Protein Kinase C (PKC) is a serine/threonine kinase that involved in controlling of many cellular processes such as cell proliferation and differentiation. We have observed previously that TPA (12-O-tetradecanoylphorbol 13acetate) induces cell cycle arrest in G0/G1 phase in human hepatoma HepG2 cells. However, is there any miRNA involved in PKCα mediated cell growth arrest is still unknown. Methods: We first surveyed 270 miRNA expression profiles in 20 pairs of human hepatoma tissues. We identified 11 upregulated and 23 down-regulated miRNAs (FDR = 2) in human hepatoma tissue after Student's T-test and Mann-Whitney rank test | Chiang et al. Journal of Biomedical Science 2010 17 35 http content 17 1 35 a NSC Tha cost of publication In Journal of Blomodlcal Science Is bome by tlM National Science Council Taiwan JOURNAL OF BIOMEDICAL SCIENCE RESEARCH Open Access PKCa mediated induction of miR-101 in human hepatoma HepG2 cells Chao-Wei Chiang41 Yi Huang42 Ka-Wai Leong2 Lih-Chyang Chen3 Hua-Chien Chen4 Shu-Jen Chen4 and Chen- Kung Chou 1 2 Abstract Background Protein Kinase C PKC is a serine threonine kinase that involved in controlling of many cellular processes such as cell proliferation and differentiation. We have observed previously that TPA 12-O-tetradecanoylphorbol 13-acetate induces cell cycle arrest in G0 G1 phase in human hepatoma HepG2 cells. However is there any miRNA involved in PKCa mediated cell growth arrest is still unknown. Methods We first surveyed 270 miRNA expression profiles in 20 pairs of human hepatoma tissues. We identified 11 up-regulated and 23 down-regulated miRNAs FDR fold-change 2 in human hepatoma tissue after Student s Y-test and Mann-Whitney rank test. We then examined miRNAs expression profile in TPA treated HepG2 cells. Two miRNAs miR-101 and miR-29c were shown to be significantly down regulated in human hepatoma tissues and induced over 4-fold in HepG2 cells under TPA treatment. Results In this study we examined TPA regulated miRNA expression profile in human hepatoma HepG2 cells. We identified two miRNAs 101 and 29c were induced by TPA and down regulated in human hepatoma tissues suggest that they might play as tumor suppressor gene and in tumor formation of HCC. Since induction kinetics of miR-101 by TPA was much faster than miR-29c suggests that the induction of miR-101 may be the primary response of TPA treatment. We then further investigated how miR-101 was regulated by TPA. MiR-101 targets two subunits of PRC2 complex enhancer of zeste homolog 2 EZH2 and EED and was shown to play as a tumor suppressor gene in human prostate .
