Decreased propionyl-CoA metabolism facilitates metabolic reprogramming and promotes hepatocellular carcinoma.

BACKGROUND & AIMS: Alterations of multiple metabolites characterize distinct features of metabolic reprograming in hepatocellular carcinoma (HCC). However, the role of most metabolites, including propionyl-CoA (Pro-CoA), in metabolic reprogramming and hepatocarcinogenesis remains elusive. In this study, we aimed to dissect how Pro-CoA metabolism affects these processes. METHODS: TCGA data and HCC samples were used to analyze ALDH6A1-mediated Pro-CoA metabolism and its correlation with HCC. Multiple metabolites were assayed by targeted mass spectrometry. The role of ALDH6A1-generated Pro-CoA in HCC was evaluated in HCC cell lines as well as xenograft nude mouse models and primary liver cancer mouse models. Non-targeted metabolomic and targeted energy metabolomic analyses, as well as multiple biochemical assays, were performed. RESULTS: Decreases in Pro-CoA and its derivative propionyl-L-carnitine due to ALDH6A1 downregulation were tightly associated with HCC. Functionally, ALDH6A1-mediated Pro-CoA metabolism suppressed HCC proliferation in vitro and impaired hepatocarcinogenesis in mice. The aldehyde dehydrogenase activity was indispensable for this function of ALDH6A1, while Pro-CoA carboxylases antagonized ALDH6A1 function by eliminating Pro-CoA. Mechanistically, ALDH6A1 caused a signature enrichment of central carbon metabolism in cancer and impaired energy metabolism: ALDH6A1-generated Pro-CoA suppressed citrate synthase activity, which subsequently reduced tricarboxylic acid cycle flux, impaired mitochondrial respiration and membrane potential, and decreased ATP production. Moreover, Pro-CoA metabolism generated 2-methylcitric acid, which mimicked the inhibitory effect of Pro-CoA on citrate synthase and dampened mitochondrial respiration and HCC proliferation. CONCLUSIONS: The decline of ALDH6A1-mediated Pro-CoA metabolism contributes to metabolic remodeling and facilitates hepatocarcinogenesis. Pro-CoA, propionyl-L-carnitine and 2-methylcitric acid may serve as novel metabolic biomarkers for the diagnosis and treatment of HCC. Pro-CoA metabolism may provide potential targets for development of novel strategies against HCC. IMPACT AND IMPLICATIONS: Our study presents new insights on the role of propionyl-CoA metabolism in metabolic reprogramming and hepatocarcinogenesis. This work has uncovered potential diagnostic and predictive biomarkers, which could be used by physicians to improve clinical practice and may also serve as targets for the development of therapeutic strategies against HCC.

Rictor mediates p53 deactivation to facilitate the malignant transformation of hepatocytes and promote hepatocarcinogenesis.

BACKGROUND: Mutations in TP53 gene is considered a main driver of hepatocellular carcinoma (HCC). While TP53 mutations are the leading cause of p53 dysfunction, their occurrence rates may drop to approximately 10% in cohorts without hepatitis B virus and aflatoxin exposure. This observation suggests that the deactivation of wild-type p53 (p53wt) may be a critical factor in the majority of HCC cases. However, the mechanism undermining p53wt activity in the liver remains unclear. METHODS: Microarray analysis and luciferase assay were utilized to confirm target associations. Gain- and/or loss-of-function methods were employed to assess alterations in signaling pathways. Protein interactions were analyzed by molecular immunological methods and further visualized by confocal microscopy. Bioinformatic analysis was performed to analyze clinical significance. Tumor xenograft nude mice were used to validate the findings in vivo. RESULTS: Our study highlights the oncogenic role of Rictor, a key component of the mammalian target of rapamycin complex 2 (mTORC2), in hepatocytes. Rictor exerts its oncogenic function by binding to p53wt and subsequently blocking p53wt activity based on p53 status, requiring the involvement of mTOR. Moreover, we observed a dynamic nucleocytoplasmic distribution pattern of Rictor, characterized by its translocation from the nucleus (in precancerous lesions) to the cytoplasm (in HCCs) during malignant transformation. Notably, Rictor is directly targeted by the liver-enriched microRNA miR-192, and the disruption of the miR-192-Rictor-p53-miR-192 signaling axis was consistently observed in both human and rat HCC models. Clinical analysis associated lower miR-192/higher Rictor with shorter overall survival and more advanced clinical stages (P < 0.05). In mice, xenograft tumors overexpressing miR-192 exhibited lower Rictor expression levels, leading to higher p53 activity, and these tumors displayed slower growth compared to untreated HCC cells. CONCLUSIONS: Rictor dynamically shuttles between the nucleus and cytoplasm during HCC development. Its pivotal oncogenic role involves binding and inhibiting p53wt activity within the nucleus in early hepatocarcinogenesis. Targeting Rictor presents a promising strategy for HCC based on p53 status.

