Maura O'Neil

Hepatocyte nuclear factor 4 alpha deletion promotes diethylnitrosamine-induced hepatocellular carcinoma in rodents.

Hepatocyte nuclear factor 4 alpha (HNF4α), the master regulator of hepatocyte differentiation, has been recently shown to inhibit hepatocyte proliferation by way of unknown mechanisms. We investigated the mechanisms of HNF4α‐induced inhibition of hepatocyte proliferation using a novel tamoxifen (TAM)‐inducible, hepatocyte‐specific HNF4α knockdown mouse model. Hepatocyte‐specific deletion of HNF4α in adult mice resulted in increased hepatocyte proliferation, with a significant increase in liver‐to‐body‐weight ratio. We determined global gene expression changes using Illumina HiSeq‐based RNA sequencing, which revealed that a significant number of up‐regulated genes following deletion of HNF4α were associated with cancer pathogenesis, cell cycle control, and cell proliferation. The pathway analysis further revealed that c‐Myc‐regulated gene expression network was highly activated following HNF4α deletion. To determine whether deletion of HNF4α affects cancer pathogenesis, HNF4α knockdown was induced in mice treated with the known hepatic carcinogen diethylnitrosamine (DEN). Deletion of HNF4α significantly increased the number and size of DEN‐induced hepatic tumors. Pathological analysis revealed that tumors in HNF4α‐deleted mice were well‐differentiated hepatocellular carcinoma (HCC) and mixed HCC‐cholangiocarcinoma. Analysis of tumors and surrounding normal liver tissue in DEN‐treated HNF4α knockout mice showed significant induction in c‐Myc expression. Taken together, deletion of HNF4α in adult hepatocytes results in increased hepatocyte proliferation and promotion of DEN‐induced hepatic tumors secondary to aberrant c‐Myc activation. (HEPATOLOGY 2013;57:2480–2490)

Alteration of hepatic nuclear receptor‐mediated signaling pathways in hepatitis C virus patients with and without a history of alcohol drinking

The current study tests a hypothesis that nuclear receptor signaling is altered in chronic hepatitis C patients and that the altered pattern is specific to alcohol drinking history. The expression of a panel of more than 100 genes encoding nuclear receptors, coregulators, and their direct/indirect targets was studied in human livers. Gene expression pattern was compared between 15 normal donor livers and 23 hepatitis C virus (HCV) genotype 1–positive livers from patients without a drinking history (matched for age, sex, and body mass index). HCV infection increased the expression of nuclear receptors small heterodimer partner and constitutive androstane receptor (CAR) as well as genes involved in fatty acid trafficking, bile acid synthesis and uptake, and inflammatory response. However, the expression of retinoid X receptor (RXR) α, peroxisomal proliferator‐activated receptor (PPAR) α and β as well as steroid regulatory element‐binding protein (SREBP)‐1c was decreased in HCV‐infected livers. Gene expression pattern was compared in chronic hepatitis C patients with and without a drinking history. Alcohol drinking increased the expression of genes involved in fatty acid uptake, trafficking, and oxidation, but decreased the expression of genes responsible for gluconeogenesis. These changes were consistent with reduced fasting plasma glucose levels and altered expression of upstream regulators that include RXRα, PPARα, and CAR. The messenger RNA levels of fibroblast growth factor 21, interleukin‐10, and fatty acid synthase, which are all regulated by nuclear receptors, showed independent correlation with hepatic HCV RNA levels. Conclusion: Our findings suggest that those genes and pathways that showed altered expression could potentially be therapeutic targets for HCV infection and/or alcohol drinking‐induced liver injury. (HEPATOLOGY 2011)

Donor PNPLA3 rs738409 genotype affects fibrosis progression in liver transplantation for hepatitis C

