AllergoOncology: Biomarkers and refined classification for research in the allergy and glioma nexus-A joint EAACI-EANO position paper.

Epidemiological studies have explored the relationship between allergic diseases and cancer risk or prognosis in AllergoOncology. Some studies suggest an inverse association, but uncertainties remain, including in IgE-mediated diseases and glioma. Allergic disease stems from a Th2-biased immune response to allergens in predisposed atopic individuals. Allergic disorders vary in phenotype, genotype and endotype, affecting their pathophysiology. Beyond clinical manifestation and commonly used clinical markers, there is ongoing research to identify novel biomarkers for allergy diagnosis, monitoring, severity assessment and treatment. Gliomas, the most common and diverse brain tumours, have in parallel undergone changes in classification over time, with specific molecular biomarkers defining glioma subtypes. Gliomas exhibit a complex tumour-immune interphase and distinct immune microenvironment features. Immunotherapy and targeted therapy hold promise for primary brain tumour treatment, but require more specific and effective approaches. Animal studies indicate allergic airway inflammation may delay glioma progression. This collaborative European Academy of Allergy and Clinical Immunology (EAACI) and European Association of Neuro-Oncology (EANO) Position Paper summarizes recent advances and emerging biomarkers for refined allergy and adult-type diffuse glioma classification to inform future epidemiological and clinical studies. Future research is needed to enhance our understanding of immune-glioma interactions to ultimately improve patient prognosis and survival.

A fingerprint of 2-[18F]FDG radiometabolites - How tissue-specific metabolism beyond 2-[18F]FDG-6-P could affect tracer accumulation.

Studies indicate that the radiotracer 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) can be metabolized beyond 2-[18F]FDG-6-phosphate (2-[18F]FDG-6-P), but its metabolism is incompletely understood. Most importantly, it remains unclear whether downstream metabolism affects tracer accumulation in vivo. Here we present a fingerprint of 2-[18F]FDG radiometabolites over time in cancer cells, corresponding tumor xenografts and murine organs. Strikingly, radiometabolites representing glycogen metabolism or the oxPPP correlated inversely with tracer accumulation across all examined tissues. Recent studies suggest that not only hexokinase, but also hexose-6-phosphate dehydrogenase (H6PD), an enzyme of the oxidative pentose phosphate pathway (oxPPP), determines 2-[18F]FDG accumulation. However, little is known about the corresponding enzyme glucose-6-phosphate dehydrogenase (G6PD). Our mechanistic in vitro experiments on the role of the oxPPP propose that 2-[18F]FDG can be metabolized via both G6PD and H6PD, but data from separate enzyme knockdown suggest diverging roles in downstream tracer metabolism. Overall, we propose that tissue-specific metabolism beyond 2-[18F]FDG-6-P could matter for imaging.

Targeting DNA repair to enhance the efficacy of sorafenib in hepatocellular carcinoma.

The multityrosine kinase inhibitor sorafenib remains an important systemic treatment option for hepatocellular carcinoma (HCC). Signaling pathways, which are targeted by sorafenib, are involved in checkpoint and DNA repair response, RAD51 being a candidate protein. Here, we aim to evaluate the effect of the human RAD51 inhibitor B02 in combination with sorafenib in human HCC cells. Impact of RAD51 expression on HCC patient survival was evaluated by an in silico approach using Human Protein Atlas dataset. Cell viability of HUH7, AKH12, AKH13, and 3P was assessed by neutral red assay. To measure the cytotoxicity, we quantified loss of membrane integrity by lactate dehydrogenase release. We also employed colony formation assay and hanging drop method to assess clonogenic and invasive ability of HCC cell lines upon sorafenib and B02 treatment. Cell cycle distribution and characterization of apoptosis was evaluated by flow cytometry. In silico approach revealed that HCC patients with higher expression of RAD51 messenger RNA had a significantly shorter overall survival. The RAD51 inhibitor B02 alone and in combination with sorafenib significantly reduced viability, colony formation ability, and invasion capacity of HCC cells. Cell cycle analysis revealed that the combination of both agents reduces the proportion of cells in the G2/M phase while leading to an accumulating in the subG1 phase. The RAD51 inhibitor B02 seems to be a promising agent for HCC treatment and enhances the antitumor effects of sorafenib in vitro.

If It Works, Don't Touch It? A Cell-Based Approach to Studying 2-[18F]FDG Metabolism.

