Clinical factors associated with the therapeutic efficacy of atezolizumab plus bevacizumab in patients with unresectable hepatocellular carcinoma: A multicenter prospective observational study.

The treatment efficiency and predictors of atezolizumab plus bevacizumab therapy for unresectable hepatocellular carcinoma in real-world practice have not been established. This study aimed to assess the efficacy and safety of atezolizumab plus bevacizumab and to investigate predictors of progression-free survival and overall survival. Patients with unresectable hepatocellular carcinoma treated with atezolizumab plus bevacizumab therapy in 19 hospitals were enrolled before treatment and observed prospectively. The outcomes of 222 patients in this cohort were analyzed. The objective response rate and disease control rate were 22.0% and 70.6%, respectively, whereas the median progression-free survival was 5.7 months. Independent risk factors for shortened progression-free survival were younger age (<75 years; 3.9 months vs. 8.6 months), higher number of intrahepatic tumors (≥5; 4.0 months vs. 7.9 months), macrovascular invasion (2.3 months vs. 6.7 months), and higher neutrophil-to-lymphocyte ratio (≥3.03; 3.0 months vs. 7.8 months). The median overall survival was not reached; however, independent risk factors for shortened overall survival were absence of hyperlipidemia, higher number of intrahepatic tumors (≥5), macrovascular invasion, higher α-fetoprotein level (≥400 ng/mL), worse Child-Pugh score (≥6), and higher neutrophil-to-lymphocyte ratio (≥3.03). Severe adverse events (grade ≥3) were observed in 96 patients (36.0%), with proteinuria being the most frequent. In conclusion, patients with older age, lower number of intrahepatic tumors, absent macrovascular invasion, and lower neutrophil-to-lymphocyte ratio are expected to have better progression-free survival with atezolizumab plus bevacizumab therapy for unresectable hepatocellular carcinoma.

Posttreatment liver function, but not baseline liver function stratifies patient survival after direct-acting antiviral treatment in decompensated cirrhosis with hepatitis C virus.

BACKGROUND: The prognosis of cirrhosis is clearly stratified by liver function. Although direct-acting antiviral (DAA) has recently been used to eliminate hepatitis C virus (HCV), it is not clear whether liver function stratifies the prognosis of decompensated cirrhotic patients treated with DAA. METHODS: A total of 206 HCV-associated decompensated cirrhotic patients who started DAA from February 2019 to December 2021 at 31 Japanese hospitals were prospectively registered. RESULTS: The median age was 68, and the proportions of patients with Child-Pugh class A (CP-A), CP-B and CP-C were 10% (20/206), 76% (156/206) and 15% (30/206), respectively. Twenty-six patients died, and two patients underwent liver transplantation (LT); the 2- and 3-year LT-free survival rates were 90.0% and 83.2%, respectively. We examined factors associated with LT-free survival using 2 models including either CP class (Model 1) or MELD score (Model 2). In multivariate Cox proportional hazard analysis, CP class at 12 weeks after the end of treatment (EOT) in Model 1 and MELD score at 12 weeks after the EOT in Model 2 were significant factors, while baseline CP class or MELD score was not. Two-year LT-free survival rates were 100%, 91.6% and 60.4% for patients with CP-A, CP-B and CP-C at 12 weeks after the EOT and 95.2% and 69.6% for patients with MELD < 15 and MELD ≥ 15 at 12 weeks after the EOT, respectively. CONCLUSIONS: The prognosis of decompensated cirrhotic patients receiving DAA was stratified by liver function at 12 weeks after the EOT, not by baseline liver function.

Postoperative bleeding after percutaneous transhepatic gallbladder drainage and aspiration in patients receiving antithrombotic therapy.

This study aimed to investigate the bleeding risk associated with percutaneous transhepatic gallbladder interventions in patients with acute cholecystitis receiving antithrombotic therapy. In this retrospective study, 194 consecutive patients who underwent percutaneous transhepatic gallbladder interventions for acute cholecystitis between April 2011 and April 2021 were enrolled. Patients were sorted into four groups: no prior antithrombotic therapy, discontinued antithrombotic drugs, single antithrombotic drug continued perioperatively, and multiple antithrombotic drugs continued perioperatively. The risk of postoperative bleeding after percutaneous transhepatic gallbladder interventions was evaluated via multivariate logistic regression analysis. Of the 116 (59.8%) patients receiving antithrombotic therapy, 32 (16.5%) discontinued antithrombotic drugs before their respective procedure, 50 (25.8%) continued a single antithrombotic drug, and 34 (17.5%) continued multiple antithrombotic drugs during the perioperative period. The rates of significant and severe bleeding were 10.3% (20/194) and 3.1% (6/194), respectively. The rate of significant bleeding was significantly higher in patients who continued multiple antithrombotic drugs than in patients who received no prior antithrombotic therapy (P = 0.006). In the multivariate logistic regression analysis, the continuation of multiple antithrombotic drugs during the perioperative period was a risk factor for significant bleeding after percutaneous transhepatic gallbladder interventions. In conclusion, the perioperative continuation of multiple antithrombotic drugs is a risk factor for postoperative bleeding after percutaneous transhepatic gallbladder interventions.

