Transjugular intrahepatic portosystemic shunt creation (TIPS) in the angio-CT-a hybrid intervention with image fusion

OBJECTIVE

For transjugular intrahepatic portosystemic shunt (TIPS) creation, ultrasound guidance for portal vein puncture is strongly recommended. However, outside regular hours of service, a skilled sonographer might be lacking. Hybrid intervention suites combine CT imaging with conventional angiography allowing to project 3D information into the conventional 2D imaging and further CT-fluoroscopic puncture of the portal vein. The purpose of this study was to assess whether TIPS using angio-CT facilitates the procedure for a single interventional radiologist.

METHODS

All TIPS procedures from 2021 and 2022 which took place outside regular working hours were included (n = 20). Ten TIPS procedures were performed with just fluoroscopy guidance and ten procedures using angio-CT. For the angio-CT TIPS, a contrast-enhanced CT was performed on the angiography table. From the CT, a 3D volume was created using virtual rendering technique (VRT). The VRT was blended with the conventional angiography image onto the live monitor and used as guidance for the TIPS needle. Fluoroscopy time, area dose product, and interventional time were assessed.

RESULTS

Hybrid intervention with angio-CT did lead to a significantly shorter fluoroscopy time and interventional time (p = 0.034 for both). Mean radiation exposure was significantly reduced, too (p = 0.04). Furthermore, the mortality rate was lower in patients who underwent the hybrid TIPS (0% vs 33%).

CONCLUSION

TIPS procedure in angio-CT performed by only one interventional radiologist is quicker and reduces radiation exposure for the interventionalist compared to mere fluoroscopy guidance. The results further indicate increased safety using angio-CT.

CLINICAL RELEVANCE STATEMENT

This study aimed to evaluate the feasibility of using angio-CT in TIPS procedures during non-standard working hours. Results indicated that the use of angio-CT significantly reduced fluoroscopy time, interventional time, and radiation exposure, while also leading to improved patient outcomes.

KEY POINTS

• Image guiding such as ultrasound is recommended for transjugular intrahepatic portosystemic shunt creation but might be not available for emergency cases outside of regular working hours. • Transjugular intrahepatic portosystemic shunt creation using an angio-CT with image fusion is feasible for only one physician under emergency settings and results in lower radiation exposure and faster procedures. • Transjugular intrahepatic portosystemic shunt creation using an angio-CT with image fusion seems to be safer than using mere fluoroscopy guidance.

Changing treatment landscape associated with improved survival in advanced hepatocellular carcinoma: a nationwide, population-based study

BACKGROUND AND AIMS

The treatment of hepatocellular carcinoma (HCC) is undergoing a historic transformation with the approval of several new systemic therapies in the last few years. This study aimed to examine the impact of this changing landscape on survival and costs in a Western nationwide, real-world cohort.

METHODS

A nationwide representative claims database (InGef) was screened for HCC cases between 2015 and 2020. Survival in an era with only sorafenib (period A, January 2015 to July 2018) and after approval of lenvatinib and other systemic treatments (period B, August 2018 to December 2020) was analysed. Health care costs were assessed.

RESULTS

We identified 2876 individuals with HCC in the study period. The proportion of patients receiving systemic therapy increased significantly over time, from 11.8% in 2015 to 15.1% in 2020 (p < 0.0001). The median overall survival in period B was 6.5 months (95% confidence interval [CI]: 4.9-8.9) and in period A was 5.3 months (95% CI: 4.5-6.3; p = 0.046). In period B, the median overall survival with lenvatinib was 9.7 months (95% CI: 6.3-18.4) versus 4.8 months with sorafenib (95% CI: 4.0-7.1, p = 0.008). Costs for prescription drugs per patient increased from €6150 in 2015 to €9049 in 2020 (p < 0.0001), and costs for outpatient care per patient increased from €1646 to €2149 (p = 0.0240).

CONCLUSION

The approval of new systemic therapies resulted in a survival benefit in patients with HCC. The magnitude of the effect is modest and associated with a moderate increase in health costs.

Frequent Follow-Up of Delisted Liver Transplant Candidates Is Necessary: An Observational Study about Characteristics and Outcomes of Delisted Liver Transplant Candidates

This observational study focuses on the characteristics and survival of patients taken off of the liver transplant waiting list. Assessment of post-delisting survival and a frequent follow-up of patients after delisting are important keys to improve the survival rate of patients with liver failure after being delisted. Within this study, delisted liver transplant candidates were divided into the following groups: (1) "too good" (54%) or (2) "too sick" (22%) for transplantation, (3) adherence issues (12%) or (4) therapy goal changed (11%). The 5-year survival after delisting within these groups was 84%, 9%, 50%, and 68%, respectively. Less than 3% of the delisted patients had to be relisted again. The clinical expert decision of the multidisciplinary transplant team was sufficiently accurate to differentiate between patients requiring liver transplantation and those who were delisted after a stable recovery of liver function. The assessment of post-delisting survival may serve as a complementary metric to assess differences in center practices and to estimate cumulative post-delisting mortality risk.

Fulminant Liver Failure after Treatment with a Checkpoint Inhibitor for Gastric Cancer: A Case Report and Review of the Literature

Nivolumab is a promising monoclonal antibody inhibitor of programmed death-1, a protein on the surface of T-cells. As such, it is approved for use in patients with multiple advanced malignancies and can significantly elongate progression-free survival. However, monoclonal antibody inhibitors can lead to adverse hepatic reactions, which in rare cases result in further hepatic damage. Herein, we present a case of a patient with locally advanced gastric carcinoma treated with fluorouracil, oxaliplatin, docetaxel and the checkpoint inhibitor nivolumab. Five months after her first dosage of nivolumab and without a preexisting liver disease, she presented with transaminitis. During the course of her stay, the patient developed status epilepticus, which required mechanical ventilation followed by fulminant hepatic failure. A subsequent liver biopsy revealed severe liver damage with extensive confluent parenchymal necrosis corresponding to checkpoint-inhibitor-induced hepatitis. Alternative reasons for this hepatic failure were ruled out. Despite aggressive therapeutic interventions including corticosteroids and plasma exchange, the patient died due to liver failure. Although hepatic failure is rarely seen in patients with checkpoint inhibitor therapy, it requires early awareness and rapid intervention.

Regional transplant rates depend more on physician-dependent variables than on proximity to transplant center

PURPOSE

The objective of this work was to uncover inequalities in access to liver transplantation in Bavaria, Germany.

METHODS

For this purpose, the annual transplantation rate per 1 million inhabitants for the respective districts was determined from the aggregated postal codes of the place of residence of transplanted patients. The variables examined were proximity and travel time to the nearest transplant center, as well as the care category of the regional hospital. In addition, we assessed whether the head of gastroenterology at the regional hospital through which liver transplant candidates are referred was trained at a liver transplant center.

RESULTS

We could not demonstrate a direct relationship between proximity or travel time to the nearest transplant center and access to liver transplantation. Multivariate regression analysis shows that liver transplant training (p < 0.0001) of the chief physician (gastroenterologist) of the regional hospital was the most decisive independent factor for access to liver transplantation within a district.

CONCLUSION

We show that the transplant training experience of the head of gastroenterology at a regional hospital is an independent factor for the regional transplantation rate. Therefore, it appears important to maintain some liver transplant expertise outside the transplant centers in order to properly identify and assign potential transplant candidates for transplantation.

