Changes in Posttreatment Spleen Volume Associated with Immunotherapy Outcomes for Advanced Hepatocellular Carcinoma.

Purpose: We investigated whether spleen volume (SV) changes were associated with treatment outcomes in advanced hepatocellular carcinoma (HCC) patients who received immunotherapy or first-line sorafenib. Patients and Methods: Patients with advanced HCC who underwent immunotherapy or first-line sorafenib at our institute were retrospectively analyzed. CT was used to measure SV before and within 3 months of treatment initiation. Tumor assessment followed Response Evaluation Criteria in Solid Tumors version 1.1. The association between SV change and tumor response or progression-free survival (PFS) was analyzed. The inverse probability of treatment weighting (IPTW) was used to adjust for differences in baseline characteristics. Results: The immunotherapy group comprised 143 patients (124 men, mean age, 59.8 years ± 11.2 [standard deviation]), while the sorafenib group had 57 (47 men, mean age, 59.6 years ± 9.9). SV increased in 108 (75.5%) immunotherapy and 21 (36.8%) sorafenib patients. In the immunotherapy group, patients with increased SV were more likely than those with decreased SV to have a higher disease control rate (76.9% vs 57.1%, p = 0.024) and durable clinical benefit (52.8% vs 25.7%, p = 0.005). It was also associated with extended PFS in the immunotherapy group in both the univariate (p = 0.028) and multivariate (p = 0.014) analysis. By contrast, in the sorafenib group, an increased in SV was not associated with treatment response but was presumably associated with reduced PFS (p = 0.072) in the multivariate analysis. After IPTW adjustment, the increase in SV remained a significant predictor for DCB and PFS in the immunotherapy group. Conclusion: Most patients exhibited an increase in SV after the initiation of immunotherapy, which may be used to predict response and prognosis. However, this association was not observed in patients who received sorafenib.

The study provides significant evidence that an increase in spleen volume is associated with better treatment outcomes in advanced hepatocellular carcinoma patients undergoing immunotherapy. These findings offer oncologists a new potential biomarker for optimizing treatment strategies. Specifically, increased spleen volume could be used to predict higher rates of disease control and durable clinical benefits, allowing for more personalized care.

Clinical practice guidelines and real-life practice in hepatocellular carcinoma: A Taiwan perspective.

Hepatocellular carcinoma (HCC) is the fourth most common cancer and the second leading cause of cancer-related death in Taiwan. The Taiwan Liver Cancer Association and the Gastroenterological Society of Taiwan developed and updated the guidelines for HCC management in 2020. In clinical practice, we follow these guidelines and the reimbursement policy of the government. In Taiwan, abdominal ultrasonography, alpha-fetoprotein, and protein induced by vitamin K absence or antagonist-II (PIVKA-II) tests are performed for HCC surveillance every 6 months or every 3 months for high-risk patients. Dynamic computed tomography, magnetic resonance imaging, and contrast-enhanced ultrasound have been recommended for HCC surveillance in extremely high-risk patients or those with poor ultrasonographic visualization results. HCC is usually diagnosed through dynamic imaging, and pathological diagnosis is recommended. Staging of HCC is based on a modified version of the Barcelona Clinic Liver Cancer (BCLC) system, and the HCC management guidelines in Taiwan actively promote curative treatments including surgery and locoregional therapy for BCLC stage B or C patients. Transarterial chemoembolization (TACE), drug-eluting bead TACE, transarterial radioembolization, and hepatic artery infusion chemotherapy may be administered for patients with BCLC stage B or C HCC. Sorafenib and lenvatinib are reimbursed as systemic therapies, and regorafenib and ramucirumab may be reimbursed in cases of sorafenib failure. First-line atezolizumab with bevacizumab is not yet reimbursed but may be administered in clinical practice. Systemic therapy and external beam radiation therapy may be used in specific patients. Early switching to systemic therapy in TACE-refractory patients is a recent paradigm shift in HCC management.

Sarcopenia and myosteatosis are associated with survival in patients receiving immunotherapy for advanced hepatocellular carcinoma.