Pretreatment with antibiotics is associated with reduced therapeutic response to atezolizumab plus bevacizumab in patients with hepatocellular carcinoma.

AIM: Alterations in microbial composition of gut microbiota due to antibiotics (ATB) may lead to resistance to immune checkpoint inhibitors (ICIs). This study aimed to assess the impact of ATB use on therapeutic response in patients with hepatocellular carcinoma (HCC) receiving atezolizumab plus bevacizumab. METHODS: This study retrospectively analyzed 105 patients with HCC treated with atezolizumab plus bevacizumab as a primary systemic therapy from prospectively-registered, multicenter, cohorts. Nineteen patients who received prior ATB were included in the ATB (+) group; 86 patients who did not receive prior ATB were included in the ATB (-) group. The therapeutic outcomes were compared between the two groups. RESULTS: Most of the patients' baseline characteristics were not significantly different between the two groups. The objective response rates according to the Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1) (30.1% vs. 11.1%; p = 0.143) and modified RECIST (mRECIST) (44.6% vs. 27.8%; p = 0.190) were not significantly different between the ATB (-) and ATB (+) groups. The disease control rates were higher in the ATB (-) group than in the ATB (+) group according to RECIST v1.1 (74.7% vs. 44.4%; p = 0.012) and mRECIST (78.3% vs. 50.0%; p = 0.020). Prior ATB use was found to be independently associated with radiological progressive disease of the first therapeutic assessment. The median progression-free survival according to RECIST v1.1 (9.1 months vs. 3.0 months; p = 0.049) and mRECIST (9.1 months vs. 3.0 months; p = 0.036), and overall survival (not reached vs. 11.4 months; p = 0.015) were longer in the ATB (-) group than in the ATB (+) group. CONCLUSIONS: Prior ATB use was associated with reduced therapeutic responses in patients with HCC receiving atezolizumab plus bevacizumab.

Thrombospondin-2 as a Predictive Biomarker for Hepatocellular Carcinoma after Hepatitis C Virus Elimination by Direct-Acting Antiviral.

We evaluated the value of secreted glycoprotein thrombospondin-2 (TSP-2) to predict hepatocellular carcinoma (HCC) occurrence in chronic hepatitis C (CHC) patients after Hepatitis C virus (HCV) elimination by direct-acting antiviral agents (DAAs). A total of 786 CHC patients without an HCC history who achieved a sustained virological response (SVR) with DAAs were randomly assigned 2:1, with 524 patients as the derivation cohort and 262 patients as the validation cohort. Serum TSP-2 levels at the end of treatment were measured by enzyme-linked immunosorbent assay (ELISA). In the derivation cohort, the cumulative HCC rate was significantly higher in the high TSP-2 group than in the low TSP-2 group. Multivariate Cox proportional hazards analysis revealed that TSP-2, α-fetoprotein (AFP), and the fibrosis-4 (FIB-4) index were independent HCC risk factors. The area under the receiver operating characteristic curve (AUROC) of the score calculated from these three factors (AFT score) for predicting HCC was 0.83, which was significantly higher than that of each factor alone (TSP-2: 0.70, AFP: 0.72, FIB-4: 0.69). The AFT score was used to stratify patients according to the risk of HCC occurrence in the validation cohort. Lastly, in patients with a FIB-4 index < 3.25, the serum TSP-2 levels could be used to identify those patients with a high risk of HCC occurrence. Serum TSP-2 levels are a predictive biomarker of HCC occurrence in CHC patients after HCV elimination by DAA treatment. The AFT score using TSP-2, AFP, and the FIB-4 index may identify those who require HCC surveillance.

Effect of sofosbuvir and velpatasvir therapy on clinical outcome in hepatitis C virus patients with decompensated cirrhosis.

