Citations

c‐Myc induction drives cholestatic liver injury and cholangiocarcinoma (CCA) in mice, and induction of Maf proteins (MafG and c‐Maf) contributes to cholestatic liver injury, whereas S‐adenosylmethionine (SAMe) administration is protective. Here, we determined whether there is interplay between c‐Myc, Maf proteins, and methionine adenosyltransferase α1 (MATα1), which is responsible for SAMe biosynthesis in the liver. We used bile duct ligation (BDL) and lithocholic acid (LCA) treatment in mice as chronic cholestasis models, a murine CCA model, human CCA cell lines KMCH and Huh‐28, human liver cancer HepG2, and human CCA specimens to study gene and protein expression, protein‐protein interactions, molecular mechanisms, and functional outcomes. We found that c‐Myc, MATα1 (encoded by MAT1A), MafG, and c‐Maf interact with one another directly. MAT1A expression fell in hepatocytes and bile duct epithelial cells during chronic cholestasis and in murine and human CCA. The opposite occurred with c‐Myc, MafG, and c‐Maf expression. MATα1 interacts mainly with Mnt in normal liver, but this switches to c‐Maf, MafG, and c‐Myc in cholestatic livers and CCA. Promoter regions of these genes have E‐boxes that are bound by MATα1 and Mnt in normal liver and benign bile duct epithelial cells that switched to c‐Myc, c‐Maf, and MafG in cholestasis and CCA cells. E‐box positively regulates c‐Myc, MafG, and c‐Maf, but it negatively regulates MAT1A. MATα1 represses, whereas c‐Myc, MafG, and c‐Maf enhance, E‐box‐driven promoter activity. Knocking down MAT1A or overexpressing MafG or c‐Maf enhanced CCA growth and invasion in vivo. Conclusion: There is a novel interplay between MATα1, c‐Myc, and Maf proteins, and their deregulation during chronic cholestasis may facilitate CCA oncogenesis. (Hepatology 2016;64:439‐455)

Immunostains are used to subtype hepatic adenomas to stratify for the risk of malignant transformation. The most common panel of immunostains used for this purpose includes liver fatty acid–binding protein (LFABP), serum amyloid A (SAA) protein, C-reactive protein (CRP), and glutamine synthetase (GS). Importantly, some pathologists use these stains in an attempt to distinguish hepatocellular carcinomas (HCC) from hepatic adenomas. However, there are limited data on the performance of these stains in HCCs. To investigate the staining characteristics of HCCs, we studied 159 HCCs (92 well-differentiated, 67 moderately differentiated, and 7 poorly differentiated) and 7 fibrolamellar carcinomas for the expression of LFABP, SAA, CRP, and GS. All of the stains were positive in at least a subset of HCCs: SAA was positive in 27 of 159 (17%), CRP in 86 of 159 (54%), and GS in 23 of 47 (49%) cases; LFABP showed loss of staining in 36 of 159 (23%) cases. Fibrolamellar carcinomas were consistently CRP positive (7 of 7 cases) and frequently showed loss of LFABP (4 of 7 cases). There was no association between expression of SAA, CRP, and GS as well as loss of LFABP expression and other clinicopathologic features. HCCs with loss of LFABP were more frequently associated with negative GS expression (11 of 14 cases, P =0.02). These data show that immunostains used to subtype hepatic adenomas are not useful for distinguishing HCCs from hepatic adenomas and should be used only after a diagnosis of hepatic adenoma has been made using other criteria.

Summary The transcription factor forkhead box protein A1 (FOXA1) plays a critical role in the proliferation of human breast cancer cells, particularly estrogen receptor alpha (ERα)‐positive luminal breast cancer cells. However, genetic studies of the requirement for Foxa1 in mammary tumor formation in mice have been hampered by the lack of a conditional gene ablation. We examined three mouse models of mammary‐specific ablation of Foxa1 in ductal epithelial cells to identify the best system for complete and mammary‐specific ablation of Foxa1. We found that MMTV‐Cre and MMTV‐rtTA;Tet‐On‐Cre led to partial deletion of Foxa1 and attenuated mammary duct formation, whereas Krt14‐Cre led to complete ablation of Foxa1 and abolished mammary duct formation, in Foxa1 loxP/loxP mice. These results demonstrate that Foxa1 is essential for mammary duct formation, and reveal a series of mouse models in which mammary expression of Foxa1 can be attenuated or completely blocked. Our study also suggests a potentially powerful model for complete ablation of Foxa1 in mammary epithelial cells using Krt14‐driven Cre expression in an inducible manner, such as Krt14‐rtTA;Tet‐On‐Cre . This model system will facilitate further in vivo functional studies of Foxa1 or other factors in mammary gland development and tumor formation and progression. genesis 54:277–285, 2016. © 2016 Wiley Periodicals, Inc.

Background and Purpose— Age-related changes in the cerebrovasculature, including blood–brain barrier (BBB) disruption, are emerging as potential risks for diverse neurological conditions. Because the accumulation of senescent cells in tissues is increasingly recognized as a critical step leading to age-related organ dysfunction, we evaluated whether senescent vascular cells are associated with compromised BBB integrity. Methods— Effects of vascular cell senescence on tight junction and barrier integrity were studied using an in vitro BBB model, composed of endothelial cells, pericytes, and astrocytes. In addition, tight junction coverage in microvessels and BBB integrity in BubR1 hypomorphic (BubR1 H/H ) mice, which display senescence cell-dependent phenotypes, were examined. Results— When an in vitro BBB model was constructed with senescent endothelial cells and pericytes, tight junction structure and barrier integrity (evaluated by transendothelial electric resistance and tracer efflux assay using sodium fluorescein and Evans blue-albumin were significantly impaired. Endothelial cells and pericytes from BubR1 H/H mice had increased senescent-associated β-galactosidase activity and p16 INK4a expression, demonstrating an exacerbation of senescence. The coverage by tight junction proteins in the cortical microvessels were reduced in BubR1 H/H mice, consistent with a compromised BBB integrity from permeability assays. Importantly, the coverage of microvessels by end-feet of aquaporin 4–immunoreactive astrocytes was not altered in the cortex of the BubR1 H/H mice. Conclusions— Our results indicate that accumulation of senescent vascular cells is associated with compromised BBB integrity, providing insights into the mechanism of BBB disruption related to biological aging.

