Establishment of cancer cell lines from rat hepatocholangiocarcinoma and assessment of the role of granulocyte-colony stimulating factor and hepatocyte growth factor in their growth, motility and survival

Participation of liver stem cells in cholangiocarcinogenesis after aflatoxin B1 exposure of glutathione S-transferase A3 knockout mice

Aflatoxin B1, arguably the most potent human carcinogen, induces liver cancer in humans, rats, trout, ducks, and so on, but adult mice are totally resistant. This resistance is because of a detoxifying enzyme, mouse glutathione S-transferase A3, which binds to and inactivates aflatoxin B1 epoxide, preventing the epoxide from binding to DNA and causing mutations. Glutathione S-transferase A3 or its analog has not been detected in any of the sensitive species, including humans. The generation of a glutathione S-transferase A3 knockout (represented as KO or -/-) mice has allowed us to study the induction of liver cancer in mice by aflatoxin B1. In contrast to the induction of hepatocellular carcinomas in other species, aflatoxin B1 induces cholangiocarcinomas in GSTA3-/- mice. In other species and in knockout mice, the induction of liver cancer is preceded by extensive proliferation of small oval cells, providing additional evidence that oval cells are bipolar stem cells and may give rise to either hepatocellular carcinoma or cholangiocarcinoma depending on the nature of the hepatocarcinogen and the species of animal. The recent development of mouse oval cell lines in our laboratory from aflatoxin B1-treated GSTA3-/- mice should provide a new venue for study of the properties and potential of putative mouse liver stem cells.

Gemcitabine plus platinum-based chemotherapy for first-line treatment of hepatocholangiocarcinoma: an AGEO French multicentre retrospective study

Background:

Hepatocholangiocarcinoma (cHCC-ICC) is a rare liver tumour for which no data on chemosensitivity exist. The aims of this multicentre study were to evaluate overall survival (OS), progression-free survival (PFS), and prognostic factors in cHCC-ICC treated by gemcitabine plus platinum as first-line.

Methods:

Unresectable cHCC-ICC treated by gemcitabine plus platinum-based chemotherapy between 2008 and 2017 were retrospectively analysed. Diagnosis was based on histology or, in case of ICC or HCC histology, on discordant computerised tomography scan enhancement patterns associated with discordant serum tumour marker elevation suggesting the alternative tumour. OS and PFS were evaluated by Kaplan–Meier method and prognostic factors by Log-rank test and Cox model.

Results:

Among 30 patients included, cHCC-ICC was histologically proven in 22 (73.3%). 18 (60%) received gemcitabine plus oxaliplatin (GEMOX), 9 (30%) GEMOX plus bevacizumab, and 3 (10%) gemcitabine plus cisplatin. RECIST criteria were reported in 28 patients: 8 (28.6%) showed partial response, 14 (50%) stable disease, and 6 (21.4%) tumour progression at first evaluation. Median PFS and OS were 9.0 and 16.2 months, respectively. Serum bilirubin ⩾30 μmol l⁻¹ (P=0.001) and positive serology for HBV and/or HCV (P=0.014) were independent poor prognostic factors for OS.

Conclusions:

Gemcitabine plus platinum-based chemotherapy is effective as first-line for advanced cHCC-ICC.

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.

Retinal and vitreous metastases from hepatocholangiocarcinoma

Background

To report a case of metastatic hepatocholangiocarcinoma to the vitreous and retina.

Case presentation

A 70-year-old male, who was recently diagnosed with hepatocholangiocarcinoma, was complaining of floaters in his right eye over the past 5 months and was referred to the Liverpool Ocular Oncology Centre. On presentation, his visual acuity in the right eye was 6/24. Fundus exam revealed a whitish, unilateral, full-thickness retinal lesion at the inferotemporal arcade of his right eye, with vitreous infiltration and subretinal fluid. The patient underwent 25G pars plana vitrectomy with biopsy, resection of the lesion and intravitreal bevacizumab injection. Histopathology testing of the surgical specimens confirmed the diagnosis of metastatic carcinoma to the eye. Two months postoperatively his visual acuity had improved to 6/7.5 and there was no sign of active disease in his right eye, while 9 months postoperatively his visual acuity decreased to 6/9.5 due to developing nuclear sclerotic cataract in his right eye.

