The effect of hepatic progenitor cells on experimental hepatocellular carcinoma in the regenerating liver

Pharmacological Activating Transcription Factor 6 Activation Is Beneficial for Liver Retrieval With ex vivo Normothermic Mechanical Perfusion From Cardiac Dead Donor Rats

Background: Normothermic machine perfusion (NMP) could be beneficial for organ retrieval from donors after cardiac death (DCD). Activating transcription factor 6 (ATF6) was recently shown to mitigate liver ischemia/reperfusion injury and confer protection. The aims of this study were to assess the implication of ATF6 in liver retrieval from DCD rat livers with NMP and explore the effect of pharmacologic ATF-6 activation on liver retrieval. Methods: The livers from DCD rats were exposed to 30 min of warm ischemia and 8 h cold preservation followed by 2 h NMP with or without an ATF6 activator in the perfusate. Perfusates and livers were harvested to detect ATF6 expression, liver function, and inflammation. Results: DCD livers with NMP were associated with ATF6 overexpression and activation based on IHC and WB (P < 0.05). The ATF6 activator downregulated perfusate aminotransferases, decreased the Suzuki score, downregulated CD68 and MPO based on IHC, induced the expression of cytochrome c in mitochondria and inhibited the expression of cytochrome c in cytoplasm based on WB, reduced TNFα and IL-6 levels based on ELISA, decreased levels of MDA, GSSG and ATP, and increased SOD activity and GSH levels in the perfused livers (P < 0.05). Conclusion: ATF6 is important for liver retrieval, and an exogenous ATF6 activator accelerates liver retrieval from DCD rats in an ex vivo NMP model.

Simulated model of RAPID concept: highlighting innate inflammation and liver regeneration

BACKGROUND

The resection and partial liver segment II/III transplantation with delayed total hepatectomy (RAPID) concept is a novel transplantation technique for removal of non-resectable liver tumours. The aim of this study was to establish a simulated RAPID model to explore the mechanism involved in the liver regeneration.

METHODS

A RAPID model was created in rats involving cold ischaemia and reperfusion of the selected future liver remnant (FLR), portal vein ligation, followed by resection of the deportalized lobes in a second step. Histology, liver regeneration and inflammatory markers in RAPID-treated rats were compared with those in controls that underwent 70 per cent hepatectomy with the same FLR size. The effects of interleukin (IL) 6 and macrophage polarization on hepatocyte viability were evaluated in an in vitro co-culture system of macrophages and BRL hepatocytes.

RESULTS

The survival rate in RAPID and control hepatectomy groups was 100 per cent. The regeneration rate was higher in the RAPID-treated rats, with higher levels of IL-6 and M1 macrophage polarization (P < 0·050). BRL hepatocytes co-cultured with M1 macrophages showed a higher proliferation rate through activation of the IL-6/signal transducer and activator of transcription 3/extracellular signal-regulated kinase pathway. This enhancement of proliferation was inhibited by tocilizumab or gadolinium trichloride (P < 0·050).

CONCLUSION

The surgical model provides a simulation of RAPID that can be used to study the liver regeneration profile. Surgical Relevance The mechanisms sustaining liver regeneration are a relevant field of research to reduce the 'small for size' liver syndrome when the future liver remnant is not adequate. Several surgical strategies have been introduced both for liver resection and transplant surgery, mostly related to this issue and to the scarcity of grafts, among these the RAPID concept involving the use of an auxiliary segment II/III donor liver that expands to a sufficient size until a safe second-stage hepatectomy can be performed. Understanding the mechanisms and pitfalls of the liver regeneration profile may help in tailoring surgical strategies and in selecting patients. In this experimental model the authors investigated liver histology, regeneration and inflammatory markers in RAPID-treated rats.

