Re-analysis of hepatitis B virus integration sites reveals potential new loci associated with oncogenesis in hepatocellular carcinoma.

BACKGROUND: Hepatitis B virus (HBV) is a major cause of hepatocellular carcinoma (HCC). HBV DNA can get integrated into the hepatocyte genome to promote carcinogenesis. However, the precise mechanism by which the integrated HBV genome promotes HCC has not been elucidated. AIM: To analyze the features of HBV integration in HCC using a new reference database and integration detection method. METHODS: Published data, consisting of 426 Liver tumor samples and 426 paired adjacent non-tumor samples, were re-analyzed to identify the integration sites. Genome Reference Consortium Human Build 38 (GRCh38) and Telomere-to-Telomere Consortium CHM13 (T2T-CHM13 (v2.0)) were used as the human reference genomes. In contrast, human genome 19 (hg19) was used in the original study. In addition, GRIDSS VIRUSBreakend was used to detect HBV integration sites, whereas high-throughput viral integration detection (HIVID) was applied in the original study (HIVID-hg19). RESULTS: A total of 5361 integration sites were detected using T2T-CHM13. In the tumor samples, integration hotspots in the cancer driver genes, such as TERT and KMT2B, were consistent with those in the original study. GRIDSS VIRUSBreakend detected integrations in more samples than by HIVID-hg19. Enrichment of integration was observed at chromosome 11q13.3, including the CCND1 pro-moter, in tumor samples. Recurrent integration sites were observed in mitochondrial genes. CONCLUSION: GRIDSS VIRUSBreakend using T2T-CHM13 is accurate and sensitive in detecting HBV integration. Re-analysis provides new insights into the regions of HBV integration and their potential roles in HCC development.

Cabozantinib for Advanced Hepatocellular Carcinoma in the Latest Real-World Practice: A Multicenter Retrospective Analysis.

BACKGROUND: Cabozantinib was found to be effective as a second- or third-line treatment after sorafenib in patients with advanced hepatocellular carcinoma (HCC) in the phase 3 CELESTIAL trial. So far, as immunotherapy has substituted molecular target agents as the primary systemic therapy for advanced HCC, cabozantinib is extensively used in the latest real-world clinical practice in a greatly different position than that shown by the CELESTIAL trial. In the current analysis, we examined the safety and effectiveness of cabozantinib administration in real-life settings for patients with advanced HCC. METHODS: We retrospectively obtained data from patients with advanced HCC who received cabozantinib in three institutions in Japan between 14 September 2018 and 30 November 2021. RESULTS: During the study period, 23 patients with advanced HCC received cabozantinib. Our cohort included 21.7% of patients with Child-Pugh class B, and 52.2% of patients in fourth line or later. The median progression-free survival of patients given cabozantinib was 3.7 months. Regarding patients with Child-Pugh class B or administration in fourth line or later, the discontinuation rate due to adverse events in patients who initialized at 40 or 20 mg was lower than those who initialized at 60 mg (42.9% versus 75.0%). Patients who were able to continue treatment with cabozantinib for more than 3 months were more likely to undergo dose reduction than those who did not (85.7% versus 25.0%). CONCLUSIONS: Cabozantinib has recently been administered to a diverse range of patients, including those who were not enrolled in the CELESTIAL trial. Deliberate dose reduction could potentially offer clinical benefits to patients with impaired liver function. Furthermore, managing adverse events by reducing the dose could play a crucial role in extending the duration of treatment with cabozantinib. The preprint version of this work is available on https://www.researchsquare.com/article/rs-2655181/v1 .

PKR-NF-κB Pathway Upstream of IFN-ß Induction Is Dysregulated in Oncolytic Sindbis Virus-infected HeLa Cells.