OBJECTIVES: To investigate the association of sarcopenia, myosteatosis, and sarcopenic obesity with survival outcomes among patients who underwent immunotherapy for advanced hepatocellular carcinoma (HCC). METHODS: In this retrospective analysis, patients who initiated immunotherapy for advanced HCC were enrolled. Sarcopenia and myosteatosis were evaluated on pretreatment CT at L3 level by skeletal muscle index and mean muscle attenuation using predefined cutoff values. Sarcopenic obesity was defined as concurrent sarcopenia and body mass index > 25 kg/m2. The log-rank test and the Cox proportional hazards model were used to compare overall survival (OS) and progression-free survival (PFS). RESULTS: A total of 138 patients was included (discovery cohort n = 111, validation cohort n = 27). In the discovery cohort, patients with sarcopenia exhibited significantly poorer PFS (p = 0.048) and OS (p = 0.002) than patients without sarcopenia. Patients with myosteatosis exhibited significantly poorer PFS (p < 0.001) and OS (p < 0.001) than patients without myosteatosis. Patients with sarcopenic obesity compared to patients without sarcopenic obesity exhibited significantly poorer OS (p = 0.006) but not PFS (p = 0.31). In multivariate analysis adjusting for patient demographics, tumor extent, and liver function reserve, myosteatosis remained an independent predictor of poor PFS (p = 0.014) and OS (p = 0.007); sarcopenia remained an independent predictor for poor OS (p = 0.007). The prediction models for survival outcomes built by the discovery cohort showed similar performance in the validation cohort. CONCLUSIONS: Sarcopenia and myosteatosis are independent prognostic factors in patients who received immunotherapy for advanced HCC. KEY POINTS: • Sarcopenia and myosteatosis can be evaluated by CT at L3 level. • Sarcopenia, myosteatosis, and sarcopenic obesity were associated with poor survival outcomes in patients who underwent immunotherapy for advanced HCC. • Myosteatosis was an independent predictor of PFS and OS, and sarcopenia was independent for OS in these patients.

Immune checkpoint inhibitors for hepatocellular carcinoma - A game changer in treatment landscape.

Rapidly expanding armamentarium of systemic therapy for advanced hepatocellular carcinoma (HCC) occurred in the recent few years. Multikinase inhibitors (MKI) or targeted therapy with antiangiogenic properties have been the focus of clinical studies in advanced HCC in the past decade. The remarkable efficacy of single agent immune checkpoint inhibitors (ICI), including nivolumab and pembrolizumab, in early phase studies led to accelerated approvals as second-line treatment for advanced HCC. The excellent toxicity profile of single agent ICI also lends support to be developed as combination therapy with other targeted therapies. The success of combining atezolizumab and bevacizumab over sorafenib as the first-line treatment in advanced HCC marked the newest paradigm shift in advanced HCC. The combination exhibited unprecedented objective response rate of 30% and a median survival of 19.2 months. Many other similar ICI-based combinations are expected to be approved in the foreseeable future. In this narrative review, the development of ICI alone and in combination in advanced HCC were described and the potential impact in all stages of HCC, safety issues of ICI-based combinations, and future perspectives were discussed.

Revisiting Hepatic Artery Infusion Chemotherapy in the Treatment of Advanced Hepatocellular Carcinoma.

Hepatic artery infusion chemotherapy (HAIC) is a well-established and common treatment for advanced hepatocellular carcinoma (HCC), particularly in East Asia. However, HAIC is not recognized internationally. Although several trials have demonstrated the safety and efficacy of HAIC, evidence corroborating its overall survival (OS) benefits compared with standard treatments is insufficient. Nevertheless, HAIC may provide prominent benefits in selected patients such as patients with portal vein thrombosis or high intrahepatic tumor burden. Moreover, HAIC has been combined with several therapeutic agents and modalities, including interferon-alpha, multikinase inhibitors, radiation therapy, and immunotherapy, to augment its treatment efficacy. Most of these combinations appeared to increase overall response rates compared with HAIC alone, but results regarding OS are inconclusive. Two prospective randomized controlled trials comparing HAIC plus sorafenib with sorafenib alone have reported conflicting results, necessitating further research. As immunotherapy-based combinations became the mainstream treatments for advanced HCC, HAIC plus immunotherapy-based treatments also showed encouraging preliminary results. The trials of HAIC were heterogeneous in terms of patient selection, chemotherapy regimens and doses, HAIC combination agent selections, and HAIC technical protocols. These heterogeneities may contribute to differences in treatment efficacy, thus increasing the difficulty of interpreting trial results. We propose that future trials of HAIC standardize these key factors to reveal the clinical value of HAIC-based treatments for HCC.

Limited Predictive or Prognostic Role of Tumor-Infiltrating Tissue-Resident Memory CD8 T Cells in Patients with Hepatocellular Carcinoma Receiving Immunotherapy.