Conclusion

The current report presents the first case of a hepatocholangiocarcinoma metastasis to the vitreous and retina.

Characterization of an Oncolytic Adenovirus Vector Constructed to Target the cMet Receptor

The cMet receptor is a homodimer with tyrosine kinase activity. Upon stimulation with its ligand, hepatocyte growth factor (HGF), the receptor mediates wide physiologic actions. The HGF-cMet signaling pathway is dysregulated in many cancers, which makes cMet an important target for novel therapeutic interventions. Oncolytic adenoviruses (Ads) have been used for the past three decades as a promising therapeutic approach for a wide array of neoplastic diseases. To date, achieving cancer-specific replication of oncolytic Ads has been accomplished by either viral genome deletions or by incorporating tumor selective promoters. To achieve novel specificity of oncolytic Ad infection of cancer cells that overexpress cMet, we inserted the HGF NK2 sequence, corresponding to a competitive antagonist of HGF binding to the cMet receptor, into the Ad serotype 5 (Ad5) fiber gene. The resulting vector, Ad5-pIX-RFP-FF/NK2, was rescued, amplified in HEK293 cells, and characterized. Binding specificity and viral infectivity were tested in various cancer cell lines that express varying levels of cMet and hCAR (the Ad5 receptor). We found that Ad5-pIX-RFP-FF/NK2 demonstrated binding specificity to the cMet receptor. In addition, there was enhanced viral infectivity and virus replication compared with a non-targeted Ad vector. Although NK2 weakly induces cMet receptor activation, our results showed no receptor phosphorylation in the context of an oncolytic Ad virus. In summary, these results suggest that an oncolytic Ad retargeted to the cMet receptor is a promising vector for developing a novel cancer therapeutic agent.

The multikinase inhibitor Sorafenib enhances glycolysis and synergizes with glycolysis blockade for cancer cell killing

Although the only effective drug against primary hepatocarcinoma, the multikinase inhibitor Sorafenib (SFB) usually fails to eradicate liver cancer. Since SFB targets mitochondria, cell metabolic reprogramming may underlie intrinsic tumor resistance. To characterize cancer cell metabolic response to SFB, we measured oxygen consumption, generation of reactive oxygen species (ROS) and ATP content in rat LCSC (Liver Cancer Stem Cells) -2 cells exposed to the drug. Genome wide analysis of gene expression was performed by Affymetrix technology. SFB cytotoxicity was evaluated by multiple assays in the presence or absence of metabolic inhibitors, or in cells genetically depleted of mitochondria. We found that low concentrations (2.5-5 μM) of SFB had a relatively modest effect on LCSC-2 or 293 T cell growth, but damaged mitochondria and increased intracellular ROS. Gene expression profiling of SFB-treated cells was consistent with a shift toward aerobic glycolysis and, accordingly, SFB cytotoxicity was dramatically increased by glucose withdrawal or the glycolytic inhibitor 2-DG. Under metabolic stress, activation of the AMP dependent Protein Kinase (AMPK), but not ROS blockade, protected cells from death. We conclude that mitochondrial damage and ROS drive cell killing by SFB, while glycolytic cell reprogramming may represent a resistance strategy potentially targetable by combination therapies.

Isolation of EpCAM(+)/CD133 (-) hepatic progenitor cells

Progenitor cell-derived hepatocytes are critical for hepatocyte replenishment. Therefore, we established a line of human hepatic progenitor (HNK1) cells and determined their biological characteristics for experimental and therapeutic applications. HNK1 cells, isolated from human noncirrhotic liver samples with septal fibrosis, showed high expression of the hepatic progenitor cell (HPC) markers EpCAM, CK7, CK19, alpha-fetoprotein (AFP), CD90 (Thy1), and EFNA1. Expression of CD133 was very low. Ductular reactions at the periphery of cirrhotic nodules were immunohistochemically positive for these HPC markers, including EFNA1. Sodium butyrate, a differentiation inducer, induced hepatocyte-like morphological changes in HNK1 cells. It resulted in down-regulation of the hepatic progenitor cell markers EpCAM, CK7, CK19, AFP, and EFNA1 and up-regulation of mature hepatocyte markers, including albumin, CK8, and CK18. Furthermore, sodium butyrate treatment and a serial passage of HNK1 cells resulted in enhanced albumin secretion, ureagenesis, and CYP enzyme activity, all of which are indicators of differentiation in hepatocytes. However, HNK1 cells at passage 50 did not exhibit anchorage-independent growth capability and caused no tumors in immunodeficient mice, suggesting that they had no spontaneous malignant transformation ability. From this evidence, HNK1 cells were found to be EpCAM(+)/CD133(-) hepatic progenitor cells without spontaneous malignant transformation ability. We therefore conclude that HNK1 cells could be useful for experimental and therapeutic applications.

