Late SV40 factor: A key mediator of Notch signaling in human hepatocarcinogenesis

Figure 3 Aberrant Notch-1 activation upregulates late SV40 factor levels in hepatocellular carcinoma cells. A: Western-blotting analysis of Notch1 and late SV40 factor (LSF) expression in 3 hepatocellular carcinoma (HCC) cell lines. Notch1 and LSF levels are upregulated (hepatocytes were used as the negative control); B: Inhibition of Notch-1 signaling by 50 μmol/L DAPT (a γ secretase inhibitor). Notch1-ICD and LSF levels are significantly decreased compared with those in untreated HepG2 cells; C: Overexpression of exogenous LSF in HepG2 cells. LSF levels are significantly increased compared with those in untreated HepG2 cells. Representative blots are shown from three independent experiments with identical results. β-actin was used as an internal control for equal loading of samples and the relative ratios of each band were normalized to β-actin; D: The mean ± SE of 3 experiments analyzing the relative expression of Notch1-ICD (DAPT group: ^aP < 0.05, Notch-ICD1 group: ^bP < 0.05); E: DAPT group: ^cP < 0.05, Notch-ICD1 group: ^dP < 0.05; F: Hes-1 mRNA expression levels were determined by semi-quantitative reverse transcription-polymerase chain reaction and mRNA levels were normalized to those of GADPH. Results represent the mean ± SE of 3 independent experiments (DAPT group: ^eP < 0.05, NICD1 group: ^fP < 0.05); G: Promoter assay showing an approximately 60-fold increase in LSF reporter activity in hepatic stellate cells (HSC) transfected with NICD1-pEGFP-C1 compared with controls.