PURPOSE: Tumor-infiltrating tissue-resident memory CD8 T cells (CD8 TRM; CD103+ CD8+) are considered tumor-specific and may correlate better with the tumor response to immune checkpoint blockade (ICB). This study evaluated the association of tumor-infiltrating CD8 TRM and their subsets with the efficacy of immunotherapy in patients with advanced hepatocellular carcinoma (HCC). EXPERIMENTAL DESIGN: Consecutive HCC patients who received ICB in prospective trials were analyzed. Formalin-fixed paraffin-embedded tumor sections were stained for DAPI, CD8, CD103, CD39, programmed cell death-1 (PD-1), and programmed cell death ligand 1 (PD-L1) using a multiplex immunohistochemical method. The densities of CD8 T cells, CD8 TRM, and CD39+ or PD-L1+ subsets of CD8 TRM were correlated with tumor response and overall survival (OS). RESULTS: A total of 73 patients were identified, and 48 patients with adequate pretreatment tumor specimens and complete follow-up were analyzed. A median of 32.7% (range: 0-92.6%) of tumor-infiltrating CD8 T cells were TRM. In subset analyses, 66.6% ± 34.2%, 69.8% ± 33.4%, and 0% of CD8 TRM cells coexpressed CD39, PD-L1, and PD-1, respectively. The objective response rates for CD8 T cell-high, CD8 TRM-high, CD39+ CD8 TRM-high, and PD-L1+ CD8 TRM-high groups were 41.7%, 37.5%, 37.5%, and 29.2%, respectively. Patients with CD8 T cell-high, but not those with CD8 TRM-high, CD39+ CD8 TRM-high, or PD-L1+ CD8 TRM-high, tumors, had significantly prolonged OS (p = 0.0429). CONCLUSIONS: Compared with total tumor-infiltrating CD8 T cells, tumor-infiltrating CD8 TRM or their subsets failed to provide additional advantages in predicting the efficacy of immunotherapy for HCC.

An Exploratory Study for the Association of Gut Microbiome with Efficacy of Immune Checkpoint Inhibitor in Patients with Hepatocellular Carcinoma.

BACKGROUND: Gut microbiome has been associated with the efficacy of immune checkpoint inhibitors (ICI) in patients with various types of cancers but not yet in hepatocellular carcinoma (HCC). AIMS: To investigate the association between gut microbiome and efficacy of ICI in patients with HCC. METHODS: Patients with HCC who were scheduled to receive ICI were prospectively enrolled. Fecal samples were collected within 7 days before initiation of ICI (baseline) and 8 weeks later. Gut microbiome was assessed using 16S rRNA sequencing and shotgun whole-genome sequencing and correlated with objective response (complete or partial response), disease control (objective response or stable disease for ≥16 weeks), and overall survival. RESULTS: Thirty-six patients with HCC were enrolled, and 20 of them provided both baseline and 8-week feces. Alpha diversity, richness, and compositions of baseline gut microbiome indicated no difference between responders and nonresponders or between disease control and nondisease control groups. For the 20 paired feces, immunotherapy did not change any of the major microbiome features. No specific taxa were enriched in patients with objective response. Three taxa-Bifidobacterium, Coprococcus, and Acidaminococcus-were enriched in patients with disease control. However, the baseline abundance of these three taxa did not predict overall survival benefit. CONCLUSIONS: In this exploratory study, we failed to disclose any overt association of gut microbiome with the efficacy of ICI in patients with HCC. A larger prospective study is warranted for definite conclusion.

Novel systemic therapy for hepatocellular carcinoma.

Systemic therapy for hepatocellular carcinoma (HCC) used to be limited to patients with advanced diseases and multi-kinase inhibitors targeting tumor angiogenesis the major approach of developing new treatment options. In the past 3 years, new data from trials of both molecular targeted therapy and immune checkpoint inhibitors (ICI) provided many new options of first- and second-line treatment for advanced HCC. Most notably, combination of ICI targeting the program cell death-1 (PD-1) pathway with other novel agents or conventional anti-cancer therapy may further improve treatment efficacy in different clinical settings. In this paper updated data of clinical trials of systemic therapy in the first- and second-line settings for advanced HCC were reviewed and the following issues were discussed: (1) lessons of trial design learned from positive and negative trials; (2) the balance between efficacy and safety in clinical practice; and (3) impact on future multi-disciplinary management of HCC.

Differential Organ-Specific Tumor Response to Immune Checkpoint Inhibitors in Hepatocellular Carcinoma.

BACKGROUND AND AIMS: Immune checkpoint inhibitors (ICIs) exhibit significant clinical activity in patients with advanced hepatocellular carcinoma (HCC). This study explored whether tumor response to ICIs in HCC varies among different organs. METHODS: We reviewed the data of patients with advanced HCC who had received ICIs. Patients with measurable diseases were enrolled. Organ-specific response criteria, adapted from RECIST 1.1 and immune-related RECIST, were used to evaluate the objective response to ICIs in tumors located in the liver, lung, lymph node, and other intra-abdominal sites. RESULTS: Of the 75 enrolled patients with advanced HCC, 51 and 11 patients had chronic hepatitis B virus and chronic hepatitis C virus infection, respectively. Regarding ICI treatment, 58, 1, and 16 patients had undergone anti-PD-1/anti-PD-L1 monoclonal antibody (mAb) alone, anti-CTLA4 mAb alone, and anti-PD-1 mAb plus anti-CTLA4 mAb, respectively; 20 and 55 patients had received ICIs as first-line or ≥second-line therapy. The overall objective response rate (ORR) was 28.0%. In total, 58, 34, 19, and 18 patients had measurable hepatic tumors and lung, lymph node, and other intra-abdominal metastases, and the corresponding organ-specific ORRs were 22.4, 41.2, 26.3, and 38.9%, respectively. Of the 39 patients who had both hepatic and extrahepatic tumors, 12 had disease control in extrahepatic tumors while progressive disease (PD) in hepatic tumors, whereas only 4 exhibited disease control in hepatic tumors while PD in extrahepatic tumors (p = 0.046, McNemar test). Of the 16 patients with only evaluable tumors in the liver and lungs at baseline, 8 had disease control in the lungs while PD in the liver, and none experienced disease control in the liver while PD in the lungs (p = 0.005). CONCLUSIONS: The hepatic tumors of HCC may be less responsive to ICIs than extrahepatic lesions. Lung metastases responded most favorably to ICIs. The mechanisms underlying this differential response to ICIs warrant further investigation.

