Liver stem cells: implications for hepatocarcinogenesis

LIN28 and histone H3K4 methylase induce TLR4 to generate tumor-initiating stem-like cells

Chemoresistance and plasticity of tumor-initiating stem-like cells (TICs) promote tumor recurrence and metastasis. The gut-originating endotoxin-TLR4-NANOG oncogenic axis is responsible for the genesis of TICs. This study investigated mechanisms as to how TICs arise through transcriptional, epigenetic, and post-transcriptional activation of oncogenic TLR4 pathways. Here, we expressed constitutively active TLR4 (caTLR4) in mice carrying pLAP-tTA or pAlb-tTA, under a tetracycline withdrawal-inducible system. Liver progenitor cell induction accelerated liver tumor development in caTLR4-expressing mice. Lentiviral shRNA library screening identified histone H3K4 methylase SETD7 as central to activation of TLR4. SETD7 combined with hypoxia induced TLR4 through HIF2 and NOTCH. LIN28 post-transcriptionally stabilized TLR4 mRNA via de-repression of let-7 microRNA. These results supported a LIN28-TLR4 pathway for the development of HCCs in a hypoxic microenvironment. These findings not only advance our understanding of molecular mechanisms responsible for TIC generation in HCC, but also represent new therapeutic targets for the treatment of HCC.

HCV and tumor-initiating stem-like cells

Neoplasms contain tumor-initiating stem-like cells (TICs) that are characterized by increased drug resistance. The incidence of many cancer types have trended downward except for few cancer types, including hepatocellular carcinoma (HCC). Therefore mechanism of HCC development and therapy resistance needs to be understood. These multiple hits by hepatitis C virus (HCV) eventually promotes transformation and TIC genesis, leading to HCC development. This review article describes links between HCV-associated HCC and TICs. This review discusses 1) how HCV promotes genesis of TICs and HCC development; 2) how this process avails itself as a novel therapeutic target for HCC treatment; and 3) ten hall marks of TIC oncogenesis and HCC development as targets for novel therapeutic modalities.

Immunotherapy and Microbiota for Targeting of Liver Tumor-Initiating Stem-like Cells

Cancer contains tumor-initiating stem-like cells (TICs) that are resistant to therapies. Hepatocellular carcinoma (HCC) incidence has increased twice over the past few decades, while the incidence of other cancer types has trended downward globally. Therefore, an understanding of HCC development and therapy resistance mechanisms is needed for this incurable malignancy. This review article describes links between immunotherapies and microbiota in tumor-initiating stem-like cells (TICs), which have stem cell characteristics with self-renewal ability and express pluripotency transcription factors such as NANOG, SOX2, and OCT4. This review discusses (1) how immunotherapies fail and (2) how gut dysbiosis inhibits immunotherapy efficacy. Gut dysbiosis promotes resistance to immunotherapies by breaking gut immune tolerance and activating suppressor immune cells. Unfortunately, this leads to incurable recurrence/metastasis development. Personalized medicine approaches targeting these mechanisms of TIC/metastasis-initiating cells are emerging targets for HCC immunotherapy and microbiota modulation therapy.

Crosstalk of low density lipoprotein and liposome as a paradigm for targeting of 5-fluorouracil into hepatic cells: cytotoxicity and liver deposition

This study aimed to utilize cholesterol conjugation of 5-fluorouracil (5-FUC) and liposomal formulas to enhance the partitioning of 5-FU into low density lipoprotein (LDL) to target hepatocellular carcinoma (HCC). Thus, 5-FU and 5-FUCwere loaded into liposomes. Later, the direct loading and transfer of 5-FU, and 5-FUC from liposomes into LDL were attained. The preparations were characterized in terms of particle size, zeta potential, morphology, entrapment efficiency, and cytotoxicity using the HepG2 cell line. Moreover, the drug deposition into the LDL and liver tissues was investigated. The present results revealed that liposomal preparations have a nanosize range (155 - 194 nm), negative zeta potential (- 0.82 to - 16 mV), entrapment efficiency of 69% for 5-FU, and 66% for 5-FUC. Moreover, LDL particles have a nanosize range (28-49 nm), negative zeta potential (- 17 to -27 mV), and the entrapment efficiency is 11% for 5-FU and 85% for 5-FUC. Furthermore, 5-FUC loaded liposomes displayed a sustained release profile (57%) at 24 h compared to fast release (92%) of 5-FU loaded liposomes. 5-FUC and liposomal formulas enhanced the transfer of 5-FUC into LDL compared to 5-FU. 5-FUC loaded liposomes and LDL have greater cytotoxicity against HepG2 cell lines compared to 5-FU and 5-FUC solutions. Moreover, the deposition of 5-FUC in LDL (26.87ng/mg) and liver tissues (534 ng/gm tissue) was significantly increased 5-FUC liposomes compared to 5-FU (11.7 ng/g tissue) liposomal formulation. In conclusion, 5-FUC is a promising strategy for hepatic targeting of 5-FU through LDL-mediated gateway.

Circulating MicroRNA-21 As A Novel Noninvasive Biomarker for Hepatocellular Carcinoma Compared with Alpha Fetoprotein Gold Test

Hepatocellular carcinoma (HCC) is the greatest traditional kind of pre-eminent cancer worldwide, which happens mainly in chronic liver disease and cirrhotic patients. The available surveillance strategies for suspected HCC patients include serum alpha-fetoprotein (AFP) and liver imaging have been mainly recommended. However, the sensitivity and selectivity of these diagnostic strategies especially in the early stages of HCC have many obstacles. MicroRNAs (miRNAs) are non-coding RNAs that are 18–25 nucleotides in length. Plasma miRNAs may be a promising new biomarker for cancer detection and prognosis in the early stages. Assessment of Plasma MicroRNA-21 (miRNA-21) significance as a noninvasive Hepatocellular carcinoma marker compared with AFP gold standard test to improve HCC early diagnostic power. This is a prospective research project that included 90 patients in total, split into three classes., liver cirrhosis patients (LC) without any malignancies and (HCC) patients in addition to the healthy control group. Patients and controls were subjected to the clinical studies, routine investigations, imaging studies, and detection of plasma miRNA-21 & AFP. miRNA-21 showed a highly significant difference in the 3 studied groups. Control group with LC group, control group with HCC group, and LC group with HCC group P value (P 0.0001, P1 0.0001, P2 0.0001and P3 0.0001) respectively. Also, a highly significant difference was observed between pre-TACE and post-TACE miRNA-21 in the HCC group P value (0.0001). Circulating miRNA-21 may be used as a noninvasive co biomarker with AFP to increase HCC diagnostic accuracy in its early stages.

Interleukin-17 in Liver Disease Pathogenesis

Interleukin 17A (IL-17A)-producing T helper 17 (Th17) cells were identified as a subset of T helper cells that play a critical role in host defense against bacterial and fungal pathogens. Th17 cells differentiate from Th0 naïve T-cells in response to transforming growth factor β1 (TGF-β1) and IL-6, the cytokines which also drive development of liver fibrosis, require activation of transcription factor retinoic acid receptor-related orphan nuclear receptor gamma t (RORγt). IL-17A signals through the ubiquitously expressed receptor IL-17RA. Expression of IL-17RA is upregulated in patients with hepatitis B virus/hepatitis C virus (HBV/HCV) infections, nonalcoholic steatohepatitis (NASH), alcohol-associated liver disease (AALD), hepatocellular carcinoma (HCC), and experimental models of chronic toxic liver injury. The role of IL-17 signaling in the pathogenesis of NASH- and AALD-induced metabolic liver injury and HCC will be the focus of this review. The role of IL-17A-IL-17RA axis in mediation of the cross-talk between metabolically injured hepatic macrophages, hepatocytes, and fibrogenic myofibroblasts will be discussed.