The glucose derivative 2-[18F]fluoro-2-deoxy-D-glucose (2-[18F]FDG) is still the most used radiotracer for positron emission tomography, as it visualizes glucose utilization and energy demand. In general, 2-[18F]FDG is said to be trapped intracellularly as 2-[18F]FDG-6-phosphate, which cannot be further metabolized. However, increasingly, this dogma is being questioned because of publications showing metabolism beyond 2-[18F]FDG-6-phosphate and even postulating 2-[18F]FDG imaging to depend on the enzyme hexose-6-phosphate dehydrogenase in the endoplasmic reticulum. Therefore, we aimed to study 2-[18F]FDG metabolism in the human cancer cell lines HT1080, HT29 and Huh7 applying HPLC. We then compared 2-[18F]FDG metabolism with intracellular tracer accumulation, efflux and the cells' metabolic state and used a graphical Gaussian model to visualize metabolic patterns. The extent of 2-[18F]FDG metabolism varied considerably, dependent on the cell line, and was significantly enhanced by glucose withdrawal. However, the metabolic pattern was quite conserved. The most important radiometabolites beyond 2-[18F]FDG-6-phosphate were 2-[18F]FDMannose-6-phosphate, 2-[18F]FDG-1,6-bisphosphate and 2-[18F]FD-phosphogluconolactone. Enhanced radiometabolite formation under glucose reduction was accompanied by reduced efflux and mirrored the cells' metabolic switch as assessed via extracellular lactate levels. We conclude that there can be considerable metabolism beyond 2-[18F]FDG-6-phosphate in cancer cell lines and a comprehensive understanding of 2-[18F]FDG metabolism might help to improve cancer research and tumor diagnosis.

Morphometric Analysis of Mast Cells in Tumor Predicts Recurrence of Hepatocellular Carcinoma After Liver Transplantation.

Tumor-infiltrating immune cells are relevant prognostic and immunotherapeutic targets in hepatocellular carcinoma (HCC). Mast cells play a key role in allergic response but may also be involved in anticancer immunity. Digital morphometric analysis of patient tissue sections has become increasingly available for clinical routine and provides unbiased quantitative data. Here, we apply morphometric analysis of mast cells to retrospectively evaluate their relevance for HCC recurrence in patients after orthotopic liver transplantation (OLT). A total of 173 patients underwent OLT for HCC at the Medical University of Vienna (21 women, 152 men; 55.2 ± 7.9 years; 74 beyond Milan criteria, 49 beyond up-to-7 criteria for liver transplantation). Tissue arrays from tumors and corresponding surrounding tissues were immunohistochemically stained for mast cell tryptase. Mast cells were quantified by digital tissue morphometric analysis and correlated with HCC recurrence. Mast cells were detected in 93% of HCC tumors and in all available surrounding liver tissues. Tumor tissues revealed lower mast cell density than corresponding surrounding tissues (P < 0.0001). Patients lacking intratumoral mast cells (iMCs) displayed larger tumors and higher tumor recurrence rates both in the whole cohort (hazard ratio [HR], 2.74; 95% confidence interval [CI], 1.09-6.93; P = 0.029) and in patients beyond transplant criteria (Milan HR, 2.81; 95% CI, 1.04-7.62; P = 0.01; up-to-7 HR, 3.58; 95% CI, 1.17-10.92; P = 0.02). Notably, high iMC identified additional patients at low risk classified outside the Milan and up-to-7 criteria, whereas low iMC identified additional patients at high risk classified within the alpha-fetoprotein French and Metroticket criteria. iMCs independently predicted tumor recurrence in a multivariate Cox regression analysis (Milan HR, 2.38; 95% CI, 1.16-4.91; P = 0.019; up-to-7 HR, 2.21; 95% CI, 1.05-4.62; P = 0.035). Conclusion: Hepatic mast cells might be implicated in antitumor immunity in HCC. Morphometric analysis of iMCs refines prognosis of HCC recurrence after liver transplantation.

Cytotoxic Activity of Piperazin-2-One-Based Structures: Cyclic Imines, Lactams, Aminophosphonates, and Their Derivatives.

