Gores, Gregory J.

Abstract BACKGROUND: Epithelial to Mesenchymal Transition (EMT) and Mesenchymal to Epithelial Transition (MET) may participate in pancreatic ductal adenocarcinoma (PDAC) metastasis. CD44 proteins are cell membrane proteins which function as co-receptors regulating many cellular functions. Some reports have shown that isoform switching from CD44 variant form (CD44v) to CD44 standard form (CD44s) takes place during the EMT. (Brown et al., J. Clin. Invest, 2011, Yae et al., Nat Commun., 2012). The AIM of this study was to explore the regulation of CD44 isoform switching in PDAC cells. Methods: The expression levels of CD44v and CD44s in PDAC cell lines were assessed by immunohistochemistry and immunoblot analysis. PDAC cell lines were implanted into immunodeficiency mice and treated with sulfasarazine for 14 days. Sulfasarazine, which inhibits glutamate-cysteine transport, reduces CD44v-dependent cell growth. CD44v or CD44s positive cells were isolated using flow cytometry and induced to undergo the EMT by TGF-β treatment (7.5ng/mL) for 72 hours. A doxycycline inducible system was employed to overexpress Slug, which promotes the EMT phenotype. To induce MET, the cells were released from TGF-β treatment and cultured for an additional 72 hours. E74-like ETS Transcription Factor 3 (ELF3) expression was knocked-down by siRNA transfection. RESULTS: Immunohistochemistry analysis revealed that CD44v protein is expressed specifically by PDAC with ductal structures within the complex tumor environment of these cancers. However, in contrast, CD44v expression was not observed in solitary infiltrating cancer cells. PANC-1, AsPC-1 and SUIT-2 PDAC cell lines expressed both CD44v and CD44s isoforms. Tumor mass in implanted PANC-1, AsPC-1 and SUIT-2 cells were reduced 69%, 50% and 36% respectively by sulfasarazine treatment following 2 weeks of therapy. However, CD44v null HPAC cells were resistant to sulfasarazine therapy following implantation. E-cadherin was expressed in CD44v positive cells but not in CD44s positive cells, and both CD44v and E-cadherin protein were reduced by TGF-β treatment. Slug over expressed cells were resistant to sulfasarazine treatment compared to non-Slug-induced cells. Removal of TGF-β restored both CD44v and E-cadherin expression levels which consistently occurs with MET. However, restoration of CD44v expression was diminished when ELF3 expression was reduced by siRNA transfection. CONCLUSION: The isoform switching between CD44v and CD44s was reversible. The expression of CD44v isoform appears to be controlled by ELF3 during MET. Citation Format: Ayano Kabashima-Niibe, Hiromasa Takaishi, Takanori Kanai, Hideyuki Saya, Gregory J. Gores, Hajime Higuchi. ELF3 modulates mesenchymal to epithelial transition through regulation of CD44 variant isoform expression in pancreatic cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 857. doi:10.1158/1538-7445.AM2017-857

Tumor necrosis factor‐related apoptosis‐inducing ligand (TRAIL) and its cognate receptor(s) are up‐regulated in human and murine nonalcoholic steatohepatitis (NASH); however, the consequence of this enhanced expression on NASH pathogenesis remains unclear. TRAIL may either accentuate liver injury by promoting hepatic steatosis and inflammation or it may mitigate the disease process by improving systemic insulin resistance and averting hepatic fibrosis. Herein, we investigated the role of TRAIL in an obesity‐induced murine model of NASH. C57BL/6 wild‐type mice and Trail –/– mice were placed on a 20‐week standard chow or a high‐fat, high‐fructose, and high‐cholesterol (FFC) diet, which induces obesity, insulin resistance, and NASH. Metabolic phenotype, liver injury, inflammation and fibrosis, and adipose tissue homeostasis were examined. FFC diet‐fed Trail –/– mice displayed no difference in weight gain and metabolic profile when compared to wild‐type mice on the same diet. All FFC‐fed mice developed significant hepatic steatosis, which was attenuated in Trail –/– mice. TRAIL deficiency also significantly decreased FFC diet‐induced liver injury as manifested by reduced serum alanine aminotransferase values, hepatic terminal deoxynucleotidyl transferase‐mediated deoxyuridine triphosphate nick‐end labeling‐positive cells, and macrophage‐associated inflammation. FFC diet‐associated hepatic stellate cell activation and hepatic collagen deposition were also abrogated in Trail –/– mice. In contrast to the liver, TRAIL deletion did not improve FFC diet‐induced adipose tissue injury and inflammation and actually aggravated insulin resistance. Conclusion: NASH pathogenesis may be dissociated from other features of the metabolic syndrome, and liver‐targeted inhibition of TRAIL signaling may be salutary. (Hepatology Communications 2017;1:648–662)