Nondegradable Collagen Increases Liver Fibrosis but Not Hepatocellular Carcinoma in Mice

Although hepatocellular cancer (HCC) usually occurs in the setting of liver fibrosis, the causal relationship between liver fibrosis and HCC is unclear. in vivo and in vitro models of HCC involving Colr/r mice (that produce a collagenase-resistant type I collagen) or wild-type (WT) mice were used to assess the relationship between type I collagen, liver fibrosis, and experimental HCC. HCC was either chemically induced in WT and Colr/r mice or Hepa 1-6 cells were engrafted into WT and Colr/r livers. The effect of hepatic stellate cells (HSCs) from WT and Colr/r mice on the growth of Hepa 1-6 cells was studied by using multicellular tumor spheroids and xenografts. Collagen type I deposition and fibrosis were increased in Colr/r mice, but they developed fewer and smaller tumors. Hepa 1-6 cells had reduced tumor growth in the livers of Colr/r mice. Although Colr/r HSCs exhibited a more activated phenotype, Hepa 1-6 growth and malignancy were suppressed in multicellular tumor spheroids and in xenografts containing Colr/r HSCs. Treatment with vitronectin, which mimics the presence of degraded collagen fragments, converted the Colr/r phenotype into a WT phenotype. Although Colr/r mice have increased liver fibrosis, they exhibited decreased HCC in several models. Thus, increased liver type I collagen does not produce increased experimental HCC.

The cellular origins of cancer with particular reference to the gastrointestinal tract

Stem cells or their closely related committed progenitor cells are the likely founder cells of most neoplasms. In the continually renewing and hierarchically organized epithelia of the oesophagus, stomach and intestine, homeostatic stem cells are located at the beginning of the cell flux, in the basal layer of the oesophagus, the isthmic region of gastric oxyntic glands and at the bottom of gastric pyloric-antral glands and colonic crypts. The introduction of mutant oncogenes such as Kras^G12D or loss of Tp53 or Apc to specific cell types expressing the likes of Lgr5 and Mist1 can be readily accomplished in genetically engineered mouse models to initiate tumorigenesis. Other origins of cancer are discussed including 'reserve' stem cells that may be activated by damage or through disruption of morphogen gradients along the crypt axis. In the liver and pancreas, with little cell turnover and no obvious stem cell markers, the importance of regenerative hyperplasia associated with chronic inflammation to tumour initiation is vividly apparent, though inflammatory conditions in the renewing populations are also permissive for tumour induction. In the liver, hepatocytes, biliary epithelial cells and hepatic progenitor cells are embryologically related, and all can give rise to hepatocellular carcinoma and cholangiocarcinoma. In the exocrine pancreas, both acinar and ductal cells can give rise to pancreatic ductal adenocarcinoma (PDAC), although the preceding preneoplastic states are quite different: acinar-ductal metaplasia gives rise to pancreatic intraepithelial neoplasia culminating in PDAC, while ducts give rise to PDAC via. mucinous cell metaplasia that may have a polyclonal origin.

Viral hepatitis B and C infections increase the risks of intrahepatic and extrahepatic cholangiocarcinoma: Evidence from a systematic review and meta-analysis

BACKGROUND/AIMS

Previous study has shown a positive relationship between the hepatitis B virus (HBV) or hepatitis C virus (HCV) infection and cholangiocarcinoma (CCA); however, their correlation with different anatomical sites of CCA (i.e. ICC and ECC) has not been revealed. This study aims to evaluate the association of HBV or HCV infection with CCA, including the intrahepatic cholangiocarcinoma (ICC) and extrahepatic cholangiocarcinoma (ECC), and to determine the roles of α-1 fetoprotein (AFP), CA19-9, and lymph node involvement in CCA with HBV infection.

MATERIALS AND METHODS

Relevant studies published between 2004 and 2016 were systematically searched and retrieved from PubMed, SpringerLink, and Science Direct using key terms such as "cholangiocarcinoma", "bile duct cancer", "extrahepatic cholangiocarcinoma", and "intrahepatic cholangiocarcinoma". The demographic, clinical, and laboratory data were extracted from the included studies, and the meta-analysis was performed using RevMan and STATA 11.0 software.

RESULTS

A total of 13 studies with CCA matched the inclusion criteria in this meta-analysis, including 7,113 CCA patients and 24,763 controls. This meta-analysis showed that the HBV or HCV infections can significantly increase the risk of CCA, including ICC and ECC. In addition, the higher levels of AFP, lower levels of CA19-9, and lymph node involvement were detected in the CCA patients with HBV infection as compared to those without.

CONCLUSION

The HBV and HCV infections significantly increased the risk of CCA, as well as ICC and ECC. The involvement of AFP, CA19-9, and lymph nodes may play an important role in the diagnosis of CCA.

Cell fate, metabolic reprogramming and lncRNA of tumor-initiating stem-like cells induced by alcohol

Alcoholism synergizes the development of the hepatocellular carcinoma (HCC) in patients infected with hepatitis B or C virus (HBV or HCV). Tumor-initiating stem-like cells (TICs) are refractory to therapy and have expression of stemness transcription factors. Leaky-gut-derived endotoxin stimulates TLR4-NANOG pathway that skews asymmetric cell division and that metabolically reprograms hepatocytes/liver progenitor cells, leading to self-renewal. TICs isolated from mouse HCC models or human HCCs are tumorigenic and have p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncofetal protein TBC1D15. Furthermore, dysregulation of lncRNA promotes genesis of TICs, leading to HCC development. This review describes roles of cell fate decision, metabolic reprogramming and lncRNA for TIC genesis and liver oncogenesis. This project was supported by NIH grants 1R01AA018857-01, 5R21AA025470, P50AA11999 (Animal Core, Morphology Core, and Pilot Project Program), R24AA012885 (Non-Parenchymal Liver Cell Core) and pilot project funding (5P30DK048522-13).

A Rare Colonic Metastasis Case from Hepatocellular Carcinoma

BACKGROUND

Hepatocellularcarcinoma (HCC) metastasis include intrahepatic and extrahepatic metastasis. Similar to intrahepatic metastasis, extrahepatic metastases are not unusual in cases with HCC. However, colonic metastasis is infrequent.

CASE REPORT

We describe a clinical case, he was diagnosed with HCC a year ago, treated with TACE (transarterialchemoembolisation), re-examined with abdominal pain and defecation disorder. The tests such as CT scan, colorectal endoscopy, fine needle aspiration (FNA) revealed secondary metastatic lesion of HCC in sigmoid colon. This is the first gastrointestinal (GI) tract metastatic we have encountered.

CONCLUSION

HCC metastases of the colon are rare, especially cases of hematogenous spread. The prognosis of these patients is often very critical. Indications for surgical removal of the lesion may be used if the general situation of patient is acceptable.