AIM: To determine the impact of direct-acting antiviral therapy on the long-term prognosis of decompensated cirrhotic patients. METHODS: A total of 37 patients with hepatitis C virus-induced decompensated cirrhosis treated with sofosbuvir and velpatasvir (SOF/VEL group) were prospectively enrolled. For historical control, 65 hepatitis C virus-positive decompensated cirrhotic patients who did not receive direct-acting antiviral therapy were included (control group). The incidence rates of hepatocellular carcinoma (HCC), decompensated events with hospitalization, and overall survival were compared between both groups. RESULTS: A total of 41 patients experienced decompensated events during 15.0 months in the control group, and six patients during 21.6 months in the SOF/VEL group. The cumulative incidence rates of decompensated events after 2 years were significantly higher in the control group (53.1%) than in the SOF/VEL group (14.5%; p < 0.001). A total of 27 patients died within 22.0 months in the control group, and three patients died within 25.6 months in the SOF/VEL group. The overall survival rates after 2 years were significantly lower in the control group (67.6%) than in the SOF/VEL group (91.3%; p = 0.010). A total of 13 patients in the control group developed HCC during 15.8 months, and 10 patients during 17.3 months in the SOF/VEL group. The HCC incidence rates after 2 years were 20.3% and 29.6% in the control and SOF/VEL groups, respectively, with no significant difference (p = 0.327). CONCLUSIONS: SOF/VEL therapy may suppress the development of decompensated events and improve the prognosis in decompensated cirrhotic patients; however, the incidence of HCC remains prevalent in these patients irrespective of SOF/VEL therapy.

Fucosylated haptoglobin is a novel predictive marker of hepatocellular carcinoma after hepatitis C virus elimination in patients with advanced liver fibrosis.

BACKGROUND: Patients with advanced fibrosis are at risk for developing hepatocellular carcinoma (HCC) even after hepatitis C virus (HCV) elimination. We previously reported that serum fucosylated haptoglobin (Fuc-Hp) levels increase as the disease progresses from chronic hepatitis to cirrhosis and then HCC. However, it remains unclear whether serum Fuc-Hp levels can stratify the risk of HCC occurrence after a sustained virological response (SVR) is achieved with direct-acting antivirals (DAAs) in patients with advanced liver fibrosis. METHODS: Among 3,550 patients with chronic hepatitis C treated with DAAs at Osaka University Hospital and related hospitals, the stored sera of 140 patients who were diagnosed with F3 or F4 by liver biopsy before DAA treatment, achieved SVR, and had no history of HCC were available at both baseline and the end of treatment (EOT). We measured the Fuc-Hp levels in these samples. RESULTS: The median serum levels of Fuc-Hp at EOT were significantly lower than those at baseline. During the 54.4-month follow-up period, 16 of 140 patients developed HCC. Multivariate Cox proportional hazards analysis revealed that high Fuc-Hp at EOT, high body mass index (BMI), and low albumin at EOT were independent risk factors for HCC occurrence. Patients with all three factors-high Fuc-Hp, high BMI, and low albumin-had a higher incidence of HCC than patients without these factors. CONCLUSIONS: High serum Fuc-Hp levels at EOT were an independent risk factor for HCC occurrence after SVR. Combined with BMI and albumin, Fuc-Hp can stratify the risk of HCC occurrence among those with advanced fibrosis.

Circulating Cell-Free DNA Profiling Predicts the Therapeutic Outcome in Advanced Hepatocellular Carcinoma Patients Treated with Combination Immunotherapy.

Combination immunotherapy with anti-programmed cell death1-ligand1 (PD-L1) and anti-vascular endothelial growth factor (VEGF) antibodies has become the standard treatment for patients with unresectable HCC (u-HCC). However, limited patients obtain clinical benefits. Cell-free DNA (cfDNA) in peripheral blood contains circulating tumor DNA (ctDNA) that reflects molecular abnormalities in tumor tissue. We investigated the potential of cfDNA/ctDNA as biomarkers for predicting the therapeutic outcome in u-HCC patients treated with anti-PD-L1/VEGF therapy. We enrolled a multicenter cohort of 85 HCC patients treated with atezolizumab and bevacizumab (Atezo/Bev) between 2020 and 2021. Pretreatment plasma was collected, and cfDNA levels were quantified. Ultradeep sequencing of cfDNA was performed with a custom-made panel for detecting mutations in 25 HCC-related cancer genes. We evaluated the association of cfDNA/ctDNA profiles and clinical outcomes. Patients with high plasma cfDNA levels showed a significantly lower response rate and shorter progression-free survival and overall survival (OS) than those with low cfDNA levels. ctDNA detected in 55% of HCC patients included the telomerase reverse transcriptase (TERT) promoter in 31% of these patients, tumor protein 53 (TP53) in 21%, catenin beta 1 (CTNNB1) in 13% and phosphatase and tensin homolog (PTEN) in 7%. The presence or absence of ctDNA did not predict the efficacy of Atezo/Bev therapy. Twenty-six patients with a TERT mutation had significantly shorter OS than those without. The presence of a TERT mutation and alpha-fetoprotein (AFP) ≥ 400 ng/mL were independent predictors of poor OS according to multivariate Cox proportional hazard analysis and could be used to stratify patients treated with Atezo/Bev therapy based on prognosis. In conclusion, pretreatment cfDNA/ctDNA profiling may be useful for predicting the therapeutic outcome in u-HCC patients treated with anti-PD-L1/VEGF therapy.