BACKGROUND/AIM: Sindbis virus (SINV) is a naturally occurring oncolytic virus that kills cancer cells and is less harmful to normal cells. In this study, a recombinant SINV, which expressed green and blue fluorescent proteins, was used to precisely analyze SINV infection and replication. MATERIALS AND METHODS: Antiviral responses, including IFN-ß mRNA, protein kinase R (PKR), NF-B, and caspase 3/7, were analyzed in SINV-infected cancerous HeLa cells and normal human fibroblast TIG-1-20 cells. RESULTS: SINV could infect, replicate, and proliferate both in HeLa and TIG-1-20 cells, causing lytic infection only in HeLa cells. SINV grew preferentially in HeLa cells causing remarkable apoptosis. IFN-ß mRNA expression was suppressed in SINV-infected HeLa cells compared to that in TIG-1-20 cells. Further analyses of PKR and NF-B upstream of IFN-ß induction revealed that the compromised response in the PKR-NF-B pathway during early infection coincided with IFN induction suppression in HeLa cells. CONCLUSION: Dysregulation of PKR in HeLa cells is the determinant of SINV oncolysis.

Hyperprogressive disease during atezolizumab plus bevacizumab treatment in patients with advanced hepatocellular carcinoma from Japanese real-world practice.

BACKGROUND: Hyperprogressive disease (HPD) is a phenomenon with greatly accelerated tumor growth and clinical deterioration rates compared to pre-therapy, in patients treated with immune checkpoint inhibitors (ICI). The aim of this study is to clarify the reality of HPD in patients with advanced hepatocellular carcinoma (HCC) who were treated with atezolizumab plus bevacizumab (Atez/Bev) using tumor dynamics. METHODS: Medical records of consecutive patients with advanced HCC who were treated with Atez/Bev were retrospectively reviewed. HPD was defined as a more than two- or fourfold increase in tumor growth rate (TGR) or tumor growth kinetics rate (TGKR) before and after treatment. Overall survival (OS) and baseline characteristics with or without HPD were analyzed. RESULTS: A total of 85 patients were included in the analysis. When HPD was defined as a twofold of TGR or TGKR, 8 patients (8/85, 9.4%) had HPD and 11 had PD without HPD. A total of 5 patients (5/85, 5.9%) were diagnosed with HPD and 14 with PD without HPD when HPD was defined as a fourfold of TGR or TGKR. No significant difference was observed in the baseline characteristics between HPD and non-HPD. CONCLUSION: The prevalence of HPD in patients with advanced HCC treated with Atez/Bev was lower than those treated with nivolumab monotherapy. The HPD mechanism in ICI combined with antibodies targeting vascular endothelial growth factor (VEGF) remains to be elucidated.

Use of ramucirumab for various treatment lines in real-world practice of patients with advanced hepatocellular carcinoma.

PURPOSE: Ramucirumab was shown to be effective as a second-line treatment after sorafenib in patients with advanced hepatocellular carcinoma (HCC) with alpha-fetoprotein levels > 400 ng/mL in a worldwide phase 3 trial. Ramucirumab is used in patients pretreated with various systemic therapies in clinical practice. We retrospectively examined the treatment outcomes of ramucirumab administered to advanced HCC patients after diverse systemic therapies. METHODS: Data were collected from patients with advanced HCC who received ramucirumab at three institutions in Japan. Radiological assessments were determined according to both Response Evaluation Criteria in Solid Tumours (RECIST) version 1.1 and modified RECIST and the Common Terminology Criteria for Adverse Events version 5.0 was used to assess adverse events. RESULTS: A total of 37 patients treated with ramucirumab between June 2019 and March 2021 were included in the study. Ramucirumab was administered as second, third, fourth, and fifth-line treatment in 13 (35.1%), 14 (37.8%), eight (21.6%), and two (5.4%) patients, respectively. Most patients (29.7%) who received ramucirumab as a second-line therapy were pretreated with lenvatinib. We found grade 3 or higher adverse events only in seven patients and no significant changes in the albumin-bilirubin score during ramucirumab treatment in the present cohort. The median progression-free survival of patients treated with ramucirumab was 2.7 months (95% confidence interval, 1.6-7.3). CONCLUSION: Although ramucirumab is used for various lines of treatment other than second-line immediately after sorafenib, its safety and effectiveness were not significantly different from the findings of the REACH-2 trial.

Alteration of the tumor microenvironment by pharmacological inhibition of EZH2 in hepatocellular carcinoma.