Methionine adenosyltransferases in liver cancer

Methionine adenosyltransferases (MATs) are essential enzymes for life as they produce S-adenosylmethionine (SAMe), the biological methyl donor required for a plethora of reactions within the cell. Mammalian systems express two genes, MAT1A and MAT2A, which encode for MATα1 and MATα2, the catalytic subunits of the MAT isoenzymes, respectively. A third gene MAT2B, encodes a regulatory subunit known as MATβ which controls the activity of MATα2. MAT1A, which is mainly expressed in hepatocytes, maintains the differentiated state of these cells, whilst MAT2A and MAT2B are expressed in extrahepatic tissues as well as non-parenchymal cells of the liver (e.g., hepatic stellate and Kupffer cells). The biosynthesis of SAMe is impaired in patients with chronic liver disease and liver cancer due to decreased expression and inactivation of MATα1. A switch from MAT1A to MAT2A/MAT2B occurs in multiple liver diseases and during liver growth and dedifferentiation, but this change in the expression pattern of MATs results in reduced hepatic SAMe level. Decades of study have utilized the Mat1a-knockout (KO) mouse that spontaneously develops non-alcoholic steatohepatitis (NASH) and hepatocellular carcinoma (HCC) to elucidate a variety of mechanisms by which MAT proteins dysregulation contributes to liver carcinogenesis. An increasing volume of work indicates that MATs have SAMe-independent functions, distinct interactomes and multiple subcellular localizations. Here we aim to provide an overview of MAT biology including genes, isoenzymes and their regulation to provide the context for understanding consequences of their dysregulation. We will highlight recent breakthroughs in the field and underscore the importance of MAT’s in liver tumorigenesis as well as their potential as targets for cancer therapy.

Patients' prognosis of intrahepatic cholangiocarcinoma and combined hepatocellular-cholangiocarcinoma after resection

Combined hepatocellular-cholangiocarcinoma (cHCC-CC) and intrahepatic cholangiocarcinoma (ICC) are classified into one category, but comparison of prognosis of the two carcinomas remains controversial. The aim of the current study was to investigate surgical outcomes for patients with ICC or cHCC-CC who underwent resection in order to elucidate whether the classification of ICC and cHCC-CC is justified. Subjects were 61 patients with ICC and 29 patients with cHCC-CC who underwent liver resection from 2001 to 2017. Clinic-pathological data from the two groups were compared. Tumor number and vascular invasion were independent risk factors for recurrence-free survival (RFS) in both groups (P < .001 for both). Of note, for patients with ICC, tumor cut-off size of 5 cm showed statistical significance in median RFS (>5 cm vs ≤5 cm, 0.5 years vs 4.0 years, P = .003). For patients with cHCC-CC, tumor cut-off size of 2 cm showed statistical significance in median RFS (>2 cm vs ≤2 cm, 0.6 years vs 2.6 years, P = .038). The median RFS of patients with cHCC-CC was 0.9 years (95% confidence interval: 0.3-1.6), which was poorer than that of patients with ICC (1.3 years, 0.5-2.1) (P = .028); the rate of RFS at 5 years was 0% and 37.7% respectively. Our study supports the concept of classifying ICC and cHCC-CC into different categories because of a significant difference in RFS between the two.

NANOG-Dependent Metabolic Reprogramming and Symmetric Division in Tumor-Initiating Stem-like Cells

Alcohol abuse synergistically heightens the development of the third most deadliest cancer hepatocellular carcinoma (HCC) in patients infected with hepatitis C virus (HCV). Ectopically expressed TLR4 promotes liver tumorigenesis in alcohol-fed HCV Ns5a or Core transgenic mice. CD133+/CD49f + tumor-initiating stem cell-like cells (TICs) isolated from these models are tumorigenic have p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncoprotein TBC1D15. Nutrient deprivation reduces overexpressed TBC1D15 in TICs via autophagy-mediated degradation, suggesting a possible role of this oncoprotein in linking metabolic reprogramming and self-renewal.

Enhancement Patterns of Intrahepatic Cholangiocarcinoma on Contrast-Enhanced Ultrasound: Correlation with Clinicopathologic Findings and Prognosis

To evaluate the correlations between the enhancement pattern of intrahepatic cholangiocarcinoma (ICC) on contrast-enhanced ultrasound (CEUS) and clinicopathologic findings and prognosis, a retrospective study was performed on 197 patients with mass-forming ICC who underwent pre-operative CEUS and surgical resection. The contrast medium we employed in CEUS was SonoVue, which contains microbubbles consisting of sulfur hexafluoride bubbles within a phospholipid shell. This study was approved by the institutional review board with informed consent waived. Patients were classified into an arterial rim-like enhancement group or an arterial non-rim-like enhancement group, and arterial enhancement patterns were correlated with clinicopathologic factors. Overall survival (OS) times were calculated using the Kaplan-Meier method, and differences between groups were compared with the log-rank test. Univariate and multivariate Cox regression models for OS were used to evaluate the independent prognostic factors. The mean and range of ICC tumor size of the arterial rim-like group (59.41 ± 22.09 mm, 20-100 mm) were similar to those of the arterial non-rim-like group (59.82 ± 30.35 mm, 14-162 mm, p = 0.914). Arterial enhancement patterns were correlated with chronic viral hepatitis or cirrhosis, vascular invasion, lymph node metastasis and single/multiple tumors. A total of 78 patients (39.6%) exhibited arterial rim-like enhancement, and the other 119 patients (60.4%) exhibited arterial non-rim-like enhancement. Arterial enhancement pattern (p = 0.045), vascular invasion (p = 0.005), lymph node metastasis (p = 0.000) and number of tumors (p = 0.001) were independent prognostic factors for OS. The arterial non-rim-like enhancement pattern of ICC on CEUS is an independent prognostic factor for better OS and may offer new information for predicting the prognosis of ICC patients before surgical resection.

Oncogenic Signaling Induced by HCV Infection

The liver is frequently exposed to toxins, metabolites, and oxidative stress, which can challenge organ function and genomic stability. Liver regeneration is therefore a highly regulated process involving several sequential signaling events. It is thus not surprising that individual oncogenic mutations in hepatocytes do not necessarily lead to cancer and that the genetic profiles of hepatocellular carcinomas (HCCs) are highly heterogeneous. Long-term infection with hepatitis C virus (HCV) creates an oncogenic environment by a combination of viral protein expression, persistent liver inflammation, oxidative stress, and chronically deregulated signaling events that cumulate as a tipping point for genetic stability. Although novel direct-acting antivirals (DAA)-based treatments efficiently eradicate HCV, the associated HCC risk cannot be fully eliminated by viral cure in patients with advanced liver disease. This suggests that HCV may persistently deregulate signaling pathways beyond viral cure and thereby continue to perturb cancer-relevant gene function. In this review, we summarize the current knowledge about oncogenic signaling pathways derailed by chronic HCV infection. This will not only help to understand the mechanisms of hepatocarcinogenesis but will also highlight potential chemopreventive strategies to help patients with a high-risk profile of developing HCC.

Sphingolipids at the Crossroads of NAFLD and Senescence

Nonalcoholic fatty liver disease (NAFLD) is a group of liver disorders encompassing simple hepatic steatosis and its more aggressive forms of nonalcoholic steatohepatitis and cirrhosis. It is a rapidly growing health concern and the major cause for the increasing incidence of primary liver tumors. Unequivocal evidence shows that sphingolipid metabolism is altered in the course of the disease and these changes might contribute to NAFLD progression. Recent data provide solid support to the notion that deregulated ceramide and sphingosine-1-phosphate metabolism are present at all stages of NAFLD, i.e., steatosis, nonalcoholic steatohepatitis, advanced fibrosis, and hepatocellular carcinoma (HCC). Insulin sensitivity, de novo lipogenesis, and the resulting lipotoxicity, fibrosis, and angiogenesis are all seemingly regulated in a manner that involves either ceramide and/or sphingosine-1-phosphate. Sphingolipids might also participate in the onset of hepatocellular senescence. The latter has been shown to contribute to the advancement of cirrhosis to HCC in the classical cases of end-stage liver disease, i.e., viral- or alcohol-induced; however, emerging evidence suggests that senescence is also involved in the pathogenicity of NAFLD possibly via changes in ceramide metabolism.