IMMUTACE: A biomarker-orientated phase II, single-arm, open-label AIO study of transarterial chemoembolization (TACE) in combination with nivolumab performed for intermediate-stage hepatocellular carcinoma (HCC; AIO-HEP-0217)—Updated efficacy results

4116

Background: Immunotherapy based combinations recently revolutionized the treatment of patients (pts) with advanced HCC, but its significance in earlier stages remains to be determined. TACE is commonly used as first line treatment in intermediate HCC, but outcome of patients treated with TACE in real-life cohorts is still poor with a median overall survival (OS) below 20 months. The aim of this study was to determine the safety and efficacy of TACE combined with nivolumab. Methods: This is a phase II trial, that recruited 59 patients at 10 sites in Germany between 06/2018 and 06/2020. Pts received up to two TACE treatments followed by nivolumab (240 mg/ Q2W), initiated on day 2-3 after the first TACE session and continued until progression for a maximum treatment duration of two years. Primary endpoint was ORR (mRECIST; with ORR exceeding 55% (power = 80%; actual beta 0.17) as promising for further investigations). Secondary endpoints include mPFS, mTTFS (median time to failure of strategy), mOS, QoL, and safety/tolerability. Tumor tissue was obtained at baseline and blood samples were collected longitudinally for translational research. Results: 49 pts (14.3% HCV and 8.2% HBV) were enrolled and received at least one dose of nivolumab, median tumor size was 4.5 cm (0.9 – 15 cm) and median number 3 (1 – 12). ORR by mRECIST was 71.4% (CR: 16.3%, PR: 55.1%, SD 4.1%, PD: 14.3%). At a median follow-up of 20 months, mPFS was 7.2 mo (95% CI; 5.3 – 11.2; 40 events), mTTFS was 11.2 mo (95% CI; 7.2, 13.5; 42 events) and mTTSST (median time to subsequent systemic therapy) was 24.9 mo (95% CI; 12.2, - ; 21 events). Median duration of Nivolumab was 8.3 months and mOS was 28.3 mo (95% CI; 20 – not estimable; 23 events). Grade ≥3 treatment-related adverse events occurred in 34.7% of patients. Correlative analysis of efficacy with genetic alterations, gene expression signatures and changes of immune cell populations will be reported soon. Conclusions: The study met its primary endpoint and provides evidence for the efficacy of TACE in combination with nivolumab without new safety signals in pts with intermediate HCC and no prior systemic therapy. Our findings support further evaluation of nivolumab-based combinations for the treatment of intermediate HCC. Disclaimer: This study was supported with drug and funding by Bristol-Myers-Squibb. Clinical trial information: NCT03572582.

Atezolizumab and bevacizumab with transarterial chemoembolization in hepatocellular carcinoma: the DEMAND trial protocol

The combination of the anti-PD-L1 antibody atezolizumab and the anti-VEGF bevacizumab is the first approved immunotherapeutic regimen for first-line therapy in patients with unresectable hepatocellular carcinoma (HCC), currently approved in more than 80 countries. The efficacy and tolerability of this regimen suggest that the use of atezolizumab + bevacizumab could be extended to the treatment of patients with intermediate-stage HCC in combination with transarterial chemoembolization (TACE). The authors describe the rationale and design of the DEMAND study. This investigator-initiated, multicenter, randomized phase II study is the first trial to evaluate the safety and efficacy of atezolizumab + bevacizumab prior to or in combination with TACE in patients with intermediate-stage HCC. The primary end point is the 24-month survival rate; secondary end points include objective response rate, progression-free survival, safety and quality of life. Clinical Trial Registration: NCT04224636 (ClinicalTrials.gov).

CRISPR somatic genome engineering and cancer modeling in the mouse pancreas and liver

Genetically engineered mouse models (GEMMs) transformed the study of organismal disease phenotypes but are limited by their lengthy generation in embryonic stem cells. Here, we describe methods for rapid and scalable genome engineering in somatic cells of the liver and pancreas through delivery of CRISPR components into living mice. We introduce the spectrum of genetic tools, delineate viral and nonviral CRISPR delivery strategies and describe a series of applications, ranging from gene editing and cancer modeling to chromosome engineering or CRISPR multiplexing and its spatio-temporal control. Beyond experimental design and execution, the protocol describes quantification of genetic and functional editing outcomes, including sequencing approaches, data analysis and interpretation. Compared to traditional knockout mice, somatic GEMMs face an increased risk for mouse-to-mouse variability because of the higher experimental demands of the procedures. The robust protocols described here will help unleash the full potential of somatic genome manipulation. Depending on the delivery method and envisaged application, the protocol takes 3-5 weeks.

Atezolizumab and bevacizumab with transarterial chemoembolization in hepatocellular carcinoma: The DEMAND randomized phase II clinical trial

TPS492

Background: Atezolizumab and bevacizumab is the first approved immunotherapeutic regimen for first-line treatment of patients with advanced hepatocellular carcinoma (HCC). The efficacy and tolerability of this regimen suggests that its use could be extended to the treatment of patients with intermediate-stage HCC in combination with transarterial chemoembolization (TACE). The effect of TACE combined with atezolizumab and bevacizumab could improve response and tumor control as well as prevent disease progression in non-responders to TACE. Response to the early use of immunotherapy could also reduce the number and extent of TACE cycles needed to achieve tumor control, thereby contributing to the prevention of collateral damage to the liver parenchyma and preservation of liver function. Initiating immunotherapy first may also promote the access of circulating lymphocytes into tumor lesions. The DEMAND study investigates the efficacy and ideal sequence of TACE and immunotherapy in intermediate stage HCC. Methods: This investigator-initiated, multi-center, randomized, open-label phase 2 trial is the first study to evaluate the safety and efficacy of atezolizumab and bevacizumab prior to, or in combination with TACE in patients with unresectable HCC. 106 patients (Barcelona Clinic Liver Cancer Stage A not amenable to curative therapy or B, Child-Pugh A or B7, Eastern Cooperative Oncology Group performance status 0 or 1, no prior TACE) will be randomized in a 1:1 ratio to receive either up-front atezolizumab and bevacizumab followed by TACE selectively directed against progressive lesions (Arm A, 53 patients), or TACE and synchronous treatment with atezolizumab and bevacizumab (Arm B, 53 patients). Patients receive study treatment until loss of clinical benefit or unacceptable toxicity for up to 24 months. The use of local ablation is allowed for the treatment of lesions which cannot be targeted sufficiently selectively by TACE, or of de-novo lesions. The primary endpoint is the 24-month survival rate; secondary endpoints include objective response rate, progression-free survival, safety and quality of life. Translational analyses aim at identifying predictive biomarkers and focus on immune cell phenotyping in tumor and peripheral blood, circulating tumor DNA and changes in the diversity of the gut microbiome. Recruitment is ongoing in 15 German centers with 21 of 106 patients randomized. Clinical trial information: NCT04224636.

Real-World Data for Lenvatinib in Hepatocellular Carcinoma (ELEVATOR): A Retrospective Multicenter Study

BACKGROUND

Lenvatinib is approved as first-line treatment for patients with advanced hepatocellular carcinoma (HCC). The efficacy of lenvatinib in Caucasian real-world patients is insufficiently defined. The purpose of this study was to evaluate the efficacy of lenvatinib in a multi-center cohort (ELEVATOR) from Germany and Austria.

METHODS

A retrospective data analysis of 205 patients treated with first-line systemic lenvatinib at 14 different sites was conducted. Overall survival, progression free survival, overall response rate and adverse event rates were assessed and analyzed.

RESULTS

Patients receiving lenvatinib in the real-world setting reached a median overall survival of 12.8 months, which was comparable to the results reported from the REFLECT study. Median overall survival (mOS) and progression free survival (mPFS) was superior in those patients who met the inclusion criteria of the REFLECT study compared to patients who failed to meet the inclusion criteria (mOS 15.6 vs 10.2 months, HR 0.55, 95% CI 0.38-0.81, p=0.002; mPFS 8.1 vs 4.8 months HR 0.65, 95% CI 0.46-0.91, p=0.0015). For patients with an impaired liver function according to the Albumin-Bilirubin (ALBI) grade, or reduced ECOG performance status ≥2, survival was significantly shorter compared to patients with sustained liver function (ALBI grade 1) and good performance status (ECOG performance status 0), respectively (HR 1.69, 95% CI 1.07-2.66, p=0.023; HR 2.25, 95% CI 1.19-4.23, p=0.012). Additionally, macrovascular invasion (HR 1.55, 95% CI 1.02-2.37, p=0.041) and an AFP ≥200 ng/mL (HR 1.56, 95% CI 1.03-2.34, p=0.034) were confirmed as independent negative prognostic factors in our cohort of patients with advanced HCC.