N-Heterocycles are considered as desirable scaffolds for the development of novel lead compounds for anticancer drug research. Among them, phosphorus-containing amino-derivatives play a crucial role. A series of imines and products of their further reactions with P-nucleophiles were obtained starting from vicinal bisamines. Reaction of ethylenediamine and α-carbonyl esters yielded in novel unexpected products, which structures were confirmed by crystallographic measurements. The cytotoxic activity evaluation was done on a variety of cell lines including HUH7, AKH12, DAOY, UW228-2, D283, D425, and U251. Human umbilical vein endothelial cells (HUVECs) were used as control. Two of the tested compounds, bearing TADDOL-derived, and trifluoromethyl substituents showed a significant effect on cell viability, though comparable to nonmalignant cells.

PIDDosome-induced p53-dependent ploidy restriction facilitates hepatocarcinogenesis.

Polyploidization frequently precedes tumorigenesis but also occurs during normal development in several tissues. Hepatocyte ploidy is controlled by the PIDDosome during development and regeneration. This multi-protein complex is activated by supernumerary centrosomes to induce p53 and restrict proliferation of polyploid cells, otherwise prone for chromosomal instability. PIDDosome deficiency in the liver results in drastically increased polyploidy. To investigate PIDDosome-induced p53-activation in the pathogenesis of liver cancer, we chemically induced hepatocellular carcinoma (HCC) in mice. Strikingly, PIDDosome deficiency reduced tumor number and burden, despite the inability to activate p53 in polyploid cells. Liver tumors arise primarily from cells with low ploidy, indicating an intrinsic pro-tumorigenic effect of PIDDosome-mediated ploidy restriction. These data suggest that hyperpolyploidization caused by PIDDosome deficiency protects from HCC. Moreover, high tumor cell density, as a surrogate marker of low ploidy, predicts poor survival of HCC patients receiving liver transplantation. Together, we show that the PIDDosome is a potential therapeutic target to manipulate hepatocyte polyploidization for HCC prevention and that tumor cell density may serve as a novel prognostic marker for recurrence-free survival in HCC patients.

Soluble guanylyl cyclase stimulation and phosphodiesterase-5 inhibition improve portal hypertension and reduce liver fibrosis in bile duct-ligated rats.

BACKGROUND: In cirrhosis, the nitric oxide-soluble guanylyl cyclase (sGC)-cyclic guanosine monophosphate (cGMP) pathway is impaired, which contributes to increased intrahepatic vascular resistance (IHVR) and fibrogenesis. We investigated if sGC stimulation (riociguat (RIO)), sGC activation (cinaciguat (CINA)) or phosphodiesterase (PDE)-5 inhibition (tadalafil (TADA)) improves portal hypertension (PHT) and liver fibrosis. METHODS: Fifty male Sprague-Dawley rats underwent bile-duct ligation (BDL) or sham operation. RIO (0.5 mg/kg), CINA (1 mg/kg), TADA (1.5 mg/kg) or vehicle (VEH) was administered from weeks 2 to 4 after BDL. At week 4, invasive haemodynamic measurements were performed, and liver fibrosis was assessed by histology (chromotrope-aniline blue (CAB), Picro-Sirius red (PSR)) and hepatic hydroxyproline content. RESULTS: Cirrhotic bile duct-ligated rats presented with PHT (13.1 ± 1.0 mmHg) and increased IHVR (4.9 ± 0.5 mmHg⋅min/mL). Both RIO (10.0 ± 0.7 mmHg, p = 0.021) and TADA (10.3 ± 0.9 mmHg, p = 0.050) decreased portal pressure by reducing IHVR (RIO: -41%, p = 0.005; TADA: -21%, p = 0.199) while not impacting heart rate, mean arterial pressure and portosystemic shunting. Hepatic cGMP levels increased upon RIO (+239%, p = 0.006) and TADA (+32%, p = 0.073) therapy. In contrast, CINA dosed at 1 mg/kg caused weight loss, arterial hypotension and hyperlactataemia in bile duct-ligated rats. Liver fibrosis area was significantly decreased by RIO (CAB: -48%, p = 0.011; PSR: -27%, p = 0.121) and TADA (CAB: -21%, p = 0.342; PSR: -52%, p = 0.013) compared to VEH-treated bile duct-ligated rats. Hepatic hydroxyproline content was reduced by RIO (from 503 ± 20 to 350 ± 30 µg/g, p = 0.003) and TADA (282 ± 50 µg/g, p = 0.003), in line with a reduction of the hepatic stellate cell activation markers smooth-muscle actin and phosphorylated moesin. Liver transaminases decreased under RIO (AST: -36%; ALT: -32%) and TADA (AST: -24%; ALT: -27%) treatment. Hepatic interleukin 6 gene expression was reduced in the RIO group (-56%, p = 0.053). CONCLUSION: In a rodent model of biliary cirrhosis, the sGC stimulator RIO and the PDE-5 inhibitor TADA improved PHT. The decrease of sinusoidal vascular resistance was paralleled by a reduction in liver fibrosis and hepatic inflammation, while systemic haemodynamics were not affected.