SUMOylation and phosphorylation cross-talk in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary malignancy of the liver and occurs predominantly in patients with underlying chronic liver disease and cirrhosis. The large spectrum of protein post-translational modification (PTM) includes numerous critical signaling events that occur during neoplastic transformation. PTMs occur to nearly all proteins and increase the functional diversity of proteins. We have reviewed the role of two major PTMs, SUMOylation and phosphorylation, in the altered signaling of key players in HCC. SUMOylation is a PTM that involves addition of a small ubiquitin-like modifiers (SUMO) group to proteins. It is known to regulate protein stability, protein-protein interactions, trafficking and transcriptional activity. The major pathways that are regulated by SUMOylation and may influence HCC are regulation of transcription, cell growth pathways associated with B-cell lymphoma 2 (Bcl-2) and methionine adenosyltransferases (MAT), oxidative stress pathways [nuclear erythroid 2-related factor 2 (Nrf2)], tumor suppressor pathways (p53), hypoxia-inducible signaling [hypoxia-inducible factor-1 (HIF-1)], glucose and lipid metabolism, nuclear factor kappa B (NF-κB) and β-Catenin signaling. Phosphorylation is an extensively studied PTM in HCC. The mitogen-activated protein kinase (MAPK), phosphatidyl inositol/AK-strain transforming (PI3K/AKT), and C-SRC pathways have been extensively studied for deregulation of kinases and alteration in signaling of targets through phosphorylation of their substrates. Cross-talk between phosphorylation and SUMOylation is known to influence transcriptional activity of proteins and protein-protein interactions. In HCC, several SUMOylation-dependent phosphorylation events have been studied such as MAPK activation and c-SRC activity that have been reviewed in this work. The drastic effects of site-specific phosphorylation or SUMOylation on enzyme activity of signaling players and its effect on growth and tumorigenesis suggests that these PTMs are novel targets for therapeutic intervention in HCC.

Physiogenomics in Etiopathogenesis of Cholangiocarcinoma

Objective

Cholangiocarcinoma is a serious malignancy that is very common in the tropical countries. It is a kind of deadly primary hepatobiliary tumor. There is a wide spectrum of tumors with varying differentiation and malignancy grades. Although it has been known for a long time inmmedicine, there is no clear cut that this deadly cancer is genetic disorder or not. A systemic approach on the pathophysiology and genomics can provide useful information and help better understand the pathogenesis of cholangiocarcinoma.

Methods

In this work, a standard bioinformatics physiological genomics analysis of cholangiocarcinoma was performed.

Result

According to this work, there is no identified physiogenomics relationship for the cholangiocarcinoma.

Conclusion

This might imply that the cholangiocarcinoma is directly due to environmental insult. It implies that there should be no specific gene that might contribute to the increased risk in the etiopathogenesis of cholangiocarcinoma.

Involvement of inflammation and its related microRNAs in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is the fifth most commonly diagnosed type of cancer. The tumor inflammatory microenvironment regulates almost every step towards liver tumorigenesis and subsequent progression, and regulation of the inflammation-related signaling pathways, cytokines, chemokines and non-coding RNAs influences the proliferation, migration and metastasis of liver tumor cells. Inflammation fine-tunes the cancer microenvironment to favor epithelial-mesenchymal transition, in which cancer stem cells maintain tumorigenic potential. Emerging evidence points to inflammation-related microRNAs as crucial molecules to integrate the complex cellular and molecular crosstalk during HCC progression. Thus understanding the mechanisms by which inflammation regulates microRNAs might provide novel and admissible strategies for preventing, diagnosing and treating HCC. In this review, we will update three hypotheses of hepatocarcinogenesis and elaborate the most predominant inflammation signaling pathways, i.e. IL-6/STAT3 and NF-κB. We also try to summarize the crucial tumor-promoting and tumor-suppressing microRNAs and detail how they regulate HCC initiation and progression and collaborate with other critical modulators in this review.

Characterization of liver injury, oval cell proliferation and cholangiocarcinogenesis in glutathione S-transferase A3 knockout mice

We recently generated glutathione S-transferase (GST) A3 knockout (KO) mice as a novel model to study the risk factors for liver cancer. GSTA3 KO mice are sensitive to the acute cytotoxic and genotoxic effects of aflatoxin B1 (AFB1), confirming the crucial role of GSTA3 in resistance to AFB1. We now report histopathological changes, tumor formation, biochemical changes and gender response following AFB1 treatment as well as the contribution of oxidative stress. Using a protocol of weekly 0.5 mg AFB1/kg administration, we observed extensive oval (liver stem) cell (OC) proliferation within 1-3 weeks followed by microvesicular lipidosis, megahepatocytes, nuclear inclusions, cholangiomas and small nodules. Male and female GSTA3 KO mice treated with 12 and 24 weekly AFB1 injections followed by a rest period of 12 and 6 months, respectively, all had grossly distorted livers with macro- and microscopic cysts, hepatocellular nodules, cholangiomas and cholangiocarcinomas and OC proliferation. We postulate that the prolonged AFB1 treatment leads to inhibition of hepatocyte proliferation, which is compensated by OC proliferation and eventually formation of cholangiocarcinoma (CCA). At low-dose AFB1, male KO mice showed less extensive acute liver injury, OC proliferation and AFB1-DNA adducts than female KO mice. There were no significant compensatory changes in KO mice GST subunits, GST enzymatic activity, epoxide hydrolase, or CYP1A2 and CYP3A11 levels. Finally, there was a modest increase in F2-isoprostane and isofuran in KO mice that confirmed putative GSTA3 hydroperoxidase activity in vivo for the first time.

Vitamin D and K signaling pathways in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a primary liver malignancy, and is now the six most common in between malignancies. Early diagnosis of HCC with prompt treatment increases the opportunity of patients to survive. With the advances in understanding the molecular biology of HCC, new therapeutic strategies to treat HCC have emerged. There is a growing consensus that vitamins are important for the control of various cancers. Biochemical evidence clearly indicates that HCC cells are responsive to the inhibitory effect of vitamin D, vitamin D analogues and vitamin K. In this review, we summarize the mechanisms used by vitamin D and K to influence the development of HCC and the latest development of vitamin analogues for potential HCC therapy.

New insights into the antioxidant and apoptotic potential of Glycyrrhiza glabra L. during hydrogen peroxide mediated oxidative stress: An in vitro and in silico evaluation

Plant-derived substances (phytochemicals) are well recognized as sources of pharmacologically potent drugs in the treatment of several oxidative stress related disorders. Our study aims to evaluate the antioxidant and apoptotic effects of Glycyrrhiza glabra L. in both cell free and cell culture system. Plant fractions have been prepared with hexane, chloroform, ethyl acetate, methanol and water and their antioxidant properties are reviewed. Potent antioxidant activity has been well established in both in vitro and in silico studies which is believed to be responsible for the anticancerous nature of the plant. Results obtained indicate that methanol fraction of G. glabra L. exhibited maximum scavenging activity against DPPH and nitric oxide free radicals comparable to standard antioxidant L-AA. Administration of methanol fraction also considerably reduced the malondialdehyde produced due to lipid peroxidation in mammalian liver tissues. Moreover, the levels of antioxidant enzymes SOD, CAT, GST, GPx and GR in the oxidative stress induced tissues were refurbished significantly after treatment with plant's methanol fraction. Moreover, methanol fraction was found to be nontoxic to normal human cell line whereas it inhibited cancer cells HeLa and HepG2 considerably. Apoptosis was established by DAPI fluorescent staining and western blot analysis of pro apoptotic protein caspase-8, caspase-3 and anti-apoptotic protein Bcl-2.There is an up regulation in the levels of pro apoptotic caspase-8 and caspase-3 and down regulation of anti-apoptotic Bcl-2. Furthermore, GC-MS analysis of the methanol fraction revealed the presence of many compounds. In silico experiments using Autodock 4.2 tools showed strong affinity of plant compounds towards antioxidant enzymes (proteins) thus validating with the conclusions of antioxidant enzyme assays and establishing a role in cancer pathogenesis.