Short- and Long-Term Outcomes of Indocyanine Green Fluorescence Navigation- Versus Conventional-Laparoscopic Hepatectomy for Hepatocellular Carcinoma: A Propensity Score-Matched, Retrospective, Cohort Study.

BACKGROUND: Indocyanine green (ICG) fluorescence imaging technology is increasingly widely used in laparoscopic hepatectomy. However, whether it can provide long-term survival benefits to patients with liver malignancies remains unclear. This study investigated the clinical effect of laparoscopic hepatectomy for hepatocellular carcinoma (HCC) using ICG imaging technology. METHODS: We retrospectively analyzed HCC patients who underwent laparoscopic hepatectomy at Zhongnan Hospital of Wuhan University from January 2016 to December 2020. Propensity score matching (PSM) was used to match patients undergoing ICG fluorescence navigation laparoscopic hepatectomy (ICG-FNLH) with those undergoing conventional laparoscopic hepatectomy (CLH) in a 1:1 ratio to minimize the influence of confounding factors. We compared perioperative status and long-term prognosis between the two groups and performed multivariate analysis to identify risk factors associated with overall survival and recurrence-free survival. RESULTS: The original cohort consisted of 141 patients, with 50 patients in each group (100 patients in total) after PSM. The anatomical liver resection rate, R0 resection rate, and resection margin distance in the ICG-FNLH group were higher than those in the CLH group. The intraoperative blood loss was lower than that in the CLH group. The recurrence-free survival and overall survival of the ICG-FNLH group were better than those of the CLH group. ICG-FNLH improved the recurrence-free survival of HCC patients (hazard ratio [HR] = 2.165, 95% confidence interval [CI]: 1.136-4.127, P = 0.024). CONCLUSIONS: Compared with CLH, ICG-FNLH can improve the recurrence-free survival rate of patients with hepatocellular carcinoma and may help to improve the long-term prognosis of patients.

Application of a biodegradable poly(butylene adipate-co-terephthalate) membrane for phenol pervaporation recovery.

In the field of membrane separation, the environmental concerns caused by spent membranes are becoming increasingly serious, which contradicts the concept of sustainable development. Based on this, a biodegradable poly(butylene adipate-co-terephthalate) (PBAT) membrane was used for the first time in the pervaporation separation of phenol, a high boiling point organic compound (HBOC). By using the PBAT membrane, outstanding separation efficiency was achieved, and environmental pollution and disposal issues were also avoided. The separation process and mechanism of the PBAT membrane were systematically studied through the experiment together with molecular dynamics (MD) simulation. The swelling experiment and intermolecular interaction energy calculation demonstrated that the PBAT membrane had a strong affinity for phenol. Further simulation concluded that higher phenol concentration increased the number of hydrogen bonds so that the membrane was more greatly swollen. Meanwhile, the simulations on the adsorption, diffusion and permeation predicted that the PBAT membrane had excellent separation performance for phenol. Besides MD simulation, the influences of feed concentration and temperature on pervaporation performance were also investigated by experiment. The results showed that the flux of each component increased with the feed concentration. This phenomenon was attributed to the preferential adsorption of phenol by the PBAT membrane, which resulted in large free volumes and cavities within the membrane, accelerating the diffusion of molecules. In addition, it was found that the optimal operating temperature was 333 K with the best separation performance. This study confirms that the biodegradable PBAT membrane is valuable for the recovery of high boiling point organic compounds (HBOCs) such as phenol.

Indocyanine green fluorescent cholangiography improves the clinical effects of difficult laparoscopic cholecystectomy.