Synthesis and Cytotoxic Activity of Chiral Sulfonamides Based on the 2-Azabicycloalkane Skeleton.

A series of chiral sulfonamides containing the 2-azabicycloalkane scaffold were prepared from aza-Diels-Alder cycloadducts through their conversion to amines based on 2-azanorbornane or the bridged azepane skeleton, followed by the reaction with sulfonyl chlorides. The cytotoxic activity of the obtained bicyclic derivatives was evaluated using human hepatocellular carcinoma (HCC), medulloblastoma (MB), and glioblastoma (GBM) cell lines. Chosen compounds were shown to notably reduce cell viability as compared to nonmalignant cells.

Association of Platelet Count and Mean Platelet Volume with Overall Survival in Patients with Cirrhosis and Unresectable Hepatocellular Carcinoma.

BACKGROUND: Platelets have been reported to influence tumor biology and may promote metastasis. Traditionally, thrombocytopenia, a hallmark of cirrhosis, was associated with hepatocellular carcinoma (HCC) development. However, the impact of platelet count on outcome in patients with established HCC is not well studied. METHODS: Outcomes of patients with cirrhosis diagnosed with HCC between 1995 and 2013 (derivation cohort) and 2000-2016 (validation cohort) who were not eligible for surgical treatment and did not receive antiplatelet therapy were retrospectively studied. Thrombocytopenia was defined as platelet count < 150 g/L. High mean platelet volume (MPV) was defined as ≥median value of the respective cohort (derivation cohort: ≥11 fL; validation cohort: ≥10.6 fL). RESULTS: Among 626 patients with unresectable HCC, thrombocytopenia was present in 378 (60.4%) and was associated with favorable baseline tumor characteristics: lower diameter of the largest nodule (5.6 ± 3.2 vs. 7.6 ± 4.2 cm), less extrahepatic spread (9.5 vs. 20.2%, both p < 0.001), less macrovascular invasion (21.2 vs. 31.0%, p = 0.005), and lower BCLC stages (63.0 vs. 73.4% BCLC C/D; p = 0.007) as compared to patients with normal platelet count. On univariate analysis, thrombocytopenia and larger MPV were associated with longer overall survival (OS) (thrombocytopenia: median OS [95% CI], 11.5 [9.3-13.8] vs. 5.5 [3.8-7.1] months; p = 0.001; MPV ≥11 fL: 11.7 [9.1-14.2] vs. 6.0 [4.4-7.6] months; p < 0.001). In multivariate analysis, the combined variable of thrombocytopenia and larger MPV was independently associated with longer OS (HR [95% CI], 0.80 [0.65-0.98]; p = 0.029). These results were confirmed in an independent external validation cohort of 525 patients with cirrhosis and HCC. Again, patients with thrombocytopenia and high MPV had significantly longer OS (15.3 [11.7-18.9] vs. 9.3 [7.4-11.2] months; p < 0.001). CONCLUSIONS: Thrombocytopenia and higher MPV are associated with better outcome in patients with advanced HCC. These findings may prompt further clinical research on additive antiplatelet therapy in the prevention and management of HCC.

Analysis of Liver Cancer Cell Lines Identifies Agents With Likely Efficacy Against Hepatocellular Carcinoma and Markers of Response.