CONCLUSION

Overall, our data confirm the efficacy of lenvatinib as first-line treatment and did not reveal new or unexpected side effects in a large retrospective Caucasian real-world cohort, supporting the use of lenvatinib as meaningful alternative for patients that cannot be treated with IO-based combinations in first-line HCC.

Isavuconazole and Liposomal Amphotericin B as Successful Combination Therapy of Refractory Invasive Candidiasis in a Liver Transplant Recipient: A Case Report and Literature Review

Invasive fungal infections in liver transplant recipients are associated with elevated morbidity and mortality and pose a challenge to the treating physicians. Despite of lacking clinical data, the use of antifungal combination therapy is often considered to improve response rates in an immunocompromised patient population. We herein report a case of refractory invasive candidiasis in a liver transplant recipient treated successfully with a combination of isavuconazole und high-dose liposomal amphotericin B. The antimycotic combination treatment was able to clear a bloodstream infection with C. glabrata and led to regression of bilomas among tolerable side effects. The use of the above-mentioned antifungal combination therapy in a liver transplant recipient has not been reported previously. This case highlights the efficacy and safety of antifungal combination therapy in immunocompromised patients with refractory invasive candidiasis.

High rate of complete histopathological response in hepatocellular carcinoma patients after combined transarterial chemoembolization and stereotactic body radiation therapy

BACKGROUND

Liver transplantation (LT) presents a curative treatment option in patients with early stage hepatocellular carcinoma (HCC) who are not eligible for resection or ablation therapy. Due to a risk of up 30% for waitlist drop-out upon tumor progression, bridging therapies are used to halt tumor growth. Transarterial chemoembolization (TACE) and less commonly stereotactic body radiation therapy (SBRT) or a combination of TACE and SBRT, are used as bridging therapies in LT. However, it remains unclear if one of those treatment options is superior. The analysis of explant livers after transplantation provides the unique opportunity to investigate treatment response by histopathology.

AIM

To analyze histopathological response to a combination of TACE and SBRT in HCC in comparison to TACE or SBRT alone.

METHODS

In this multicenter retrospective study, 27 patients who received liver transplantation for HCC were analyzed. Patients received either TACE or SBRT alone, or a combination of TACE and SBRT as bridging therapy to liver transplantation. Liver explants of all patients who received at least one TACE and/or SBRT were analyzed for the presence of residual vital tumor tissue by histopathology to assess differences in treatment response to bridging therapies. Statistical analysis was performed using Fisher-Freeman-Halton exact test, Kruskal-Wallis and Mann-Whitney-U tests.

RESULTS

Fourteen patients received TACE only, four patients SBRT only, and nine patients a combination therapy of TACE and SBRT. There were no significant differences between groups regarding age, sex, etiology of underlying liver disease or number and size of tumor lesions. Strikingly, analysis of liver explants revealed that almost all patients in the TACE and SBRT combination group (8/9, 89%) showed no residual vital tumor tissue by histopathology, whereas TACE or SBRT alone resulted in significantly lower rates of complete histopathological response (0/14, 0% and 1/4, 25%, respectively, P value < 0.001).

CONCLUSION

Our data suggests that a combination of TACE and SBRT increases the rate of complete histopathological response compared to TACE or SBRT alone in bridging to liver transplantation.

CaboRISE: A phase II study evaluating reduced starting dose and dose escalation of cabozantinib as second-line therapy for advanced HCC in patients with compensated liver cirrhosis

TPS4163

Background: The multi-targeted tyrosine kinase inhibitor cabozantinib is approved for the treatment of advanced hepatocellular carcinoma (HCC) in adults, who have previously been treated with sorafenib. In the pivotal phase 3 CELESTIAL trial a significant improvement for OS and PFS was shown for cabozantinib in comparison to placebo treated patients (Abou-Alfa GK et al. N Engl J Med 2018; 379:54-63). However, in 62% of patients a dose reduction of cabozantinib was necessary and the median average daily dose was 35.8 mg. The discontinuation rate due to treatment-related adverse events (TRAEs) was 16% and grade 3-4 TRAEs occurred in 68% of patients. For HCC patients treated with sorafenib in first-line, a reduced starting dose of 200 mg BID was not inferior in terms of OS but showed a trend toward a decreased rate of sorafenib discontinuation(Reiss KA et al. J Clin Oncol 2017; 35:3575-3581). The aim of the CaboRISE trial is to study the effect of a reduced starting dose of cabozantinib on tolerability, safety, and efficacy. Methods: The CaboRISE trial is an open-label, single arm, multicenter phase II trial, including patients with advanced stage hepatocellular carcinoma (HCC) with compensated liver cirrhosis (Child-Pugh A) in second line treatment, after first line treatment with sorafenib or lenvatinib. Forty evaluable patients will be enrolled in the study to receive a reduced starting dose of 40 mg cabozantinib once-daily for 4 weeks and subsequent dose escalation to 60 mg cabozantinib once-daily to be maintained until disease progression or intolerable toxicities. The objective of the trial is to assess the tolerability of a reduced starting dose of cabozantinib, in order to reduce the treatment discontinuation rates due to treatment-related adverse events below 10%. Primary endpoint is the treatment discontinuation rate due to TRAEs. Secondary endpoints are overall survival, progression free survival at 10 weeks, objective response rate, time on treatment, treatment exposure, toxicity, and quality of life. Study start of the CaboRISE trial was in October 2020. By February 2021, 7 centers across Germany have been initiated and a total of 4 out of 40 planned patients have been enrolled. The study is currently ongoing. This study is financially supported by Ipsen. ClinicalTrials.gov: NCT04522908 EudraCT: 2020-000775-20. Clinical trial information: NCT04522908.

Liver transplantation versus watchful waiting in hepatocellular carcinoma patients with complete response to bridging therapy - a retrospective observational study

Bridging therapy to prevent progression on the waiting list can result in a sustained complete response (sCR). In some patients, the liver transplantation (LT) risk might exceed those of tumor recurrence. We thus evaluated whether a watchful waiting (CR-WW) strategy could be a feasible alternative to transplantation (CR-LT). We performed a retrospective analysis of overall survival (OS) and recurrence-free survival (RFS) of patients with a sCR (CR > 6 months). Permitted bridging included thermoablation, resection, and combinations of either with transarterial chemoembolization. Patients were divided into the intended treatment strategies CR-WW and CR-LT. 39 (18.40%) sCR patients from 212 were investigated. 22 patients were treated with a CR-LT and 17 patients a CR-WW strategy. Five-year RFS was lower in the CR-WW than in the CR-LT group [53.3% (22.1%; 77.0%) and 84.0% (57.6%; 94.7%)]. 29.4% (5/17) CR-WW patients received salvage transplantation because of recurrence. OS (5-year) was 83.9% [56.8%; 94.7%] after LT and 75.4% [39.8%; 91.7%] after WW. Our analysis shows that the intuitive decision made by our patients in agreement with their treating physicians for a watchful waiting strategy in sCR can be justified. Applied on a larger scale, this strategy could help to reduce the pressure on the donor pool.

Age independent survival benefit for patients with hepatocellular carcinoma (HCC) without metastases at diagnosis: a population-based study

OBJECTIVE

Hepatocellular carcinoma (HCC) is a major cause of death worldwide and its incidence is expected to increase globally. Aim of this study was to assess whether the implementation of screening policies and the improvement of treatment options translated into a real-world survival benefit in HCC patients.

DESIGN

4078 patients diagnosed with HCC between 1998 and 2016 from the Munich Cancer Registry were analysed. Tumour characteristics and outcome were analysed by time period and according to age and presence of metastases at diagnosis. Overall survival (OS) was analysed using Kaplan-Meier method and relative survival (RS) was computed for cancer-specific survival. Cox proportional hazard models were conducted to control for prognostic variables.