BACKGROUND: Near-infrared fluorescent cholangiography (NIRFC) with indocyanine green (ICG) as the developer yields clear visualization of the extrahepatic bile ducts and is effective in identifying key structures. Here, we analyzed and compared the surgical outcomes of fluorescent and conventional laparoscopy in cholecystectomy of various difficulties and then assessed the value of NIRFC. MATERIALS AND METHODS: This retrospective study collected clinical data from partial patients who underwent laparoscopic cholecystectomy (LC) at the Department of Hepatobiliary and Pancreatic Surgery, Zhongnan Hospital of Wuhan University between 2020 and 2021. The study subjects were classified into ICG-assisted and white-light laparoscopy. Two cohorts with homogeneous baseline status were selected based on 1:1 ratio propensity score matching (PSM). Multivariate logistic regression analysis was performed to predict independent risk factors for LC difficulty. Thereafter, the matched cases were classified into difficult and easy subgroups by combining difficulty score and gallbladder disease type, and then the surgical outcomes of the two groups were compared. RESULTS: This study included a total of 624 patients. The patients were classified into the ICG group (n = 218) and the non-ICG group (n = 218) after a 1:1 ratio PSM. Our data showed significant differences between the groups in operative time (P = 0.020), blood loss (P = 0.016), length of stay (P = 0.036), and adverse reaction (P = 0.023). Stratified analysis demonstrated that ICG did not significantly improve the surgical outcomes in simple cases (n = 208). On the other hand, in difficult cases (n = 228), NIRFC shortened operative time (P = 0.003) and length of stay (P = 0.015), reduced blood loss (P = 0.028) and drain placement rate (P = 0.015), and had fewer adverse reactions (P = 0.023). The data showed that five cases were converted to laparotomy while two cases had minor bile leaks in the non-ICG group. There was no bile duct injury (BDI) in all the cases. Furthermore, high BMI, history of urgent admission and abdominal surgery, palpable gallbladder, thickened wall, and pericholecystic collection were risk factors for surgical difficulty. CONCLUSION: ICG-assisted NIRFC provides real-time biliary visualization. In complicated conditions such as acute severe inflammation, dense adhesions, and biliary variants, the navigating ability of fluorescence can enhance the operation progress, reduce the possibility of conversion or serious complications, and improve the efficiency and safety of difficult LC.

OH planar laser-induced fluorescence imaging system using a kilohertz-rate 283 nm UV Ti:sapphire laser.

A narrow linewidth Ti:sapphire laser is developed and characterized for the generation of an ultraviolet nanosecond laser pulses for the planar laser-induced fluorescence (PLIF) imaging of hydroxyl (OH). With a pump power of 11.4 W at 1 kHz, the Ti:sapphire laser produces 3.5 mJ at 849 nm with pulse duration of 17 ns and achieves a conversion efficiency of 28.2%. Accordingly, its third-harmonic generation outputs 0.56 mJ at 283 nm in BBO with type I phase match. An OH PLIF imaging system has been built; a 1 to 4 kHz fluorescent image of OH of a propane Bunsen burner has been captured based on this laser system.

Analysis of Musculoskeletal Biomechanics of Lower Limbs of Drivers in Pedal-Operation States.

In this study, to establish the biomechanical characteristics of commercial vehicle drivers' muscles and bones while operating the three pedals, a driver pedal-operation simulator was built, and the real-life situation was reconstructed in OpenSim 3.3 software. We set up three seat heights to investigate the drivers' lower limbs, and the research proceeded in two parts: experiment and simulation. Chinese adult males in the 95th percentile were selected as the research participants. In the experiment, Delsys wireless surface electromyography (EMG) sensors were used to collect the EMG signals of the four main muscle groups of the lower limbs when the drivers operated the three pedals. Then, we analyzed the muscle activation and the degree of muscle fatigue. The simulation was based on OpenSim software to analyze the driver's lower limb joint angles and joint torque. The results show that the activation of the hamstrings, gastrocnemius, and rectus femoris muscles were higher in the four muscle groups. In respect of torque, in most cases, hip joint torque > knee joint torque > ankle joint torque. The knee joint angles were the largest, and the ankle joint angles changed the most. The experimental results provide a reference for improving drivers' handling comfort in commercial vehicles and provide theoretical bases for cab design and layout optimization.

Indocyanine green fluorescence imaging-guided laparoscopic right posterior hepatectomy.