BACKGROUND AND AIMS: Hepatocellular carcinomas (HCCs) are heterogeneous aggressive tumors with low rates of response to treatment at advanced stages. We screened a large panel of liver cancer cell lines (LCCLs) to identify agents that might be effective against HCC and markers of therapeutic response. METHODS: We performed whole-exome RNA and microRNA sequencing and quantification of 126 proteins in 34 LCCLs. We screened 31 anticancer agents for their ability to decrease cell viability. We compared genetic, RNA, and protein profiles of LCCLs with those of primary HCC samples and searched for markers of response. RESULTS: The protein, RNA and mutational signatures of the LCCLs were similar to those of the proliferation class of HCC, which is the most aggressive tumor type. Cell lines with alterations in genes encoding members of the Ras-MAPK signaling pathway and that required fibroblast growth factor (FGF)19 signaling via FGF receptor 4 for survival were more sensitive to trametinib than to FGF receptor 4 inhibitors. Amplification of FGF19 resulted in increased activity of FGF19 only in tumor cells that kept a gene expression pattern of hepatocyte differentiation. We identified single agents and combinations of agents that reduced viability of cells with features of the progenitor subclass of HCC. LCCLs with inactivating mutations in TSC1 and TSC2 were sensitive to the mammalian target of rapamycin inhibitor rapamycin, and cells with inactivating mutations in TP53 were sensitive to the Aurora kinase A inhibitor alisertib. Amplification of MET was associated with hypersensitivity to cabozantinib and the combination of sorafenib and inhibitors of MAP kinase 1 and MAP kinase2 had a synergistic antiproliferative effect. CONCLUSION: LCCLs can be screened for drugs and agents that might be effective for treatment of HCC. We identified genetic alterations and gene expression patterns associated with response to these agents. This information might be used to select patients for clinical trials.

The soluble guanylate cyclase stimulator riociguat reduces fibrogenesis and portal pressure in cirrhotic rats.

In cirrhotic patients, portal hypertension (PHT) deteriorates survival, yet treatment options are limited. A major contributor to increased intrahepatic vasoconstriction in PHT is dysfunctional nitric-oxide signaling. Soluble guanylate cyclase (sGC) is the receptor of nitric-oxide and can be stimulated by riociguat. Riociguat is approved for pulmonary hypertension but has not been studied in liver cirrhosis. In this study we assessed the effects of riociguat on PHT and liver fibrosis in cholestatic (bile duct ligation, BDL) and toxic (carbon-tetrachloride, CCl4) rat models. In cirrhotic livers sGC expression was upregulated. In BDL rats, riociguat reduced liver fibrosis and decreased portal pressure without affecting systemic hemodynamics. In an early BDL disease stage, riociguat decreased bile duct proliferation, improved sinusoidal vascular dysfunction and inhibited angiogenesis. In advanced BDL riociguat exhibited anti-inflammatory effects. In CCl4 rats the beneficial effects of riociguat treatment were less pronounced and confined to an early disease stage. Similarly, in patients with cholestatic cirrhosis and PHT nitrates (that induce sGC activity) decreased portal pressure more effectively than in patients with non-cholestatic etiology. We also found an improvement of transaminases in patients with pulmonary hypertension receiving riociguat. Our findings support the clinical development of sGC stimulators in patients with cirrhotic PHT.

Deviations of the immune cell landscape between healthy liver and hepatocellular carcinoma.

Tumor-infiltrating immune cells are highly relevant for prognosis and identification of immunotherapy targets in hepatocellular carcinoma (HCC). The recently developed CIBERSORT method allows immune cell profiling by deconvolution of gene expression microarray data. By applying CIBERSORT, we assessed the relative proportions of immune cells in 41 healthy human livers, 305 HCC samples and 82 HCC adjacent tissues. The obtained immune cell profiles provided enumeration and activation status of 22 immune cell subtypes. Mast cells were evaluated by immunohistochemistry in ten HCC patients. Activated mast cells, monocytes and plasma cells were decreased in HCC, while resting mast cells, total and naïve B cells, CD4+ memory resting and CD8+ T cells were increased when compared to healthy livers. Previously described S1, S2 and S3 molecular HCC subclasses demonstrated increased M1-polarized macrophages in the S3 subclass with good prognosis. Strong total immune cell infiltration into HCC correlated with total B cells, memory B cells, T follicular helper cells and M1 macrophages, whereas weak infiltration was linked to resting NK cells, neutrophils and resting mast cells. Immunohistochemical analysis of patient samples confirmed the reduced frequency of mast cells in human HCC tumor tissue as compared to tumor adjacent tissue. Our data demonstrate that deconvolution of gene expression data by CIBERSORT provides valuable information about immune cell composition of HCC patients.

Impact of glutathione peroxidase 4 on cell proliferation, angiogenesis and cytokine production in hepatocellular carcinoma.