The Novel Oncolytic Compound LTX-401 Induces Antitumor Immune Responses in Experimental Hepatocellular Carcinoma

LTX-401 is a novel oncolytic compound designed for the local treatment of solid tumors. In the present study, we have examined the applicability and efficacy of LTX-401 in a rat model JM1 hepatocellular carcinoma, with particular interest in its ability to induce antitumor immunity. LTX-401 induces necrotic cell death followed by the release of immunogenic cell death mediators such as high-mobility group box 1 protein, ATP, and cytochrome c. When injected into subcutaneous and orthotopic JM1 tumors, LTX-401 treatment resulted in a strong antitumoral effect followed by complete tumor regression in the majority of animals. Additionally, LTX-401 could affect the growth of distal tumor deposits simulating metastases, hence indicating immune-mediated abscopal responses. Furthermore, LTX-401 treatment induced tumor-specific immune responses as seen by protection against tumor rechallenge and increased production of interferon-gamma (IFN-γ) by splenic cells in response to stimulation with tumor cells. Taken together, our data demonstrate that the oncolytic compound LTX-401 provides local tumor control followed by protective immune responses and may be exploited as a novel immunotherapeutic agent in hepatocellular carcinoma.

Recognition of HER2 expression in hepatocellular carcinoma and its significance in postoperative tumor recurrence

BACKGROUND

The ERBB2 oncogene hypothesis is challenged in hepatocellular carcinoma (HCC) with the conflicting evidences of human epidermal growth factor receptor 2 (HER2) overexpression. HER2 could be a new target as a treatment option for HCC as well as tumor recurrence after surgery. HER2 in HCC biology needs further explorations.

METHODS

Clinical and mRNA data of HCC patients were obtained from TCGA HCC cohort, GSE89377 and GSE115018. Western Blotting and immunohistochemistry were employed to test expression of HER2, E-cadherin, and Vimentin. In HepG2, JM1, HER2-transfected McA cells, and TGF-β cocultured JM1 cells, HCC biology, including cell survival, proliferation, and epithelial-to-mesenchymal transition (EMT) phenotypes were evaluated.

RESULTS

ERBB2 mRNA amplification was found in HCC datasets, and its expression was downregulated in high grade HCC with a worse overall survival. HER2 overexpression was identified in H4IIE, HepG2, JM1 cells, and 82% (14/17) HCC samples, and tumor stage was correlated with expression of HER2, E-cadherin, and Vimentin (P < 0.05). Trastuzumab with the high concentrations suppressed proliferation of HER2-positive hepatoma cells (P < 0.05); in the coculture model to induce EMT of JM1 cells, HER2 expression increased with downregulated E-cadherin and upregulated Vimentin. Trastuzumab intravenous injection inhibited in vivo tumor size and metastases (P < 0.05). Signal analysis revealed that HER2 functioned through upregulation of β-catenin and inhibition of SMAD3.

CONCLUSION

HER2 expression pattern is linked with tumor stage and overall survival; the transforming function of HER2 is found more relevant through β-catenin and SMAD3. HER2-targeted treatment is recommended to suppress the HER2-mediated tumor growth during postoperative liver regeneration.

Tropism of liver epithelial cells toward hepatocellular carcinoma in vitro and in vivo with altering gene expression of cancer stem cells

BACKGROUND

Rat liver epithelial (RLE) cells could inhibit the proliferation and invasiveness of hepatoma cells in vitro. This study is to understand the tropism and the effect of RLE cells on mouse hepatoma cells both in vitro and in vivo.

METHODS

RLE cells were isolated from new-born rats and characterized their stem cell markers. Co-culture and HCC mouse model was established to detect therapeutic effect of RLE cells.

RESULTS

RLE cells (including Thy-1⁺ RLE cells, Thy-1^- RLE cells, RLE cells) displayed a selective tropism toward ML-1 hepatoma cells both in vitro and in vivo. They altered the gene expression of some cancer stem cell markers in the liver tumor.

CONCLUSION

Liver epithelial cells have a selective tropism toward HCC in vitro and in vivo. They could alter the gene expression of cancer stem cells.

Experimental evaluation of liver regeneration patterns and liver function following ALPPS

Background

The underlying mechanism of liver regeneration after Associating Liver Partition and Portal vein ligation (PVL) for Staged hepatectomy (ALPPS) is still unclear. The aim of this study was to evaluate the relationship between future liver remnant (FLR) volume, liver regeneration characteristics and restoration of function in an experimental model of ALPPS.

Methods

An ALPPS model in rats was developed with selective PVL, parenchymal transection and partial hepatectomy (step 1), followed by resection of the liver (step 2). Three different ALPPS groups with FLR sizes of 30, 20 and 10 per cent of total liver volume were compared with sham‐operated controls and animals undergoing resection of left lateral lobe and 90 per cent PVL with respect to morbidity, mortality, liver regeneration and function.