RESULTS

While incidence of HCC remained substantially stable, tumours were diagnosed at increasingly earlier stages, although the median age at diagnosis increased. The 3 years RS in HCC improved from 19.8% in 1998-2002, 22.4% in 2003-2007, 30.6% in 2008-2012 up to 31.0% in 2013-2016. Median OS increased from 6 months in 1998-2002 to 12 months in 2008-2016. However, analysis according to the metastatic status showed that survival improved only in patients without metastases at diagnosis whereas the prognosis of patients with metastatic disease remained unchanged.

CONCLUSION

These real-world data show that, in contrast to the current assumptions, the incidence of HCC did not increase in a representative German region. Earlier diagnosis, likely related to the implementation of screening programmes, translated into an increasing employment of effective therapeutic options and a clear survival benefit in patients without metastases at diagnosis, irrespective of age.

Abstract 4612: HOXA13 drives hepatocytes proliferation and liver tumorigenesis in mice

Introduction: Hepatocellular carcinoma (HCC) is the most common primary malignancy of the liver and the third most common cause of cancer related mortality worldwide. For patients suffering from advanced stage disease, the few therapeutic options available are not curative and improve patient survival by only a few months. Therefore, new molecular targets that can be explored as therapeutic options are highly needed. Class I Homeobox (HOX) genes are fundamental components of embryonic patterning and morphogenesis, with expression persisting into adulthood. They are also implicated in neoplastic transformations. However, the role of HOX genes is poorly understood and the functional relationship between the malignant phenotype and abnormal expression of HOX genes is still unclear. In this study we sought to define the role of the HOXA13 gene in hepatocarcinogenesis using in vivo models.

Methods: To unravel the molecular mechanism of HOXA13 driven tumorigenesis in liver and its direct oncogenicity in vivo, a murine model of HOXA13 overexpression in liver was generated using hydrodynamic injection coupled with a transposase system. This model led to the stable and specific HOXA13 expression in C57BL6\J mouse hepatocytes up to 5 months post injection. Mouse phenotype was followed over time, from 2 weeks up to 1 year post injection. 16 mice (8 for CTRL vector and 8 for HOXA13) were injected and sacrificed for every time point. RNA sequencing was performed to monitor the transcriptomic changes over time.

Results: 1 year post injection 50% (4/8) of the injected mice with HOXA13 developed liver tumors of various histological grades and types, from very well differentiated HCCs to very highly undifferentiated and cholangiocarcinoma like nodules. HOXA13 overexpression in the liver led to highly proliferative hepatocytes after only 2 weeks and the proliferative phenotype was maintained until 5 months post injection, when pre neoplastic lesions began to form. HOXA13 overexpression correlated not only with proliferation but also with the DNA damage marker yH2AX, suggesting a possible mechanism of tumorigenesis driven by genome instability. Gene set enrichment analysis of RNA-seq performed on whole liver extracts of 2 week old mice and tumors showed that the main pathways involved in HOXA13 expression are cell cycle, in particular G2/M transition and mitotic assembly checkpoint, angiogenesis, TP53 pathway, IL6JAKSTAT3 signaling, Notch signaling and epithelial to mesenchymal transition.

Conclusion: Our study highlights the key role of HOXA13 as a potential novel oncogene in HCC development and suggests possible mechanisms through which it drives liver tumorigenesis. We expect that the generated data in vivo, coupled with mass spectrometry and ChIP sequencing experiments performed in vitro, will further help us identify downstream effectors of HOXA13 thus providing new potential therapeutic targets for HCC.

Citation Format: Gaia Bianco, Hesam Montazeri, Luca Quagliata, Tracy O'Connor, Ursula Ehmer, Rupert Oellinger, Mathias Matter, Christofori Gerhard M., Charlotte K.Y. Ng, Salvatore Piscuoglio, Mathias Heikenwaelder, Luigi M. Terracciano. HOXA13 drives hepatocytes proliferation and liver tumorigenesis in mice [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4612.

Hippo Signaling in the Liver - A Long and Ever-Expanding Story

The first description of Hippo signaling in mammals a little more than 10 years ago showed a striking phenotype in the liver, linking the role of this signaling pathway to organ size control and carcinogenesis. Even though Hippo signaling has been extensively studied in the liver and other organs over the recent years, many open questions remain in our understanding of its role in hepatic physiology and disease. The functions of Hippo signaling extend well beyond cancer and organ size determination: components of upstream Hippo signaling and the downstream effectors YAP and TAZ are involved in a multitude of cell and non-cell autonomous functions including cell proliferation, survival, development, differentiation, metabolism, and cross-talk with the immune system. Moreover, regulation and biological functions of Hippo signaling are often organ or even cell type specific – making its role even more complex. Here, we give a concise overview of the role of Hippo signaling in the liver with a focus on cell-type specific functions. We outline open questions and future research directions that will help to improve our understanding of this important pathway in liver disease.

Progression after Immunotherapy for Fibrolamellar Carcinoma

Background

Fibrolamellar carcinoma (FLC) is a rare malignancy of the liver that differs from typical hepatocellular carcinoma (HCC) in several aspects such as the absence of underlying liver disease and occurrence in younger patients. Even though the survival rates in FLC are slightly better than in typical HCC, the prognosis of metastatic FLC remains deleterious. Several reports suggest that systemic chemotherapy regimens can successfully be used to halt disease progression in FLC, while targeted tumor therapy with sorafenib seems to be of limited efficiency. However, results from controlled clinical trials investigating systemic therapies in FLC are virtually nonexistent. Therefore, the choice of treatment often relies on case series with limited numbers of patients. Immunotherapy with checkpoint inhibitors is an emerging cancer therapy in several solid malignancies including HCC. Currently, there do not exist any reports on the use of checkpoint inhibitors in FLC.

Case Report

Here, we describe a case of advanced FLC in a young man receiving immunotherapy, who progressed after 3 months of treatment - similar to 2 other patients with advanced FLC at our hospital.

Conclusion

While immunotherapy seems to be a promising treatment with limited side effects in several other tumor entities, there is currently no data supporting tumor response in FLC.

An in vivo transfection system for inducible gene expression and gene silencing in murine hepatocytes

BACKGROUND

Hydrodynamic tail vein injection (HTVI) of transposon-based integration vectors is an established system for stably transfecting mouse hepatocytes in vivo that has been successfully employed to study key questions in liver biology and cancer. Refining the vectors for transposon-mediated hepatocyte transfection will further expand the range of applications of this technique in liver research. In the present study, we report an advanced transposon-based system for manipulating gene expression in hepatocytes in vivo.

METHODS

Transposon-based vector constructs were generated to enable the constitutive expression of inducible Cre recombinase (CreER) together with tetracycline-inducible transgene or miR-small hairpin RNA (shRNA) expression (Tet-ON system). Transposon and transposase expression vectors were co-injected into R26R-mTmG reporter mice by HTVI. Cre-mediated gene recombination was induced by tamoxifen, followed by the administration of doxycycline to drive tetracycline-inducible gene or shRNA expression. Expression was visualized by immunofluorescence staining in livers of injected mice.

RESULTS

After HTVI, Cre recombination by tamoxifen led to the expression of membrane-bound green fluorescent protein in transfected hepatocytes. Activation of inducible gene or shRNA expression was detected by immunostaining in up to one-third of transfected hepatocytes, with an efficiency dependent on the promoter driving the Tet-ON system.

CONCLUSIONS

Our vector system combines Cre-lox mediated gene mutation with inducible gene expression or gene knockdown, respectively. It provides the opportunity for rapid and specific modification of hepatocyte gene expression and can be a useful tool for genetic screening approaches and analysis of target genes specifically in genetically engineered mouse models.

