Background: -catenin mutations that constitutively activate the canonical Wnt signaling have been observed in a subset of hepatocellular carcinomas (HCCs). These mutations are associated with chromosomal stability, low histological grade, low tumor invasion and better patient survival. We hypothesized that canonical Wnt signaling is selectively activated in well-differentiated, but repressed in poorly differentiated HCCs. To this aim, we characterized differentiation status of HCC cell lines and compared their expression status of Wnt pathway genes, and explored their activity of canonical Wnt signaling.

SummaryOrganoid technologies have become a powerful emerging tool to model liver diseases, for drug screening, and for personalized treatments. These applications are, however, limited in their capacity to generate functional hepatocytes in a reproducible and efficient manner. Here, we generated and characterized the hepatic organoid (eHEPO) culture system using human induced pluripotent stem cell (iPSC)-derived EpCAM-positive endodermal cells as an intermediate. eHEPOs can be produced within 2 weeks and expanded long term (>16 months) without any loss of differentiation capacity to mature hepatocytes. Starting from patient-specific iPSCs, we modeled citrullinemia type 1, a urea cycle disorder caused by mutations in the argininosuccinate synthetase (ASS1) enzyme. The disease-related ammonia accumulation phenotype in eHEPOs could be reversed by the overexpression of the wild-type ASS1 gene, which also indicated that this model is amenable to genetic manipulation. Thus, eHEPOs are excellent unlimited cell sources to generate functional hepatic organoids in a fast and efficient manner.

BackgroundCaveolin-1 is the main component of caveolae membrane structures and has different roles during tumorigenesis in different cancer types with varying expression profiles, indicating that the role of caveolin-1 varies according to tumor type. In this study, we investigated the role and expression of caveolin-1 in hepatocellular carcinogenesis.MethodsWe analyzed the expression of Caveolin-1 in 96 hepatocellular carcinoma (HCC), 29 cirrhosis, 20 normal liver tissues and 9 HCC cell lines by immunostaining and western blotting, respectively. After caveolin-1 was stably transfected to HepG2 and Huh7 cells, the effects of Caveolin-1 on the cellular motility, matrix invasion and anchorage-independent growth were studied. Also, caveolae structure was disrupted in endogenously caveolin expressing cells, SNU 449 and SNU 475 by addition of methyl-β-cyclodextrin and analyzed cellular motility and invasion.ResultsIn HCC cell lines, Caveolin-1 expression is correlated to differentiation and basal motility status of these cells. The percentage of Caveolin-1 positivity was found extremely low in normal liver tissue (5%) while it was increased in cirrhosis (45%) and in HCC (66%) (p = 0.002 and p = 0.001 respectively). Cav-1 expression in poorly differentiated HCC samples has been found significantly higher than well differentiated ones (p = 0.001). The caveolin-1 expression was found significantly higher in tumor cells than its peritumoral cirrhotic tissues in HCC samples (p < 0.001). Additionally, the patients with positive staining for Caveolin-1 had significantly higher portal vein invasion than those with negative staining (p = 0.02). Caveolin-1 overexpression increased motility and invasion of HepG2 and Huh7 cells. And disruption of caveolae results in a dramatic decline in both motility and invasion abilities in SNU-449 and SNU-475 cells. Furthermore, caveolin-1 overexpression resulted in down-regulation of E-cadherin while up-regulation of Vimentin. Also, it increased secreted MMP-2 and expression levels of MMP-9 and MT1-MMP. There was no significant difference in colony formation in soft agar between stable clones and parental ones.ConclusionIn conclusion, stepwise increase in Cav-1 expression in neoplastic stage with respect to pre-neoplastic stage during hepatocellular carcinogenesis and its ability to stimulate HCC cell motility and invasiveness indicate that this protein plays a crucial role in tumor progression.