AbstractThe Hippo pathway effector YAP is implicated in the pathogenesis of cholangiocarcinoma (CCA). The Hippo pathway relies on signaling cross talk for its regulation. Given the importance of platelet derived growth factor receptor (PDGFR) signaling in CCA biology, our aim was to examine potential YAP regulation by PDGFR. We employed human and mouse CCA specimens and cell lines for these studies. Initially, we confirmed upregulation of PDGFRβ and PDGFR ligands in human and mouse CCA specimens and cell lines. YAP, a transcriptional co‐activator, was localized to the nucleus in human CCA specimens and a cell line, as well as patient derived xenografts (PDX). PDGFR pharmacologic inhibition led to a redistribution of YAP from the nucleus to cytosol and downregulation of YAP target genes in a human CCA cell line. siRNA silencing of PDGFR‐β similarly downregulated YAP target genes. YAP activation (nuclear localization and target gene expression) was regulated by Src family kinases (SFKs) downstream of PDGFR. SFK activity resulted in phosphorylation of YAP on tyrosine357 (YAPY357). The importance of YAPY357 phosphorylation in regulating YAP activation was confirmed utilizing the SB‐1 cell line, a mouse cell line expressing YAP S127A precluding canonical serine phosphorylation. PDGFR inhibition decreased cellular abundance of the survival protein Mcl‐1, a known YAP target gene, and accordingly increased cell death in CCA cells in vitro and in vivo. These preclinical data demonstrate that a PDGFR‐SFK cascade regulates YAP activation via tyrosine phosphorylation in CCA. Inhibiting this cascade may provide a viable therapeutic strategy for this human malignancy.

AbstractThe epidemiology of infection after liver transplantation for hilar cholangiocarcinoma has not been systematically investigated. In this study of 124 patients, 255 infections occurred in 105 patients during the median follow‐up of 4.2 years. The median time to first infection was 15.1 weeks (IQR 1.6‐62.6). The most common sites were the abdomen, bloodstream, and musculoskeletal system. Risk factors for any post‐transplant infection were pre‐transplant VRE colonization (Hazard Ratio [HR] 1.9, P=.002), living donor transplantation (HR 6.6, P<.001), longer cold ischemia time (HR 1.05 per 10 minutes, P<.001), donor CMV seropositivity (HR 2.2, P<.001), hepatic artery thrombosis (HR 2.6, P=.005), biliary stricture (HR 3.8, P=.002), intra‐abdominal fluid collection (HR 4.2, P<.001), and re‐operations within 1 month after transplantation (HR 1.7, P=.020). Abdominal infections were independently associated with hemodialysis requirement within 1 month after transplantation (HR 5.6, P=.006), hepatic artery thrombosis (HR 3.3, P=.007), biliary stricture (HR 5.2, P<.001), and abdominal fluid collection (HR 3.7, P=.0002). Bloodstream infections were independently associated with allograft ischemia (HR 17.8, P<.001), biliary stricture (HR 6.5, P=.005), and recipient VRE colonization (HR 4, P<.001). Abdominal infections (HR 2.3, P=.02) and Clostridium difficile infections (HR 4.6, P=.01) were independently associated with increased mortality.