Constitutive and Inducible Systems for Genetic In Vivo Modification of Mouse Hepatocytes Using Hydrodynamic Tail Vein Injection

In research models of liver cancer, regeneration, inflammation, and fibrosis, flexible systems for in vivo gene expression and silencing are highly useful. Hydrodynamic tail vein injection of transposon-based constructs is an efficient method for genetic manipulation of hepatocytes in adult mice. In addition to constitutive transgene expression, this system can be used for more advanced applications, such as shRNA-mediated gene knock-down, implication of the CRISPR/Cas9 system to induce gene mutations, or inducible systems. Here, the combination of constitutive CreER expression together with inducible expression of a transgene or miR-shRNA of choice is presented as an example of this technique. We cover the multi-step procedure starting from the preparation of sleeping beauty-transposon constructs, to the injection and treatment of mice, and the preparation of liver tissue for analysis by immunostaining. The system presented is a reliable and efficient approach to achieve complex genetic manipulations in hepatocytes. It is specifically useful in combination with Cre/loxP-based mouse strains and can be applied to a variety of models in the research of liver disease.

Human hepatic organoids for the analysis of human genetic diseases

We developed an in vitro model system where induced pluripotent stem cells (iPSCs) differentiate into 3-dimensional human hepatic organoids (HOs) through stages that resemble human liver during its embryonic development. The HOs consist of hepatocytes, and cholangiocytes, which are organized into epithelia that surround the lumina of bile duct-like structures. The organoids provide a potentially new model for liver regenerative processes, and were used to characterize the effect of different JAG1 mutations that cause: (a) Alagille syndrome (ALGS), a genetic disorder where NOTCH signaling pathway mutations impair bile duct formation, which has substantial variability in its associated clinical features; and (b) Tetralogy of Fallot (TOF), which is the most common form of a complex congenital heart disease, and is associated with several different heritable disorders. Our results demonstrate how an iPSC-based organoid system can be used with genome editing technologies to characterize the pathogenetic effect of human genetic disease-causing mutations.

Regulation of localization and function of the transcriptional co-activator YAP by angiomotin

The Hippo-YAP pathway is a central regulator of cell contact inhibition, proliferation and death. There are conflicting reports regarding the role of Angiomotin (Amot) in regulating this pathway. While some studies suggest a YAP-inhibitory function other studies indicate Amot is required for YAP activity. Here, we describe an Amot-dependent complex comprised of Amot, YAP and Merlin. The phosphorylation of Amot at Serine 176 shifts localization of this complex to the plasma membrane, where it associates with the tight-junction proteins Pals1/PATJ and E-cadherin. Conversely, hypophosphorylated Amot shifts localization of the complex to the nucleus, where it facilitates the association of YAP and TEAD, induces transcriptional activation of YAP target genes and promotes YAP-dependent cell proliferation. We propose that phosphorylation of Amot^S176 is a critical post-translational modification that suppresses YAP’s ability to promote cell proliferation and tumorigenesis by altering the subcellular localization of an essential YAP co-factor.

DOI:http://dx.doi.org/10.7554/eLife.23966.001

Cells in animals and other multi-cellular organisms need to know when and where they should grow and divide. Individual cells communicate with their surrounding environment and each other via signaling pathways such as the Hippo-YAP pathway, which stimulates cells to grow and therefore influences the size of organs. When the Hippo part of the pathway is active it causes a protein known as YAP to move out of a compartment in the cell called the nucleus. Inside the nucleus, YAP helps to activate genes that promote cell growth. If the Hippo pathway can no longer respond to cues from the environment, YAP becomes over-active and can contribute to the development of various cancers. Therefore researchers are trying to better understand how it is regulated.

Many signals both from inside and outside the cell influence YAP activity. For example, some signals block YAP from entering the nucleus, whereas others cause YAP to be broken down entirely. Several studies have recently identified a signal protein called angiomotin as a regulator of YAP. However, the studies provide conflicting reports as to whether angiomotin promotes or inhibits cell growth.

Like many other proteins, angiomotin can be tagged with a small molecule called a phosphate group that can alter its activity. Moleirinho, Hoxha et al. studied human cells containing versions of angiomotin that mimic different forms of the protein with or without the phosphate. The experiments indicate that when a phosphate is attached at a particular position (known as serine 176), angiomotin predominantly interacts with YAP and another protein called Merlin at the cell surface. On the other hand, when angiomotin does not have a phosphate attached to it, all three proteins can move into the nucleus, where YAP is able to activate genes and promote cell growth.

Overall, these findings indicate that adding a phosphate group to angiomotin can act as a switch to regulate where in the cell it and YAP are found and thus, whether YAP is active. Future experiments will investigate which enzymes add the phosphate group to serine 176, and when they are able to do so.

DOI:http://dx.doi.org/10.7554/eLife.23966.002

Usefulness of 1,3 Beta-D-Glucan Detection in non-HIV Immunocompromised Mechanical Ventilated Critically Ill Patients with ARDS and Suspected Pneumocystis jirovecii Pneumonia

INTRODUCTION

Pneumocystis jirovecii pneumonia (PCP) is a major cause of disease in immunocompromised individuals. Diagnosis is typically obtained by microscopy and/or PCR. For ambiguous PCR results, we evaluated the new biomarker 1,3-Beta-D-Glucan (BDG).

METHODS

BDG serum levels were assessed and correlated to PCR results in immunosuppressed patients with ARDS.

RESULTS

11 (22%) out of 50 patients had suspected PCP. APACHE II (26 vs. 24; p < 0.002), SOFA score (16 vs. 14; p < 0.010) and mortality rate (34 vs. 69% p < 0.004; 34 vs. 80% p < 0.003) were significantly altered in patients with positive (pPCR) and slightly positive (spPCR) PCJ PCR as compared to patients with no-PCP (nPCP). BDG levels were significantly lower in patients with nPCP (86; 30-315 pg/ml) than in patients with pPCR (589; 356-1000 pg/ml; p < 0.001) and spPCP (398; 297-516 pg/ml; p < 0.004) referring to the cutoff in this study for PCP of 275 pg/ml. An overall sensitivity (S) of 92% (95% CI 86-96%) and specificity (SP) of 84% (95% CI 79-85%) for PCP were found for the BDG Fungitell assay. In detail, S of 98% (95% CI 94-100%) and SP of 86% (95% CI 82-92%) for pPCP and S of 98% (95% CI 96-100%) and SP of 88% (95% CI 86-96%) for spPCO were found.

CONCLUSION

Serum BDG levels were strongly elevated in PCP, and the negative predictive value is high. BDG could be used as a preliminary test for patients with suspected PCP, especially in patients with slightly positive PCR results.

Pseudallescheria boydii with Aspergillus fumigatus and Aspergillus terreus in a Critically Ill Hematopoietic Stem Cell Recipient with ARDS

Pseudallescheria boydii is a fungal organism known to affect immunocompromised patients. This organism is known to cause, in severe cases, invasive infection of various organs such as the central nervous, cardiovascular, and respiratory systems. We report an unusual case of pulmonary P. boydii pneumonia in an immunocompromised critically ill patient with a co-infection of Aspergillus fumigatus and Aspergillus terreus with ARDS. This case highlights the importance of a high index of suspicion for superimposed fungal infections in patients who are critically ill and immunocompromised. Uncommon fungal pathogens should be considered in the differential diagnosis of respiratory failure, especially if diagnostic markers such as galactomannan (from BAL and serum) or 1,3-beta-d-glucan are elevated. Further diagnostic interventions are warranted when insufficient clinical improvement is observed to prevent treatment failure and adverse outcomes.

Control of Proliferation and Cancer Growth by the Hippo Signaling Pathway

The control of cell division is essential for normal development and the maintenance of cellular homeostasis. Abnormal cell proliferation is associated with multiple pathological states, including cancer. Although the Hippo/YAP signaling pathway was initially thought to control organ size and growth, increasing evidence indicates that this pathway also plays a major role in the control of proliferation independent of organ size control. In particular, accumulating evidence indicates that the Hippo/YAP signaling pathway functionally interacts with multiple other cellular pathways and serves as a central node in the regulation of cell division, especially in cancer cells. Here, recent observations are highlighted that connect Hippo/YAP signaling to transcription, the basic cell-cycle machinery, and the control of cell division. Furthermore, the oncogenic and tumor-suppressive attributes of YAP/TAZ are reviewed, which emphasizes the relevance of the Hippo pathway in cancer.

