The study of pathophysiological mechanisms in human liver disease has been constrained by the inability to expand primary hepatocytes in vitro while maintaining proliferative capacity and metabolic function. We and others have previously shown that mouse mature hepatocytes can be converted to liver progenitor-like cells in vitro with defined chemical factors. Here we describe a protocol achieving efficient conversion of human primary hepatocytes into liver progenitor-like cells (HepLPCs) through delivery of developmentally relevant cues, including NAD + -dependent deacetylase SIRT1 signaling. These HepLPCs could be expanded significantly during in vitro passage. The expanded cells can readily be converted back into metabolically functional hepatocytes in vitro and upon transplantation in vivo. Under three-dimensional culture conditions, differentiated cells generated from HepLPCs regained the ability to support infection or reactivation of hepatitis B virus (HBV). Our work demonstrates the utility of the conversion between hepatocyte and liver progenitor-like cells for studying HBV biology and antiviral therapies. These findings will facilitate the study of liver diseases and regenerative medicine.

No abstract

Solid tumors often suffer from suboptimal oxygen and nutrient supplies. This stress underlies the requirement for metabolic adaptation. Aberrantly activated de novo lipogenesis is critical for development and progression of human hepatocellular carcinoma (HCC). However, whether de novo lipogenesis influences biological behaviors of HCCs under conditions of metabolic stress are still poorly understood. Here, we show that HCCs display distinct levels of glucose-derived de novo lipogenesis, which are positively correlated with their survival responses to glucose limitation. The enhanced lipogenesis in HCCs is characterized by an increased expression of rate-limiting enzyme acetyl-coenzyme A carboxylase alpha (ACCa). ACCa-mediated fatty acid (FA) synthesis determines the intracellular lipid content that is required to maintain energy hemostasis and inhibit cell death by means of FA oxidation (FAO) during metabolic stress. In accord, overexpression of ACCa facilitates tumor growth. ACCa forms a complex with carnitine palmitoyltransferase 1A (CPT1A) and prevents its mitochondria distribution under nutrient-sufficient conditions. During metabolic stress, phosphorylation of ACCa leads to dissociation of the complex and mitochondria localization of CPT1A, thus promoting FAO-mediated cell survival. Therefore, ACCa could provide both the substrate and enzyme storage for FAO during glucose deficiency. Up-regulation of ACCa is also significantly correlated with poorer overall survival and disease recurrence postsurgery. Multivariate Cox's regression analysis identified ACCa as an effective predictor of poor prognosis. Conclusion: ACCa plays a pivotal role in maintaining HCC survival under metabolic stress. It could be exploited as a novel diagnostic marker and therapeutic target. (HEPATOLOGY 2016;63:1272-1286 H epatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide.(1,2) Most HCC patients are considered to be incurable as a result of extensive heterogeneity in clinical presentations and tumor biology, which complicates the classification for therapy. (3,4) Identifying distinct subgroups in the HCC population with similar tumor biology is thus imperative to improve responses to various types of cancer treatment.Although many malignant tumors share common metabolic transformations, such as aerobic glycolysis, (5,6) the cellular metabolic phenotypes of cancer cellsAbbreviations: 2-DG, 2-deoxyglucose; 2-NBDG, 2-(N-(7-nitrobenz-2-oxa-1,3-diazol-4-yl)Amino)-2-deoxyglucose; ACC, acetyl-CoA carboxylase;

Background and aimsThe unique expression pattern makes oncofetal proteins ideal diagnostic biomarkers and therapeutic targets in cancer. However, few oncofetal proteins have been identified and entered clinical practice.MethodsFetal liver, adult liver and hepatocellular carcinoma (HCC) tissues were employed to assess the expression of hepatic leukaemia factor (HLF). The impact of HLF on HCC onset and progression was investigated both in vivo and in vitro. The association between HLF and patient prognosis was determined in patient cohorts. The correlation between HLF expression and sorafenib benefits in HCC was further evaluated in patient cohorts and patient-derived xenografts (PDXs).ResultsHLF is a novel oncofetal protein which is reactivated in HCC by SOX2 and OCT4. Functional studies revealed that HLF transactivates c-Jun to promote tumour initiating cell (TIC) generation and enhances TIC-like properties of hepatoma cells, thus driving HCC initiation and progression. Consistently, our clinical investigations elucidated the association between HLF and patient prognosis and unravelled the close correlation between HLF levels and c-Jun expression in patient HCCs. Importantly, HLF/c-Jun axis determines the responses of hepatoma cells to sorafenib treatment, and interference of HLF abrogated c-Jun activation and enhanced sorafenib response. Analysis of patient cohorts and PDXs further suggests that HLF/c-Jun axis might serve as a biomarker for sorafenib benefits in HCC patients.ConclusionsOur findings uncovered HLF as a novel oncofetal protein and revealed the crucial role of the HLF/c-Jun axis in HCC development and sorafenib response, rendering HLF as an optimal target for the prevention and intervention of HCC.