Tumor microenvironment: a main actor in the metastasis process

Over recent decades, various studies have argued that the metastatic tissue microenvironment is fully controlled by the intrinsic properties of the cancer cells (growth, motility and invasion, angiogenesis, extracellular matrix remodeling, immune escape) and additional cells types. Overall, the extrinsic factors and determinants mediate the contribution of the host microenvironment to metastasis formation. The tumor microenvironment carries out these functions by secretion of molecules that can influence and modulate its phenotype, making these complex interactions the basis for support for the progression of a cancer. Here, we undertake a summary of the "state of the art" of the functions and actions of these cells, as the main actors in the promotion of the formation of the microenvironment of the metastatic niche, and the associated network of interactions. The unraveling of the relationships between tumorigenic cells and their microenvironment represents an important issue for the development of new therapeutic agents that can fight both initiation and recurrence of cancer.

Heterozygosity for the alpha1-antitrypsin Z allele may confer genetic risk of cholangiocarcinoma

BACKGROUND

Alpha1-antitrypsin (α1AT) deficiency caused by Z allele homozygosity represents a well-established risk factor for hepatocellular carcinoma. Previous studies have also implicated α1AT Z heterozygosity in cholangiocarcinogenesis.

AIM

To assess the 'common' Z and S alleles as well as the promoter variant rs8004738 for association with cholangiocarcinoma.

METHODS

We genotyped 182 Caucasian patients and 350 controls for rs28929474 (Z), rs17580 (S) and the variant rs8004738. Exploratory analyses were performed in relation to gender and cholangiocarcinoma localisation.

RESULTS

rs28929474 was significantly enriched in the cholangiocarcinoma group (4.1 vs. 1.7%; OR 2.46, 95% CI 1.14-5.32; Bonferroni corrected p(c) = 0.036), reinforced by Armitage trend testing (OR 2.53; p(c) = 0.032). The rs8004738 (promoter) minor allele tended to be overrepresented in Z heterozygotes (30.0 vs. 16.7%: P = 0.13). Exploratory data analyses suggested a high genetic risk for extrahepatic tumour localisation (OR 3.0; p(c) = 0.016) and potentially female Z allele carriers (OR 3.37; unadjusted P = 0.022, p(c) = 0.088).

CONCLUSIONS

These data point to a novel role of α1AT Z heterozygosity as a potential genetic susceptibility factor for cholangiocarcinoma formation and suggest a contribution of aberrant α1AT function in biliary carcinogenesis. However, given the overall low rs28929474 minor allele frequency, larger studies are warranted to confirm and extend our findings.

Primary isolated hepatic oval cells maintain progenitor cell phenotypes after two-year prolonged cultivation

BACKGROUND & AIMS

Although expandable hepatic progenitors provide renewable cell sources for treatment of hepatic disorders, long-term cultivation of hepatic progenitors may affect proliferation and differentiation abilities, and even initiate the formation of malignant cancer stem cells. This study aims to determine characteristics of primary cultured hepatic oval cells after prolonged cultivation in vitro.

METHODS

Hepatic oval cells isolated from rats fed with a choline-deficient, ethionine-supplemented diet were continuously propagated every 5-7 days, to 100 passages over two years. Hepatocytic differentiation was induced by sodium butyrate and characterized using western blot, periodic acid Schiff assays, albumin secretion and urea production. Proliferation capacity was evaluated using growth-curve and cell-cycle analysis; anchorage-independent growth and tumorigenicity were determined using soft agar and xenograft assay.