A conditional piggyBac transposition system for genetic screening in mice identifies oncogenic networks in pancreatic cancer

Here we describe a conditional piggyBac transposition system in mice and report the discovery of large sets of new cancer genes through a pancreatic insertional mutagenesis screen. We identify Foxp1 as an oncogenic transcription factor that drives pancreatic cancer invasion and spread in a mouse model and correlates with lymph node metastasis in human patients with pancreatic cancer. The propensity of piggyBac for open chromatin also enabled genome-wide screening for cancer-relevant noncoding DNA, which pinpointed a Cdkn2a cis-regulatory region. Histologically, we observed different tumor subentities and discovered associated genetic events, including Fign insertions in hepatoid pancreatic cancer. Our studies demonstrate the power of genetic screening to discover cancer drivers that are difficult to identify by other approaches to cancer genome analysis, such as downstream targets of commonly mutated human cancer genes. These piggyBac resources are universally applicable in any tissue context and provide unique experimental access to the genetic complexity of cancer.

Gilbert syndrome redefined: a complex genetic haplotype influences the regulation of glucuronidation

Gilbert syndrome (GS) is characterized by intermittent unconjugated hyperbilirubinemia without structural liver damage, affecting about 10% of the white population. In GS the UGT1A1*28 variant reduces bilirubin conjugation by 70% and is associated with irinotecan and protease inhibitor side effects. The aim of this study was to characterize potential in vivo consequences of UGT1A gene variability in GS. Three hundred GS patients (UGT1A1*28 homozygous) and 249 healthy blood donors (HBD) were genotyped for UGT1A (UGT1A1*28, UGT1A3-66 T>C, UGT1A6*3a, UGT1A7*3) and transporter single nucleotide polymorphisms (SNPs) (SCLO1B1 p.V174A, SCLO1B1 p.N130D, ABCC2 p.I1324I, ABCC2-24 UTR) using TaqMan-5'-nuclease-assays. A humanized transgenic UGT1A-SNP and corresponding wildtype mouse model were established carrying the GS-associated UGT1A variant haplotype. UGT1A transcript and protein expression, and transcriptional activation were studied in vivo. Homozygous UGT1A1*28 GS individuals were simultaneously homozygous for UGT1A3-66 T>C (91%), UGT1A6*2a (77%), and UGT1A7*3 (77%). Seventy-six percent of GS and only 9% of HBD were homozygous for the variant haplotype spanning four UGT1A genes. SCLO1B1 and ABCC2 SNPs showed no differences. In transgenic humanized UGT1A SNP and wildtype mice this UGT1A haplotype led to lower UGT1A messenger RNA (mRNA) expression and UGT1A protein synthesis. UGT1A transcriptional activation by dioxin, phenobarbital, and endotoxin was significantly reduced in SNP mice.

CONCLUSION

Our data redefine the genetic basis behind GS. In vivo data studying the genotype present in 76% of GS individuals suggest that transcription and transcriptional activation of glucuronidation genes responsible for conjugation and detoxification is directly affected, leading to lower responsiveness. This study suggests that GS should be considered a potential risk factor for drug toxicity.

Notch signaling inhibits hepatocellular carcinoma following inactivation of the RB pathway

Mice lacking all three Rb genes in the liver develop tumors resembling specific subgroups of human hepatocellular carcinomas, and Notch activity appears to suppress the growth and progression of these tumors.

Hepatocellular carcinoma (HCC) is the third cancer killer worldwide with >600,000 deaths every year. Although the major risk factors are known, therapeutic options in patients remain limited in part because of our incomplete understanding of the cellular and molecular mechanisms influencing HCC development. Evidence indicates that the retinoblastoma (RB) pathway is functionally inactivated in most cases of HCC by genetic, epigenetic, and/or viral mechanisms. To investigate the functional relevance of this observation, we inactivated the RB pathway in the liver of adult mice by deleting the three members of the Rb (Rb1) gene family: Rb, p107, and p130. Rb family triple knockout mice develop liver tumors with histopathological features and gene expression profiles similar to human HCC. In this mouse model, cancer initiation is associated with the specific expansion of populations of liver stem/progenitor cells, indicating that the RB pathway may prevent HCC development by maintaining the quiescence of adult liver progenitor cells. In addition, we show that during tumor progression, activation of the Notch pathway via E2F transcription factors serves as a negative feedback mechanism to slow HCC growth. The level of Notch activity is also able to predict survival of HCC patients, suggesting novel means to diagnose and treat HCC.

RB deletion disrupts coordination between DNA replication licensing and mitotic entry in vivo

The retinoblastoma tumor suppressor (RB) is functionally inactivated at high frequency in nearly all tumor types. Herein the acute deletion of RB in the liver reveals an immediate and profound dysregulation of spatiotemporal coordination in cell-cycle phases, resulting in robust DNA damage and aneuploidy that is not found in other tissues.

The integrity of the retinoblastoma tumor suppressor (RB) pathway is critical for restraining inappropriate proliferation and suppressing tumor development in a plethora of tissues. Here adenovirus-mediated RB deletion in the liver of adult mice led to DNA replication in the absence of productive mitotic condensation. The replication induced by RB loss was E2F-mediated and associated with the induction of DNA damage and a nontranscriptional G2/M checkpoint that targeted the accumulation of Cyclin B1. In the context of RB deletion or E2F activation, there was an increase in hepatocyte ploidy that was accompanied by hyperphysiological assembly of prereplication complexes. In keeping with this dysregulation, initiation of DNA replication was readily observed in hepatocytes that were phenotypically in G2/M. Under such conditions, uncoupling of replication initiation from mitotic progression led to altered genome ploidy in the liver. Interestingly, these findings in hepatocytes were not recapitulated in the basally proliferative tissues of the gastrointestinal tract, where RB deletion, while increasing DNA replication, did not lead to a profound uncoupling from mitosis. Combined, these findings demonstrate the critical role of RB in controlling cell-cycle transitions and underscore the importance of intrinsic tissue environments in resultant phenotypes.

Coffee induces expression of glucuronosyltransferases by the aryl hydrocarbon receptor and Nrf2 in liver and stomach

BACKGROUND & AIMS

Coffee is one of the most widely consumed beverages worldwide. Epidemiologic data indicate that coffee consumption protects against the progression of chronic liver disease and development of hepatocellular carcinoma and diabetes, but the mechanisms are not clear. UDP glucuronosyltransferases (UGT1A) are proteins with indirect antioxidant, cytoprotective, and genoprotective capabilities; we examined UGT1A regulation in response to coffee in cultured cells and mice.

METHODS

HepG2 and CaCo2 cells were incubated with regular, metal- or paper-filtered, decaffeinated, or instant coffee; green or black tea; cocoa; or metabolic products of caffeine. The effects of UGT1A regulation were investigated with reporter gene assays, immunoblot, TaqMan polymerase chain reaction, mutagenesis, and short interfering (si)RNA analyses. We also studied the effects of coffee in humanized transgenic mice that express human UGT1A.

RESULTS

Incubation of cells with coffee induced transcription of UGT1A1 (5.4-fold), UGT1A3 (5.2-fold), UGT1A4 (4.8-fold), UGT1A7 (6.2-fold), UGT1A8 (5.2-fold), UGT1A9 (3.5-fold), and UGT1A10 (6.1-fold). Induction was independent of caffeine, methylxanthines, or the diterpenes cafestol and kahweol. Mutagenesis and short interfering RNA knockdown studies showed that UGT1A is regulated by the aryl hydrocarbon receptor (AhR) and the nuclear factor erythroid-related factor 2 (Nrf2) by cis-acting antioxidant and xenobiotic response elements (ARE/XRE). In transgenic UGT1A mice, administration of coffee resulted in a 10- and 14-fold induction of UGT1A transcription in liver and stomach, respectively.