Incidence and risk factors of hepatocellular carcinoma in patients with hepatitis C who achieved a sustained virological response through direct-acting antiviral agents among the working population in Japan.

Background and Aim: The development of hepatocarcinogenesis after a sustained virological response (SVR) remains an important issue affecting the balance between treatment and occupational life of workers with chronic hepatitis C virus (HCV) infection in Japan. Here, we aimed to evaluate the hepatocellular carcinoma (HCC) reducing effect and risk factors for developing HCC after SVR in patients treated with direct-acting antiviral agents (DAAs) among the working population. Methods: We studied 2579 working patients with chronic HCV infection who achieved SVR after antiviral treatment. We compared the difference in the cumulative incidence of post-SVR HCC between the interferon (IFN)-based n = 1615 and DAA (n = 964) groups. The risk factors for post-SVR HCC development were determined in the DAA group. Results: After propensity score matching (n = 644 in each group), the HCC development rates were not significantly different between the groups (P = 0.186). Multivariate Cox regression and the cutoff values determined by the receiver operating characteristic curve analyses revealed that age ≥61 years, diabetes, lower serum albumin levels <4.0 g/dL at 24 weeks after the end of treatment (EOT), and higher serum α-fetoprotein levels ≥4.1 ng/mL at 24 weeks after the EOT were associated with the development of HCC. Conclusion: The HCC suppressing effect after SVR through DAA treatment is equivalent to that of IFN treatment in patients in the working population. Intensive follow-up is required after SVR with DAA treatment in Japanese workers with these risk factors to ensure the promotion of health and employment support.

Risk of hepatocellular carcinoma after sustained virologic response in hepatitis C virus patients without advanced liver fibrosis.

AIM: Hepatocellular carcinoma (HCC) after sustained virologic response (SVR) has been observed even in hepatitis C virus (HCV) patients without advanced liver fibrosis. Identifying predictors for HCC incidence in patients without advanced liver fibrosis will enable efficient post-SVR HCC surveillance. This study aimed to develop a scoring system to predict the incidence of HCC after SVR in HCV patients without advanced liver fibrosis. METHODS: A total of 1682 HCV patients without advanced liver fibrosis (defined as Fibrosis-4 index <3.25) with no history of HCC who initiated direct-acting antiviral treatment between September 2014 and October 2020 at 26 institutions, and achieved SVR24, were included. We divided 1682 patients into training (1122) and validation (560) cohorts. RESULTS: In the multivariate analysis, baseline age ≥ 65 years (p = 0.030), alanine aminotransferase (ALT) levels at SVR24 ≥ 30 U/l (p = 0.001), and α-fetoprotein (AFP) levels at SVR24 ≥ 5.0 ng/ml (p = 0.001) were independent predictors for HCC incidence in the training cohort. We developed a scoring system to predict HCC incidence after SVR24 using these three factors (1 point was added for each factor). The cumulative HCC incidence rates at 5 years were 7.1% in patients who scored 2 or 3, and no patients developed HCC in those who scored 0 in the validation cohort. CONCLUSIONS: Our scoring system using the three factors of baseline age, ALT levels at SVR, and AFP levels at SVR is useful for post-SVR HCC surveillance of patients without advanced liver fibrosis.

Prognostic impact of worsening of esophageal varices after balloon-occluded retrograde transvenous obliteration.

