Publications by authors named "Jürgen Borlak"

149 Publications

Advances in Liver Cancer Stem Cell Isolation and their Characterization.

Stem Cell Rev Rep 2021 Jan 11. Epub 2021 Jan 11.

Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Over the last decade research on cancer stem cells (CSC) significantly contributed to a better understanding of tumor biology. Given their similarity to normal stem cells, i.e. self-renewal and pluripotency the need arises to develop robust protocols for the isolation and characterization of CSCs. As with other malignancies, hepatic tumors are composed of a heterogeneous population of cells including liver cancer stem cells (LCSC). Yet, a precise understanding of why stem cells become cancerous is still lacking. There is unmet need to develop robust protocols for the successful isolation of LCSCs from human tissue resection material as to assist in the development of molecular targeted therapies. Here we review the research progress made in the isolation and characterization of LCSCs by considering a wide range of cell surface markers and sorting methods, as applied to side populations, microsphere cultures and the gradient centrifugation method. We emphasize the different fluorescence activated cell sorting methods and the possibility to enrich LCSCs by immunomagnetic beads. We review the specificity of functional assays by considering ABCG transporter and ALDH1 enzyme activities and evaluate the in vivo tumorigenicity of LCSCs in highly sensitive bioassays. Finally, we evaluate different LCSC markers in association with viral and non-viral liver disease and explore the potential of novel drug delivery systems targeting CD133, EpCAM, CD13 and CD90 for the development of molecular targeted therapies. Graphical Abstract.
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http://dx.doi.org/10.1007/s12015-020-10114-6DOI Listing
January 2021

miRNAs in lung cancer. A systematic review identifies predictive and prognostic miRNA candidates for precision medicine in lung cancer.

Transl Res 2021 Apr 28;230:164-196. Epub 2020 Nov 28.

Centre for Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany. Electronic address:

Lung cancer (LC) is the leading cause of cancer-related death worldwide and miRNAs play a key role in LC development. To better diagnose LC and to predict drug treatment responses we evaluated 228 articles encompassing 16,697 patients and 12,582 healthy controls. Based on the criteria of ≥3 independent studies and a sensitivity and specificity of >0.8 we found blood-borne miR-20a, miR-10b, miR-150, and miR-223 to be excellent diagnostic biomarkers for non-small cell LC whereas miR-205 is specific for squamous cell carcinoma. The systematic review also revealed 38 commonly regulated miRNAs in tumor tissue and the circulation, thus enabling the prediction of histological subtypes of LC. Moreover, theranostic biomarker candidates with proven responsiveness to checkpoint inhibitor treatments were identified, notably miR-34a, miR-93, miR-106b, miR-181a, miR-193a-3p, and miR-375. Conversely, miR-103a-3p, miR-152, miR-152-3p, miR-15b, miR-16, miR-194, miR-34b, and miR-506 influence programmed cell death-ligand 1 and programmed cell death-1 receptor expression, therefore providing a rationale for the development of molecularly targeted therapies. Furthermore, miR-21, miR-25, miR-27b, miR-19b, miR-125b, miR-146a, and miR-210 predicted response to platinum-based treatments. We also highlight controversial reports on specific miRNAs. In conclusion, we report diagnostic miRNA biomarkers for in-depth clinical evaluation. Furthermore, in an effort to avoid unnecessary toxicity we propose predictive biomarkers. The biomarker candidates support personalized treatment decisions of LC patients and await their confirmation in randomized clinical trials.
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http://dx.doi.org/10.1016/j.trsl.2020.11.012DOI Listing
April 2021

Cancer genomics predicts disease relapse and therapeutic response to neoadjuvant chemotherapy of hormone sensitive breast cancers.

Sci Rep 2020 05 18;10(1):8188. Epub 2020 May 18.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, 72079, USA.

Several studies provide insight into the landscape of breast cancer genomics with the genomic characterization of tumors offering exceptional opportunities in defining therapies tailored to the patient's specific need. However, translating genomic data into personalized treatment regimens has been hampered partly due to uncertainties in deviating from guideline based clinical protocols. Here we report a genomic approach to predict favorable outcome to treatment responses thus enabling personalized medicine in the selection of specific treatment regimens. The genomic data were divided into a training set of N = 835 cases and a validation set consisting of 1315 hormone sensitive, 634 triple negative breast cancer (TNBC) and 1365 breast cancer patients with information on neoadjuvant chemotherapy responses. Patients were selected by the following criteria: estrogen receptor (ER) status, lymph node invasion, recurrence free survival. The k-means classification algorithm delineated clusters with low- and high- expression of genes related to recurrence of disease; a multivariate Cox's proportional hazard model defined recurrence risk for disease. Classifier genes were validated by Immunohistochemistry (IHC) using tissue microarray sections containing both normal and cancerous tissues and by evaluating findings deposited in the human protein atlas repository. Based on the leave-on-out cross validation procedure of 4 independent data sets we identified 51-genes associated with disease relapse and selected 10, i.e. TOP2A, AURKA, CKS2, CCNB2, CDK1 SLC19A1, E2F8, E2F1, PRC1, KIF11 for in depth validation. Expression of the mechanistically linked disease regulated genes significantly correlated with recurrence free survival among ER-positive and triple negative breast cancer patients and was independent of age, tumor size, histological grade and node status. Importantly, the classifier genes predicted pathological complete responses to neoadjuvant chemotherapy (P < 0.001) with high expression of these genes being associated with an improved therapeutic response toward two different anthracycline-taxane regimens; thus, highlighting the prospective for precision medicine. Our study demonstrates the potential of classifier genes to predict risk for disease relapse and treatment response to chemotherapies. The classifier genes enable rational selection of patients who benefit best from a given chemotherapy thus providing the best possible care. The findings encourage independent clinical validation.
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http://dx.doi.org/10.1038/s41598-020-65055-4DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7235228PMC
May 2020

An adverse outcome pathway for immune-mediated and allergic hepatitis: a case study with the NSAID diclofenac.

Arch Toxicol 2020 08 5;94(8):2733-2748. Epub 2020 May 5.

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625, Hannover, Germany.

Many drugs have the potential to cause drug-induced liver injury (DILI); however, underlying mechanisms are diverse. The concept of adverse outcome pathways (AOPs) has become instrumental for risk assessment of drug class effects. We report AOPs specific for immune-mediated and drug hypersensitivity/allergic hepatitis by considering genomic, histo- and clinical pathology data of mice and dogs treated with diclofenac. The findings are relevant for other NSAIDs and drugs undergoing iminoquinone and quinone reactive metabolite formation. We define reactive metabolites catalyzed by CYP monooxygenase and myeloperoxidases of neutrophils and Kupffer cells as well as acyl glucuronides produced by uridine diphosphoglucuronosyl transferase as molecular initiating events (MIE). The reactive metabolites bind to proteins and act as neo-antigen and involve antigen-presenting cells to elicit B- and T-cell responses. Given the diverse immune systems between mice and dogs, six different key events (KEs) at the cellular and up to four KEs at the organ level are defined with mechanistic plausibility for the onset and progression of liver inflammation. With mice, cellular stress response, interferon gamma-, adipocytokine- and chemokine signaling provided a rationale for the AOP of immune-mediated hepatitis. With dogs, an erroneous programming of the innate and adaptive immune response resulted in mast cell activation; their infiltration into liver parenchyma and the shift to M2-polarized Kupffer cells signify allergic hepatitis and the occurrence of granulomas of the liver. Taken together, diclofenac induces divergent immune responses among two important preclinical animal species, and the injury pattern seen among clinical cases confirms the relevance of the developed AOP for immune-mediated hepatitis.
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http://dx.doi.org/10.1007/s00204-020-02767-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7395045PMC
August 2020

The landscape of hepatobiliary adverse reactions across 53 herbal and dietary supplements reveals immune-mediated injury as a common cause of hepatitis.