Results

Three of 15 animals that had ALPPS with 10 per cent FLR (ALPPS10) died after step 1. Ascites developed in two of five rats that had ALPPS with 20 per cent FLR and in three of four animals in the ALPPS10 group after step 2. Although the relative increments in FLR size and growth rates were highest in the ALPPS groups, small FLR size was associated with a sustained increase in levels of serum aminotransferases and bilirubin, a lower albumin concentration, severe sinusoidal injury, increased expression of proliferation markers and increased activation of hepatic progenitor cells after step 2.

Conclusion

There is discordance between FLR volume increase and functional restoration after the ALPPS procedure.

Lipopolysaccharide induces the differentiation of hepatic progenitor cells into myofibroblasts via activation of the Hedgehog signaling pathway

Normally, hepatic progenitor cells (HPCs) are activated and differentiate into hepatocytes or bile ductular cells to repair liver damage during liver injury. However, it remains controversial whether the abnormal differentiation of HPCs occurs under abnormal conditions. Lipopolysaccharide (LPS), a component of the microenvironment, promotes liver fibrosis. In the present study, HPCs promoted liver fibrosis in rats following carbon tetrachloride (CCl₄) treatment. Meanwhile, the LPS level in the portal vein was elevated and played a primary role in the fate of HPCs. In vitro, LPS inhibited the hepatobiliary differentiation of HPCs. Concurrently, HPCs co-cultured with LPS for 2 weeks showed a tendency to differentiate into myofibroblasts (MFs). Thus, we conclude that LPS promotes the aberrant differentiation of HPCs into MFs as a third type of descendant. This study provides insight into a novel differentiation fate of HPCs in their microenvironment, and could thus lead to the development of HPCs for treatment methods in liver fibrosis.

Pre-stimulated Mice with Carbon Tetrachloride Accelerate Early Liver Regeneration After Partial Hepatectomy

BACKGROUND AND AIM

The liver has a high capacity of its regeneration. Most hepatic cells are quiescent unless otherwise stimulated such as their injury or ablation. A previous study suggest that pre-activated hepatic cells have a positive effect on their regeneration. In this study, we examined whether the pre-activated hepatic cells for regeneration accelerate the subsequent liver regeneration.

METHODS

We administered a single injection of carbon tetrachloride (CCl4) to mice 7 days before partial hepatectomy (PHx). Liver weight/body weight ratio and several parameters for cell proliferation such as mitotic index and the number of Ki67 positive cells in the liver were examined after PHx as indexes of liver regeneration.

RESULTS

Compared to control mice, those pre-stimulated with CCl4 showed earlier liver regeneration 48 h after PHx. Regardless of their accelerated regeneration, pre-stimulated mice showed less cell proliferation than did control mice during liver regeneration. Hepatic fibrosis was not observed in both control and CCl4-pretreated mice after PHx. Mice pre-treated with CCl4 showed the higher matrix metalloproteinase 9 (MMP9) expression than those pre-treated with olive oil. When matrix metalloproteinase 9 (MMP9) activity was inhibited, the pre-stimulated mice did not demonstrate accelerated liver regeneration and they returned to the original state for cell proliferations after PHx.

CONCLUSIONS

Pre-activated liver by CCl4 promoted its subsequent regeneration after PHx. This was not a cause of fibrosis and partly dependent on MMP9 pre-activity rather than cell proliferation in liver. Our findings would not only provide a novel strategy for liver regeneration without cell proliferation as much as possible and also propose a new method for liver transplantation.

Management of hepatocellular carcinoma: Predictive value of immunohistochemical markers for postoperative survival

Hepatocellular carcinoma (HCC) accounts for over 90% of all primary liver cancers. With an ever increasing incidence trend year by year, it has become the third most common cause of death from cancer worldwide. Hepatic resection is generally considered to be one of the most effective therapies for HCC patients, however, there is a high risk of recurrence in postoperative HCC. In clinical practice, there exists an urgent need for valid prognostic markers to identify patients with prognosis, hence the importance of studies on prognostic markers in improving the prediction of HCC prognosis. This review focuses on the most promising immunohistochemical prognostic markers in predicting the postoperative survival of HCC patients.