Insufficient supplementation with the micronutrient selenium and persistent hepatic inflammation predispose to hepatocellular carcinoma (HCC). Inflammation-associated reactive oxygen species attack membrane lipids and form lipid hydroperoxides able to propagate oxidative hepatic damage. Selenium-containing enzyme glutathione peroxidase 4 (GPx4) antagonizes this damage by reducing lipid hydroperoxides to respective hydroxides. However, the role of GPx4 in HCC remains elusive. We generated two human HCC cell lines with stable overexpression of GPx4, performed xenotransplantation into NOD.Cg-PrkdcscidIl2rgtm1Wjl/SzJ (NSG) host mice and characterized the tumors formed. The experimental data were verified using gene expression data from two independent HCC patient cohorts. GPx4 overexpression protected from oxidative stress and reduced intracellular free radical level. GPx4-overexpressing cells displayed impaired tumor growth, reduced proliferation, altered angiogenesis and decreased expression of clinically relevant cytokine interleukin-8 and C-reactive protein. Moreover, GPx4 overexpression impaired migration of endothelial cells in vitro, and enhanced expression of thrombospondin 1, an endogenous inhibitor of angiogenesis. In patients, GPx4 expression in tumors positively correlated with survival and was linked to pathways which regulate cell proliferation, motility, tissue remodelling, immune response and M1 macrophage polarization. The patient data largely confirmed experimental findings especially in a subclass of poor prognosis tumors with high proliferation. GPx4 suppresses formation and progression of HCC by inhibition of angiogenesis and tumor cell proliferation as well as by immune-mediated mechanisms. Modification of GPx4 expression may represent a novel tool for HCC prevention or treatment.

Oxidative stress mediates an increased formation of vascular endothelial growth factor in human hepatocarcinoma cells exposed to erlotinib.

The tyrosine kinase inhibitor erlotinib targets the receptor of epidermal growth factor (EGFR) involved in development of hepatocellular carcinoma (HCC). Although inefficient in established HCC, erlotinib has been recently proposed for HCC chemoprevention. Since Cyp3A4 and Cyp1A2 enzymes metabolize erlotinib in the liver, the insights into the mechanisms of erlotinib effects on liver cells with maintained drug metabolizing activity are needed. We applied erlotinib to both commercially available (SNU398, Huh7) and established in Austria HCC cell lines (HCC-1.2, HCC-3). Cyp3A4 and Cyp1A2, microarray gene expression, cell viability, LDH release, DHFC fluorescence were assessed. VEGF expression was analysed by real-time RT-PCR and ELISA. Higher cumulative expression of erlotinib metabolizing enzymes was observed in HCC-1.2 and HCC-3 cells. Gene expression microarray analysis showed upregulation of VEGF signalling by erlotinib. VEGF was increased up to 134 ± 14% (n = 5, p = 0.002) in HCC-1.2, HCC-3 and Huh7 cells. Interventions by Cyp1A2 and Mek2siRNA, MEK inhibitor UO126, diphenylene iodonium, as well as a combination of N-acetylcysteine with selenium all inhibited VEGF upregulation caused by erlotinib. Thus, erlotinib increases VEGF production by mechanisms involving Cyp1A2, oxidative stress and MEK1/2. VEGF may favour angiogenesis and growth of early HCC tumours limiting the therapeutic and chemopreventive effects of erlotinib.

Photoactivation provides a mechanistic explanation for pan-assay interference behaviour of 2-aminopyrroles in lipoxygenase inhibition.

Human 15-lipoxygenase-1 (h-15-LOX-1) is a promising drug target in inflammation and cancer. In this study substitution-oriented screening (SOS) has been used to identify compounds with a 2-aminopyrrole scaffold as inhibitors for h-15-LOX-1. The observed structure activity relationships (SAR) proved to be relatively flat. IC50's for the most potent inhibitor of the series did not surpass 6.3 µM and the enzyme kinetics demonstrated uncompetitive inhibition. Based on this, we hypothesized that the investigated 2-aminopyrroles are pan assay interference compounds (PAINS) with photoactivation via a radical mechanism. Our results demonstrated clear photoactivation of h-15-LOX-1 inhibition under UV and visible light. In addition, the investigated 2-aminopyrroles decreased viability of cultured human hepatocarcinoma cells HCC-1.2 in a dose-dependent manner with LD50 ranging from 0.55 ± 0.15 µM (21B10) to 2.75 ± 0.91 µM (22). Taken together, this indicates that photoactivation can play an important role in the biological activity of compounds with a 2-amino-pyrrole scaffold as investigated here.

Proliferation Markers Are Associated with MET Expression in Hepatocellular Carcinoma and Predict Tivantinib Sensitivity In Vitro.