Abstract We previously reported, on the basis of a genome-wide association study for aromatase inhibitor-induced musculoskeletal symptoms, that single-nucleotide polymorphisms (SNPs) near the T-cell leukemia/lymphoma 1A (TCL1A) gene were associated with aromatase inhibitor-induced musculoskeletal pain and with estradiol (E2)-induced TCL1A expression. Furthermore, variation in TCL1A expression influenced the downstream expression of proinflammatory cytokines and cytokine receptors. Specifically, the top hit genome-wide association study SNP, rs11849538, created a functional estrogen response element (ERE) that displayed estrogen receptor (ER) binding and increased E2 induction of TCL1A expression only for the variant SNP genotype. In the present study, we pursued mechanisms underlying the E2-SNP-dependent regulation of TCL1A expression and, in parallel, our subsequent observations that SNPs at a distance from EREs can regulate ERα binding and that ER antagonists can reverse phenotypes associated with those SNPs. Specifically, we performed a series of functional genomic studies using a large panel of lymphoblastoid cell lines with dense genomic data that demonstrated that TCL1A SNPs at a distance from EREs can modulate ERα binding and expression of TCL1A as well as the expression of downstream immune mediators. Furthermore, 4-hydroxytamoxifen or fulvestrant could reverse these SNP-genotype effects. Similar results were found for SNPs in the IL17A cytokine and CCR6 chemokine receptor genes. These observations greatly expand our previous results and support the existence of a novel molecular mechanism that contributes to the complex interplay between estrogens and immune systems. They also raise the possibility of the pharmacological manipulation of the expression of proinflammatory cytokines and chemokines in a SNP genotype-dependent fashion.

Abstract Purpose: Responses to therapy with chimeric antigen receptor T cells recognizing CD19 (CART19, CTL019) may vary by histology. Mantle cell lymphoma (MCL) represents a B-cell malignancy that remains incurable despite novel therapies such as the BTK inhibitor ibrutinib, and where data from CTL019 therapy are scant. Using MCL as a model, we sought to build upon the outcomes from CTL019 and from ibrutinib therapy by combining these in a rational manner. Experimental Design: MCL cell lines and primary MCL samples were combined with autologous or normal donor-derived anti-CD19 CAR T cells along with ibrutinib. The effect of the combination was studied in vitro and in mouse xenograft models. Results: MCL cells strongly activated multiple CTL019 effector functions, and MCL killing by CTL019 was further enhanced in the presence of ibrutinib. In a xenograft MCL model, we showed superior disease control in the CTL019- as compared with ibrutinib-treated mice (median survival not reached vs. 95 days, P < 0.005) but most mice receiving CTL019 monotherapy eventually relapsed. Therefore, we added ibrutinib to CTL019 and showed that 80% to 100% of mice in the CTL019 + ibrutinib arm and 0% to 20% of mice in the CTL019 arm, respectively, remained in long-term remission (P < 0.05). Conclusions: Combining CTL019 with ibrutinib represents a rational way to incorporate two of the most recent therapies in MCL. Our findings pave the way to a two-pronged therapeutic strategy in patients with MCL and other types of B-cell lymphoma. Clin Cancer Res; 22(11); 2684–96. ©2016 AACR.

The hypoxia‐inducible factor (HIF), HIF‐1, is a central regulator of the response to low oxygen or inflammatory stress and plays an essential role in survival and function of immune cells. However, the mechanisms regulating nonhypoxic induction of HIF‐1 remain unclear. Here, we assess the impact of germline heterozygosity of a novel, oxygen‐independent ubiquitin ligase for HIF‐1α: hypoxia‐associated factor (HAF; encoded by SART1). SART1−/− mice were embryonic lethal, whereas male SART1+/− mice spontaneously recapitulated key features of nonalcoholic steatohepatitis (NASH)‐driven hepatocellular carcinoma (HCC), including steatosis, fibrosis, and inflammatory cytokine production. Male, but not female, SART1+/− mice showed significant up‐regulation of HIF‐1α in circulating and liver‐infiltrating immune cells, but not in hepatocytes, before development of malignancy. Additionally, Kupffer cells derived from male, but not female, SART1+/− mice produced increased levels of the HIF‐1‐dependent chemokine, regulated on activation, normal T‐cell expressed and secreted (RANTES), compared to wild type. This was associated with increased liver‐neutrophilic infiltration, whereas infiltration of lymphocytes and macrophages were not significantly different. Neutralization of circulating RANTES decreased liver neutrophilic infiltration and attenuated HCC tumor initiation/growth in SART1+/− mice. Conclusion: This work establishes a new tumor‐suppressor role for HAF in immune cell function by preventing inappropriate HIF‐1 activation in male mice and identifies RANTES as a novel therapeutic target for NASH and NASH‐driven HCC. (Hepatology 2016;63:1576‐1591)