Enhancer of zeste homolog 2 (EZH2), a core component of polycomb repressive component 2 is overexpressed in a variety of cancers and recognized as a therapeutic target molecule. However, EZH2 possesses immunomodulatory functions in the tumor microenvironment (TME). The impact of EZH2 on TME of hepatocellular carcinoma (HCC) using immunocompetent mouse model was evaluated in the present study. UNC1999, an EZH2 inhibitor, impaired growth of the murine HCC cells (H22 cells) and induced apoptosis in a dose-dependent manner. Although UNC1999 significantly inhibited the growth of H22 cells-derived and Hepa1-6 cells-derived tumors in nonobese diabetic/severe combined immunodeficiency mice, its antitumor effect was diminished in allogenic BALB/c and C57BL/6 mice. Flow cytometric analyses of TME cells in BALB/c mice demonstrated a significant decrease in the number of interferon­Î³+ CD8+ T cells and regulatory T cells and a significant increase in the number of myeloid-derived suppressor cells (MDSCs). Administration of Gr-1 neutralizing antibody concomitant with UNC1999 restored antitumor effect accompanied by an increase in the number of CD8+ T cells followed by a decrease in the number of MDSCs. Chemokine antibody array demonstrated an enhanced expression of chemokines responsible for MDSCs recruitment such as C5a, CCL8, and CCL9. In conclusion, the study results demonstrated that EZH2 inhibitor contributed to attenuation of tumor immunity caused by TME arrangement. Combination therapy with EZH2 inhibitors and agents that reduce MDSCs might represent a novel therapeutic strategy for HCC.

Successful Identification of a Novel Therapeutic Compound for Hepatocellular Carcinoma Through Screening of ADAM9 Inhibitors.

BACKGROUND/AIM: MHC-class I-related chain A (MICA) functions as a ligand for natural killer group D, an activating receptor on natural killer (NK) cells, and its expression correlates with the carcinogenesis and progression of hepatocellular carcinoma (HCC). Although membranous MICA (mMICA) activates NK cells, soluble forms of MICA (sMICA), shed by cleaving enzymes, such as A disintegrin and metalloprotease (ADAM) 9, suppress NK cells. Therefore, the prevention of MICA shedding through the inhibition of ADAM9 has the potential to activate cancer immunity. Although we have discovered several ADAM inhibitors, many did not sufficiently activate NK cells without being cytotoxic, and, thus, new ADAM9 inhibitor candidates are needed. MATERIALS AND METHODS: To identify possible compounds for drug development, chemical library screening (a total of 741 compounds) was conducted using a fluorescence assay. Compounds with reduced fluorescence intensity were used as hit compounds in a subsequent analysis. Their impact on sMICA and mMICA in HCC cell lines was assessed using ELISA and flow cytometry, respectively. The cytotoxicity of NK cells was also evaluated by co-culturing NK cells with HCC cells. RESULTS: CCL347, a symmetrical compound with five benzene rings, was identified as a hit compound. CCL347 significantly reduced sMICA levels in the culture medium supernatant with negligible cytotoxicity. Although mMICA was also reduced, CCL347 successfully enhanced NK cell cytotoxicity in co-cultures of NK cells and HCC cells. CONCLUSION: CCL347 has potential as a novel therapeutic drug for HCC.

Miglustat, a glucosylceramide synthase inhibitor, mitigates liver fibrosis through TGF-ß/Smad pathway suppression in hepatic stellate cells.