Purpose: Tivantinib was initially reported as a selective MET inhibitor and is under phase III evaluation in "MET-high" hepatocellular carcinoma (HCC) patients. However, it has been also proposed as an antimitotic agent. We aimed to evaluate the antitumor effect of tivantinib in HCC cells by combining pharmacologic and molecular profiling.Experimental Design: Sensitivity to tivantinib, JNJ-38877605, PHA-665752, vinblastine, and paclitaxel was tested in a panel of 35 liver cancer cell lines analyzed with exome sequencing, mRNA expression of 188 genes, and protein expression. Drug effect was investigated by Western blot analysis and mitotic index quantification. Expression of candidate biomarkers predicting drug response was analyzed in 310 HCCs.Results: Tivantinib sensitivity profiles in the 35 cell lines were similar to those obtained with antimitotic drugs. It induced blockage of cell mitosis, and high cell proliferation was associated with sensitivity to tivantinib, vinblastine, and paclitaxel. In contrast, tivantinib did not suppress MET signaling, and selective MET inhibitors demonstrated an antiproliferative effect only in MHCC97H, the unique cell line displaying MET gene amplification. HCC tumors with high expression of cell proliferation genes defined a group of patients with poor survival. Interestingly, highly proliferative tumors also demonstrated high MET expression, likely explaining better therapeutic response of MET-high HCC patients to tivantinib.Conclusions: Tivantinib acts as an antimitotic compound, and cell proliferation markers are the best predictors of its antitumor efficacy in cell lines. Ki67 expression should be tested in clinical trials to predict tivantinib response. Clin Cancer Res; 23(15); 4364-75. ©2017 AACR.

The FXR agonist PX20606 ameliorates portal hypertension by targeting vascular remodelling and sinusoidal dysfunction.

BACKGROUND & AIMS: Steroidal farnesoid X receptor (FXR) agonists demonstrated potent anti-fibrotic activities and lowered portal hypertension in experimental models. The impact of the novel non-steroidal and selective FXR agonist PX20606 on portal hypertension and fibrosis was explored in this study. METHODS: In experimental models of non-cirrhotic (partial portal vein ligation, PPVL, 7days) and cirrhotic (carbon tetrachloride, CCl4, 14weeks) portal hypertension, PX20606 (PX,10mg/kg) or the steroidal FXR agonist obeticholic acid (OCA,10mg/kg) were gavaged. We then measured portal pressure, intrahepatic vascular resistance, liver fibrosis and bacterial translocation. RESULTS: PX decreased portal pressure in non-cirrhotic PPVL (12.6±1.7 vs. 10.4±1.1mmHg; p=0.020) and cirrhotic CCl4 (15.2±0.5 vs. 11.8±0.4mmHg; p=0.001) rats. In PPVL animals, we observed less bacterial translocation (-36%; p=0.041), a decrease in lipopolysaccharide binding protein (-30%; p=0.024) and splanchnic tumour necrosis factor α levels (-39%; p=0.044) after PX treatment. In CCl4 rats, PX decreased fibrotic Sirius Red area (-43%; p=0.005), hepatic hydroxyproline (-66%; p<0.001), and expression of profibrogenic proteins (Col1a1, α smooth muscle actin, transforming growth factor ß). CCl4-PX rats had significantly lower transaminase levels and reduced hepatic macrophage infiltration. Moreover, PX induced sinusoidal vasodilation (upregulation of cystathionase, dimethylaminohydrolase (DDAH)1, endothelial nitric oxide synthase (eNOS), GTP-cyclohydrolase1) and reduced intrahepatic vasoconstriction (downregulation of endothelin-1, p-Moesin). In cirrhosis, PX improved endothelial dysfunction (decreased von-Willebrand factor) and normalized overexpression of vascular endothelial growth factor, platelet-derived growth factor and angiopoietins. While short-term 3-day PX treatment reduced portal pressure (-14%; p=0.041) by restoring endothelial function, 14week PX therapy additionally inhibited sinusoidal remodelling and decreased portal pressure to a greater extent (-22%; p=0.001). In human liver sinusoidal endothelial cells, PX increased eNOS and DDAH expression. CONCLUSIONS: The non-steroidal FXR agonist PX20606 ameliorates portal hypertension by reducing liver fibrosis, vascular remodelling and sinusoidal dysfunction. LAY SUMMARY: The novel drug PX20606 activates the bile acid receptor FXR and shows beneficial effects in experimental liver cirrhosis: In the liver, it reduces scarring and inflammation, and also widens blood vessels. Thus, PX20606 leads to an improved blood flow through the liver and decreases hypertension of the portal vein. Additionally, PX20606 improves the altered intestinal barrier and decreases bacterial migration from the gut.