The rs738409 G>C single nucleotide polymorphism occurring in the patatin‐like phospholipase 3 gene has been identified as a novel genetic marker for hepatic steatosis. Recent studies also associated rs738409 with fibrosis in hepatitis C (HCV). Therefore, we sought to determine the impact of donor and recipient rs738409 genotype on the progression of fibrosis after liver transplantation for HCV. This cohort study included 101 patients infected with HCV who underwent liver transplantation between January 2008, and June 2011. Donor and recipient rs738409 genotypes were determined from donor wedge biopsies and recipient explants. The time to Ishak stage 3 fibrosis, or HCV‐related mortality/graft loss was analyzed by the Cox model adjusting for HCV‐Donor Risk Index, warm ischemic time, pretransplant Model for Endstage Liver Disease (MELD) and viral load. The rs738409 CC variant was present in 56% of donors and 57% of recipients. The median follow‐up period was 620 days. A total of 39 patients developed the primary outcome of ≥stage 3 fibrosis or HCV‐related mortality/graft loss, the time to which differed by donor (P = 0.019) but not recipient (P = 0.89) genotype. In the multivariate model, donor GC or GG variants had 2.53 times the risk (95% confidence interval [CI] 1.25‐5.02, P = 0.008) compared to CC variants. In the alternative endpoint: stage 3 fibrosis or all‐cause mortality/graft loss, the effect of donor genotype was attenuated but remained significant at 1.98 (95% CI 1.11‐3.53). Conclusions: The rs738409 genotype is an important predictor of posttransplant outcome in HCV. Liver, and not adipocytes, is the site at which this effect occurs. Our finding may be useful in donor selection for liver transplantation with HCV, and may guide decisions regarding early antiviral treatment. (Hepatology 2014;59:453–460)

The Interaction of rs738409, Obesity, and Alcohol: A Population-Based Autopsy Study

OBJECTIVES:The objective of this study was to access the prevalence of alcoholic liver disease (ALD) and nonalcoholic fatty liver disease (NAFLD) histology in the general population, which had been otherwise difficult to access because of inherent misclassification bias in surrogate marker studies and referral bias in patient case series. The interaction among rs738409, obesity, and alcohol remains controversial. This population-based autopsy study investigated the histological prevalence of ALD and NAFLD, and interactions among rs738409, obesity, and alcoholism.METHODS:A total of 170 alcoholic and 235 nonalcoholic cases were selected from 1,034 adult car accident autopsies in 17 Kansas and Missouri counties from 2000 to 2010. The nonalcoholic group had undetectable blood alcohol concentration, while the alcoholic group had a blood alcohol concentration ≥0.08%.RESULTS:The age-standardized prevalences of hepatic steatosis, steatohepatitis, and advanced fibrosis were 56, 6, and 18% among alcoholics and 36, 4, and 6% in nonalcoholics, respectively. The interaction terms among alcohol, body mass index (BMI), and genotype were not significant. rs738409 GC or GG genotype was associated with 1.9-fold odds (95% confidence interval (CI), 1.2–2.9) of a higher NAFLD Activity Score (NAS). Alcohol had 3.5-fold odds (95% CI, 2.0–5.9), while every 5-unit increase in BMI had 1.9-fold odds (95% CI, 1.7–2.5). A negative interaction between alcohol and BMI towards fibrosis had been observed (P=0.045). Every 5-unit increase in BMI had 2.2-fold odds (95% CI, 1.5–2.5) of fibrosis among nonalcoholics, but not in alcoholics.CONCLUSIONS:This study assessed the prevalence of fatty liver histology in the general population from an autopsy study perspective. The finding of an additive interaction among rs738409, obesity, and alcohol towards NAS may be useful in targeting preventative care to patients at highest risk for ALD. The negative interaction between alcohol and obesity towards fibrosis supported previous findings and suggests the need for future research to explore potential mechanisms that may improve treatment of nonalcoholic steatohepatitis-related fibrosis.

Pituitary carcinoma recurrent to the lumbar intradural extramedullary space: case report.