BACKGROUND: Laparoscopic right posterior hepatectomy is considered difficult on the basis of the surgery difficulty scoring system. In this study, we evaluated the safety and effectiveness of the technical application of indocyanine green (ICG) fluorescence imaging-guided laparoscopic right posterior hepatectomy. METHODS: Twenty-six patients who underwent ICG fluorescence imaging-guided laparoscopic right posterior hepatectomy at Hepatobiliary and Pancreatic Surgery Department of Zhongnan Hospital, Wuhan University, from June 2018 to December 2019, were included. The influence of patient position, trocar placement, hepatic inflow occlusion, central venous pressure (CVP), and the ICG fluorescence imaging-guided method were analyzed. RESULTS: In 17 patients, the left lateral position was maintained when the main tumor was in the S7, and in the remaining nine patients, the supine position was maintained with the right side of the body raised when the main tumor was in the S6. Ten patients who underwent preoperative injection of ICG were successfully developed for nonanatomical hepatectomy. Sixteen patients received intraoperative ICG injection for anatomical hepatectomy (2 cases had positive imaging findings, 14 cases had negative imaging findings, and 2 cases had failed imaging findings). All patients underwent the Pringle maneuver during the procedure. Four patients were preset with subhepatic vena cava blocking and one patient with suprahepatic inferior vena cava blocking. CVP was controlled at 3.00 ± 0.63 (mean ± SD) cmH2O. The operative time was 216.14 ± 52.05 min, and the bleeding volume was 128.57 ± 75.55 ml. Four patients had Clavien-Dindo level I complications, and one had level III complications. Postoperative hospitalization duration was 6.19 ± 1.40 days. There were 14 patients with hepatocellular carcinoma, 9 with metastatic liver malignancies, 2 with hepatic hemangioma, 1 with focal nodular hyperplasia of the liver, and 10 with hepatitis B liver cirrhosis. CONCLUSIONS: ICG fluorescence imaging guidance could be helpful for the safe implementation of laparoscopic right posterior hepatectomy.

Inhibition of MTA2 and MTA3 induces mesendoderm specification of human embryonic stem cells.

Fully understanding the regulatory network under the pluripotency of embryonic stem cells (ESC) is a prerequisite for their safe application. Here, we addressed the characteristics of metastasis-associated (MTA) family members in human ESCs and found that knockdown of the expression of MTA2 and MTA3, but not MTA1, would induce differentiation. High-throughput sequence and quantitative real-time PCR showed that the decreased MTA2 or MTA3 gene transcript mainly led to the emergence of mesendoderm associated markers. Finally, based on the chemical small molecule library screening, we observed that addition of ID8, a specific inhibitor of the dual-specificity tyrosine phosphorylation-regulated kinases (DYRKs), was able to impair the differentiation phenotype induced by MTA2 and MTA3 reduction. Functional assay showed that ID8 could mediate differentiation caused by MTA2 or MTA3 knockdown mainly through inhibition of DYRK4 activity. Therefore, our finding provides the evidence that the functions of MTA family genes in human ESCs are different. Revealing the function of MTA in ESCs with different pluripotency states will help us better understand and apply stem cells.

Ethylene and salicylic acid synergistically accelerate leaf senescence in Arabidopsis.

The phytohormones ethylene and salicylic acid (SA) have long been known to promote senescence, but their interplay during this process remains elusive. Here we report the synergistic effects of ethylene and SA on promoting leaf senescence in Arabidopsis. EIN3, a key transcription factor of ethylene signaling, physically interacted with the core SA signaling regulator NPR1 in senescing leaves. EIN3 and NPR1 synergistically promoted the expression of the senescence-associated genes ORE1 and SAG29. The senescence phenotype was more delayed for the ein3eil1npr1 triple mutant than ein3eil1 or npr1 with ethylene or/and SA treatment. NPR1-promoted leaf senescence may depend on functional EIN3/EIL1.

Effect of CLIC1 gene silencing on proliferation, migration, invasion and apoptosis of human gallbladder cancer cells.

This study aimed to explore the effects of CLIC1 gene silencing on proliferation, migration, invasion and apoptosis of human gallbladder cancer (GBC). GBC and normal gallbladder tissues were extracted for the detection of mRNA and protein expressions of CLIC1. GBC-SD and NOZ cells in the logarithmic growth phase were selected to conduct the experiment. Three different siRNA recombined expression vectors were established using CLIC1 as a target at different sites. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) and Western blotting were, respectively, used to detect the CLIC1 mRNA and protein expressions. MTT assay was performed to detect the cell proliferation. Flow cytometry was applied to measure the cell apoptosis and cell cycle distribution. The variations of cell migration and invasion were evaluated using Transwell assay. GBC tissues showed higher CLIC1 mRNA and protein expressions than normal gallbladder tissues. The CLIC1 mRNA and protein expressions in the CLIC1 siRNA group were significantly lower than those in the NC and blank groups. Compared with the NC and blank groups, the CLIC1 siRNA group showed a significant decrease in cell proliferation but an obvious increase in apoptosis rate in GBC cells. Besides, in the CLIC1 siRNA group, cell percentage in G0/G1 and G2/M phase was gradually increased but decreased in S phases. The migration and invasion abilities in GBC cells were significantly lower than those in the NC and blank groups. Our study demonstrates that CLIC1 gene silencing could promote apoptosis and inhibit proliferation migration and invasion of GBC cells.

