title: Epigallocatechin gallate up-regulation of miR-16 and induction of apoptosis in human cancer cells.
abstract: Epigallocatechin gallate (EGCG) is a major type of green tea polyphenols and is known to have cancer prevention effect. MicroRNAs (miRNAs) are 19 to 25 nucleotides and are believed to be important in gene regulation. In the present study, the influence of EGCG on the expressions of miRNAs in human cancer cells was investigated as this has not yet been reported. By miRNA microarray analysis, EGCG treatment was found to modify the expressions of some of the miRNAs in human hepatocellular carcinoma HepG2 cells, 13 were up-regulated and 48 were down-regulated. miR-16 is one of the miRNAs up-regulated by EGCG and one of its target genes is confirmed to be the anti-apoptotic protein Bcl-2. EGCG treatment induced apoptosis and down-regulated Bcl-2 in HepG2 cells. Transfection with anti-miR-16 inhibitor suppressed miR-16 expression and counteracted the EGCG effects on Bcl-2 down-regulation and also induction of apoptosis in cells. Results from the present study confirm the role of miR-16 in mediating the apoptotic effect of EGCG and also support the importance of miRNAs in the regulation of the biological activity of EGCG.
authors.affiliation: Department of Biochemistry, The Chinese University of Hong Kong, Shatin, Hong Kong SAR, China.
authors.forename: Wing Pui
authors.initials: WP
authors.lastname: Tsang
authors.forename: Tim Tak
authors.initials: TT
authors.lastname: Kwok
mesh_terms: D016588:Anticarcinogenic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002392:Catechin / Q000031:analogs & derivatives* / Q000494:pharmacology; D053938:DNA Fragmentation / Q000187:drug effects; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D017930:Genes, Reporter; D019254:Genes, bcl-2 / Q000187:drug effects; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000378:metabolism*; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D016133:Polymerase Chain Reaction; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000235:genetics / Q000378:metabolism; D013662:Tea / Q000737:chemistry; D015854:Up-Regulation / Q000187:drug effects*
chemical_list: D016588:Anticarcinogenic Agents; C505362:MIRN16 microRNA, human; D035683:MicroRNAs; D019253:Proto-Oncogene Proteins c-bcl-2; D013662:Tea; D002392:Catechin; C045651:epigallocatechin gallate