CONCLUSIONS

UGT1A genes are induced in vitro and in vivo by coffee, independent of caffeine content, cafestol, or kahweol. Coffee up-regulates glucuronidation by AhR signaling and Nrf2 binding to the ARE/XRE. Glucuronidation could mediate the protective and antioxidant effects of coffee.

Regulation of the human bile acid UDP-glucuronosyltransferase 1A3 by the farnesoid X receptor and bile acids

BACKGROUND & AIMS

Cholestasis is a serious complication of many liver diseases leading to increased serum bile acids (BA) and their conjugates. Chenodeoxycholic (CDCA) acid is a substrate of the human hepatic UDP-glucuronosyltransferase (UGT) 1A3. UGT1A3 may, therefore, be a BA-inducible gene relevant to BA regulation.

METHODS

BA and human bile were used to induce UGT1A3 in HepG2 cells. Genomic DNA was analyzed by PCR amplification and sequencing. Transcriptional regulation was studied by DNA mutagenesis, RT-PCR, luciferase reporter gene constructs and electrophoretic mobility shift assays (EMSA).

RESULTS

CDCA differentially induced UGT1A3 but not UGT1A4 expression. Bile from ursodeoxycholic acid (UDCA)-treated and untreated patients differentially induced UGT1A3. A farnesoid X receptor (FXR) half-site DNA motif was identified in the UGT1A3 5' upstream region. The FXR inducer GW4064 activated UGT1A3 transcription, and electrophoretic mobility shift assays identified UGT1A3 as a FXR target gene.

CONCLUSIONS

Transcriptional regulation of the human bile acid and xenobiotic UGT1A3 by its substrate CDCA and FXR is shown. CDCA glucuronidation can be controlled by feed back inhibition proceeding via the glucuronidation of CDCA. UDCA does not induce UGT1A3 transcription. Since UGT1A3 is significantly induced by xenobiotics this physiologically links xenobiotic and bile acid metabolism to cholestasis.

Interaction between oxidative stress sensor Nrf2 and xenobiotic-activated aryl hydrocarbon receptor in the regulation of the human phase II detoxifying UDP-glucuronosyltransferase 1A10

The defense against oxidative stress is a critical feature that prevents cellular and DNA damage. UDP-glucuronosyltransferases (UGTs) catalyze the glucuronidation of xenobiotics, mutagens, and reactive metabolites and thus act as indirect antioxidants. Aim of this study was to elucidate the regulation of UGTs expressed in the mucosa of the gastrointestinal tract by xenobiotics and the main mediator of antioxidant defense, Nrf2 (nuclear factor erythroid 2-related factor 2). Xenobiotic (XRE) and antioxidant (ARE) response elements were detected in the promoters of UGT1A8, UGT1A9, and UGT1A10. Reporter gene experiments demonstrated XRE-mediated induction by dioxin in addition to tert-butylhydroquinone (ARE)-mediated induction of UGT1A8 and UGT1A10, which are expressed in extrahepatic tissue in humans in vivo. The responsible XRE and ARE motifs were identified by mutagenesis. Small interfering RNA knockdown, electrophoretic mobility shifts, and supershifts identified a functional interaction of Nrf2 and the aryl hydrocarbon receptor (AhR). Induction of UGT1A8 and UGT1A10 requires Nrf2 and AhR. It proceeds by utilizing XRE- as well as ARE-binding motifs. In summary, we demonstrate the coordinated AhR- and Nrf2-dependent transcriptional regulation of human UGT1As. Cellular protection by glucuronidation is thus inducible by xenobiotics via AhR and by oxidative metabolites via Nrf2 linking glucuronidation to cellular protection and defense against oxidative stress.

Gilbert's syndrome and hyperbilirubinemia in protease inhibitor therapy--an extended haplotype of genetic variants increases risk in indinavir treatment

BACKGROUND/AIMS

Gilbert's syndrome is a frequent genetic conjugation abnormality associated with adverse drug effects. Genetic UDP glucuronosyltransferase (UGT)1A gene variants can influence gene transcription, inducibility and glucuronidation activity. Protease inhibitors used in human immunodeficiency virus (HIV) infection and chronic viral hepatitis can inhibit UGTs. Indinavir (IDV) can lead to hyperbilirubinemia in Gilbert's syndrome (UGT1A1*28), which does not explain interindividual severity differences and may thus involve additional UGT1A variants.

METHODS

One hundred and twenty-five HIV patients receiving IDV and 427 healthy blood donors were genotyped for the presence of UGT1A1*28, UGT1A3 -66T/C, UGT1A7 -57T/G, UGT1A7(N129K/R131K) using Taqman 5' nuclease assays.

RESULTS

Hyperbilirubinemia was observed in 42%. UGT1A1*28 frequencies did not differ between HIV patients and controls but were significantly higher in hyperbilirubinemic patients. The frequency of homozygous carriers of the 4 UGT1A marker haplotype increased with hyperbilirubinemia affecting all patients with bilirubin levels >85 micromol/l.

CONCLUSIONS

In IDV treatment the risk of severe hyperbilirubinemia is associated with genetic variants of the UGT1A3 and UGT1A7 genes in addition to Gilbert's syndrome (UGT1A1*28). This haplotype is a useful predictor of protease inhibitor-induced side effects.

Variability and function of family 1 uridine-5'-diphosphate glucuronosyltransferases (UGT1A)

The substrate spectrum of human UDP-glucuronosyltransferase 1A (UGT1A) proteins includes the glucuronidation of non-steroidal anti-inflammatory drugs, anticonvulsants, chemotherapeutics, steroid hormones, bile acids, and bilirubin. The unique genetic organization of the human UGT1A gene locus, and an increasing number of functionally relevant genetic variants define tissue specificity as well as a broad range of interindividual variabilities of glucuronidation. Genetic UGT1A variability has been conserved throughout the protein's evolution and shows ethnic diversity. It is the biochemical and genetic basis for clinical phenotypes such as Gilbert's syndrome and Crigler-Najjar's disease as well as for the potential for severe, unwanted drug side effects such as in irinotecan treatment. UGT1A variants influence the metabolic effects of xenobiotic exposure and therefore have been linked to cancer risk. Detailed knowledge of the organization, function, and pharmacogenetics of the human UGT1A gene locus is likely to significantly contribute to the improvement of drug safety and efficacy as well as to the provision of steps toward the goal of individualized drug therapy and disease risk prediction.

Rapid allelic discrimination by TaqMan PCR for the detection of the Gilbert's syndrome marker UGT1A1*28

Gilbert's syndrome causes mild, unconjugated hyperbilirubinemia and is present in approximately 10% of the Caucasian population. The basis of the disorder is a 70% reduction in bilirubin glucuronidation catalyzed by the UDP-glucuronosyltransferase 1A1 (UGT1A1), which, in Caucasians, is the result of a homozygous TA insertion into the promoter region of the UGT1A1 gene (UGT1A1*28). Homozygous carriers of UGT1A1*28 as well as those with additional UGT1A variants can suffer from severe irinotecan toxicity or jaundice during treatment with the protease inhibitor atazanavir. UGT1A1*28 genotyping identifies patients at risk for drug toxicity and can increase drug safety by dose individualization. Rapid and facile UGT1A1*28 genotyping is therefore of great clinical importance. Two hundred ninety-one patients with suspected Gilbert's syndrome were genotyped using the TaqMan 5'nuclease assay with minor groove binder-non fluorescent quench probes; results were confirmed by direct sequencing. Ninety-six patients (33%) were homozygous for UGT1A1*28, which was verified by direct sequencing of a different PCR product showing 100% concordance with the TaqMan PCR results. We describe a novel UGT1A1*28 genotyping method that employs allelic discrimination by TaqMan PCR. This assay provides a rapid, high-throughput, and cost-effective method for Gilbert's syndrome genotyping, which is of value for pretreatment screening of potential irinotecan toxicity. The method utilizes a technological platform that is widely used in clinical practice and could therefore be easily adapted for routine clinical applications.