Transforming growth factor (TGF)-ß/Smad pathway is implicated in the pathogenesis of liver fibrosis, a condition characterized by excessive deposition of extracellular matrix (ECM) proteins such as collagen in response to chronic inflammation. It has been reported that ceramide regulates collagen production through TGF-ß/Smad pathway activation. In this study, we examined whether miglustat, an inhibitor of glucosylceramide synthase, can suppress liver fibrosis by reducing TGF-ß/Smad pathway activity. Human hepatic stellate cells (HHSteCs) were cultured with TGF-ß and multiple miglustat concentrations to examine dose-dependent effects on the expression levels of ECM-related genes and Smad proteins. To evaluate the efficacy of miglustat for fibrosis mitigation, C57BL/6 mice were treated with carbon tetrachloride (CCl4) for 4 weeks to induce liver fibrosis, followed by combined CCl4 plus miglustat for a further 2 weeks. To examine if miglustat can also prevent fibrosis, mice were treated with CCl4 for 2 weeks, followed by CCl4 plus miglustat for 2 weeks. Miglustat dose-dependently downregulated expression of α-smooth muscle actin and ECM components in TGF-ß-treated HHSteCs. Both phosphorylation and nuclear translocation of Smad2 and Smad3 were also suppressed by miglustat treatment. Sirius-Red staining and hydroxyproline assays of model mouse liver samples revealed that miglustat reduced fibrosis, an effect accompanied by decreased expression of ECM. Our findings suggest that miglustat can both prevent and reverse liver fibrosis by inhibiting TGF-ß/Smad pathway.

Clinical effects and emerging issues of atezolizumab plus bevacizumab in patients with advanced hepatocellular carcinoma from Japanese real-world practice.

BACKGROUND: Although the efficacy of atezolizumab has been demonstrated in randomized controlled trials, its long-term efficacy and association with adverse events in real-world practice are unknown. This study was designed to shed light on these issues. METHODS: In this multicenter retrospective study, data were collected from patients with advanced hepatocellular carcinoma treated with atezolizumab plus bevacizumab in seven institutions in Japan. The authors focused on the efficacy and adverse events related to vascular endothelial growth factor (VEGF) inhibition. RESULTS: A total of 123 patients were enrolled in this study. The median progression-free survival (PFS) for the first-line treatment group was 8.0 months (95% confidence interval [CI], 6.1-9.9), whereas the median PFS for the second- or later-line treatment group was 4.1 months (95% CI, 2.6-5.7), which was significantly worse than that of the first-line treatment group (p = .005). Twenty-seven patients had interrupted bevacizumab treatment. Proteinuria accounted for the largest proportion of bevacizumab treatment interruptions. The cumulative incidence rate of bevacizumab interruption due to anti-VEGF-related adverse events was significantly higher in patients with hypertension and/or diabetes mellitus than in those without (p = .026). The landmark analysis showed that patients experienced bevacizumab interruption by 24 weeks from treatment initiation had poorer PFS than those who did not (p = .013). CONCLUSIONS: The PFS of atezolizumab plus bevacizumab as first-line treatment mostly replicates that of a global phase 3 trial. Interrupted bevacizumab treatment was more common in patients with hypertension and/or diabetes mellitus, which may be associated with worsening long-term PFS. PLAIN LANGUAGE SUMMARY: Atezolizumab plus bevacizumab has been the standard front line systemic therapy for advanced hepatocellular carcinoma. With the growing incidence of fatty liver due to metabolic syndrome as a background liver disease for hepatocellular carcinoma, the rate of comorbid hypertension and diabetes mellitus has been increasing accordingly. The present study demonstrated the cumulative incidence rate of bevacizumab interruption due to anti-VEGF-related adverse events was significantly higher in patients with hypertension and/or diabetes mellitus. The landmark analysis clarified that interruption of bevacizumab might be a risk of impaired efficacy of atezolizumab plus bevacizumab over the long term in patients with advanced hepatocellular carcinoma.

Antiviral Compounds Screening Targeting HBx Protein of the Hepatitis B Virus.

A functional cure of hepatitis B virus (HBV) infection or HB antigen loss is rarely achieved by nucleos(t)ide analogs which target viral polymerase. HBx protein is a regulatory protein associated with HBV replication. We thought to identify antiviral compounds targeting HBx protein by analyzing HBx binding activity. Recombinant GST-tagged HBx protein was applied on an FDA-approved drug library chip including 1018 compounds to determine binding affinity by surface plasmon resonance imaging (SPRi) using a PlexArray HT system. GST protein alone was used for control experiments. Candidate compounds were tested for anti-HBV activity as well as cell viability using HepG2.2.15.7 cells and HBV-infected human hepatocytes. Of the 1018 compounds screened, 24 compounds showed binding to HBx protein. Of the top 6 compounds with high affinity to HBx protein, tranilast was found to inhibit HBV replication without affecting cell viability using HepG2.2.15.7 cells. Tranilast also inhibited HBV infection using cultured human hepatocytes. Tranilast reduced HB antigen level dose-dependently. Overall, theSPRi screening assay identified novel drug candidates targeting HBx protein. Tranilast and its related compounds warrant further investigation for the treatment of HBV infection.

