP expression by miR-512-3p contributes to taxol-induced apoptosis in hepatocellular carcinoma cells.
Dysregulation of the antiapoptotic protein cellular FLICE-like inhibitory protein (c-FLIP) has been proven to be associated with tumorigenesis and progress of most human cancers. However, its aberrant expression is poorly elucidated. MicroRNAs (miRNAs) are small non-coding RNAs that are involved in tumorigenesis through negatively regulating gene expression. Our study disclosed that c-FLIP was overexpressed in HepG2 hepatocellular carcinoma cells and down-regulation of c-FLIP enhanced taxol-induced apoptosis. Taxol induction significantly decreased the protein level of c-FLIP. While no decrease in c-FLIP mRNA level was observed, indicating taxol decreased c-FLIP expression through a post-transcriptional mechanism. miR-512-3p was a predicted suppressor of c-FLIP and exhibited an opposite expression manner to c-FLIP before and after taxol induction. Luciferase report assay demonstrated miR-512-3p negatively regulated c-FLIP expression via a conserved miRNA-binding site in 3' untranslated region (3'UTR) of c-FLIP. The decrease of c-FLIP protein due to transfection of miR-512-3p further validated the inhibitory effect of miR-512-3p on c-FLIP. Additional transfection of miR-512-3p remarkably promoted taxol-induced apoptosis, confirming its involvement in apoptosis. In summary, our study disclosed a novel regulatory mechanism that down-regulation of c-FLIP by miR-512-3p contributed to taxol-induced apoptosis. Importantly, the pivotal role of miR-512-3p in determining c-FLIP abundance helps to broaden the implications for cancer therapy by developing small molecules to directly target c-FLIP at mRNA level.
Chen
Feng
F
State Key Laboratory of Infectious Disease Diagnosis and Treatment, First Affiliated Hospital, College of Medicine, Zhejiang University, Hangzhou 310003, P.R. China.
Zhu
Hai-Hong
HH
Zhou
Lin-Fu
LF
Wu
Shan-Shan
SS
Wang
Jing
J
Chen
Zhi
Z
D020413:3' Untranslated Regions; D000972:Antineoplastic Agents, Phytogenic / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects* / Q000235:genetics; D001483:Base Sequence; D001665:Binding Sites; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein / Q000235:genetics / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D019295:Computational Biology; D015536:Down-Regulation; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D035683:MicroRNAs / Q000378:metabolism*; D008969:Molecular Sequence Data; D017239:Paclitaxel / Q000494:pharmacology*; D034622:RNA Interference; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors; D014162:Transfection
D020413:3' Untranslated Regions; D000972:Antineoplastic Agents, Phytogenic; D053446:CASP8 and FADD-Like Apoptosis Regulating Protein; C506386:CFLAR protein, human; D035683:MicroRNAs; D012333:RNA, Messenger; D017239:Paclitaxel