BACKGROUND AND AIM: Balloon-occluded retrograde transvenous obliteration (BRTO) is widely performed for treating gastric varices (GVs). However, worsening of esophageal varices (EVs) can be observed after BRTO. This study aimed to investigate the impact of EV worsening on prognosis after BRTO. METHODS: Overall, 258 patients who underwent initial BRTO for GV treatment between January 2004 and May 2019 at 12 institutions were retrospectively registered. RESULTS: Technical success was achieved in 235 patients (91.1%). Based on the exclusion criteria, 37 patients were excluded, and 198 were evaluated. The cumulative worsening rates of EVs at 1, 2, and 3 years were 39.0%, 59.4%, and 68.4%, respectively. In the univariate Cox proportional hazards model, sex, EV size, history of EV treatment, left gastric vein dilatation, platelet count, aspartate transaminase (AST), alanine aminotransferase (ALT), total bilirubin, albumin, albumin-bilirubin score, prothrombin time-international normalized ratio, fibrosis-4 index, AST to platelet ratio index, and spleen width were significantly associated with worsening of EV after BRTO. Multivariate analysis showed that sex (adjusted hazard ratio [aHR] 1.72; 95% confidence interval [CI] 1.03-2.86; P = 0.04), left gastric vein dilatation (aHR 1.90; 95% CI 1.17-3.10; P = 0.01), ALT (aHR 1.01; 95% CI 1.00-1.03; P = 0.02), albumin (aHR 0.61; 95% CI 0.43-0.87; P < 0.01), and spleen width (aHR 1.02; 95% CI 1.01-1.03; P < 0.01) were independent risk factors for worsening of EV after BRTO. Patients with EV worsening within 1 year after BRTO had a significantly worse prognosis than the other patients (P = 0.007). CONCLUSIONS: Early worsening of EV after BRTO was associated with poor prognosis after BRTO.

Comparison of atezolizumab plus bevacizumab and lenvatinib in terms of efficacy and safety as primary systemic chemotherapy for hepatocellular carcinoma.

AIM: Atezolizumab plus bevacizumab and lenvatinib have each shown efficacy as primary systemic chemotherapies for hepatocellular carcinoma (HCC) in clinical trials. However, comparative trials of these two treatments have not been conducted. This study aimed to compare the therapeutic outcomes of these two treatments. METHODS: This prospectively registered multicenter study analyzed 272 patients with HCC who received atezolizumab plus bevacizumab (the Atezo + Beva group; n = 90) or lenvatinib (the Len group; n = 182) as primary systemic chemotherapy. After propensity score matching (PSM), 66 patients were assigned to each group. RESULTS: After PSM, the median progression-free survival (PFS) was significantly longer in the Atezo + Beva group than in the Len group (8.8 vs. 5.2 months; p = 0.012). No significant differences were noted between the two groups in terms of median overall survival (not reached vs. 20.6 months; p = 0.577), objective response rates (43.8% vs. 52.4%; p = 0.330), and disease control rates (76.6% vs. 82.5%; p = 0.404). The percentage of patients with modified albumin-bilirubin grades of one or 2a was maintained during treatment in the Atezo + Beva group but decreased over time in the Len group. The rate of discontinuation due to adverse events (AEs) was lower in the Atezo + Beva group than in the Len group (12.1% vs. 28.8%; p = 0.018). CONCLUSIONS: Atezolizumab plus bevacizumab showed prolonged PFS, maintained hepatic reserve, and had lower rates of severe AEs compared with that on using lenvatinib as primary systemic chemotherapy for HCC.

Interleukin-6 Is a Circulating Prognostic Biomarker for Hepatocellular Carcinoma Patients Treated with Combined Immunotherapy.

Atezolizumab/bevacizumab (Atezo/Bev) combination therapy has become a front-line therapy for advanced hepatocellular carcinoma (HCC), but approximately 20% of patients are nonresponders. We investigated circulating biomarkers to predict therapeutic outcomes. We performed simultaneous measurement of 34 proteins using a multiplex bead-based immunoassay in baseline plasma from 34 patients who underwent Atezo/Bev therapy as first- or second-line treatment. Logistic regression analysis showed that plasma IL-6 and interferon alpha (IFNα) levels were significant predictors of non-responders (odds ratio of 13.33 and FDR p = 0.021 for IL-6 and IFNα). The progression-free survival (PFS) and overall survival (OS) of patients with high IL-6 levels were significantly shorter than those of patients with low IL-6 levels. Next, we measured baseline plasma IL-6 levels in 64 HCC patients who underwent Atezo/Bev therapy by ELISA. The IL-6-high group showed higher female ratio, AST levels, tumor markers, Child-Pugh score, and vascular invasion ratio. The PFS and OS of the IL-6-high group were significantly shorter than those of the IL-6-low group. Multivariate Cox proportional hazards analysis showed that IL-6 level and age were independent risk factors for disease progression (hazard ratio of 2.785 and p = 0.015 for IL-6, and hazard ratio 0.306 and p = 0.03 for age). In conclusion, circulating IL-6 levels are a novel prognostic biomarker for advanced HCC patients who undergo combined immunotherapy.