Theoretical and experimental investigations of the electronic/ionic conductivity and deprotonation of Ni3-xCoxAl-LDHs in an electrochemical energy storage system.

The remarkable effect of divalent transition metal ions on the electrochemical performance of transition metal-based layered double hydroxides (LDHs) was systematically investigated via computational and experimental approaches. Ni3-xCoxAl-LDHs (x = 0, 1, 2, and 3) were synthesized on carbon paper by a unipolar pulse electrodeposition (UPED) method and used as electrodes in energy storage systems. The structures were characterized by X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). Their electrochemical performance was evaluated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The mechanism of different electrochemical performances with various divalent transition metal ions was investigated by the density functional theory (DFT) plus U method and molecular dynamics (MD) simulations. The computational and experimental data demonstrated that the electronic and ionic conductivity and deprotonation of NiAl-LDHs were improved by doping Co species, and the incorporation of Co and Ni cations enabled LDHs to exhibit a larger interlayer spacing which can facilitate the diffusion of OH- ions, indicating that NiCo2Al-LDHs had the highest specific capacitance.

The ERF11 Transcription Factor Promotes Internode Elongation by Activating Gibberellin Biosynthesis and Signaling.

The phytohormone gibberellin (GA) plays a key role in promoting stem elongation in plants. Previous studies show that GA activates its signaling pathway by inducing rapid degradation of DELLA proteins, GA signaling repressors. Using an activation-tagging screen in a reduced-GA mutant ga1-6 background, we identified AtERF11 to be a novel positive regulator of both GA biosynthesis and GA signaling for internode elongation. Overexpression of AtERF11 partially rescued the dwarf phenotype of ga1-6 AtERF11 is a member of the ERF (ETHYLENE RESPONSE FACTOR) subfamily VIII-B-1a of ERF/AP2 transcription factors in Arabidopsis (Arabidopsis thaliana). Overexpression of AtERF11 resulted in elevated bioactive GA levels by up-regulating expression of GA3ox1 and GA20ox genes. Hypocotyl elongation assays further showed that overexpression of AtERF11 conferred elevated GA response, whereas loss-of-function erf11 and erf11 erf4 mutants displayed reduced GA response. In addition, yeast two-hybrid, coimmunoprecipitation, and transient expression assays showed that AtERF11 enhances GA signaling by antagonizing the function of DELLA proteins via direct protein-protein interaction. Interestingly, AtERF11 overexpression also caused a reduction in the levels of another phytohormone ethylene in the growing stem, consistent with recent finding showing that AtERF11 represses transcription of ethylene biosynthesis ACS genes. The effect of AtERF11 on promoting GA biosynthesis gene expression is likely via its repressive function on ethylene biosynthesis. These results suggest that AtERF11 plays a dual role in promoting internode elongation by inhibiting ethylene biosynthesis and activating GA biosynthesis and signaling pathways.

See-through near-eye displays enabling vision correction.

We propose a see-through near-eye display, which is dedicated to the visually impaired users who suffer from refractive anomalies. Our solution is characterized by a pair of corrective lenses coated with multiplexed volume holograms. Its key performance including diffraction efficiency, field of view, modulation transfer function, and distortion has been studied.

Crosstalk-free dual-view liquid crystal display using patterned E-type polarizer.

We present a dual-view liquid crystal display that allows two faces of the display to be viewed in opposite directions to show different image/video content simultaneously. This device is characterized by a two-domain twisted nematic liquid crystal and a patterned E-type polarizer. Its key optical performance, including the voltage-luminance curve, crosstalk, and viewing angle, has been investigated. When observed at the best viewing angle, the crosstalk between the right and left views is less than 0.07% for all grayscales. In addition, this type of crosstalk can be immune to the misalignment between the polarizers and the liquid crystal layer. For each right/left view, the range of the viewing angle spans roughly 50°.

A Novel Organ Culture Model of Mouse Intervertebral Disc Tissues.