AbstractEpigenomics, the study of modifications to genetic material that do not alter the underlying DNA sequence, is generating increasing interest as a means to help clarify disease pathogenesis and outcomes. Although genome-wide association studies have identified several potential candidate genes that may be implicated in primary biliary cholangitis (PBC) and primary sclerosing cholangitis (PSC), it is estimated that these genes explain less than 20% of the heritability of these diseases. Thus, to date, the origins of “missing heritability” for PBC and PSC remain elusive. The epigenome may provide a potentially elegant solution to this phenomenon, as it can be modified by both internal and external exposures (coined the “exposome”). This may explain differences in disease presentation, treatment response, and rates of progression between individuals. Epigenetic changes may also provide a framework for discovering potential biomarkers for diagnosis and screening of PBC and PSC. Importantly, because the epigenome is modifiable, it may also highlight novel pathways for therapeutic discovery and interventions of these diseases.

Cholangiocarcinoma (CCA) includes a heterogeneous group of biliary cancers with poor prognosis. Several conditions, such as primary sclerosing cholangitis (PSC), are risk factors. Noninvasive differential diagnosis between intrahepatic CCA and hepatocellular carcinoma (HCC) is sometimes difficult. Accurate noninvasive biomarkers for PSC, CCA, and HCC are not available. In the search for novel biomarkers, serum extracellular vesicles (EV) were isolated from CCA (n = 43), PSC (n = 30), or HCC (n = 29) patients and healthy individuals (control, n = 32); and their protein content was characterized. By using nanoparticle tracking analysis, serum EV concentration was found to be higher in HCC than in all the other groups. Round morphology (by transmission electron microscopy), size (∼180 nm diameter by nanoparticle tracking analysis), and markers (clusters of differentiation 9, 63, and 81 by immunoblot) indicated that most serum EV were exosomes. Proteome profiles (by mass spectrometry) revealed multiple differentially expressed proteins among groups. Several of these proteins showed high diagnostic values with maximum area under the receiver operating characteristic curve of 0.878 for CCA versus control, 0.905 for CCA stage I‐II versus control, 0.789 for PSC versus control, 0.806 for noncirhottic PSC versus control, 0.796 for CCA versus PSC, 0.956 for CCA stage I‐II versus PSC, 0.904 for HCC versus control, and 0.894 for intrahepatic CCA versus HCC. Proteomic analysis of EV derived from CCA human cells in vitro revealed higher abundance of oncogenic proteins compared to EV released by normal human cholangiocytes. Orthotopic implant of CCA human cells in the liver of immunodeficient mice resulted in the release to serum of EV containing some similar human oncogenic proteins. Conclusion : Proteomic signatures found in serum EV of CCA, PSC, and HCC patients show potential usefulness as diagnostic tools. (H epatology 2017;66:1125‐1143).

Background/Aim: The epidemiology of hepatocellular carcinoma (HCC) has changed in the United States recently. The aim of this study is to evaluate the recent trends of HCC epidemiology in Olmsted County, MN. Methods: Residents aged over 20 with newly diagnosed HCC were identified using the Rochester Epidemiology Project database. Clinical information was compared among patients diagnosed between 2000 and 2009 (era 1) and 2010 to 2014 (era 2). Results: Over 1.6 million person years of follow-up, 93 residents were diagnosed with HCC. The mean age was 67 and 71% were male. The age-adjusted and sex-adjusted incidence rates were 6.3 and 7.0 per 100,000 person years in the first and second eras (P=0.64). The proportion with hepatitis B virus etiology increased from 4% to 21% between the 2 eras (P<0.01), whereas there was a trend toward a decreasing proportion of hepatitis C virus etiology from 42% to 29% (P=0.20). Only 39% of HCC surveillance candidates had HCCs detected under surveillance and 41% of cirrhotic patients had unrecognized cirrhosis at the time of HCC diagnosis. Nonalcoholic fatty liver disease was associated with unrecognized cirrhosis and absence of cirrhosis at HCC diagnosis. More than half (56%) of patients presented at Barcelona Clinic Liver Cancer stage C or D and the median survival was 9.7 months. The overall survival had not changed over time. Conclusions: The incidence of HCC remained stable after 2010 in Olmsted County. The proportion of hepatitis B virus-induced HCC increased, whereas there was a trend of decreasing proportion of hepatitis C virus-induced HCC. The overall survival in community residents with HCC remains poor.