The RNA-Binding Protein ELAVL1 Regulates Hepatitis B Virus Replication and Growth of Hepatocellular Carcinoma Cells.

Previous RNA immunoprecipitation followed by proteomic approaches successfully demonstrated that Embryonic Lethal, Abnormal Vision, Drosophila-Like 1 (ELAVL1) interacts with hepatitis B virus (HBV)-derived RNAs. Although ELAVL family proteins stabilize AU-rich element (ARE)-containing mRNAs, their role in HBV transcription remains unclear. This study conducted loss-of-function assays of ELAVL1 for inducible HBV-replicating HepAD38 cells and HBx-overexpressed HepG2 cells. In addition, clinicopathological analyses in primary hepatocellular carcinoma (HCC) surgical samples were also conducted. Lentivirus-mediated short hairpin RNA knockdown of ELAVL1 resulted in a decrease in both viral RNA transcription and production of viral proteins, including HBs and HBx, probably due to RNA stabilization by ELAVL1. Cell growth of HepAD38 cells was more significantly impaired in ELAVL1-knockdown than those in the control group, with or without HBV replication, indicating that ELAVL1 is involved in proliferation by factors other than HBV-derived RNAs. Immunohistochemical analyses of 77 paired HCC surgical specimens demonstrated that diffuse ELAVL1 expression was detected more frequently in HCC tissues (61.0%) than in non-tumor tissues (27.3%). In addition, the abundant expression of ELAVL1 tended to affect postoperative recurrence in HBV-related HCC patients. In conclusion, ELAVL1 contributes not only to HBV replication but also to HCC cell growth. It may be a potent therapeutic target for HBV-related HCC treatment.

A diet-induced murine model for non-alcoholic fatty liver disease with obesity and insulin resistance that rapidly develops steatohepatitis and fibrosis.

Non-alcoholic fatty liver disease (NAFLD) has become the leading cause of chronic liver disease worldwide. Patients with NAFLD often suffer steatohepatitis, which can progress to cirrhosis and hepatocellular carcinoma. The presence of visceral obesity or type 2 diabetes mellitus (T2DM) is a major risk factor and potential therapeutic target for NAFLD. The establishment of animal models with these metabolic comorbidities and with the rapid progression of the disease is needed for developing treatments for NAFLD but remains to be archived. In the present study, KK-Ay mice, widely used as T2DM models, or C57BL6 mice were fed a high-fat, high-fructose, and high-cholesterol diet supplemented with cholic acid (NAFLD diet). The KK-Ay mice fed a NAFLD diet exhibited remarkable obesity and insulin resistance. A prominent accumulation of triglycerides and cholesterol in the liver was observed at 4 weeks. These mice developed steatohepatitis at 4 weeks and fibrosis at 12 weeks. In contrast, C57BL6 mice fed a NAFLD diet remained lean, although they still developed steatohepatitis and fibrosis. In summary, we established a diet-induced murine NAFLD model with the rapid development of steatohepatitis and fibrosis, bearing obesity and insulin resistance. This model could be useful as preclinical models for drug development of NAFLD.

Effect of Atezolizumab plus Bevacizumab in Patients with Hepatocellular Carcinoma Harboring CTNNB1 Mutation in Early Clinical Experience.