Gab1 in livers with persistent hepatocyte apoptosis has an antiapoptotic effect and reduces chronic liver injury, fibrosis, and tumorigenesis.

Grb2-associated binder 1 (Gab1) is an adaptor protein that is important for intracellular signal transduction by receptor tyrosine kinases that are receptors for various growth factors and plays an important role in rapid liver regeneration after partial hepatectomy and during acute hepatitis. On the other hand, mild liver regeneration is induced in livers of individuals with chronic hepatitis, where hepatocyte apoptosis is persistent; however, the impact of Gab1 on such livers remains unclear. We examined the role of Gab1 in chronic hepatitis. Gab1 knockdown enhanced the decrease in cell viability and apoptosis induced by ABT-737, a Bcl-2/-xL/-w inhibitor, in BNL.CL2 cells, while cell viability and caspase activity were unchanged in the absence of ABT-737. ABT-737 treatment induced Gab1 cleavage to form p35-Gab1. p35-Gab1 was also detected in the livers of mice with hepatocyte-specific Mcl-1 knockout (KO), which causes persistent hepatocyte apoptosis. Gab1 deficiency exacerbated hepatocyte apoptosis in Mcl-1 KO mice with posttranscriptional downregulation of Bcl-XL. In BNL.CL2 cells treated with ABT-737, Gab1 knockdown posttranscriptionally suppressed Bcl-xL expression, and p35-Gab1 overexpression enhanced Bcl-xL expression. Gab1 deficiency in Mcl-1 KO mice activated STAT3 signaling in hepatocytes, increased hepatocyte proliferation, and increased the incidence of liver cancer with the exacerbation of liver fibrosis. In conclusion, Gab1 is cleaved in the presence of apoptotic stimuli and forms p35-Gab1 in hepatocytes. In chronic liver injury, the role of Gab1 in suppressing apoptosis and reducing liver damage, fibrosis, and tumorigenesis is more important than its role in liver regeneration.NEW & NOTEWORTHY Grb2-associated binder 1 (Gab1) is known to contribute to liver regeneration after acute liver injury. However, in chronic liver diseases, Gab1 plays a greater role in suppressing hepatocyte apoptosis than in liver regeneration, resulting in suppression of hepatocyte proliferation, liver fibrosis, and liver carcinogenesis.

Persistent hepatocyte apoptosis promotes tumorigenesis from diethylnitrosamine-transformed hepatocytes through increased oxidative stress, independent of compensatory liver regeneration.

Hepatocellular carcinoma highly occurs in chronic hepatitis livers, where hepatocyte apoptosis is frequently detected. Apoptosis is a mechanism that eliminates mutated cells. Hepatocyte apoptosis induces compensatory liver regeneration, which is believed to contribute to tumor formation. Hepatocyte-specific Mcl-1 knockout mice (Mcl-1Δhep mice) developed persistent hepatocyte apoptosis and compensatory liver regeneration with increased oxidative stress in adulthood but had not yet developed hepatocyte apoptosis at the age of 2 weeks. When diethylnitrosamine (DEN) was administered to 2-week-old Mcl-1Δhep mice, multiple liver tumors were formed at 4 months, while wild-type mice did not develop any tumors. These tumors contained the B-Raf V637E mutation, indicating that DEN-initiated tumorigenesis was promoted by persistent hepatocyte apoptosis. When N-acetyl-L-cysteine was given from 6 weeks of age, DEN-administered Mcl-1Δhep mice had reduced oxidative stress and suppressed tumorigenesis in the liver but showed no changes in hepatocyte apoptosis or proliferation. In conclusion, enhanced tumor formation from DEN-transformed hepatocytes by persistent hepatocyte apoptosis is mediated by increased oxidative stress, independent of compensatory liver regeneration. For patients with livers harboring transformed cells, the control of oxidative stress may suppress hepatocarcinogenesis based on chronic liver injury.

Hyperglycemia enhances pancreatic cancer progression accompanied by elevations in phosphorylated STAT3 and MYC levels.