Metabolic preconditioning protects BSEP/ABCB11-/- mice against cholestatic liver injury.

BACKGROUND & AIMS: Cholestasis is characterized by intrahepatic accumulation of potentially cytotoxic bile acids (BAs) subsequently leading to liver injury with disruption of hepatocellular integrity, inflammation, fibrosis and ultimately liver cirrhosis. Bile salt export pump (BSEP/ABCB11) is the main canalicular BA transporter and therefore the rate limiting step for hepatobiliary BA excretion. In this study we aimed to investigate the role of BSEP/ABCB11 in the development of acquired cholestatic liver and bile duct injury. METHODS: Wild-type (WT) and BSEP knockout (BSEP-/-) mice were subjected to common bile duct ligation (CBDL) or 3.5-diethoxycarbonyl-1.4-dihydrocollidine (DDC) feeding as models for cholestasis with biliary obstruction and bile duct injury. mRNA expression profile, serum biochemistry, liver histology, immunohistochemistry, hepatic hydroxyproline levels and BA composition as well as biliary pressure were assessed. RESULTS: BSEP-/- mice were protected against acquired cholestatic liver injury induced by 7days of CBDL or 4weeks of DDC feeding, as reflected by unchanged serum levels of liver transaminases, alkaline phosphatase and BAs. Notably, BSEP-/- mice were also protected from cholestasis-induced hepatic inflammation and biliary fibrosis. In line with induced BA detoxification/hydroxylation pathways in BSEP-/- mice, polyhydroxylated BAs were increased 4-fold after CBDL and 6-fold after DDC feeding in comparison with cholestatic WT mice. Finally, following CBDL, biliary pressure in WT mice increased up to 47mmH2O but remained below 11mmH2O in BSEP-/- mice. CONCLUSION: Metabolic preconditioning with subsequent changes in BA metabolism favors detoxification of potentially toxic BAs and thereby protects BSEP-/- mice from cholestatic liver and bile duct injury. LAY SUMMARY: Reduced hepatobiliary bile acid transport due to loss of BSEP function leads to increased hydroxylation of bile acids in the liver. Metabolic preconditioning with a hydrophilic bile pool protects the BSEP-/- mice from acquired cholestatic liver disease.

Food-derived peroxidized fatty acids may trigger hepatic inflammation: a novel hypothesis to explain steatohepatitis.

BACKGROUND & AIMS: Obesity and hepatic steatosis are frequently associated with the development of a non-alcoholic steatohepatitis (NASH). The mechanisms driving progression of a non-inflamed steatosis to NASH are largely unknown. Here, we investigated whether ingestion of peroxidized lipids, as being present in Western style diet, triggers the development of hepatic inflammation. METHODS: Corn oil containing peroxidized fatty acids was administered to rats by gavage for 6 days. In a separate approach, hepatocytes (HC), endothelial (EC) and Kupffer cells (KC) were isolated from untreated livers, cultured, and incubated with peroxidized linoleic acid (LOOH; linoleic acid (LH) being the main fatty acid in corn oil). Samples obtained from in vivo and in vitro studies were mainly investigated by qRT-PCR and biochemical determinations of lipid peroxidation products. RESULTS: Rat treatment with peroxidized corn oil resulted in increased hepatic lipid peroxidation, upregulation of nitric oxide synthetase-2 (NOS-2), cyclooxygenase-2 (COX-2), interleukin-1ß (IL-1ß), and tumor necrosis factor-α (TNFα), elevation of total nitric oxides, and increase in cd68-, cd163-, TNFα-, and/or COX-2 positive immune cells in the liver. When investigating liver cell types, LOOH elevated the secretion of TNFα, p38MAPK phosphorylation, and mRNA levels of NOS-2, COX-2, and TNFα, mainly in KC. The elevation of gene expression could be abrogated by inhibiting p38MAPK, which indicates that p38MAPK activation is involved in the pro-inflammatory effects of LOOH. CONCLUSIONS: These data show for the first time that ingestion of peroxidized fatty acids carries a considerable pro-inflammatory stimulus into the body which reaches the liver and may trigger the development of hepatic inflammation.