Cytotoxic potential of rhizome extracts of Hedychium spicatum L. in HepG2 cell line using MTT

The present study was designed to evaluate the cytotoxic effects of extract of Hedychium spicatum rhizome extract on human liver hepatocellular carcinoma (HepG2) cell line using MTT assay. The crude extract of H. spicatum was prepared by cold maceration method, filtered, concentrated in different organic solution and tested for phytochemical evaluation and finally on HepG2 cell line. Dose-dependent cytotoxic activities were exhibited on HepG2 cell line. As the dose of the extract increased, the number of viable cells decreased. This confirms the cytotoxic potential of the rhizome of H. spicatum. The IC50 value of different extracts was determined and concluded that the methanolic extract had better potential than the other extracts.

Longterm prognosis of combined hepatocellular carcinoma-cholangiocarcinoma following liver transplantation and resection

Combined hepatocellular carcinoma-cholangiocarcinoma (cHCC-CC) is a rare disease. We investigated the clinicopathological features of cHCC-CC and compared the longterm outcomes following liver transplantation (LT) and hepatic resection (HR). We identified 32 LT patients with cHCC-CC through an institutional database search. The HR control group (n = 100) was selected through propensity score-matching. The incidence of cHCC-CC among all adult LT patients was 1.0%. Mean patient age was 53.4 ± 6.7 years, and 26 patients were male. Thirty patients had hepatitis B virus infection. All patients of cHCC-CC were diagnosed incidentally in the explanted livers. Mean tumor diameter was 2.5 ± 1.3 cm, and 28 patients had single tumors. Tumor stage was stage I in 23 and II in 9. Concurrent hepatocellular carcinoma (HCC) was detected in 12 patients with stage I in 5 and II in 7. Mean tumor diameter was 1.9 ± 1.2 cm, and 5 had single tumors. Tumor recurrence and survival rates were 15.6% and 84.4% at 1 year and 32.2% and 65.8% at 5 years, respectively. Patients with very early stage cHCC-CC (1 or 2 tumors ≤ 2.0 cm) showed 13.3% tumor recurrence and 93.3% patient survival rates at 5 years, which were significantly improved than those with advanced tumors (P = 0.002). Tumor recurrence and survival rates did not differ significantly between the LT and HR control groups (P = 0.22 and P = 0.91, respectively); however, postrecurrence patient survival did (P = 0.016). In conclusion, cHCC-CC is rarely diagnosed following LT, and one-third of such patients have concurrent HCC. The longterm posttransplant prognosis was similar following LT and HR. Very early cHCC-CC resulted in favorable posttransplant prognosis, thus this selection condition can be prudently considered for LT indication. Liver Transplantation 23 330-341 2017 AASLD.

Autocrine and Paracrine Mechanisms Promoting Chemoresistance in Cholangiocarcinoma

Resistance to conventional chemotherapeutic agents, a typical feature of cholangiocarcinoma, prevents the efficacy of the therapeutic arsenal usually used to combat malignancy in humans. Mechanisms of chemoresistance by neoplastic cholangiocytes include evasion of drug-induced apoptosis mediated by autocrine and paracrine cues released in the tumor microenvironment. Here, recent evidence regarding molecular mechanisms of chemoresistance is reviewed, as well as associations between well-developed chemoresistance and activation of the cancer stem cell compartment. It is concluded that improved understanding of the complex interplay between apoptosis signaling and the promotion of cell survival represent potentially productive areas for active investigation, with the ultimate aim of encouraging future studies to unveil new, effective strategies able to overcome current limitations on treatment.

Hepatitis B virus is associated with the clinical features and survival rate of patients with intrahepatic cholangiocarcinoma

BACKGROUND AND OBJECTIVE

The pathogenesis and development of intrahepatic cholangiocarcinoma (ICC) may be triggered by hepatitis B virus (HBV). We conducted this retrospective study to explore the potential association between HBV infection and the clinical features and survival rate of patients with ICC.

METHODS

Patients with ICC who had undergone a curative resection were enrolled and divided into three groups according to the seropositivity of the hepatitis B surface antigen (HBsAg) and the hepatitis B core antibody (anti-HBc). The groups were as follows: group I, HBsAg (+)/anti-HBc (+); group II, HBsAg (-)/anti-HBc (+); group III HBsAg (-)/anti-HBc (-). The symptoms, pathologic findings, and outcome information of all patients were retrospectively reviewed. The patient sera were isolated to detect anti-HCV, HBsAg, and anti-HBc. Surgical specimens were assessed by hematoxylin and eosin (HE) staining. The expression of cytokeratin 7 was evaluated by immunohistochemistry. Finally, the 1-, 3-, and 5-year cumulative survival rates were analyzed.

RESULTS

Ninety-seven patients with ICC were enrolled in group I (n=26); group II, (n=50), and group III (n=21). A total of 26.8% (26/97) patients with ICC were positive for HBsAg. Patients with HBV-associated ICC tended to be younger (P=0.018), have lower CA19-9 levels (P=0.000), a higher alpha fetal protein (AFP) level (P=0.012) and prothrombin time (P=0.030), a higher risk of hepatic cirrhosis (P=0.001), and poor differentiation (P=0.028). The 1-, 3-, and 5-year cumulative survival rates for patients within the three groups were as follows: 27.3%, 0%, and 0% for group I, respectively; 62.5%, 30.0%, and 0% for group II, respectively; and 87.5%, 66.7%, and 50.0% for group III, respectively. The results were significantly different in an overall comparison (P=0.000).

CONCLUSION

Patients with HBV-associated ICC showed different clinicopathological features and lower survival rates compared to patients with ICC without HBV infection.

HBV Infection Status and the Risk of Cholangiocarcinoma in Asia: A Meta-Analysis

Background. The inconsistent finding was between hepatitis B virus (HBV) infections and cholangiocarcinoma (CCA). This meta-analysis is to explore this relationship in Asia. Methods. A literature search was performed using PubMed, Web of Science, and Cochrane Library to October 30, 2015. Pooled incidence rate and OR with 95% CI were calculated using STATA 11.0. Results. Thirty-nine studies were included. The pooled incidence rate of CCA patients with HBV infection was 31% (95% CI 22%–39%). The pooled OR showed increased risk of CCA incidence with HBV infection (OR = 2.72, 95% CI 1.90–3.88), especially in ICC (OR = 3.184, 95% CI 2.356–4.302), while it showed no risk in ECC (OR = 1.407, 95% CI 0.925–2.141). Also, the pooled OR showed increased risk of ICC and ECC incidence (OR = 6.857, 95% CI 4.421–10.633 and OR = 1.740, 95% CI 1.260–2.404) in patients with HBsAg+/HBcAb+. The pooled OR showed increased risk of ICC incidence (OR = 1.410, 95% CI 1.095–1.816) in patients with HBsAg−/HBcAb+. Conclusion. It is suggested that HBV infection is associated with an increased risk of CCA in Asia. Two HBV infection models (HBsAg+/HBcAb+ and HBsAg−/HBcAb+) increase the risk of CCA, and patients with HBsAg−/HBcAb+ also had a risk of ICC. This trial is registered with PROSPERO CRD42015029264.