Abstract Context Pituitary tumors are rare, and pituitary carcinomas are rarer still. Prognosis is poor, with less than 50% of patients surviving past 1 year after diagnosis. In this case of spinal metastasis from an adrenocorticotropic hormone-secreting pituitary carcinoma, the intradural extramedullary metastases recurred in the same lumbar area 6 years apart. Findings Fourteen years prior to presentation in our clinic, a 48-year-old woman was diagnosed with pituitary adenoma which was treated with resection followed by radiation. Eight years later, an intradural extramedullary spinal drop metastasis at L2–L3 was again treated with resection and radiation. Three years later, magnetic resonance imaging (MRI) revealed a mass encasing the right carotid artery, which was treated for 1 year with chemotherapy using temozolomide (Temodar). Three years later, MRI showed intradural extramedullary metastases at the L3–L4 intervertebral disc space and behind the L3 vertebral body; treatment was again resection followed by radiation. Back pain and weakness resolved after surgery and her neurological examination returned to baseline. There was no evidence of recurrence 1 year after surgery. Conclusion/clinical relevance In this unusual case, this pituitary carcinoma metastasized twice in 6 years to virtually the same intradural extramedullary lumbar region. Surgical resection of these masses aided in relieving neurological symptoms and prolonging life.

Bile acids promote diethylnitrosamine-induced hepatocellular carcinoma via increased inflammatory signaling.

Hepatocellular carcinoma (HCC) is the most common hepatic malignancy and the third leading cause of cancer related deaths. Previous studies have implicated bile acids in pathogenesis of HCC, but the mechanisms are not known. We investigated the mechanisms of HCC tumor promotion by bile acids the diethylnitrosamine (DEN)-initiation-cholic acid (CA)-induced tumor promotion protocol in mice. The data show that 0.2% CA treatment resulted in threefold increase in number and size of DEN-induced liver tumors. All tumors observed in DEN-treated mice were well-differentiated HCCs. The HCCs observed in DEN-treated CA-fed mice exhibited extensive CD3-, CD20-, and CD45-positive inflammatory cell aggregates. Microarray-based global gene expression studies combined with Ingenuity Pathway Analysis revealed significant activation of NF-κB and Nanog in the DEN-treated 0.2% CA-fed livers. Further studies showed significantly higher TNF-α and IL-1β mRNA, a marked increase in total and phosphorylated-p65 and phosphorylated IκBα (degradation form) in livers of DEN-treated 0.2% CA-fed mice. Treatment of primary mouse hepatocytes with various bile acids showed significant induction of stemness genes including Nanog, KLF4, Sox2, and Oct4. Quantification of total and 20 specific bile acids in liver, and serum revealed a tumor-associated bile acid signature. Finally, quantification of total serum bile acids in normal, cirrhotic, and HCC human samples revealed increased bile acids in serum of cirrhotic and HCC patients. Taken together, these data indicate that bile acids are mechanistically involved pathogenesis of HCC and may promote HCC formation via activation of inflammatory signaling.

Abnormal Wnt signaling and stem cell activation in reactive lymphoid tissue and low-grade marginal zone lymphoma

The variable natural history of mucosa-associated lymphoid tissue (MALT) lymphoma poses a challenge in predicting clinical outcome. Since Wnt signaling, as indicated by nuclear localization of β-catenin, is believed to be key in stem cell activation and stem cell self-renewal, we explored the possibility that it might have a predictive value in marginal zone lymphoma. We chose to analyze pβ-catenin-S552 because its nuclear localization by immunohistochemistry appears to coincide with Wnt signaling-initiated tumorigenesis in intestinal and hematopoietic tissues. Wnt signaling and activation was studied in 22 tissue samples of extranodal marginal zone lymphoma, atypical lymphoid hyperplasia, reactive lymphoid hyperplasia, and normal lymphoid tissue to determine whether Wnt signaling could help distinguish MALT lymphoma from benign lesions. Compared to normal or reactive lymphoid tissue, we found increased nuclear expression of localized pβ-catenin-S552 in atypical lymphoid hyperplasia and extranodal marginal zone lymphoma. We show that the anti-pβ-catenin-S552 antibody may be useful in diagnosing and monitoring the progression of or response to therapy of MALT lymphoma.

