Acquired Resistance to Antiangiogenic Therapies in Hepatocellular Carcinoma Is Mediated by Yes-Associated Protein 1 Activation and Transient Expansion of Stem-Like Cancer Cells.

Induction of neoangiogenesis is a hallmark feature during disease progression of hepatocellular carcinoma (HCC). Antiangiogenetic compounds represent a mainstay of therapeutic approaches; however, development of chemoresistance is observed in the majority of patients. Recent findings suggest that tumor-initiating cells (TICs) may play a key role in acquisition of resistance, but the exact relevance for HCC in this process remains to be defined. Primary and established hepatoma cell lines were exposed to long-term sorafenib treatment to model acquisition of resistance. Treatment effects on TICs were estimated by sphere-forming capacity in vitro, tumorigenicity in vivo, and flow cytometry. Adaptive molecular changes were assessed by whole transcriptome analyses. Compensatory mechanisms of resistance were identified and directly evaluated. Sustained antiproliferative effect following sorafenib treatment was observed in three of six HCC cell lines and was followed by rapid regrowth, thereby mimicking responses observed in patients. Resistant cells showed induction in sphere forming in vitro and tumor-initiating capacity in vivo as well as increased number of side population and epithelial cell adhesion molecule-positive cells. Conversely, sensitive cell lines showed consistent reduction of TIC properties. Gene sets associated with resistance and poor prognosis, including Hippo/yes-associated protein (YAP), were identified. Western blot and immunohistochemistry confirmed increased levels of YAP. Combined treatment of sorafenib and specific YAP inhibitor consistently revealed synergistic antioncogenic effects in resistant cell lines. Conclusion: Resistance to antiangiogenic therapy might be driven by transient expansion of TICs and activation of compensatory pro-oncogenic signaling pathways, including YAP. Specific targeting of TICs might be an effective therapeutic strategy to overcome resistance in HCC.

Ginkgo biloba induces different gene expression signatures and oncogenic pathways in malignant and non-malignant cells of the liver.

Ginkgo biloba (EGb761) is a widely used botanical drug. Several reports indicate that EGb761 confers preventive as well as anti-tumorigenic properties in a variety of tumors, including hepatocellular carcinoma (HCC). We here evaluate functional effects and molecular alterations induced by EGb761 in hepatoma cells and non-malignant hepatocytes. Hepatoma cell lines, primary human HCC cells and immortalized human hepatocytes (IH) were exposed to various concentrations (0-1000 µg/ml) of EGb761. Apoptosis and proliferation were evaluated after 72h of EGb761 exposure. Response to oxidative stress, tumorigenic properties and molecular changes were further investigated. While anti-oxidant effects were detected in all cell lines, EGb761 promoted anti-proliferative and pro-apoptotic effects mainly in hepatoma cells. Consistently, EGb761 treatment caused a significant reduction in colony and sphere forming ability in hepatoma cells and no mentionable changes in IH. Transcriptomic changes involved oxidative stress response as well as key oncogenic pathways resembling Nrf2- and mTOR signaling pathway. Taken together, EGb761 induces differential effects in non-transformed and cancer cells. While treatment confers protective effects in non-malignant cells, EGb761 significantly impairs tumorigenic properties in cancer cells by affecting key oncogenic pathways. Results provide the rational for clinical testing of EGb761 in preventive and therapeutic strategies in human liver diseases.

Resminostat plus sorafenib as second-line therapy of advanced hepatocellular carcinoma - The SHELTER study.

BACKGROUND & AIMS: No established therapies for patients with hepatocellular carcinoma (HCC) and progression on first-line sorafenib treatment currently exist. This phase I/II trial investigated safety, pharmacokinetics and potential biomarkers of the histone deacetylase inhibitor resminostat and a combination therapy with resminostat and sorafenib. METHODS: Patients with HCC and radiologically confirmed progression on sorafenib were treated in an exploratory, multi-center, open-label, uncontrolled, non-randomized, parallel group phase I/II study. In the combination group (n=38) four dose levels ranged from daily 200 to 600mg resminostat plus 400 to 800mg sorafenib. The monotherapy group (n=19) received 600mg resminostat. RESULTS: 57 patients received treatment. Most common adverse events were gastrointestinal disorders, thrombocytopenia and fatigue. Median maximal histone deacetylase inhibition and highest increase in H4-acetylation matched Tmax of resminostat. Sorafenib or the Child-Pugh score did not affect typical pharmacokinetics characteristics of resminostat. Efficacy assessment as progression-free survival-rate after 6 treatment cycles (12weeks, primary endpoint) was 12.5% for resminostat and 62.5% for resminostat plus sorafenib. Median time to progression and overall survival were 1.8 and 4.1months for resminostat and 6.5 and 8.0months for the combination, respectively. Zinc finger protein 64 (ZFP64) baseline expression in blood cells was found to correlate with overall survival. CONCLUSIONS: The combination of sorafenib and resminostat in HCC patients was safe and showed early signs of efficacy. Sorafenib did not alter the pharmacokinetic profile of resminostat or its histone deacetylase inhibitory activity in vivo. A prognostic and potentially predictive role of ZFP64 for treatment with resminostat should be further investigated in HCC and possibly other cancer indications. LAY SUMMARY: No established therapy for patients with advanced hepatocellular carcinoma and progression under first-line systemic treatment with sorafenib currently exists. Epigenetic modulation by inhibition of histone deacetylases might be able to overcome therapy resistance. This exploratory phase I/II clinical study in patients with radiologically confirmed progression under first-line treatment with sorafenib investigated the histone deacetylases inhibitor resminostat as single agent or in combination with continued application of sorafenib. CLINICAL TRIAL REGISTRATION: The clinical trial has been registered at www.clinicaltrials.gov as NCT00943449.