Diabetes mellitus is a well-known risk factor for pancreatic cancer. We focused on hyperglycemia, a main feature of diabetes mellitus, and uncovered its effect on precancerous pancreatic intraepithelial neoplasia (PanIN) progression. In vivo induction of hyperglycemia with 100 mg/kg streptozotocin in KrasLSL G12D Pdx1Cre (KP) mice promoted the PanIN formation and progression. Preconditioning with a high- or low-glucose medium for 28 days showed that a high-glucose environment increased cell viability and sphere formation in PANC-1, a Kras-mutant human pancreatic ductal adenocarcinoma cell line, and mPKC1, a Kras-mutant murine pancreatic cancer cell line. In contrast, no changes were observed in BxPC3, a Kras-wild-type human pancreatic cancer cell line. Orthotopic injection of mPKC1 into the pancreatic tails of BL6/J mice showed that cells maintained in high-glucose medium grew into larger tumors than did those maintained in low-glucose medium. Hyperglycemia strengthened the STAT3 phosphorylation, which was accompanied by elevated MYC expression in Kras-mutant cells. Immunohistochemistry showed stronger phosphorylated STAT3 (pSTAT3) and MYC staining in PanINs from diabetic KP mice than in those from euglycemic counterparts. STAT3 inhibition with 1 µM STAT3 inhibitor STATTIC in Kras-mutant pancreatic cell lines blocked the cell viability- and sphere formation-enhancing effects of the hyperglycemic environment and reversed the elevated pSTAT3 and MYC expression. MYC knockdown did not affect cell viability but did reduce sphere formation. No decrease in pSTAT3 expression was observed upon siMYC treatment. In conclusion, hyperglycemia, on a Kras-mutant background, aggravates the PanIN progression, which is accompanied by elevated pSTAT3 and MYC expression.

DNase II activated by the mitochondrial apoptotic pathway regulates RIP1-dependent non-apoptotic hepatocyte death via the TLR9/IFN-ß signaling pathway.

Cell death, including apoptotic and non-apoptotic cell death, is frequently observed in liver disease. Upon activation of the mitochondrial apoptotic pathway, mitochondria release not only apoptogenic cytochrome c but also mitochondrial DNA (mtDNA) into the cytosol. The impact of DNase II, a lysosomal acid DNase that degrades mtDNA, on hepatocyte death remains unclear. Administration of ABT-737, a Bcl-xL inhibitor, upregulated DNase II activity in murine hepatocyte cell line BNL CL.2 cells and induced apoptosis. In cells treated with DNase II siRNA, ABT-737 led to accumulation of mtDNA in the cytosol and increased expression of interferon (IFN)-ß and induction of propidium iodide (PI)-positive cells, in addition to apoptosis. Induced PI-positive cells were suppressed by RIP1 inhibitor, Necrostatin-1, but not by pan-caspase inhibitor, ZVAD-FMK, suggesting non-apoptotic cell death. Both the increase in IFN-ß and the induction of non-apoptotic cell death were abolished by administering a TLR9 antagonist, ODN2088, or by the removal of mtDNA from cells with ethidium bromide. Hepatocyte-specific Mcl-1 knockout mice developed hepatocyte apoptosis accompanied by upregulated DNase II activity in their livers. Further knockout of DNase II induced IFN-ß expression and RIP1-dependent non-apoptotic hepatocyte death, both of which were suppressed by the administration of ODN2088. Mice fed a high-fat diet (HFD), an obesity-associated fatty liver model, showed increased expression of IFN-ß with suppression of DNase II activity in their livers and developed not only hepatocyte apoptosis but also non-apoptotic hepatocyte death. Hepatocyte-specific knockout of DNase II exacerbated HFD-induced non-apoptotic hepatocyte death and liver fibrosis. In conclusion, without DNase II, apoptotic stimulation on hepatocytes induces TLR9-dependent IFN-ß production and RIP1-dependent non-apoptotic cell death originating from mtDNA. In fatty livers, DNase II activity is suppressed in contrast to simple inactivation of Bcl-xL or Mcl-1, and both apoptotic and non-apoptotic hepatocyte death can develop, leading to the progression of liver fibrosis.

Rubicon inhibits autophagy and accelerates hepatocyte apoptosis and lipid accumulation in nonalcoholic fatty liver disease in mice.