Utility of peritoneal washing cytology in staging and prognosis of ovarian and fallopian tube neoplasms: a 10-year retrospective analysis

The prognostic significance of peritoneal washing cytology in gynecologic neoplasms is controversial. The presence of neoplastic cells in peritoneal washings is currently part of the Federation of Gynecology and Obstetrics and American Joint Committee on Cancer TNM staging systems in cases of ovarian and fallopian tube neoplasms without metastasis beyond the pelvis. In this study, we retrospectively reviewed all cases of ovarian and fallopian tube neoplasms in which cytologic studies were performed. The utility of cytology in tumor staging and the relationship between cytology results and patient outcome are studied. All cases of ovarian and fallopian tube neoplasms in our institution between July 2002 and July 2012 were reviewed. Primary tumor characteristics including type and pelvic extension were collected, categorized, and correlated with peritoneal washing cytology. Final tumor staging was reviewed and the impact of positive cytology was evaluated. A total of 120 cases of ovarian and fallopian tube neoplasms without extrapelvic metastasis were identified within the study period. Peritoneal washing cytology was positive in 24% (29/120) of neoplasms and upstaged the tumor 83% (24/29) of the time when positive. Overall, 20% (24/120) of reviewed cases were upstaged based on positive cytology results. Peritoneal washing cytology remains a useful staging tool for ovarian and fallopian tube neoplasms limited to the pelvic cavity. Positive cytology results in upstaging in a significant proportion of the cases regardless of the tumor type. A larger study is needed to analyze follow-up data to determine if upstaging based on positive cytology adversely affects outcome.

Liver Pathology for Clinicians

Liver Pathology for Clinians , Liver Pathology for Clinians , کتابخانه مرکزی دانشگاه علوم پزشکی تهران

PRMT1 and JMJD6 dependent arginine methylation regulate HNF4α expression and hepatocyte proliferation

Alcohol is a well‐established risk factor for hepatocellular carcinoma (HCC), but the mechanisms by which it promotes liver cancer are not well understood. Several studies have shown that cellular protein arginine methylation is inhibited by alcohol. Arginine methylation is controlled by the reciprocal activity of protein arginine methyltransferases, primarily protein arginine methyl transferase 1 (PRMT1), and a demethylase Jumonji C domain‐containing protein 6 (JMJD6). The aim of this study was to explore the role of arginine methylation changes in alcohol pathogenesis. We found that PRMT1 activity is inhibited in livers of mice fed with alcohol compared to pair‐fed mice. Using hepatocyte‐specific PRMT1 knockout mice, we identified that loss of PRMT1 results in enhanced hepatocyte proliferation and a 33% increase in liver size. This increased hepatocyte proliferation was associated with reduced expression of hepatocyte nuclear factor 4 alpha (Hnf4α), an important regulator of liver tumorigenesis. We found that PRMT1 regulates Hnf4α expression directly through arginine methylation at the (Hnf4α) promoter. In the absence of PRMT1, JMJD6 can demethylate the Hnf4α promoter and suppress its expression. We were able to restore Hnf4α expression and abolish the increase in hepatocyte proliferation by knockdown of JMJD6 in PRMT1 knockout mice. Knockdown of JMJD6 in alcohol‐fed mice similarly increased Hnf4α expression. We then examined whether loss of arginine methylation might play a role in alcohol‐associated liver cancers. We examined 25 human HCC specimens and found a strong correlation (R = 0.8; P < 0.01) between arginine methylation levels and Hnf4α expression in these specimens, suggesting that the above mechanism is relevant in patients. Conclusion: Taken together, these data suggest that PRMT1 inhibition, such as induced by alcohol, may result in epigenetic changes leading to loss of Hnf4α. This effect may contribute to alcohols ability to promote liver tumors. (Hepatology 2018;67:1109–1126)