The intervertebral disc (IVD) is a fibrocartilaginous joint between two vertebral bodies. An IVD unit consists of a gelatinous central nucleus pulposus, encased by the annulus fibrosus, which is sandwiched between cartilaginous endplates (EPs). The IVD homeostasis can be disrupted by injuries, ageing and/or genetic predispositions, leading to degenerative disc disorders and subsequent lower back pain. The complex structure and distinct characteristics of IVDs warrant the establishment of robust in vitro IVD organ culture for studying the etiology and treatment of disc degeneration. Here, we isolate mouse lumbar IVDs and culture the minimal IVD units in submersion or suspension medium supplemented with 2% bovine serum or 10% fetal bovine serum (FBS). We find the minimal IVD units remain healthy for up to 14 days when cultured in submersion culture supplemented with 10% FBS. New bone formation in the EPs of the cultured IVDs can be assessed with calcein labeling. Furthermore, the cultured IVDs can be effectively transduced by recombinant adenovirus, and transgene expression lasts for 2 weeks. Thus, our findings demonstrate that the optimized IVD organ culture system can be used to study IVD biology and screen for biological factors that may prevent, alleviate and/or treat disc degeneration.

The Prodomain-Containing BMP9 Produced from a Stable Line Effectively Regulates the Differentiation of Mesenchymal Stem Cells.

BACKGROUND: BMPs play important roles in regulating stem cell proliferation and differentiation. Using adenovirus-mediated expression of the 14 types of BMPs we demonstrated that BMP9 is one of the most potent BMPs in inducing osteogenic differentiation of mesenchymal stem cells (MSCs), which was undetected in the early studies using recombinant BMP9 proteins. Endogenous BMPs are expressed as a precursor protein that contains an N-terminal signal peptide, a prodomain and a C-terminal mature peptide. Most commercially available recombinant BMP9 proteins are purified from the cells expressing the mature peptide. It is unclear how effectively these recombinant BMP9 proteins functionally recapitulate endogenous BMP9. METHODS: A stable cell line expressing the full coding region of mouse BMP9 was established in HEK-293 cells by using the piggyBac transposon system. The biological activities and stability of the conditioned medium generated from the stable line were analyzed. RESULTS: The stable HEK-293 line expresses a high level of mouse BMP9. BMP9 conditioned medium (BMP9-cm) was shown to effectively induce osteogenic differentiation of MSCs, to activate BMP-R specific Smad signaling, and to up-regulate downstream target genes in MSCs. The biological activity of BMP9-cm is at least comparable with that induced by AdBMP9 in vitro. Furthermore, BMP9-cm exhibits an excellent stability profile as its biological activity is not affected by long-term storage at -80ºC, repeated thawing cycles, and extended storage at 4ºC. CONCLUSIONS: We have established a producer line that stably expresses a high level of active BMP9 protein. Such producer line should be a valuable resource for generating biologically active BMP9 protein for studying BMP9 signaling mechanism and functions.

Functional characteristics of reversibly immortalized hepatic progenitor cells derived from mouse embryonic liver.

BACKGROUND/AIMS: Liver is a vital organ and retains its regeneration capability throughout adulthood, which requires contributions from different cell populations, including liver precursors and intrahepatic stem cells. To overcome the mortality of hepatic progenitors (iHPs) in vitro, we aim to establish reversibly immortalized hepatic progenitor cells from mouse embryonic liver. METHODS AND RESULTS: Using retroviral system to stably express SV40 T antigen flanked with Cre/LoxP sites, we establish a repertoire of iHP clones with varied differentiation potential. The iHP cells maintain long-term proliferative activity and express varied levels of progenitor markers (Pou5f1/Oct4 and Dlk) and hepatocyte markers (AFP, Alb and ApoB). Five representative iHP clones express hepatic/pancreatic transcription factors HNF3α/Foxa1, HNF3ß/Foxa2, and HNF4α/MODY1. Dexamethasone is shown to promote the expression of hepatocyte markers AFP and TAT, along with ICG-uptake and glycogen storage functions in the iHP clones. Cre-mediated removal of SV40 T antigen reverses the proliferative activity of iHP cells. When iHP cells are subcutaneously implanted in athymic nude mice, no tumor formation is observed for up to 8 weeks. CONCLUSIONS: We demonstrate that the established iHP cells are stable, reversible, and non-tumorigenic hepatic progenitor-like cells, which should be valuable for studying liver organogenesis, metabolic regulations, and hepatic lineage-specific differentiation.