Nonalcoholic fatty liver disease (NAFLD) is the most prevalent liver disease worldwide. It encompasses a spectrum ranging from simple steatosis to fatty liver with hepatocellular injury, termed nonalcoholic steatohepatitis. Recent studies have demonstrated hepatic autophagy being impaired in NAFLD. In the present study, we investigated the impact of Rubicon, a Beclin1-interacting negative regulator for autophagosome-lysosome fusion, in the pathogenesis of NAFLD. In HepG2 cells, BNL-CL2 cells, and murine primary hepatocytes, Rubicon was posttranscriptionally up-regulated by supplementation with saturated fatty acid palmitate. Up-regulation of Rubicon was associated with suppression of the late stage of autophagy, as evidenced by accumulation of both LC3-II and p62 expression levels as well as decreased autophagy flux. Its blockade by small interfering RNA attenuated autophagy impairment and reduced palmitate-induced endoplasmic reticulum stress, apoptosis, and lipid accumulation. Rubicon was also up-regulated in association with autophagy impairment in livers of mice fed a high-fat diet (HFD). Hepatocyte-specific Rubicon knockout mice generated by crossing Rubicon floxed mice with albumin-Cre transgenic mice did not produce any phenotypes on a normal diet. In contrast, on an HFD, they displayed significant improvement of both liver steatosis and injury as well as attenuation of both endoplasmic reticulum stress and autophagy impairment in the liver. In humans, liver tissues obtained from patients with NAFLD expressed significantly higher levels of Rubicon than those without steatosis. CONCLUSION: Rubicon is overexpressed and plays a pathogenic role in NAFLD by accelerating hepatocellular lipoapoptosis and lipid accumulation, as well as inhibiting autophagy. Rubicon may be a novel therapeutic target for regulating NAFLD development and progression. (Hepatology 2016;64:1994-2014).

Sodium taurocholate cotransporting polypeptide inhibition efficiently blocks hepatitis B virus spread in mice with a humanized liver.

Sodium taurocholate cotransporting polypeptide (NTCP) is a recently discovered hepatitis B virus (HBV) receptor. In the present study, we used TK-NOG mice with a humanized liver to examine the impact of endogenous NTCP expression on HBV infection. Upon inoculation with HBV, these mice exhibited clear viremia in 2 weeks, and serum HBV DNA levels gradually increased. The frequency of HBsAg-positive hepatocytes in the liver was 5.1 ± 0.6% at 2 weeks and increased with increasing HBV DNA levels, reaching 92.9 ± 2.8% at 10 to 12 weeks. In vivo siRNA-mediated NTCP knockdown before and after HBV inoculation significantly suppressed the levels of HBV replication and the frequency of HBsAg-positive hepatocytes at 2 weeks, whereas NTCP knockdown 13 weeks after infection did not affect these parameters. Similar to the humanized mouse livers in the early phase of HBV infection, human liver samples from chronic hepatitis B patients, especially those treated with nucleos(t)ide analogues, contained a considerable number of hepatocytes that were negative for the anti-HBs antibody. In conclusion, NTCP inhibition prevents the spread of HBV-infected hepatocytes in mice with a humanized liver. NTCP-targeted therapy has potential for regulating HBV infection in patients with chronic hepatitis B.

Activation of the Mitochondrial Apoptotic Pathway Produces Reactive Oxygen Species and Oxidative Damage in Hepatocytes That Contribute to Liver Tumorigenesis.

Chronic hepatitis, including viral hepatitis and steatihepatitis, is a well-known high-risk condition for hepatocellular carcinoma. We previously reported that continuous hepatocyte apoptosis drives liver tumors in hepatocyte-specific Bcl-xL or Mcl-1 knockout mice. In this study, we further examine the underlying cellular mechanisms of generating tumors in apoptosis-prone liver. In cultured hepatocytes, the administration of ABT-737, a Bcl-xL/-2/-w inhibitor, led to production of reactive oxygen species (ROS) as well as activation of caspases. Mitochondria isolated from murine liver, upon administration of truncated-Bid, a proapoptotic Bcl-2 family protein, released cytochrome c and produced ROS, which was dependent on mitochondrial respiration. Hepatic apoptosis, regeneration, accumulation of oxidative damages, and tumorigenesis observed in hepatocyte-specific Mcl-1 knockout mice were substantially attenuated by further deficiency of Bax or Bid, suggesting that a balance of mitochondrial Bcl-2 family proteins governs generation of oxidative stress and other pathologies. Whole-exome sequencing clarified that C>A/G>T transversion, which is often caused by oxidative DNA damage in proliferating cells, was a frequently observed mutation pattern in liver tumors of Mcl-1 knockout mice. The administration of antioxidant L-N-acetylcysteine did not affect apoptosis, compensatory regeneration, or fibrotic responses but significantly reduced oxidative DNA damage and incidence and multiplicity of live tumors in Mcl-1 knockout mice. In conclusion, activation of the mitochondrial apoptotic pathway in hepatocytes accumulates intracellular oxidative damages, leading to liver tumorigenesis, independently of liver regeneration or fibrosis. This study supports a concept that antioxidant therapy may be useful for suppressing liver carcinogenesis in patients with chronic liver disease.