2012 Aug 1;123(4):225–239. 2. Lubel JS., Selleckchem JNK inhibitor et al., Angiotensin-(1-7), an alternative metabolite of the renin-angiotensin system, is up-regulated in human liver disease and has antifibrotic activity in the bile-duct-ligated rat. Clin Sci (Lond). 2009 Sep 14;117(11):375–386. 3. Osterreicher CH., et al., Angiotensin-converting-enzyme 2 inhibits liver fibrosis in mice. Hepatology. 2009 Sep;50(3):929–938. G WU, G WILSON, J GEORGE, L QIAO Storr Liver Unit, Westmead Millennium Institute, The University of Sydney, Westmead, NSW, Australia Introduction: Hepatocellular carcinoma
(HCC) is an aggressive disease with poor clinical outcomes. Liver cancer stem cells (LCSCs) are thought to be the major mediators of HCC tumor progression, metastasis and treatment resistance. However, the mechanisms by which these LCSC populations are maintained are not well understood or characterized. Methods: LCSC and non-LCSC populations were generated based on the expression of the stem cell marker Oct4 using an exogenous human
Oct-4 promoter GFP vector. The expression of Notch receptors, Notch ligands, and Notch downstream targets were determined by western blot and quantitative PCR (qPCR). LCSCs (Oct4+) and non-LCSCs (Oct4-) were treated with siRNA targeting Jagged2 and recombinant Jagged2 protein. BrDU cell proliferation assay, Annexin V apoptosis assay, sorafenib resistance assay and tumor sphere assays were undertaken on the cell populations with Stem Cells inhibitor modulated Jagged2 activity. Results: Notch signaling components Jagged2 and Notch1 were found to be upregulated in the LCSC (Oct4+) population. Treatment of these LCSCs with siRNA targeting Jagged2 resulted in the inhibition of Notch signaling, reduced cell proliferation and increased apoptosis. Jagged2 knockdown also sensitized these LCSCs to sorafenib treatment. Conversely, activation of the Notch pathway with recombinant Jagged2 in the non-LCSC (Oct4-) population increased tumor sphere formation and increased the expression of SOX-2,
a major transcription factor which OSBPL9 induces stem-like characteristics and is also a novel predictor of poor prognosis in HCC. Conclusions: Jagged 2 is a critical mediator of Notch signaling in LCSCs. Jagged2 mediated Notch signaling is critical for the maintenance and treatment resistance of LCSCs in HCC and can increase stem-like characteristics of differentiated cells. Given these findings we believe Jagged2 is a potential therapeutic target for the treatment of HCC. LT GAN,1 DM VAN ROOYEN,1 M COOPER,2 A ROBERTSON,2 S MASTERS,3 N TEOH,1 G FARRELL1 1Liver Research Group, ANU Medical School at The Canberra Hospital, Garran, ACT, 2Institute of Molecular Biology, University of Queensland, QLD, 3Walter and Eliza Hall Institute, Parkville, VIC Introduction: Increasing evidence implicates free cholesterol (FC) in pathogenesis of non-alcoholic steatohepatitis (NASH).