Arch Toxicol 2020 01 13;94(1):273-293. Epub 2019 Nov 13.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, 3900 NCTR Road, Jefferson, AR, 72079, USA.

Recent evidence suggests herbal-induced liver injury (HILI) to account for 20% of cases among the U.S. Drug-Induced-Liver-Injury-Network. To define injury patterns of HILI, we reviewed the clinical data of 413 patients exposed to 53 HDS products by considering the evidence for HILI and its grades of severity. Outstandingly, females developed HILI more rapidly (p = 0.018) and the time to recovery was significantly increased (p = 0.0153). > 90% of reported cases were severe and half of HDS products caused acute liver failure (ALF) requiring liver transplantation or resulted in fatal outcomes. Liver biopsies of 243 patients defined 13 histological features; two-thirds of products elicited immune-mediated hepatitis and included 154 Hy's law positive cases. The histological injury patterns were confirmed among unrelated patients, while accidental re-challenges evidenced culprits as causative. Furthermore, one-fifth of patients presented elevated autoantibody titres indicative of autoimmune-like HILI, and one-third of the products were linked to chronic hepatitis and cholestatic injuries not resolving within 6 months. Lastly, INR and TBL are critical laboratory parameters to predict progression of severe HILI to ALF. Our study highlights the need for a regulatory framework to minimize the risk for HILI. Better education of the public and a physician-supervised self-medication plan will be important measures to abate risk of HILI.
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http://dx.doi.org/10.1007/s00204-019-02621-4DOI Listing
January 2020

Hepatobiliary Events in Migraine Therapy with Herbs-The Case of Petadolex, A Petasites Hybridus Extract.

J Clin Med 2019 May 10;8(5). Epub 2019 May 10.

Hannover Medical School, Centre for Pharmacology and Toxicology, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.

Petadolex, a defined butterbur extract has clinically proven efficacy against migraine attacks. However, spontaneous reports indicate cases of herbal induced liver injury (HILI). While most HILI patients presented mild serum biochemistry changes (<3 ULN, dose range 50 to 225 mg/day; treatment duration 4-730 days) nine developed severe HILI (average time-to-onset 103 days, ALT-range 3-153; AST 2-104-fold ULN). HILI cases resolved after medication withdrawal though two patients required liver transplantation. Liver biopsies revealed an inconsistent injury pattern, i.e. necrosis, macrovesicular steatosis, inflammation, cholestasis, and bile duct proliferation. Causality assessment rated 3 cases likely, 13 possible, 8 unlikely and 24 as unclassifiable/unclassified. Note, 22 patients reported hepatotoxic co-medications especially during periods of pain. A no-observable-adverse-effect-level at 15-fold of the maximal clinical dose (3 mg/kg/day MCD) was established for rats. At >45 and 90-fold MCD bile duct hyperplasia was observed but could not be confirmed in an explorative minipig study at 218-fold MCD. Human hepatocyte studies at 49-fold C serum petasins (=active ingredient) and therapeutic Ibuprofen, Paracetamol and Naratriptan concentrations evidenced liver transaminase and CYP-monooxygenase changes. Collectively, Petadolex HILI cases are rare, idiosyncratic and frequently confounded by co-medications. A physician-supervised self-medication plan with herbs and pain relief medication is needed to minimize risk for HILI.
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http://dx.doi.org/10.3390/jcm8050652DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6572430PMC
May 2019

Correction: Oncogenomics of c-Myc transgenic mice reveal novel regulators of extracellular signaling, angiogenesis and invasion with clinical significance for human lung adenocarcinoma.

Oncotarget 2018 12 14;9(98):37269. Epub 2018 Dec 14.

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.

[This corrects the article DOI: 10.18632/oncotarget.21981.].
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http://dx.doi.org/10.18632/oncotarget.26489DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6324690PMC
December 2018

Genomics of lipid-laden human hepatocyte cultures enables drug target screening for the treatment of non-alcoholic fatty liver disease.

BMC Med Genomics 2018 Dec 14;11(1):111. Epub 2018 Dec 14.

Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.

Background: Non-alcoholic fatty liver disease (NAFLD) is a major health burden in need for new medication. To identify potential drug targets a genomic study was performed in lipid-laden primary human hepatocyte (PHH) and human hepatoma cell cultures.

Methods: PHH, HuH7 and HepG2 hepatoma cell cultures were treated with lipids and/or TNFα. Intracellular lipid load was quantified with the ORO assay. The Affymetrix HG-U133+ array system was employed to perform transcriptome analysis. The lipid droplet (LD) growth and fusion was determined by fluorescence microscopy. LD associated proteins were imaged by confocal immunofluorescence microscopy and confirmed by Western immunoblotting. Bioinformatics defined perturbed metabolic pathways.

Results: Whole genome expression profiling identified 227, 1031 and 571 significant regulated genes. Likewise, the combined lipid and TNFα treatment of PHH, HuH7 and HepG2 cell cultures revealed 154, 1238 and 278 differentially expressed genes. Although genomic responses differed among in-vitro systems, commonalities were ascertained by filtering the data for LD associated gene regulations. Among others the LD-growth and fusion associated cell death inducing DFFA like effector C (CIDEC), perilipins (PLIN2, PLIN3), the synaptosome-associated-protein 23 and the vesicle associated membrane protein 3 were strongly up-regulated. Likewise, the PPAR targets pyruvate-dehydrogenase-kinase-4 and angiopoietin-like-4 were up-regulated as was hypoxia-inducible lipid droplet-associated (HILPDA), flotilin and FGF21. Their inhibition ameliorates triglyceride and cholesterol accumulation. TNFα treatment elicited strong induction of the chemokine CXCL8, the kinases MAP3K8, MAP4K4 and negative regulators of cytokine signaling, i.e. SOCS2&SOCS3. Live cell imaging of DsRED calreticulin plasmid transfected HuH7 cells permitted an assessment of LD growth and fusion and confocal immunofluorescence microscopy evidenced induced LD-associated PLIN2, CIDEC, HIF1α, HILPDA, JAK1, PDK4 and ROCK2 expression. Notwithstanding, CPT1A protein was repressed to protect mitochondria from lipid overload. Pharmacological inhibition of the GTPase-dynamin and the fatty acid transporter-2 reduced lipid uptake by 28.5 and 35%, respectively. Finally, a comparisons of in-vitro/NAFLD patient biopsy findings confirmed common gene regulations thus demonstrating clinical relevance.