Distinct subpopulations of hepatitis C virus infectious cells with different levels of intracellular hepatitis C virus core protein

Chronic infection by hepatitis C virus (HCV) is a major risk factor for the development of hepatocellular carcinoma (HCC). Despite the clear clinical importance of virus-associated HCC, the underlying molecular mechanisms remain largely unclarified. Oxidative stress, in particular, DNA lesions associated with oxidative damage, plays a major role in carcinogenesis, and is strongly linked to the development of many cancers, including HCC. However, in identifying hepatocytes with HCV viral RNA, estimates of the median proportion of HCV-infected hepatocytes have been found as high as 40% in patients with chronic HCV infection. In order to explore the gene alternation and association between different viral loads of HCV-infected cells, we established a method to dissect high and low viral load cells and examined the expression of DNA damage-related genes using a quantitative polymerase chain reaction array. We found distinct expression patterns of DNA damage-related genes between high and low viral load cells. This study provides a new method for future study on virus-associated gene expression research.

Inflammation-Related DNA Damage and Cancer Stem Cell Markers in Nasopharyngeal Carcinoma

Nitrative and oxidative DNA damage plays an important role in inflammation-related carcinogenesis. To investigate the involvement of stem cells in Epstein-Barr virus infection-related nasopharyngeal carcinoma (NPC), we used double immunofluorescence staining to examine several cancer stem/progenitor cell markers (CD44v6, CD24, and ALDH1A1) in NPC tissues and NPC cell lines. We also measured 8-nitroguanine formation as an indicator of inflammation-related DNA lesions. The staining intensity of 8-nitroguanine was significantly higher in cancer cells and inflammatory cells in the stroma of NPC tissues than in chronic nasopharyngitis tissues. Expression levels of CD44v6 and ALDH1A1 were significantly increased in cancer cells of primary NPC specimens in comparison to chronic nasopharyngitis tissues. Similarly, more intense staining of CD44v6 and ALDH1A1 was detected in an NPC cell line than in an immortalized nasopharyngeal epithelial cell line. In the case of CD24 staining, there was no significant difference between NPC and chronic nasopharyngitis tissues. 8-Nitroguanine was detected in both CD44v6- and ALDH1A1-positive stem cells in NPC tissues. In conclusion, CD44v6 and ALDH1A1 are candidate stem cell markers for NPC, and the increased formation of DNA lesions by inflammation may result in the mutation of stem cells, leading to tumor development in NPC.

The inhibition of Akt-Pdpk1 interaction efficiently suppresses the growth of murine primary liver tumor cells

The lack of primary liver tumor cells has hampered testing of potential chemotherapeutic agents in vitro. To overcome this issue we developed a primary mouse liver tumor cell line K07074. The K07074 cells were immortal, exhibited a biliary phenotype, formed colonies in soft agar and displayed an increase in Hedgehog, Notch and Akt signaling. To study the effect of single and combined inhibition of the liver tumor-related pathways on the growth of K07074 cells we treated these with small-molecule antitumor agents. While the inhibition of Akt and Notch pathways strongly inhibited the growth of K07074 cells the inhibition of Wnt and Hedgehog pathways was less efficient in cell growth suppression. Interestingly, the inhibition of Akt pathway at the level of Akt-Pdpk1 interaction was sufficient to suppress the growth of tumor cells and no significant additive effect could be detected when co-treated with the inhibitors of Wnt, Hedgehog or Notch pathways. Only when suboptimal doses of Akt-Pdpk1 interaction inhibitor NSC156529 were used an additive effect with Notch inhibition was seen. We conclude that the Akt pathway inhibitor NSC156529 is potentially useful as single treatment for liver tumors with hyperactivated Akt signaling.

Human ductal plate and its derivatives express antigens of cholangiocellular, hepatocellular, hepatic stellate/progenitor cell, stem cell, and neuroendocrine lineages, and proliferative antigens

Molecular mechanisms of human ductal plate (DP) development and differentiation (DD) are unclear. The author immunohistochemically investigated expressions of cholangiocellular antigens (CEA, CA19-9, EMA, MUC1, MUC2, MUC5AC, MUC6, mucins, CK7, and CK19), hepatocellular antigens (HepPar1, AFP, CK8, and CK18), hepatic stellate/progenitor cell (HSC) antigens or stem cell (SC) antigens (C-erbB2, CD56, chromogranin, synaptophysin, bcl2, NSE, NCAM, KIT, and PDGFRA), and proliferating antigen (Ki67) in 32 human fetal livers (HFL). The DD of human intrahepatic bile duct (IBD) could be categorized into four stages: DP, remodeling DP, remodeled DP, and immature IBD. All the molecules examined were expressed in the DP and DP derivatives. These results suggest that human DP or DP derivatives have capacities to differentiate into cholangiocellular, hepatocellular, HSC, SC, and neuroendocrine lineages. The data also suggest that NCAM, KIT/SC factor-signaling, NSE, HGF/MET signaling, PDGFa/PDGFRA signaling, chromogranin, synaptophysin, and CD56 play important roles in DD of DP and biliary cells of HFL. DP, DP derivatives, and IBD in HFL have proliferative capacity.

Hepatitis B viral infection of hepatic progenitor cells. Resolving unresolved questions?

Accumulated data to date do not entirely explain the; propensity of the hepatitis B virus (HBV) to cause chronic infections in newborns; failure of antiviral agents to resolve infections or precise mechanism whereby HBV causes hepatocellular carcinoma (HCC). Based on the increased numbers of hepatic stem/progenitor cells (HPCs) present within the neonatal liver, the refractoriness of these cells to the effects of interferons and xenobiotics and their ability to undergo malignant transformation, we hypothesize that HBV infection of HPCs could explain these and perhaps other clinical features of chronic HBV.

Multiple cellular origins and molecular evolution of intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (ICC) is an aggressive malignancy associated with unfavorable prognosis and for which no effective treatments are available. Its molecular pathogenesis is poorly understood. Genome-wide sequencing and high-throughput technologies have provided critical insights into the molecular basis of ICC while sparking a heated debate on the cellular origin. Cancer exhibits variabilities in origin, progression and cell biology. Recent evidence suggests that ICC has multiple cellular origins, including differentiated hepatocytes; intrahepatic biliary epithelial cells (IBECs)/cholangiocytes; pluripotent stem cells, such as hepatic stem/progenitor cells (HPCs) and biliary tree stem/progenitor cells (BTSCs); and peribiliary gland (PBG). However, both somatic mutagenesis and epigenomic features are highly cell type-specific. Multiple cellular origins may have profoundly different genomic landscapes and key signaling pathways, driving phenotypic variation and thereby posing significant challenges to personalized medicine in terms of achieving the optimal drug response and patient outcome. Considering this information, we have summarized the latest experimental evidence and relevant literature to provide an up-to-date view of the cellular origin of ICC, which will contribute to establishment of a hierarchical model of carcinogenesis and allow for improvement of the anatomical-based classification of ICC. These new insights have important implications for both the diagnosis and treatment of ICC patients.