RESULTS

After 2 years of serial passages, hepatic oval cells with typical epithelial morphology continuously expressed OV-6, BD-1, BD-2, and Dlk as markers for hepatic progenitors, cytokeratin 19 as a cholangiocyte marker, and alpha-fetoprotein and albumin as hepatocyte markers. Furthermore, sodium butyrate could induce these cells to become glycogen-storage cells with the functions of albumin secretion and ureagenesis from ammonia clearance, indicating hepatocytic differentiation. Although proliferation slightly accelerated after the 50th passage, hepatic oval cells stayed diploid cells with features of chromosomal stability, which did not acquire anchorage-independent growth capacity and caused no tumor in immunodeficient mice, suggesting no spontaneous malignant transformation.

CONCLUSIONS

Hepatic oval cells retain the progenitor cell features without spontaneous malignant transformation after prolonged cultivation, and thus may serve as an expandable cell source for future exploitation of stem cell technology.

An update on cholangiocarcinoma associated with primary sclerosing cholangitis

PURPOSE OF REVIEW

Primary sclerosing cholangitis (PSC) is being diagnosed with increasing frequency. The most feared complication is the presence or development of cholangiocarcinoma (CCA). The present review summarizes recent data with regards to diagnosis, pathobiology and treatment.

RECENT FINDINGS

Several investigations have focused on aspects of the molecular biology of CCA in general; such data should be explored now in the context of PSC-related CCA to yield new diagnostic markers and approaches for therapy.

SUMMARY

CCA has to be suspected in any new PSC patient presenting with jaundice. Exploration should include carbohydrate antigen19-9 and two imaging techniques. Endoscopic cholangioscopy might become very rewarding. Important progress has been achieved in liver transplantation by the use of preoperative radio-chemotherapy. Molecular biology points to inflammation-induced cytokines with mutagenic action and to the relevance of extracellular matrix proteins for invasion but also for proliferation. Micro-RNAs prove to be very important in the control of cell proliferation, differentiation and apoptosis. Mutated p53, cyclins, wnt/beta-catenin signaling, proliferation indices, mucins, carbohydrate antigen19-9, CRP and aneuploidy appear to hold significant potential as predictors of outcome in CCA. It is expected that the further unraveling of these molecular processes will ultimately lead to development of tests allowing early diagnosis and to development of medical approaches to retard tumor formation or recurrence following surgical interventions.

Lung metastasis fails in MMTV-PyMT oncomice lacking S100A4 due to a T-cell deficiency in primary tumors

Interactions between tumor and stroma cells are essential for the progression of cancer from its initial growth at a primary site to its metastasis to distant organs. The metastasis-stimulating protein S100A4 exerts its function as a stroma cell-derived factor. Genetic depletion of S100A4 significantly reduced the metastatic burden in lungs of PyMT-induced mammary tumors. In S100A4(+/+) PyMT mice, massive leukocyte infiltration at the site of the growing tumor at the stage of malignant transition was associated with increased concentration of extracellular S100A4 in the tumor microenvironment. In contrast, in S100A4(-/-) PyMT tumors, a significant suppression of T-cell infiltration was documented at the transition period. In vitro, the S100A4 protein mediated the attraction of T cells. Moreover, S100A4(+/+), but not S100A4(-/-), fibroblasts stimulated the invasion of T lymphocytes into fibroblast monolayers. In vivo, the presence of S100A4(+/+), but not S100A4(-/-), fibroblasts significantly stimulated the attraction of T lymphocytes to the site of the growing tumor. Increased levels of T cells were also observed in the premetastatic lungs of tumor-bearing mice primed to metastasize by S100A4(+/+) fibroblasts. Treatment of T cells with the S100A4 protein stimulated production of cytokines, particularly granulocyte colony-stimulating factor and eotaxin-2. The same cytokines were detected in the fluid of S100A4(+/+) PyMT tumors at the transition period. We suggest that release of S100A4 in the primary tumor stimulates infiltration of T cells and activates secretion of cytokines, thus triggering sequential events that fuel tumor cells to metastasize. Similar processes could occur in the premetastatic lungs, facilitating generation of inflammatory milieu favorable for metastasis formation.