Conclusion: The genomics of fat-laden hepatocytes revealed LD-associated gene regulations and perturbed metabolic pathways. Immunofluorescence microscopy confirmed expression of coded proteins to provide a rationale for therapeutic intervention strategies. Collectively, the in-vitro system permits testing of drug candidates.
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http://dx.doi.org/10.1186/s12920-018-0438-7DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6295111PMC
December 2018

The Development of a Database for Herbal and Dietary Supplement Induced Liver Toxicity.

Int J Mol Sci 2018 Sep 28;19(10). Epub 2018 Sep 28.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.

The growing use of herbal dietary supplements (HDS) in the United States provides compelling evidence for risk of herbal-induced liver injury (HILI). Information on HDS products was retrieved from MedlinePlus of the U.S. National Library of Medicine and the herbal monograph of the European Medicines Agency. The hepatotoxic potential of HDS was ascertained by considering published case reports. Other relevant data were collected from governmental documents, public databases, web sources, and the literature. We collected information for 296 unique HDS products. Evidence of hepatotoxicity was reported for 67, that is 1 in 5, of these HDS products. The database revealed an apparent gender preponderance with women representing 61% of HILI cases. Culprit hepatotoxic HDS were mostly used for weight control, followed by pain and inflammation, mental stress, and mood disorders. Commonly discussed mechanistic events associated with HILI are reactive metabolites and oxidative stress, mitochondrial injury, as well as inhibition of transporters. HDS⁻drug interactions, causing both synergistic and antagonizing effects of drugs, were also reported for certain HDS. The database contains information for nearly 300 commonly used HDS products to provide a single-entry point for better comprehension of their impact on public health.
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http://dx.doi.org/10.3390/ijms19102955DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6213387PMC
September 2018

Serum proteome mapping of EGF transgenic mice reveal mechanistic biomarkers of lung cancer precursor lesions with clinical significance for human adenocarcinomas.

Biochim Biophys Acta Mol Basis Dis 2018 10 28;1864(10):3122-3144. Epub 2018 Jun 28.

Hannover Medical School, Centre for Pharmacology and Toxicology, Carl-Neuberg-Str. 1, 30625 Hannover, Germany.

Atypical adenomatous hyperplasia (AAH) of the lung is a pre-invasive lesion (PL) with high risk of progression to lung cancer (LC). However, the pathways involved are uncertain. We searched for novel mechanistic biomarkers of AAH in an EGF transgenic disease model of lung cancer. Disease regulated proteins were validated by Western immunoblotting and immunohistochemistry (IHC) of control and morphologically altered respiratory epithelium. Translational work involved clinical resection material. Collectively, 68 unique serum proteins were identified by 2DE-MALDI-TOF mass spectrometry and 13 reached statistical significance (p < 0.05). EGF, amphiregulin and the EGFR endosomal sorting protein VPS28 were induced up to 5-fold while IHC confirmed strong induction of these proteins. Furthermore, ApoA1, α-2-macroglobulin, and vitamin-D binding protein were nearly 6- and 2-fold upregulated in AAH; however, ApoA1 was oppositely regulated in LC to evidence disease stage dependent regulation of this tumour suppressor. Conversely, plasminogen and transthyretin were highly significantly repressed by 3- and 20-fold. IHC confirmed induced ApoA1, Fetuin-B and transthyretin expression to influence calcification, inflammation and tumour-infiltrating macrophages. Moreover, serum ApoA4, ApoH and ApoM were 2-, 2- and 6-fold repressed; however tissue ApoM and sphingosine-1-phosphate receptor expression was markedly induced to suggest a critical role of sphingosine-1-phosphate signalling in PL and malignant transformation. Finally, a comparison of three different LC models revealed common and unique serum biomarkers mechanistically linked to EGFR, cMyc and cRaf signalling. Their validation by IHC on clinical resection material established relevance for distinct human lung pathologies. In conclusion, we identified mechanistic biomarker candidates recommended for in-depth clinical evaluation.
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http://dx.doi.org/10.1016/j.bbadis.2018.06.019DOI Listing
October 2018

Treatment of cyclosporine induced hypertension: Results from a long-term observational study using different antihypertensive medications.

Vascul Pharmacol 2019 04 19;115:69-83. Epub 2018 Jun 19.

Centre for Pharmacology and Toxicology, Hannover Medical School, Germany. Electronic address:

Post-transplant hypertension (PTH) is a common complication in cyclosporine immunosuppressed patients; however choosing the right antihypertensive medication is challenging. In a long-term observational study (≤13y) we examined different antihypertensive medications on graft/patient survival of kidney recipients with pre-existing and PTH. Altogether thirty-three co-variables were analyzed including dose and type of immunosuppressive and antihypertensive medication, co-medications, serum biochemistries and the glomerular filtration rate (GFR). A Cox proportional-hazard multivariable survival model was developed to detect a Hazard Ratio (HR) of 3.0 at the Bonferroni corrected level α = 0.0015. Importantly, a significant relationship between immunosuppressive cyclosporine dose/serum concentration, systolic blood pressure (SBP) and GFR (p < 0.001) was observed with post-transplant hypertension being a major risk factor (HR6.1) for graft/patient survival. Although all medications lowered effectively elevated SBP the risk of graft failure/death was significantly increased when hypertension was treated with ACE inhibitors or β-blockers (HR3.3 and 3.1) but not with angiotensin receptor- and/or Ca-channel blockers. Antihypertensive medication was associated with a decline in GFR but β-blockers alone or in combination with ARB and/or CCB improved GFR. Neither BMI nor any of the drug combinations used in immunosuppression, i.e. prednisolone, mycophenolic acid, azathioprine and/or sirolimus influenced patient and/or graft survival while decision tree analyses informed on complex dependencies between immunosuppressive medications, dose of anti-hypertensive drug and diuretics in the management of hypertension. In conclusion, our study is suggestive for graft/patient survival to be influenced by the class of antihypertensive medication. A prospective randomized clinical trial is needed to confirm the results.
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http://dx.doi.org/10.1016/j.vph.2018.06.012DOI Listing
April 2019

The pathogenesis of diclofenac induced immunoallergic hepatitis in a canine model of liver injury.

Oncotarget 2017 Dec 23;8(64):107763-107824. Epub 2017 Sep 23.

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.

Hypersensitivity to non-steroidal anti-inflammatory drugs is a common adverse drug reaction and may result in serious inflammatory reactions of the liver. To investigate mechanism of immunoallergic hepatitis beagle dogs were given 1 or 3 mg/kg/day (HD) oral diclofenac for 28 days. HD diclofenac treatment caused liver function test abnormalities, reduced haematocrit and haemoglobin but induced reticulocyte, WBC, platelet, neutrophil and eosinophil counts. Histopathology evidenced hepatic steatosis and glycogen depletion, apoptosis, acute lobular hepatitis, granulomas and mastocytosis. Whole genome scans revealed 663 significantly regulated genes of which 82, 47 and 25 code for stress, immune response and inflammation. Immunopathology confirmed strong induction of IgM, the complement factors C3&B, SAA, SERPING1 and others of the classical and alternate pathway. Alike, marked expression of CD205 and CD74 in Kupffer cells and lymphocytes facilitate antigen presentation and B-cell differentiation. The highly induced HIF1A and KLF6 protein expression in mast cells and macrophages sustain inflammation. Furthermore, immunogenomics discovered 24, 17, 6 and 11 significantly regulated marker genes to hallmark M1/M2 polarized macrophages, lymphocytic and granulocytic infiltrates; note, the latter was confirmed by CAE staining. Other highly regulated genes included alpha-2-macroglobulin, CRP, hepcidin, IL1R1, S100A8 and CCL20. Diclofenac treatment caused unprecedented induction of myeloperoxidase in macrophages and oxidative stress as shown by SOD1/SOD2 immunohistochemistry. Lastly, bioinformatics defined molecular circuits of inflammation and consisted of 161 regulated genes. Altogether, the mechanism of diclofenac induced liver hypersensitivity reactions involved oxidative stress, macrophage polarization, mastocytosis, complement activation and an erroneous programming of the innate and adaptive immune system.
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http://dx.doi.org/10.18632/oncotarget.21201DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5746105PMC
December 2017

Oncogenomics of c-Myc transgenic mice reveal novel regulators of extracellular signaling, angiogenesis and invasion with clinical significance for human lung adenocarcinoma.