The role of IL-17 signaling in regulation of the liver-brain axis and intestinal permeability in Alcoholic Liver Disease

Alcoholic liver disease (ALD) progresses from a normal liver, to steatosis, steatohepatitis, fibrosis and hepatocellular carcinoma (HCC). Despite intensive studies, the pathogenesis of ALD is poorly understood, in part due to a lack of suitable animal models which mimic the stages of ALD progression. Furthermore, the role of IL-17 in ALD has not been evaluated. We and others have recently demonstrated that IL-17 signaling plays a critical role in development of liver fibrosis and cancer. Here we summarize the most recent evidence supporting the role of IL-17 in ALD. As a result of a collaborative effort of Drs. Karin, Gao, Tsukamoto and Kisseleva, we developed several improved models of ALD in mice: 1) chronic-plus-binge model that mimics early stages of steatohepatitis, 2) intragastric ethanol feeding model that mimics alcoholic steatohepatitis and fibrosis, and 3) diethylnitrosamine (DEN)+alcohol model that mimics alcoholic liver cancer. These models might provide new insights into the mechanism of IL-17 signaling in ALD and help identify novel therapeutic targets.

Metformin prevents hepatocellular carcinoma development by suppressing hepatic progenitor cell activation in a rat model of cirrhosis

BACKGROUND

Hepatocellular carcinoma (HCC)-associated mortality is increasing at an alarming rate, and there is a readily identifiable cohort of at-risk patients with cirrhosis, viral hepatitis, nonalcoholic fatty liver disease, and diabetes. These patients are candidates for chemoprevention. Metformin is an attractive agent for chemoprevention because it is inexpensive, has a favorable safety profile, and is well tolerated over long time periods.

METHODS

The authors studied the efficacy of metformin as a prevention agent in a clinically relevant rat model of HCC, in which tumors develop in the setting of chronic inflammation and cirrhosis. Repeated injections of diethylnitrosamine were used to induce sequential cirrhosis and HCC, and metformin was administered at the first signs of either fibrosis or cirrhosis.

RESULTS

Prolonged metformin exposure was safe and was associated with decreases in fibrotic and inflammatory markers, especially when administered early at the first signs of fibrosis. In addition, early metformin treatment led to a 44% decrease in HCC incidence, whereas tumor burden was unchanged when metformin was administered at the first signs of cirrhosis. It is noteworthy that activation of the hepatic progenitor/stem cell compartment was first observed at the onset of cirrhosis; therefore, only early metformin treatment suppressed receptor for advanced glycation end products and inhibited the activation of hepatic progenitor cells.

CONCLUSIONS

The current results are the first to demonstrate an effect on progenitor/stem cells in the setting of chemoprevention and provide further rationale to explore metformin as an early intervention in clinical trials of patients with chronic liver disease at high risk for HCC.

Postresection Outcomes of Combined Hepatocellular Carcinoma-Cholangiocarcinoma, Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma

INTRODUCTION

Combined hepatocellular carcinoma and cholangiocarcinoma (cHCC-CC) is rare. This study investigated the clinicopathological features of cHCC-CC and compared the postresection survival outcomes of cHCC-CC, hepatocellular carcinoma (HCC), and intrahepatic cholangiocarcinoma (IHC).

METHODS

Between January 2000 and September 2012, 53 patients with cHCC-CC underwent tumor resection, accounting for 1.1 % of surgeries for primary liver malignancies. Control groups included patients with HCC (n = 1452) and IHC (n = 149) who underwent R0 resection of stage I/II tumors ≤5 cm.

RESULTS

Mean tumor diameter of cHCC-CC group was 5.5 ± 2.9 cm, and single tumor was identified in 50. Pathological classification included combined (n = 41), mixed (n = 11), and double (n = 1) tumors. The 1-, 3-, 5-, and 10-year tumor recurrence rates were 60.8, 71.8, 80.7, and 80.7 %, respectively. The 1-, 3-, 5-, and 10-year overall survival rates were 73.3, 35.6, 30.5, and 11.1 %, respectively. Tumor recurrence and patient survival did not differ significantly according to AJCC tumor staging and histological type (all p ≥ 0.2). Tumor recurrence rates did not differ significantly between the cHCC-CC, HCC, and IHC groups (p = 0.43), whereas differences in survival rates were significant (p = 0.000), with a median survival after tumor recurrence of 8, 51, and 6 months, respectively (p = 0.000).

CONCLUSIONS

Patients with cHCC-CC showed similar recurrence rates to those of control patients with HCC and IHC, whereas their survival outcomes were worse than those of control HCC patients because of poor responses to recurrence treatment. Further evaluation of differences in tumor characteristics and tumor biology is necessary to accurately predict the prognosis of patients with cHCC-CC.

Urotensin-II-Mediated Reactive Oxygen Species Generation via NADPH Oxidase Pathway Contributes to Hepatic Oval Cell Proliferation

Urotensin II (UII), a somatostatin-like cyclic peptide, is involved in tumor progression due to its mitogenic effect. Our previous study demonstrated that UII and its receptor UT were up-regulated in human hepatocellular carcinoma (HCC), and exogenous UII promoted proliferation of human hepatoma cell line BEL-7402. Hepatic progenitor cell (HPCs) are considered to be one of the origins of liver cancer cells, but their relationship with UII remains unclear. In this work, we aimed to investigate the effect of UII on ROS generation in HPCs and the mechanisms of UII-induced ROS in promoting cell proliferation. Human HCC samples were used to examine ROS level and expression of NADPH oxidase. Hepatic oval cell line WB-F344 was utilized to investigate the underlying mechanisms. ROS level was detected by dihydroethidium (DHE) or 2’, 7’-dichlorofluorescein diacetate (DCF-DA) fluorescent probe. For HCC samples, ROS level and expression of NADPH oxidase were significantly up-regulated. In vitro, UII also increased ROS generation and expression of NADPH oxidase in WB-F344 cells. NADPH oxidase inhibitor apocynin pretreatment partially abolished UII-increased phosphorylation of PI3K/Akt and ERK, expression of cyclin E/cyclin-dependent kinase 2. Cell cycle was then analyzed by flow cytometry and UII-elevated S phase proportion was inhibited by apocynin pretreatment. Finally, bromodeoxyuridine (Brdu) incorporation assay showed that apocynin partially abolished UII induced cell proliferation. In conclusion, this study indicates that UII-increased ROS production via the NADPH oxidase pathway is partially associated with activation of the PI3K/Akt and ERK cascades, accelerates G1/S transition, and contributes to cell proliferation. These results showed that UII plays an important role in growth of HPCs, which provides novel evidence for the involvement of HPCs in the formation and pathogenesis of HCC.

How do persistent infections with hepatitis C virus cause liver cancer?

Persistent infection with hepatitis C virus (HCV) is associated with an increased risk of hepatocellular carcinoma (HCC). Cancer typically develops in a setting of chronic hepatic inflammation and advanced fibrosis or cirrhosis, and such tissue represents a pre-neoplastic 'cancer field'. However, not all persistent infections progress to HCC and a combination of viral and host immune factors likely contributes to carcinogenesis. HCV may disrupt cellular pathways involved in detecting and responding to DNA damage, potentially adding to the risk of cancer. Efforts to unravel how HCV promotes HCC are hindered by lack of a robust small animal model, but a better understanding of molecular mechanisms could identify novel biomarkers for early detection and allow for development of improved therapies.