Atezolizumab plus bevacizumab (ATZ/BV) treatment is a combined immunotherapy consisting of immune checkpoint inhibitor (ICI) and anti-vascular endothelial growth factor monoclonal antibody, which has brought a major paradigm shift in the treatment of unresectable hepatocellular carcinoma (HCC). Gain-of-function mutation of CTNNB1 contributes to resistance of ICI monotherapy through the framework of non-T-cell-inflamed tumor microenvironment. However, whether CTNNB1 mutation renders resistance to ATZ/BV similar to ICI monotherapy remains to be elucidated. In this study, a liquid biopsy sample in plasma of 33 patients with HCC treated with ATZ/BV was subjected to droplet digital PCR for detecting hotspot mutations at the exon 3 of CTNNB1 locus. A total of eight patients (24.2%) exhibited at least one CTNNB1 mutation. The objective response rate (ORR) in patients with wild-type (WT) and mutant (MT) CTNNB1 was 8.0% and 12.5%, respectively, and the disease control rate (DCR) was 68.0% and 87.5%, respectively. No significant difference in both ORR and DCR has been observed between the two groups. The median progression-free survival in patients with WT and MT CTNNB1 was 6.6 and 7.6 months, respectively (not statistically significant). Similarly, no significant difference in overall survival has been observed between patients with WT and MT CTNNB1 (13.6 vs. 12.3 months). In conclusion, the treatment effect of ATZ/BV in patients with HCC with MT CTNNB1 was comparable to those patients with WT CTNNB1. These results implicate that BV added to ATZ might improve immunosuppressive tumor microenvironment caused by CTNNB1 mutation.

Liver biopsy technique in the era of genomic cancer therapies: a single-center retrospective analysis.

BACKGROUND: With the evolution of personalized medicine in the field of oncology, which includes optimal treatment selection using next-generation sequencing-based companion diagnostic systems and tumor-agnostic treatments according to common biomarkers, a liver tumor biopsy technique that can obtain a sufficient specimen volume must be established. The current study aimed to evaluate the safety and availability of a liver tumor biopsy technique with multiple puncture sites made using a coaxial introducer needle and embolization with gelatin sponge particles. METHODS: Patients with primary or metastatic liver cancer who underwent liver tumor biopsies with puncture tract embolization using gelatin sponge (Spongel®) from October 2019 to September 2020 were included in the study. The complication and diagnostic rates were evaluated, and whether the specimen volume was sufficient for Foundation® CDx was investigated. RESULTS: In total, 96 patients were enrolled in this analysis. The median total number of puncture times per patient was 3 (range 1-8). The pathological diagnostic rate was 79.2%. Using the FoundationOne® CDx, specimens with a sufficient volume required for genomic medicine were collected in 84.9% of patients. The incidence rate of bleeding was 4.2% (n = 4), and only one patient presented with major bleeding requiring transfusion. CONCLUSIONS: Liver biopsy with puncture tract embolization using a gelatin sponge may be safe and effective for collecting specimens with a volume sufficient for modern cancer treatments.

Baseline soluble MICA levels act as a predictive biomarker for the efficacy of regorafenib treatment in colorectal cancer.

BACKGROUND: To evaluate the effect of regorafenib on soluble MHC class I polypeptide-related sequence A (MICA) (sMICA) level in vitro. In addition, we clinically examined whether its plasma levels were associated with regorafenib activity in terms of progression-free survival (PFS) in patients with CRC. METHODS: Human CRC cell line HCT116 and HT29 cells were treated with regorafenib and its pharmacologically active metabolites, M2 or M5 at the same concentrations as those in sera of patients. We also examined the sMICA levels and the area under the plasma concentration-time curve of regorafenib, M2 and M5. RESULTS: Regorafenib, M2, and M5 significantly suppressed shedding of MICA in human CRC cells without toxicity. This resulted in the reduced production of sMICA. In the clinical examination, patients with CRC who showed long median PFS (3.7 months) had significantly lower sMICA levels than those with shorter median PFS (1.2 months) (p = 0.045). CONCLUSIONS: MICA is an attractive agent for manipulating the immunological control of CRC and baseline sMICA levels could be a predictive biomarker for the efficacy of regorafenib treatment.

Durvalumab with or without tremelimumab combined with particle therapy for advanced hepatocellular carcinoma with macrovascular invasion: protocol for the DEPARTURE phase Ib trial.