Oncotarget 2017 Nov 23;8(60):101808-101831. Epub 2017 Oct 23.

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.

The c-Myc transcription factor is frequently deregulated in cancers. To search for disease diagnostic and druggable targets a transgenic lung cancer disease model was investigated. Oncogenomics identified c-Myc target genes in lung tumors. These were validated by RT-PCR, Western Blotting, EMSA assays and ChIP-seq data retrieved from public sources. Gene reporter and ChIP assays verified functional importance of c-Myc binding sites. The clinical significance was established by RT-qPCR in tumor and matched healthy control tissues, by RNA-seq data retrieved from the TCGA Consortium and by immunohistochemistry recovered from the Human Protein Atlas repository. In transgenic lung tumors 25 novel candidate genes were identified. These code for growth factors, Wnt/β-catenin and inhibitors of death receptors signaling, adhesion and cytoskeleton dynamics, invasion and angiogenesis. For 10 proteins over-expression was confirmed by IHC thus demonstrating their druggability. Moreover, c-Myc over-expression caused complete gene silencing of 12 candidate genes, including and to influence lung morphogenesis, invasiveness and cell signaling events. Conversely, among the 75 repressed genes TNFα and TGF-β pathways as well as negative regulators of IGF1 and MAPK signaling were affected. Additionally, anti-angiogenic, anti-invasive, adhesion and extracellular matrix remodeling and growth suppressive functions were repressed. For 15 candidate genes c-Myc-dependent DNA binding and transcriptional responses in human lung cancer samples were confirmed. Finally, Kaplan-Meier survival statistics revealed clinical significance for 59 out of 100 candidate genes, thus confirming their prognostic value. In conclusion, previously unknown c-Myc target genes in lung cancer were identified to enable the development of mechanism-based therapies.
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http://dx.doi.org/10.18632/oncotarget.21981DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5731916PMC
November 2017

ApoE is a major determinant of hepatic bile acid homeostasis in mice.

J Nutr Biochem 2018 02 28;52:82-91. Epub 2017 Sep 28.

Centre for Pharmacology and Toxicology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. Electronic address:

Apolipoprotein E (ApoE) plays a central role in lipid transport and cholesterol metabolism, with surplus cholesterol being removed from the liver through bile acid (BA) synthesis. Furthermore, BAs are of critical importance in fat absorption by forming intestinal lipid-bile salt mixed micelles. To define ApoE's role in BA homeostasis, the metabolism of cholesterol and BA was investigated in liver tissue and gallbladder bile of ApoE-deficient mice given a chow or high-cholesterol/high-fat diet (HCHF) diet for 6 months. When compared to wild-type mice, muricholic acid (MCA) and chenodeoxycholic acid (CDCA) increased approximately 15-, 82-, 22- and 38-fold, respectively, in hepatic tissue of ApoE-deficient mice given a chow or HCHF diet. Moreover, ApoE-deficient mice on an HCHF diet increased the amounts of hepatic free cholesterol, MCA and CDCA by 61%, 61% and 50% (P<.05). Conversely, total cholesterol and cholesterol esters were unchanged, and the bile acids taurohyodeoxycholic acid, taurodeoxycholic acid and hyodeoxycholic acid decreased to one third as compared to the chow diet (P<.05). Additionally, quantitative reverse-transcription polymerase chain reaction assays revealed induced expression of the bile acid receptor (Fxr) and associated transcription factors, i.e.Fxr, Lrh, Lxra and Srebp1c. Transcript expression of Cyp2a12, Cyp1b1, Cyp2e1, Cyp3a16 and Cyp4a10 was also induced. Note that Cyp4a10 catalyzes ω-hydroxylation of arachidonic acid to epoxy- and hydroxyeicosatrienoic acids to control vascular tone. Altogether, MCA and CDCA synthesis is selectively induced in ApoE-deficient mice. These hydrophilic BAs alter micellar size and structure to lower intestinal cholesterol solubilization. Furthermore, CDCA and MCA are potent FXR agonist and antagonist, respectively, and function in a regulatory loop to mitigate impaired ApoE function.
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http://dx.doi.org/10.1016/j.jnutbio.2017.09.008DOI Listing
February 2018

N-acetylcysteine and prednisolone treatment improved serum biochemistries in suspected flupirtine cases of severe idiosyncratic liver injury.

Liver Int 2018 02 8;38(2):365-376. Epub 2017 Sep 8.

Section of Hepatology, Clinic for Gastroenterology and Rheumatology, University Hospital Leipzig, Leipzig, Germany.

Background & Aims: The analgesic flupirtine has been linked to cases of severe idiosyncratic drug-induced liver injury (sFILI). We therefore examined whether N-acetylcysteine (NAC) and glucocorticoid therapy is effective in the management of sFILI.

Methods: In a retrospective cohort study efficacy of NAC-infusion and oral prednisolone treatments on liver-function-tests (LFTs) and clinical outcome of 21 sFILI cases was evaluated by comparing it to an external cohort of 30 sFILI cases not receiving the antidote. LFTs were also assayed in human hepatocyte cultures treated with flupirtine for 96 hours. Additionally, modulation of glutathione stores in cultures of human hepatocytes treated with 80 drugs was investigated.

Results: Upon admission, patients presented Alanine aminotransferase (ALT), aspartate aminotransferase (AST) and bilirubin elevations of up to 90-, 35- and 30-fold of upper limits of normal (ULN) respectively. The average INR was 2.2, and 50% of patients had a high Model for end-stage liver disease (MELD) score of ≥25 and included 5 cases of 28-32. The combined NAC/prednisolone treatment was well tolerated and led to significant ALT, AST and INR improvements within 2 weeks. However, the hyperbilirubinaemia resolved slowly. Two patients with late start of NAC/prednisolone treatment developed hepatic encephalopathy and required liver transplantation; the remaining patients recovered without long-term sequela. Based on serum biochemistries sFILI cases resolved more rapidly (P < .01) when compared to untreated sFILI patients and included a case with fatal outcome. Additionally, in vitro studies revealed glutathione depletion as a common culprit for drugs with liver liabilities.

Conclusions: Based on these initial findings a prospective randomized clinical trial (RCT) is needed to confirm safety and efficacy of NAC/prednisolone treatment in sFILI.
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http://dx.doi.org/10.1111/liv.13538DOI Listing
February 2018

A unifying mathematical model of lipid droplet metabolism reveals key molecular players in the development of hepatic steatosis.