Abstract Background: The utility of alpha-fetoprotein (AFP) for hepatocellular carcinoma (HCC) surveillance is controversial. We aimed to identify factors associated with elevated AFP and define the patients for whom AFP is effective for surveillance. Methods: Data from the NCI Early Detection Research Network phase II HCC biomarker study (233 early-stage HCC and 412 cirrhotic patients) were analyzed. We analyzed 110 early-stage HCC and 362 cirrhotic hepatitis C virus (HCV) patients for external validation. Sensitivity, specificity, and area under the ROC curve (AUC) for HCC were calculated. Results: HCV etiology, non-White race, and serum alanine transaminase (ALT) predicted elevated AFP in cirrhotics. Non-White race and ALT predicted elevated AFP in HCC patients. Higher AUC of AFP for HCC was noted in patients with HBV (0.85) and alcohol (0.84), whereas it was lower in patients with hepatitis C virus (HCV; 0.80) and nonviral/alcohol etiology (0.76). The AUC was higher in HCV patients with serum ALT ≤40 U/L than patients with serum ALT &gt;40 U/L (0.91 vs. 0.75, P &lt; 0.01). At 90% specificity, the sensitivity of AFP increased from 44% to 74% in Whites with HCV and from 50% to 85% in non-Whites with HCV. There was a trend toward higher AUC in HCV patients with serum ALT ≤40 U/L than those with serum ALT &gt;40 U/L (0.79 vs. 0.69, P = 0.10) in the validation cohort. Conclusions: The satisfactory performance of AFP in HCV patients with normal ALT should be further validated. Impact: The AFP may serve as a valuable surveillance test in HCV patients with normal ALT. Cancer Epidemiol Biomarkers Prev; 26(7); 1085–92. ©2017 AACR.

Prohibitin 1 (PHB1) is best known as a mitochondrial chaperone, and its role in cancer is conflicting. Mice lacking methionine adenosyltransferase α1 (MATα1) have lower PHB1 expression, and we reported that c‐MYC interacts directly with both proteins. Furthermore, c‐MYC and MATα1 exert opposing effects on liver cancer growth, prompting us to examine the interplay between PHB1, MATα1, and c‐MYC and PHB1's role in liver tumorigenesis. We found that PHB1 is highly expressed in normal hepatocytes and bile duct epithelial cells and down‐regulated in most human hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA). In HCC and CCA cells, PHB1 expression correlates inversely with growth. PHB1 and MAT1A positively regulate each other's expression, whereas PHB1 negatively regulates the expression of c‐MYC, MAFG, and c‐MAF. Both PHB1 and MATα1 heterodimerize with MAX, bind to the E‐box element, and repress E‐box promoter activity. PHB1 promoter contains a repressive E‐box element and is occupied mainly by MAX, MNT, and MATα1 in nonmalignant cholangiocytes and noncancerous tissues that switched to c‐MYC, c‐MAF, and MAFG in cancer cells and human HCC/CCA. All 8‐month‐old liver‐specific Phb1 knockout mice developed HCC, and one developed CCA. Five‐month‐old Phb1 heterozygotes, but not Phb1 flox mice, developed aberrant bile duct proliferation; and one developed CCA 3.5 months after left and median bile duct ligation. Phb1 heterozygotes had a more profound fall in the expression of glutathione synthetic enzymes and higher hepatic oxidative stress following left and median bile duct ligation. Conclusion: We have identified that PHB1, down‐regulated in most human HCC and CCA, heterodimerizes with MAX to repress the E‐box and positively regulates MAT1A while suppressing c‐MYC, MAFG, and c‐MAF expression; in mice, reduced PHB1 expression predisposes to the development of cholestasis‐induced CCA. (Hepatology 2017;65:1249‐1266).