INTRODUCTION: Advanced hepatocellular carcinoma (HCC) with macrovascular invasion (MVI) has the worst prognosis among all phenotypes. This trial aims to evaluate whether treatment with durvalumab, alone or in combination with tremelimumab, plus particle therapy is a safe and synergistically effective treatment in patients with advanced HCC and MVI. METHODS AND ANALYSIS: This phase Ib, multicentre (two sites in Japan), open-label, single-arm, investigator-initiated clinical trial will assess durvalumab monotherapy in combination with particle therapy (cohort A) and that of durvalumab plus tremelimumab in combination with particle therapy (cohort B) for patients with advanced HCC with MVI. Cohort A will receive 1500 mg durvalumab every 4 weeks. Cohort B will receive 1500 mg durvalumab every 4 weeks in principle and 300 mg tremelimumab only on day 1 of the first cycle. Carbon-ion radiotherapy will be administered after day 8 of the first cycle. The primary endpoints are rates of any and severe adverse events, including dose-limiting toxicities (DLTs); secondary endpoints are overall survival, 6-month survival, objective response, 6-month progression-free survival and time to progression. Patients are initially enrolled into cohort A. If cohort A treatment is confirmed to be tolerated (ie, no DLT in three patients or one DLT in six patients), the trial proceeds to enrol more patients into cohort B. Similarly, if cohort B treatment is confirmed to be tolerated (ie, no DLT in three patients or one DLT in six patients), a total of 15 patients will be enrolled into cohort B. ETHICS AND DISSEMINATION: This study was approved by the ethics committees of the two participating institutions (Chiba University Hospital and National Institutes for Quantum (approval number: 2020040) and Radiological Science and Technology, QST Hospital (approval number: C20-001)). Participants will be required to provide written informed consent. Trial results will be reported in a peer-reviewed journal publication. TRIAL REGISTRATION NUMBER: jRCT2031210046.

Fusion HBx from HBV integrant affects hepatocarcinogenesis through deregulation of ER stress response.

Hepatitis B virus (HBV) infection is a major cause of hepatocellular carcinoma (HCC) worldwide. HBV X protein (HBx) is potentially the most oncogenic among HBV-encoding proteins, while HBV integration, which is frequently observed in HCC, contributes to HCC development. However, the molecular mechanism underlying HBV-induced hepatocarcinogenesis remains unclear. In this study, we identified the fusion HBx, the HBx-human fusion protein derived from HBV integrant, in Hep3B cells and investigated its role in hepatocarcinogenesis. The identified full-length fusion mRNA was 3,725 bp in length, and the fusion HBx, which consisted of 1-140 amino acids of HBx followed by 61 amino acids from the human genome, was translated from the fusion mRNA. The fusion HBx knockdown resulted in reduced cell proliferation and invasion, and loss of tumor development in nude mice. Moreover, the fusion HBx, but not wild HBx, provided anchorage-independent growth ability in soft agar although its transactivation ability was abrogated. Microarray analysis revealed that fusion HBx deregulated endoplasmic reticulum (ER) stress response by modifying ATF3, ATF4, and ATF6 transcription. Interestingly, the effects of fusion HBx on ER stress signaling pathway were similar to those of C-terminal truncated HBx, but significantly different from those of wild HBx. Our findings suggest that the fusion HBx plays a significant role in hepatocarcinogenesis by modifying ER stress response and could be an attractive target for the treatment of HBV-induced HCC.

Changes in therapeutic options for hepatocellular carcinoma in Asia.