FEBS J 2017 10 6;284(19):3245-3261. Epub 2017 Sep 6.

Institute of Biochemistry, Computational Systems Biochemistry Group, Charite - University Medicine Berlin, Germany.

The liver responds to elevated plasma concentrations of free fatty acids (FFAs) with an enhanced uptake of FFAs and their esterification to triacylglycerol (TAG). On the long term, this may result in massive hepatic TAG accumulation called steatosis hepatitis. In hepatocytes, the poor water-soluble TAG is packed in specialized organelles: Lipid droplets (LDs) serving as transient cellular deposit and lipoproteins (LPs) transporting TAG and cholesterol esters to extra-hepatic tissues. The dynamics of these organelles is controlled by a variety of regulatory surface proteins (RSPs). Assembly and export of VLDLs are mainly regulated by the microsomal transfer protein (MTP) and apoprotein B100. Formation and lipolysis of LDs are regulated by several RSPs. The best studied regulators belong to the PAT (Perilipin/Adipophilin/TIP47) and CIDE families. Knockdown or overexpression of SRPs may significantly affect the total number and size distribution of LDs. Intriguingly, a large cell-to-cell heterogeneity with respect to the number and size of LDs has been found in various cell types including hepatocytes. These findings suggest that the extent of cellular lipid accumulation is determined not only by the imbalance between lipid supply and utilization but also by variations in the expression of RSPs and metabolic enzymes. To better understand the relative regulatory impact of individual processes involved in the cellular TAG turnover, we developed a comprehensive kinetic model encompassing the pathways of the fatty acid and triglyceride metabolism and the main molecular processes governing the dynamics of LDs. The model was parametrized such that a large number of experimental in vitro and in vivo findings are correctly recapitulated. A control analysis of the model revealed that variations in the activity of FFA uptake, diacylglycerol acyltransferase (DGAT) 2, and adipose triglyceride lipase (ATGL) have the strongest influence on the cellular TAG level. We used the model to simulate LD size distributions in human hepatoma cells and hepatocytes exposed to a challenge with FFAs. A random fold change by a factor of about two in the activity of RSPs was sufficient to reproduce the large diversity of droplet size distributions observed in individual cells. Under the premise that the same extent of variability of RSPs holds for the intact organ, our model predicts variations in the TAG content of individual hepatocytes by a factor of about 3-6 depending on the nutritional regime. Taken together, our modeling approach integrates numerous experimental findings on individual processes in the cellular TAG metabolism and LD dynamics metabolism to a consistent state-of-the-art dynamic network model that can be used to study how changes in the external conditions or systemic parameters will affect the TAG content of hepatocytes.
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http://dx.doi.org/10.1111/febs.14189DOI Listing
October 2017

Associations of Drug Lipophilicity and Extent of Metabolism with Drug-Induced Liver Injury.

Int J Mol Sci 2017 Jun 22;18(7). Epub 2017 Jun 22.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR 72079, USA.

Drug-induced liver injury (DILI), although rare, is a frequent cause of adverse drug reactions resulting in warnings and withdrawals of numerous medications. Despite the research community's best efforts, current testing strategies aimed at identifying hepatotoxic drugs prior to human trials are not sufficiently powered to predict the complex mechanisms leading to DILI. In our previous studies, we demonstrated lipophilicity and dose to be associated with increased DILI risk and, and in our latest work, we factored reactive metabolites into the algorithm to predict DILI. Given the inconsistency in determining the potential for drugs to cause DILI, the present study comprehensively assesses the relationship between DILI risk and lipophilicity and the extent of metabolism using a large published dataset of 1036 Food and Drug Administration (FDA)-approved drugs by considering five independent DILI annotations. We found that lipophilicity and the extent of metabolism alone were associated with increased risk for DILI. Moreover, when analyzed in combination with high daily dose (≥100 mg), lipophilicity was statistically significantly associated with the risk of DILI across all datasets ( < 0.05). Similarly, the combination of extensive hepatic metabolism (≥50%) and high daily dose (≥100 mg) was also strongly associated with an increased risk of DILI among all datasets analyzed ( < 0.05). Our results suggest that both lipophilicity and the extent of hepatic metabolism can be considered important risk factors for DILI in humans, and that this relationship to DILI risk is much stronger when considered in combination with dose. The proposed paradigm allows the convergence of different published annotations to a more uniform assessment.
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http://dx.doi.org/10.3390/ijms18071335DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5535828PMC
June 2017

Primary non-function is frequently associated with fatty liver allografts and high mortality after re-transplantation.

Liver Int 2017 08 15;37(8):1219-1228. Epub 2017 May 15.

Centre for Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany.

Background & Aims: The shortage of liver donations demands the use of suboptimal grafts with steatosis being a frequent finding. Although ≤30% macrovesicular steatosis is considered to be safe the risk for primary non-function (PNF) and outcome after re-transplantation (re-OLT) is unknown.

Methods: Among 1205 orthotopic liver transplantations performed at our institution the frequency, survival and reason of re-OLT were evaluated. PNF (group A) cases and those with initial transplant function but subsequent need for re-OLT (group B) were analysed. Histopathology and clinical judgement determined the cause of PNF and included an assessment of hepatic steatosis. Additionally, survival of fatty liver allografts (group C) not requiring re-OLT was considered in Kaplan-Meier and multivariate regression analysis.

Results: A total of 77 high urgency re-OLTs were identified and included 39 PNF cases. Nearly 70% of PNF cases were due to primary fatty liver allografts. The 3-month in-hospital mortality for PNF cases after re-OLT was 46% and the mean survival after re-OLT was 0.5 years as compared to 5.2 and 5.1 years for group B, C, respectively, (P<.008). In multivariate Cox regression analysis only hepatic steatosis was associated with an inferior survival (HR 4.272, P=.002). The MELD score, donor BMI, age, cold ischaemic time, ICU stay, serum sodium and transaminases did not influence overall survival.

Conclusions: Our study highlights fatty liver allografts to be a major cause for PNF with excessive mortality after re-transplantation. The findings demand the development of new methods to predict risk for PNF of fatty liver allografts.
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http://dx.doi.org/10.1111/liv.13404DOI Listing
August 2017

Drug-Induced Liver Injury.

Biomed Res Int 2017 9;2017:2461694. Epub 2017 Jan 9.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.

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http://dx.doi.org/10.1155/2017/2461694DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253497PMC
February 2017

In vitro to in vivo extrapolation for drug-induced liver injury using a pair ranking method.

ALTEX 2017 11;34(3):399-407. Epub 2017 Jan 11.

National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR, USA.