Family 1 uridine-5'-diphosphate glucuronosyltransferases (UGT1A): from Gilbert's syndrome to genetic organization and variability

The human UDP-glucuronosyltransferase 1A gene locus is organized to generate enzymes, which share a carboxyterminal portion and are unique at their aminoterminal variable region. Expression is tissue-specific and overlapping substrate specificities include a broad spectrum of endogenous and xenobiotic compounds as well as many therapeutic drugs targeted for detoxification and elimination by glucuronidation. The absence of glucuronidation leads to fatal hyperbilirubinemia. A remarkable interindividual variability of UDP-glucuronosyltransferases is evidenced by over 100 identified genetic variants leading to alterations of catalytic activites or transcription levels. Variant alleles with lower carcinogen detoxification activity have been associated with cancer risk such as colorectal cancer and hepatocellular carcinoma. Genetic variants and haplotypes have been identified as risk factors for unwanted drug effects of the anticancer drug irinotecan and the antiviral proteinase inhibitor atazanavir. Glucuronidation and its variability are likely to represent an important factor for individualized drug therapy and risk prediction impacting the drug development and licensing processes.

Genetic variability of aryl hydrocarbon receptor (AhR)-mediated regulation of the human UDP glucuronosyltransferase (UGT) 1A4 gene

UDP glucuronosyltransferases (UGTs) play an important role for drug detoxification and toxicity. UGT function is genetically modulated by single nucleotide polymorphisms (SNPs) which lead to the expression of functionally altered protein, or altered expression levels. UGT1A4 activity includes anticonvulsants, antidepressants and environmental mutagens. In this study the induction of the human UGT1A4 gene and a potential influence of genetic variation in its promoter region were analyzed. SNPs at bp -219 and -163 occurred in 9% among 109 blood donors reducing UGT1A4 transcription by 40%. UGT1A4 transcription was dioxin inducible. Reporter gene experiments identified 2 xenobiotic response elements (XRE), which were functionally confirmed by mutagenesis analyses, and binding was demonstrated by electromobility shift assays. Constitutive human UGT1A4 gene expression and induction was aryl hydrocarbon receptor (AhR)-dependent, and reduced in the presence of SNPs at bp -219 and -163. AhR-mediated regulation of the human UGT1A4 gene by two XRE and a modulation by naturally occurring genetic variability by SNPs is demonstrated, which indicates gene-environment interaction with potential relevance for drug metabolism.

Variation of hepatic glucuronidation: Novel functional polymorphisms of the UDP-glucuronosyltransferase UGT1A4

UDP-glucuronosyltransferases are a family of drug metabolizing enzymes contributing to hepatic drug metabolism and protection against environmental toxins. The aim of this study was to identify polymorphisms at the human UGT1A gene locus and to characterize their function and potential association with hepatocellular carcinoma (HCC). Genomic DNA from the blood of 363 subjects (128 patients with HCC, 235 blood donors) was analyzed for polymorphisms of the UGT1A3, UGT1A4, UGT1A8, UGT1A9, UGT1A10 genes using polymerase chain reaction, sequencing analysis. Recombinant variant UGT protein was analyzed by activity assays. In the UGT1A8 gene an A173G variant and a conserved G to A exchange at position 765 were detected in 25% and 15%. UGT1A9 exhibited two variants C3Y and M33T in 1% and 3%. UGT1A10 exhibited conserved nucleotide exchanges (128 G-->A and 696 C-->T) in 2% and 13%. In the UGT1A3 gene a W11R, a V47A variant, and a conserved G to A exchange at position 81 with an incidence of 65%, 58%, and 65%, respectively, were identified. UGT1A4 exhibited a P24T and an L48V variant in 8% and 9%. UGT1A SNPs were not associated with HCC. UGT1A4 P24T and L48V exhibited reduced glucuronidation activities: beta-naphthylamine 30% and 50%, and dihydrotestosterone 50% and 0%, respectively. In conclusion, the high prevalence of SNPs throughout the human UGT1A gene locus illustrates a genetic basis of interindividual variations of hepatic metabolism. Two polymorphisms of the hepatic UGT1A4 protein show a differential metabolic activity toward mutagenic amines and endogenous steroids, altering hepatic metabolism and detoxification.

Internet-capable publication database system

Scientific databases are generally accessible to the public via the Internet. Reports of most peer-reviewed (quotable) research is thus available to researchers and others. However, other reports and information of interest to researchers and teachers such as poster presentations at congresses, articles describing techniques and teaching material, and details of vocational and continuing education courses (nonquotable literature) generally do not appear in such databases. This nonquotable literature is often of great use to teachers. A project was therefore initiated at the Münster Dental Clinic which aimed to address the problem by developing a database of all publications and other printed material produced by the staff (faculty). After a systematic search, all such publications (quotable and nonquotable) were entered in the database which is partially accessible via the Internet and fully accessible via the Münster Dental Clinic's Intranet. The complete list can be found in the protected Intranet areas, which can be accessed by all the Dental Clinic's staff members. The database also permits Münster Clinic staff to access the Internet and locate those publications that are on the Internet by year of publication and topic.

Combined space management through Delaire/Joos osteotomy and postoperative orthodontic treatment. A retrospective longitudinal study

The diagnostic records of all patients who had undergone Delaire/Joos osteotomy with mandibular setback at the Muenster University Hospital (period 1995-2000, n=22) were used for space management evaluation in the context of combined surgical-orthodontic treatment.Twenty-eight dental spaces were present prior to the start of treatment and 14 were created by extracting teeth as a pretreatment measure. In two patients, unilateral setback was performed according to Obwegeser/Dal Pont. Thus, 42 tooth-bounded spaces were present at the time of Delaire/Joos osteotomy with mandibular setback, most of them in the first molar region, followed by the second premolar region. A significant space reduction was achieved by the surgical intervention, but not by the subsequent orthodontic treatment. The best results with respect to complete space closure by orthognathic surgery/orthodontic treatment without the need for subsequent prosthetic rehabilitation were recorded in the second premolar region. In the absence of spaces and with a similar long-term prognosis for all potentially extractable teeth and adequate space for the necessary surgical repositioning, the second premolars should therefore be regarded as the 'extraction teeth of choice' for mandibular setback within the context of Delaire/Joos osteotomy.

Polymorphisms of the carcinogen detoxifying UDP-glucuronosyltransferase UGT1A7 in proximal digestive tract cancer

Cancer of the proximal digestive tract is associated with tobacco smoke and ethanol exposure. The UDP-glucuronosyltransferase (UGT) 1A7 is a detoxifying enzyme capable of tobacco-borne carcinogen detoxification and cellular protection and has been implicated as a cancer risk gene. In this study, UGT1A7 expression is demonstrated in oral, esophageal, and gastric tissue, which are the principle sites of proximal digestive tract cancer. Genomic DNA from the blood of 76 patients with esophageal, orolaryngeal and gastric cancer as well as from 210 healthy blood donors was analysed for the presence of UGT1A7 polymorphisms by sequencing and temperature gradient gel electrophoresis. Wild type UGT1A7 alleles were equally distributed between controls (19 %) and cancer patients (22 %). However, the UGT1A7*3 allele combining W208R, N129K and R131K missense mutations and exhibiting substantially reduced carcinogen detoxification activity was significantly associated with proximal gastrointestinal cancer and identified as a risk allele present in 32 % of cancer patients and 19 % of controls (P = 0.0008, OR 2,02 (95 %-CI 1.33-3.07)). We identify the significant association of the UGT1A7*3 allele encoding a low catalytic activity protein as a risk gene in proximal digestive tract cancer and as a potential marker for cancer susceptibility.