The incidence rate of hepatocellular carcinoma (HCC) is expected to increase, with most cases occurring in Asia. In some parts of Asia, the occurrence of HCC developing from metabolic-related liver disease has markedly increased in recent years, whereas the occurrence of HCC developing from viral-hepatitis-related liver disease has decreased. Advancements in the treatment of HCC over the past few decades has been remarkable, with most treatment strategies to remove or control liver tumours (hepatic resection, local ablation, radiation therapy, transarterial chemoembolisation, hepatic arterial infusion chemotherapy) primarily developing in Asia. In addition, recent progress in systemic therapies has prolonged the prognosis of advanced HCC. Nowadays, six regimens of systemic therapies have become available in most countries, according to phase III trials (atezolizumab plus bevacizumab, sorafenib, lenvatinib, regorafenib, cabozantinib and ramucirumab). In a global randomised phase III trial (IMbrave 150 trial), the most effective of the latest drug designs was newly emerged combination immunotherapy (atezolizumab plus bevacizumab), which has shown significantly prolonged overall survival compared with sorafenib, which was the first-line systemic therapy for more than a decade. Now, the treatment dynamics for HCC are undergoing a major transition as a result of two important changes: the replacement of viral-related HCC by metabolic-related HCC and the emergence of combination immune therapy.

EZH1/2 inhibition augments the anti-tumor effects of sorafenib in hepatocellular carcinoma.

Both EZH2 and its homolog EZH1 function as histone H3 Lysine 27 (H3K27) methyltransferases and repress the transcription of target genes. Dysregulation of H3K27 trimethylation (H3K27me3) plays an important role in the development and progression of cancers such as hepatocellular carcinoma (HCC). This study investigated the relationship between the expression of EZH1/2 and the level of H3K27me3 in HCC. Additionally, the role of EZH1/2 in cell growth, tumorigenicity, and resistance to sorafenib were also analyzed. Both the lentiviral knockdown and the pharmacological inhibition of EZH1/2 (UNC1999) diminished the level of H3K27me3 and suppressed cell growth in liver cancer cells, compared with EZH1 or EZH2 single knockdown. Although a significant association was observed between EZH2 expression and H3K27me3 levels in HCC samples, overexpression of EZH1 appeared to contribute to enhanced H3K27me3 levels in some EZH2lowH3K27me3high cases. Akt suppression following sorafenib treatment resulted in an increase of the H3K27me3 levels through a decrease in EZH2 phosphorylation at serine 21. The combined use of sorafenib and UNC1999 exhibited synergistic antitumor effects in vitro and in vivo. Combination treatment canceled the sorafenib-induced enhancement in H3K27me3 levels, indicating that activation of EZH2 function is one of the mechanisms of sorafenib-resistance in HCC. In conclusion, sorafenib plus EZH1/2 inhibitors may comprise a novel therapeutic approach in HCC.

Exploring microsatellite instability in patients with advanced hepatocellular carcinoma and its tumor microenvironment.

BACKGROUND AND AIM: Immune checkpoint inhibitors and their combination with other agents have recently been available in advanced hepatocellular carcinoma (HCC). Hence, a thorough understanding of the tumor microenvironment based on tumor samples is yet to be achieved. This study aimed to explore the tumor microenvironment in advanced HCC in terms of microsatellite instability-high (MSI-H) by using tumor samples from advanced HCC patients eligible for systemic therapy. METHODS: MSI-H was assessed by polymerase chain reaction, and the expression of mismatch repair proteins, PD-L1, CD8, VEGF, and HLA-class1 was evaluated by immunohistochemistry. Whole-exome sequencing was performed for MSI-H tumor samples. RESULTS: Of 50 patients, one (2.0%) was confirmed with MSI-H. In the MSI-H advanced HCC tumor, a high tumor mutation burden, infiltration of CD8+ lymphocytes, and low expression of VEGF were identified. Although PD-L1 expression was negative, there was shrinkage of tumor following pembrolizumab. However, another tumor nonresponsive to pembrolizumab was present simultaneously. Checking the Cancer Genome Atlas (TCGA) database, we found a similar case to this patient. The TCGA case had unique gene features of miR-21 and miR-155 overexpression and hypermethylation of the MSH2 gene. CONCLUSION: We identified a very small number of MSI-H cases in HCC using one tumor biopsy sample for each patient with advanced HCC. In addition, epigenetic aberrations possibly lead to MSI-H in HCC patients. Since different HCC clones might coexist in the liver, sampling from multiple tumors should be considered to clarify the true proportion of MSI-H in HCC and to analyze tumor microenvironments.