Preclinical animal toxicity studies may not accurately predict human toxicity. In light of this, in vitro systems have been developed that have the potential to supplement or even replace animal use. We examined in vitro to in vivo extrapolation (IVIVE) of gene expression data obtained from The Open Japanese Toxicogenomics Project-Genomics Assisted Toxicity Evaluation System (Open TG-GATEs) for 131 compounds given to rats for 28 days, and to human or rat hepatocytes for 24 hours. Notably, a pair ranking (PRank) method was developed to assess IVIVE potential with a PRank score based on the preservation of the order of similarity rankings of compound pairs between the platforms using a receiver operating characteristic (ROC) curve analysis to measure area under the curve (AUC). A high IVIVE potential was noted for rat primary hepatocytes when compared to rat 28-day studies (PRank score = 0.71) whereas the IVIVE potential for human primary hepatocytes compared to rat 28-day studies was lower (PRank score = 0.58), indicating that species difference plays a critical role in IVIVE. When limiting the analysis to only those drugs causing drug-induced liver injury, the IVIVE potential was slightly improved both for rats (from 0.71 to 0.76) and for humans (from 0.58 to 0.62). Similarly, PRank scores were improved when the analysis focused on specific hepatotoxic endpoints such as hepatocellular injury, or cholestatic injury. In conclusion, toxicogenomic data generated in vitro yields a ranking of drugs regarding their potential to cause toxicity which is comparable to that generated by in vivo analyses.
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http://dx.doi.org/10.14573/altex.1610201DOI Listing
October 2017

Gene expression profiling of calcium-channel antagonists in the heart of hypertensive and normotensive rats reveals class specific effects.

Vascul Pharmacol 2016 12 6;87:121-128. Epub 2016 Sep 6.

Hannover Medical School, Centre for Pharmacology and Toxicology, Carl-Neuberg-Str. 1, 30625 Hannover, Germany. Electronic address:

Calcium channel blockers (CCB) differ in their effects on the cardiovascular system with diltiazem being less negatively ionotrop as compared to verapamil. Diltiazem is mainly used to treat supraventricular tachycardia, vasospastic angina and the Raynaud's syndrome. Little is known about the molecular effects of benzothiazepins on cardiac gene expression. We therefore investigated the effects of diltiazem on cardiac gene expression in normotensive and hypertensive rats with left ventricular hypertrophy and compared the results with our previous findings on verapamil and nifedipine. Spontaneously hypertensive (SHR) and normotensive Sprague Dawley (SD) rats were treated with 15mg/kg diltiazem b.i.d. for 3days. Total RNA was isolated from surgically removed hearts and the gene expression of ion channels, ion transporters and their associated partners, calcium handling proteins as well as stress and cellular differentiation markers was investigated by RT-PCR. Subsequently, hierarchical gene cluster analysis was performed to decode treatment effects of different classes of CCBs. CCB treatment of normotensive and hypertensive rats revealed class specific effects with diltiazem specifically repressing cardiac genes pertinent for ion homeostasis and excitation-contraction coupling in normotensive but not hypertensive rats. Conversely, verapamil and nifedipine caused predominantly repression of genes to affect ion homeostasis and contractile dysfunction in spontaneously hypertensive rats; nonetheless, genes coding for calcium-handling proteins were up-regulated. Unlike diltiazem treatment of normotensive rats with verapamil and/or nifedipine did not influence cardiac gene expression. The effects of diltiazem on cardiac gene expression provide a molecular rationale for its use in the treatment of vasospastic angina.
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http://dx.doi.org/10.1016/j.vph.2016.09.001DOI Listing
December 2016

c-Myc targeted regulators of cell metabolism in a transgenic mouse model of papillary lung adenocarcinoma.

Oncotarget 2016 Oct;7(40):65514-65539

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.

c-Myc's role in pulmonary cancer metabolism is uncertain. We therefore investigated c-Myc activity in papillary lung adenocarcinomas (PLAC). Genomics revealed 90 significantly regulated genes (> 3-fold) coding for cell growth, DNA metabolism, RNA processing and ribosomal biogenesis and bioinformatics defined c-Myc binding sites (TFBS) at > 95% of up-regulated genes. EMSA assays at 33 novel TFBS evidenced DNA binding activity and ChIP-seq data retrieved from public repositories confirmed these to be c-Myc bound. Dual-luciferase gene reporter assays developed for RNA-Terminal-Phosphate-Cyclase-Like-1(RCL1), Ribosomal-Protein-SA(RPSA), Nucleophosmin/Nucleoplasmin-3(NPM3) and Hexokinase-1(HK1) confirmed c-Myc functional relevance and ChIP assays with HEK293T cells over-expressing ectopic c-Myc demonstrated enriched c-Myc occupancy at predicted TFBS for RCL1, NPM3, HK1 and RPSA. Note, c-Myc recruitment on chromatin was comparable to the positive controls CCND2 and CDK4. Computational analyses defined master regulators (MR), i.e. heterogeneous nuclear ribonucleoprotein A1, nucleolin, the apurinic/apyrimidinic endonuclease 1, triosephosphate-isomerase 1, folate transporter (SLC19A1) and nucleophosmin to influence activity of up to 90% of PLAC-regulated genes. Their expression was induced by 3-, 3-, 6-, 3-, 11- and 7-fold, respectively. STRING analysis confirmed protein-protein-interactions of regulated genes and Western immunoblotting of fatty acid synthase, serine hydroxyl-methyltransferase 1, arginine 1 and hexokinase 2 showed tumor specific induction. Published knock down studies confirmed these proteins to induce apoptosis by disrupting neoplastic lipogenesis, by endorsing uracil accumulation and by suppressing arginine metabolism and glucose-derived ribonucleotide biosynthesis. Finally, translational research demonstrated high expression of MR and of 47 PLAC up-regulated genes to be associated with poor survival in lung adenocarcinoma patients (HR 3.2 p < 0.001) thus, providing a rationale for molecular targeted therapies in PLACs.
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http://dx.doi.org/10.18632/oncotarget.11804DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5323172PMC
October 2016

Genomics of human fatty liver disease reveal mechanistically linked lipid droplet-associated gene regulations in bland steatosis and nonalcoholic steatohepatitis.

Transl Res 2016 11 16;177:41-69. Epub 2016 Jun 16.

Centre for Pharmacology and Toxicology, Hannover Medical School, Hannover, Germany. Electronic address:

Nonalcoholic fatty liver disease (NAFLD) is a common disorder hallmarked by excessive lipid deposits. Based on our recent research on lipid droplet (LD) formation in hepatocytes, we investigated LD-associated gene regulations in NAFLD of different grades, that is, steatosis vs steatohepatitis by comparing liver biopsies from healthy controls (N = 13) and NAFLD patients (N = 102). On average, more than 700 differentially expressed genes (DEGs) were identified of which 146 are mechanistically linked to LD formation. We identified 51 LD-associated DEGs frequently regulated in patient samples (range ≥5 to ≤102) with the liver-receptor homolog-1(NR5A2), that is, a key regulator of cholesterol metabolism being commonly repressed among 100 patients examined. With bland steatosis, notable regulations involved hypoxia-inducible lipid droplet-associated-protein and diacylglycerol-O-acyltransferase-2 renowned for their role in LD-growth. Conversely, nonalcoholic steatohepatitis-associated DEGs coded for epidermal growth factor receptor and TLR4 signaling with decreased expression of the GTPase Rab5 and the lipid phosphohydrolase PPAP2B thus highlighting adaptive responses to inflammation, LDL-mediated endocytosis and lipogenesis, respectively. Studies with steatotic primary human hepatocyte cultures demonstrated induction of LD-associated PLIN2, CIDEC, DNAAF1, whereas repressed expression of CPT1A, ANGPTL4, and PKLR informed on burdened mitochondrial metabolism. Equally, repressed expression of the B-lymphocyte chemoattractant CXCL13 and STAT4 as well as induced FGF21 evidenced amelioration of steatosis-related inflammation. In-vitro/in-vivo patient sample comparisons confirmed C-reactive protein, SOCS3, NR5A2, and SOD2 as commonly regulated. Lastly, STRING network analysis highlighted potential "druggable" targets with PLIN2, CIDEC, and hypoxia-inducible lipid droplet-associated-protein being confirmed by immunofluorescence microscopy. In conclusion, steatosis and steatohepatitis specific gene regulations informed on the pathogenesis of NAFLD to broaden the perspective of targeted therapies.
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http://dx.doi.org/10.1016/j.trsl.2016.06.003DOI Listing
November 2016

A Model to predict severity of drug-induced liver injury in humans.