The multiple origin of cancer stem cells in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) accounts for approximately 6% of all new cancer cases diagnosed, and due to its aggressiveness, it is the second most common cause of cancer mortality worldwide. Based on different etiological factors, genetic backgrounds, and longtime development of the disease, HCC is characterized by a high phenotypic and functional heterogeneity. Tumor variability occurs both among patients (intertumoral heterogeneity) and within a single tumor (intratumoral heterogeneity). The intratumoral heterogeneity, in particular the variability of the markers of cancer stem cells (CSC) population may determine specific behavior and prognosis of the tumor. Understanding the cellular mechanisms originating CSC will provide an important hint in the management of HCC. The characterization of the cells of origin of cancer can have significant implication in early diagnosis, in the development of appropriate therapies and in the prevention of relapse. Here, we review recent evidences on the possible cellular origin of CSC that play a role in the heterogeneity of the HCC.

MicroRNAs Enhance Keratinocyte Proliferative Capacity in a Stem Cell-Enriched Epithelium

MicroRNAs are critical regulators of stem cell behavior. The miR-103/107 family is preferentially expressed in the stem cell-enriched corneal limbal epithelium and plays an important role in coordinating several intrinsic characteristics of limbal epithelial stem cells. To elucidate further the mechanisms by which miRs-103/107 function in regulating limbal epithelial stem cells, we investigate the global effects of miRs-103/107 on gene expression in an unbiased manner. Using antagomirs-103/107, we knocked down endogenous miRs-103/107 in keratinocytes and conducted an mRNA profiling study. We show that miRs-103/107 target mitogen-activated protein kinase kinase kinase 7 (MAP3K7) and thereby negatively regulate the p38/AP-1 pathway, which directs epithelial cells towards a differentiated state. Pharmacological inhibition of p38 increases holoclone colony formation, a measure of proliferative capacity. This suggests that the negative regulation of p38 by miRs-103/107 contributes to enhanced proliferative capacity, which is a hallmark of stem cells. Since miRs-103/107 also promote increased holoclone colony formation by regulating JNK activation through non-canonical Wnt signaling, we believe that this microRNA family preserves “stemness” by mediating the crosstalk between the Wnt/JNK and MAP3K7/p38/AP-1 pathways.

The adverse outcome pathway for rodent liver tumor promotion by sustained activation of the aryl hydrocarbon receptor

An Adverse Outcome Pathway (AOP) represents the existing knowledge of a biological pathway leading from initial molecular interactions of a toxicant and progressing through a series of key events (KEs), culminating with an apical adverse outcome (AO) that has to be of regulatory relevance. An AOP based on the mode of action (MOA) of rodent liver tumor promotion by dioxin-like compounds (DLCs) has been developed and the weight of evidence (WoE) of key event relationships (KERs) evaluated using evolved Bradford Hill considerations. Dioxins and DLCs are potent aryl hydrocarbon receptor (AHR) ligands that cause a range of species-specific adverse outcomes. The occurrence of KEs is necessary for inducing downstream biological responses and KEs may occur at the molecular, cellular, tissue and organ levels. The common convention is that an AOP begins with the toxicant interaction with a biological response element; for this AOP, this initial event is binding of a DLC ligand to the AHR. Data from mechanistic studies, lifetime bioassays and approximately thirty initiation-promotion studies have established dioxin and DLCs as rat liver tumor promoters. Such studies clearly show that sustained AHR activation, weeks or months in duration, is necessary to induce rodent liver tumor promotion--hence, sustained AHR activation is deemed the molecular initiating event (MIE). After this MIE, subsequent KEs are 1) changes in cellular growth homeostasis likely associated with expression changes in a number of genes and observed as development of hepatic foci and decreases in apoptosis within foci; 2) extensive liver toxicity observed as the constellation of effects called toxic hepatopathy; 3) cellular proliferation and hyperplasia in several hepatic cell types. This progression of KEs culminates in the AO, the development of hepatocellular adenomas and carcinomas and cholangiolar carcinomas. A rich data set provides both qualitative and quantitative knowledge of the progression of this AOP through KEs and the KERs. Thus, the WoE for this AOP is judged to be strong. Species-specific effects of dioxins and DLCs are well known--humans are less responsive than rodents and rodent species differ in sensitivity between strains. Consequently, application of this AOP to evaluate potential human health risks must take these differences into account.

Chemokines and their receptors play important roles in the development of hepatocellular carcinoma

The chemokine system consists of four different subclasses with over 50 chemokines and 19 receptors. Their functions in the immune system have been well elucidated and research during the last decades unveils their new roles in hepatocellular carcinoma (HCC). The chemokines and their receptors in the microenvironment influence the development of HCC by several aspects including: inflammation, effects on immune cells, angiogenesis, and direct effects on HCC cells. Regarding these aspects, pre-clinical research by targeting the chemokine system has yielded promising data, and these findings bring us new clues in the chemokine-based therapies for HCC.

Metastatic hepatocellular carcinoma in the maxilla and mandible, an extremely rare presentation

Malignancy is characterized by anaplasia, invasiveness, and metastasis. Primary oral squamous cell carcinoma is the most prevalent oral malignancy, but secondary malignancy from distant sites have also been reported. Hepatocellular carcinoma (HCC) is a common primary liver malignancy that frequently metastasizes during the course of the disease, but < 1% of cases show oral involvement. Such secondary neoplasms do not have any pathognomonic clinical or radiologic findings, and therefore they pose a diagnostic challenge. Hence, in the differential diagnosis of malignant tumors of the oral cavity, it is essential to consider the occurrence of both primary as well as metastatic tumors despite the low incidence of the latter. A rare case of HCC metastasizing to both the maxilla and mandible is presented, in which the patient succumbed to the disease as a result of the delay in diagnosis.

TLR4-dependent tumor-initiating stem cell-like cells (TICs) in alcohol-associated hepatocellular carcinogenesis

Alcohol abuse predisposes individuals to the development of hepatocellular carcinoma (HCC) and synergistically heightens the HCC risk in patients infected with hepatitis C virus (HCV). The mechanisms of this synergism have been elusive until our recent demonstration of the obligatory role of ectopically expressed TLR4 in liver tumorigenesis in alcohol-fed HCV Ns5a or Core transgenic mice. CD133+/CD49f+ tumor-initiating stem cell-like cells (TICs) isolated from these models are tumorigenic in a manner dependent on TLR4 and NANOG. TICs' tumor-initiating activity and chemoresistance are causally associated with inhibition of TGF-β tumor suppressor pathway due to NANOG-mediated expression of IGF2BP3 and YAP1. TLR4/NANOG activation causes p53 degradation via phosphorylation of the protective protein NUMB and its dissociation from p53 by the oncoprotein TBC1D15. Nutrient deprivation reduces overexpressed TBC1D15 in TICs via autophagy-mediated degradation, suggesting a possible role of this oncoprotein in linking metabolic reprogramming and self-renewal.

Oxidative stress and its significant roles in neurodegenerative diseases and cancer

Reactive oxygen and nitrogen species have been implicated in diverse pathophysiological conditions, including inflammation, neurodegenerative diseases and cancer. Accumulating evidence indicates that oxidative damage to biomolecules including lipids, proteins and DNA, contributes to these diseases. Previous studies suggest roles of lipid peroxidation and oxysterols in the development of neurodegenerative diseases and inflammation-related cancer. Our recent studies identifying and characterizing carbonylated proteins reveal oxidative damage to heat shock proteins in neurodegenerative disease models and inflammation-related cancer, suggesting dysfunction in their antioxidative properties. In neurodegenerative diseases, DNA damage may not only play a role in the induction of apoptosis, but also may inhibit cellular division via telomere shortening. Immunohistochemical analyses showed co-localization of oxidative/nitrative DNA lesions and stemness markers in the cells of inflammation-related cancers. Here, we review oxidative stress and its significant roles in neurodegenerative diseases and cancer.