Organic Cation Transporter 1 (OCT1) mRNA expression in hepatocellular carcinoma as a biomarker for sorafenib treatment.

BACKGROUND: The polyspecific organ cation transporter 1 (OCT1) is one of the most important active influx pumps for drugs like the kinase inhibitor sorafenib. The aim of this retrospective study was the definition of the role of intratumoral OCT1 mRNA expression in hepatocellular carcinoma (HCC) as a biomarker in systemic treatment with sorafenib. METHODS: OCT1 mRNA expression levels were determined in biopsies from 60 primary human HCC by real time PCR. The data was retrospectively correlated with clinical parameters. RESULTS: Intratumoral OCT1 mRNA expression is a significant positive prognostic factor for patients treated with sorafenib according to Cox regression analysis (HR 0.653, 95%-CI 0.430-0.992; p = 0.046). Under treatment with sorafenib, a survival benefit could be shown using the lower quartile of intratumoral OCT1 expression as a cut-off. Macrovascular invasion (MVI) was slightly more frequent in patients with low OCT1 mRNA expression (p = 0.037). Treatment-induced AFP response was not associated with intratumoral OCT1 mRNA expression levels (p = 0.633). CONCLUSIONS: This study indicates a promising role for intratumoral OCT1 mRNA expression as a prognostic biomarker in therapeutic algorithms in HCC. Further prospective studies are warranted on this topic.

Combination therapy with silibinin, pegylated interferon and ribavirin in a patient with hepatitis C virus genotype 3 reinfection after liver transplantation: a case report.

INTRODUCTION: Hepatitis C virus reinfection occurs universally after liver transplantation with accelerated cirrhosis rates of up to 30% within 5 years after liver transplantation. Management of hepatitis C virus reinfection is complicated by drug interactions and pre-treatment. Dual antiviral therapy with pegylated interferon and ribavirin only reaches sustained virological response rates of approximately 30% after liver transplantation. With the approval of the viral NS3/4A protease and NS5B ribonucleic acid -dependent ribonucleic acid polymerase inhibitors, combination therapy offers new therapeutic options resulting in considerably higher sustained virological response rates in the non-transplant setting. However, silibinin has also shown potent antiviral activity in non-responders to dual therapy. CASE PRESENTATION: We report the first case of antiviral therapy with pegylated interferon and ribavirin in combination with silibinin post-liver transplantation in a 50-year-old Caucasian man with genotype 3 reinfection with prior non-response.Silibinin was administered at a dose of 20mg/kg/day intravenously for 2 weeks and continued orally for 47 weeks in combination with a 48-week pegylated interferon and ribavirin therapy (180µg/week and 800mg/day), which was started on day 8. Pegylated interferon and ribavirin doses were adapted to 135µg/week and 600mg/day. After 4 weeks of therapy, the viral load declined 6 log10 and became undetectable in week 6, resulting in a sustained virological response 24 weeks after the end of therapy.In general, antiviral therapy was well tolerated. Side effects included pruritus and anaemia leading to erythropoietin therapy. CONCLUSIONS: Combination therapy with pegylated interferon, ribavirin and silibinin resulted in sustained virological response 24 weeks after the end of therapy in a patient reinfected with hepatitis C virus genotype 3 who was a prior non-responder after liver transplantation. Silibinin therapy may offer a new therapeutic option for patients reinfected with non-genotype 1 hepatitis C virus who have had a liver transplanted and are non-responders.

The impact of patient and tumour baseline characteristics on the overall survival of patients with advanced hepatocellular carcinoma treated with sorafenib.

BACKGROUND: Impact of patient and tumour baseline characteristics on the overall survival is not well characterized in patients with advanced hepatocellular carcinoma (HCC) treated with sorafenib. AIMS/METHODS: Univariate/multivariate analyses were conducted to identify retrospectively the impact of baseline characteristics on the survival of 110 patients with advanced HCC treated with sorafenib. RESULTS: Median survival of the whole cohort was 6.7 months, median survival in Child-Pugh A, B, C patients was 10.5, 6.1 and 3.0 months and median survival of patients with Barcelona Clinic Liver Cancer (BCLC) stage C/D was 6.8/2.6 months. Presence of ascites, presence of macrovascular invasion and BCLC stage D (mainly determined by Child-Pugh C status and Eastern Cooperative Oncology Group Performance Status>2) remained independent prognostic factors for the survival on multivariate analysis. Particularly, the presence of macrovascular invasion significantly influenced survival both in patients with liver cirrhosis Child-Pugh A and Child-Pugh B. CONCLUSION: Well maintained liver function and performance status are prerequisites for sorafenib treatment in patients with advanced HCC. Our findings do not support routine clinical use of sorafenib in Child-Pugh B patients. Evaluation of ascites and particularly macrovascular invasion might help to identify patients more likely to benefit from sorafenib treatment.