Hepatology 2016 09 27;64(3):931-40. Epub 2016 Jul 27.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, US Food and Drug Administration, Jefferson, AR.

Unlabelled: Drug-induced liver injury (DILI) is a major public health concern, and improving its prediction remains an unmet challenge. Recently, we reported the Rule-of-2 (RO2) and found lipophilicity (logP ≥3) and daily dose ≥100 mg of oral medications to be associated with significant risk for DILI; however, the RO2 failed to estimate grades of DILI severity. In an effort to develop a quantitative metrics, we analyzed the association of daily dose, logP, and formation of reactive metabolites (RM) in a large set of Food and Drug Administration-approved oral medications and found factoring RM into the RO2 to highly improve DILI prediction. Based on these parameters and by considering n = 354 drugs, an algorithm to assign a DILI score was developed. In univariate and multivariate logistic regression analyses the algorithm (i.e., DILI score model) defined the relative contribution of daily dose, logP, and RM and permitted a quantitative assessment of risk of clinical DILI. Furthermore, a clear relationship between calculated DILI scores and DILI risk was obtained when applied to three independent studies. The DILI score model was also functional with drug pairs defined by similar chemical structure and mode of action but divergent toxicities. Specifically, for drug pairs where the RO2 failed, the DILI score correctly identified toxic drugs. Finally, the model was applied to n = 159 clinical cases collected from the National Institutes of Health's LiverTox database to demonstrate that the DILI score correlated with the severity of clinical outcome.

Conclusions: Based on daily dose, lipophilicity, and RM, a DILI score algorithm was developed that provides a scale of assessing the severity of DILI risk in humans associated with oral medications. (Hepatology 2016;64:931-940).
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http://dx.doi.org/10.1002/hep.28678DOI Listing
September 2016

Regulation of glycosylphosphatidylinositol-anchored proteins and GPI-phospholipase D in a c-Myc transgenic mouse model of hepatocellular carcinoma and human HCC.

Biol Chem 2016 11;397(11):1147-1162

Recent research implicated glycosylphosphatidylinositol-anchored proteins (GPI-AP) and GPI-specific phospholipase D (GPI-PLD) in the pathogenesis of fatty liver disease and hepatocellular carcinoma (HCC). Given that c-Myc is frequently amplified in HCC, we investigated their regulation in a c-Myc transgenic disease model of liver cancer and HCC patient samples. Whole genome scans defined 54 significantly regulated genes coding for GPI-AP of which 29 and 14 were repressed in expression in transgenic tumors and steatotic human hepatocyte cultures, respectively, to influence lipid-mediated signal transduction, extracellular matrix and immunity pathways. Analysis of gene specific promoter revealed >95% to carry c-Myc binding sites thus establishing a link between c-Myc activity and transcriptional response. Alike, serum GPI-PLD activity was increased 4-fold in transgenic mice; however its tissue activity was reduced by 70%. The associated repression of the serine/threonine phosphatase 2A (PP2A), i.e. a key player of c-Myc proteolysis, indicates co-ordinate responses aimed at impairing tissue GPI-PLD anti-proliferative activities. Translational research identified >4-fold increased GPI-PLD serum protein expression though enzyme activities were repressed by 60% in NASH and HCC patients. Taken collectively, c-Myc influences GPI-AP signaling transcriptionally and posttranslational and represses GPI-AP anti-proliferative signaling in tumors. The findings broaden the perspective of molecular targeted therapies and disease monitoring.
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http://dx.doi.org/10.1515/hsz-2016-0133DOI Listing
November 2016

Immune-mediated liver injury of the cancer therapeutic antibody catumaxomab targeting EpCAM, CD3 and Fcγ receptors.

Oncotarget 2016 May;7(19):28059-74

Applied Cancer Research - Institution for Translational Research Vienna (ACR-ITR VIEnna) and Ludwig Boltzmann Institute for Applied Cancer Research (LBI-ACR VIEnna), Center for Oncology and Hematology, Kaiser Franz Josef-Spital, Vienna, Austria.

The immunotherapeutic catumaxomab targets EpCAM positive cancers and is approved for the treatment of peritoneal carcinomatosis. To assess the safety of intravenous applications a phase 1 clinical trial was initiated. Treatment of EpCAM positive tumor patients with catumaxomab caused dose dependent hepatitis as evidenced by significant elevations in serum alanine- and aspartate aminotransferases, bilirubin, γGT and induction of the acute phase C-reactive protein (CRP) and the cytokines IL6 and IL8. The first patient receiving 10μg catumaxomab experienced fatal acute liver failure which led to the termination of the study. Immmunopathology revealed catumaxomab to bind via its Fc-fragment to FcγR-positive Kupffer cells to stimulate CRP, chemokine and cytokine release. The observed CD3+T-cell margination at activated hepatic macrophages exacerbated T-cell mediated cytotoxicity. Strikingly, the combined Kupffer/T-cell responses against liver cells did not require hepatocytes to be EpCAM-positive. Catumaxomab's off-target activity involved T-cell mediated lysis of the granzyme B cell death pathway and the molecular interaction of hepatic sinusoidal macrophages with T-cells induced cytolytic hepatitis. Although the bile ducts were surrounded by densely packed lymphocytes these rarely infiltrated the ducts to suggest an intrahepatic cholestasis as the cause of hyperbilirubinaemia. Lastly, evidence for the programming of memory T-cells was observed with one patient that succumbed to his cancer six weeks after the last catumaxomab infusion. In conclusion, our study exemplifies off-target hepatotoxicity with molecularly targeted therapy and highlights the complexities in the clinical development of immunotherapeutic antibodies.
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5053709PMC
http://dx.doi.org/10.18632/oncotarget.8574DOI Listing
May 2016

Mechanistically linked serum miRNAs distinguish between drug induced and fatty liver disease of different grades.

Sci Rep 2016 Apr 5;6:23709. Epub 2016 Apr 5.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, Arkansas, USA.

Hepatic steatosis is characterised by excessive triglyceride accumulation in the form of lipid droplets (LD); however, mechanisms differ in drug induced (DIS) and/or non-alcoholic fatty liver disease (NAFLD). Here we hypothesized distinct molecular circuits of microRNA/LD-associated target genes and searched for mechanistically linked serum and tissue biomarkers that would distinguish between DIS and human NAFLD of different grades. We analysed >800 rat hepatic whole genome data for 17 steatotic drugs and identified 157 distinct miRNAs targeting 77 DIS regulated genes. Subsequently, genomic data of N = 105 cases of human NAFLD and N = 32 healthy controls were compared to serum miRNA profiles of N = 167 NAFLD patients. This revealed N = 195 tissue-specific miRNAs being mechanistically linked to LD-coding genes and 24 and 9 miRNAs were commonly regulated in serum and tissue of advanced and mild NAFLD, respectively. The NASH serum regulated miRNAs informed on hepatic inflammation, adipocytokine and insulin signalling, ER-and caveolae associated activities and altered glycerolipid metabolism. Conversely, serum miRNAs associated with blunt steatosis specifically highlighted activity of FOXO1&HNF4α on CPT2, the lipid droplet and ER-lipid-raft associated PLIN3 and Erlin1. Altogether, serum miRNAs informed on the molecular pathophysiology of NAFLD and permitted differentiation between DIS and NAFLD of different grades.
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http://dx.doi.org/10.1038/srep23709DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4820692PMC
April 2016

Inhibition of bile salt transport by drugs associated with liver injury in primary hepatocytes from human, monkey, dog, rat, and mouse.

Chem Biol Interact 2016 Aug 19;255:45-54. Epub 2016 Mar 19.

Division of Bioinformatics and Biostatistics, National Center for Toxicological Research, U.S. Food and Drug Administration, Jefferson, AR 72079, USA.

Interference of bile salt transport is one of the underlying mechanisms for drug-induced liver injury (DILI). We developed a novel bile salt transport activity assay involving in situ biosynthesis of bile salts from their precursors in primary human, monkey, dog, rat, and mouse hepatocytes in suspension as well as LC-MS/MS determination of extracellular bile salts transported out of hepatocytes. Glycine- and taurine-conjugated bile acids were rapidly formed in hepatocytes and effectively transported into the extracellular medium. The bile salt formation and transport activities were time‒ and bile-acid-concentration‒dependent in primary human hepatocytes. The transport activity was inhibited by the bile salt export pump (BSEP) inhibitors ketoconazole, saquinavir, cyclosporine, and troglitazone. The assay was used to test 86 drugs for their potential to inhibit bile salt transport activity in human hepatocytes, which included 35 drugs associated with severe DILI (sDILI) and 51 with non-severe DILI (non-sDILI). Approximately 60% of the sDILI drugs showed potent inhibition (with IC50 values <50 μM), but only about 20% of the non-sDILI drugs showed this strength of inhibition in primary human hepatocytes and these drugs are associated only with cholestatic and mixed hepatocellular cholestatic (mixed) injuries. The sDILI drugs, which did not show substantial inhibition of bile salt transport activity, are likely to be associated with immune-mediated liver injury. Twenty-four drugs were also tested in monkey, dog, rat and mouse hepatocytes. Species differences in potency were observed with mouse being less sensitive than other species to inhibition of bile salt transport. In summary, a novel assay has been developed using hepatocytes in suspension from human and animal species that can be used to assess the potential for drugs and/or drug-derived metabolites to inhibit bile salt transport and/or formation activity. Drugs causing sDILI, except those by immune-mediated mechanism, are highly associated with potent inhibition of bile salt transport.
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http://dx.doi.org/10.1016/j.cbi.2016.03.019DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5891329PMC
August 2016

Immunogenomics reveal molecular circuits of diclofenac induced liver injury in mice.

Oncotarget 2016 Mar;7(12):14983-5017

Centre for Pharmacology and Toxicology, Hannover Medical School, 30625 Hannover, Germany.

Diclofenac is a non-steroidal anti-inflammatory drug and its use can be associated with severe adverse reactions, notably myocardial infarction, stroke and drug-induced liver injury (DILI). In pursue of immune-mediated DILI mechanisms an immunogenomic study was carried out. Diclofenac treatment of mice at 30 mg/kg for 3 days caused significant serum ALT and AST elevations, hepatomegaly and degenerative changes including hepatic glycogen depletion, hydropic swelling, cholesterolosis and eosinophilic hepatocytes with one animal presenting subsegmental infarction due to portal vein thrombosis. Furthermore, portal/periportal induction of the rate limiting enzyme in ammonia detoxification, i.e. carbamoyl phosphate synthetase 1 was observed. The performed microarray studies informed on > 600 differential expressed genes of which 35, 37 and 50 coded for inflammation, 51, 44 and 61 for immune and 116, 129 and 169 for stress response, respectively after single and repeated dosing for 3 and 14 days. Bioinformatic analysis defined molecular circuits of hepatic inflammation with the growth hormone (Ghr)- and leptin receptor, the protein-tyrosine-phosphatase, selectin and the suppressor-of-cytokine-signaling (Socs) to function as key nodes in gene regulatory networks. Western blotting confirmed induction of fibronectin and M-CSF to hallmark tissue repair and differentiation of monocytes and macrophages. Transcript expression of the macrophage receptor with collagenous structure increased > 7-fold and immunohistochemistry of CD68 evidenced activation of tissue-resident macrophages. Importantly, diclofenac treatment prompted strong expression of phosphorylated Stat3 amongst individual animals and the associated 8- and 4-fold Soc3 and Il-6 induction reinforced Ghr degradation as evidenced by immunoblotting. Moreover, immunohistochemistry confirmed regulation of master regulatory proteins of diclofenac treated mice to suggest complex pro-and anti-inflammatory reactions in immune-mediated hepatic injury. The findings encourage translational research.
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http://dx.doi.org/10.18632/oncotarget.7698DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4924767PMC
March 2016

Evaluation of multiple mechanism-based toxicity endpoints in primary cultured human hepatocytes for the identification of drugs with clinical hepatotoxicity: Results from 152 marketed drugs with known liver injury profiles.

Chem Biol Interact 2016 Aug 12;255:3-11. Epub 2015 Nov 12.

Division of Bioinformatics and Biostatistics, NCTR/FDA, Jefferson, AR, USA. Electronic address:

We report here the results of a collaborative research program to develop a robust and reliable in vitro system to allow an accurate definition of the drug-induced liver injury (DILI) potential of new drug entities during drug development. The in vitro hepatotoxic potential of 152 drugs with known DILI profiles were evaluated in primary cultured human hepatocytes with four mechanistically-relevant endpoints: cellular ATP depletion, reactive oxygen species (ROS), glutathione (GSH) depletion, and caspase activation for apoptosis. The drugs, 80 in the testing set and 72 in the validation set, were classified based on serious clinical/regulatory outcomes as defined by reported acute liver failure, black-box warning, and/or withdrawal. The drugs were further sub-categorized for dominant types of liver injury. Logistic regression models were performed to calculate the area under the receiver operating characteristics curve (AUROC) and to evaluate the prediction potential of the selected endpoints for serious clinical/regulatory outcomes. The ROS/ATP ratio was found to yield an excellent AUROC in both the testing (0.8989, P < 0.0001) and validation set (0.8545, P < 0.0001), and was found to distinguish drugs associated with severe from non-severe DILI cases (p < 0.0001). The results suggest that evaluation of drugs in primary human hepatocytes using the ROS/ATP ratio endpoint may aid the definition of their potential to cause severe DILI.
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http://dx.doi.org/10.1016/j.cbi.2015.11.008DOI Listing
August 2016