Early alpha-foetoprotein response associated with treatment efficacy of immune checkpoint inhibitors for advanced hepatocellular carcinoma.

BACKGROUND: Post-treatment decline in serum alpha-foetoprotein (AFP) levels has been shown to predict the treatment efficacy of antiangiogenic therapy for advanced hepatocellular carcinoma (HCC). We explored whether a decline in AFP levels was also associated with treatment outcomes of immune checkpoint inhibitors (ICIs) in patients with advanced HCC. METHODS: We reviewed all patients who received ICI therapy for advanced HCC. AFP response was evaluated in patients with the pretreatment AFP level of >20 ng/mL. We defined early AFP response as a >20% decline in serum AFP levels within the first 4 weeks of treatment initiation relative to pretreatment levels. We then studied whether early AFP response was associated with treatment outcomes. RESULTS: Sixty patients were enrolled in this study; 43 of them were evaluable for early AFP response. The objective response rate of early AFP responders was significantly higher than that of early AFP nonresponders (73% vs. 14%, P < .001). Early AFP responders, compared with early AFP nonresponders, exhibited significantly longer overall survival (OS) (median, 28.0 vs 11.2 months, P = .048) and progression-free survival (PFS) (median, 15.2 vs 2.7 months, P = .002). After adjusting for other clinicopathological variables and treatments, early AFP response remained an independent predictor for longer OS (hazard ratio [HR] = 0.089, 95% confidence interval [CI] = 0.018-0.441; P = .003) and PFS (HR = 0.128, 95% CI = 0.041-0.399; P < .001). CONCLUSION: Early AFP response was associated with higher treatment efficacy of ICIs for advanced HCC. Additional validation studies are nonetheless warranted.

Outcome of stage IV cancer patients receiving in-hospital cardiopulmonary resuscitation: a population-based cohort study.

The effects of cardiopulmonary resuscitation (CPR) on patients with advanced cancer remain to be elucidated. We identified a cohort of patients with stage-IV cancer who received in-hospital CPR from the Taiwan Cancer Registry and National Health Insurance claims database, along with a matched cohort without cancer who also received in-hospital CPR. The main outcomes were post-discharge survival and in-hospital mortality. In total, 3,446 stage-IV cancer patients who underwent in-hospital CPR after cancer diagnosis were identified during January 2009-June 2014. A vast majority of the patients did not survive to discharge (n = 2,854, 82.8%). The median post-discharge survival was 22 days; 10.1% (n = 60; 1.7% of all patients) of the hospital survivors received anticancer therapy after discharge. We created 1:1 age-, sex-, Charlson comorbidity index (CCI)-, and year of CPR-matched noncancer and stage-IV cancer cohorts (n = 3,425 in both; in-hospital mortality rate = 82.1% and 82.8%, respectively). Regression analysis showed that the stage-IV cancer cohort had shorter post-discharge survival than did the noncancer cohort. The outcome of patients with advanced cancer was poor. Even among the survivors, post-discharge survival was short, with only few patients receiving further anticancer therapy.

Considerations of heterogeneity in clinical trials for hepatocellular carcinoma.

Introduction: Clinical trials in hepatocellular carcinoma (HCC) exhibit a high degree of heterogeneity. These heterogeneities may lead to unexpected results among clinical trials. Area covered: In this review, we address the heterogeneity noted in early phase HCC trials, trials involving transarterial chemoembolization, and advanced HCC trials. Furthermore, we discuss possible methods to attenuate the detrimental effects of heterogeneity when conducting clinical trials. Expert opinion: Clinical trials in HCC exhibit an inherently high degree of heterogeneity because of various reasons: tumor heterogeneity, different cirrhotic backgrounds, various etiologies of cirrhosis, and geographical differences in practice and expertise. Such heterogeneity may cause imbalance among the enrolled patient population, premature withdrawal from the clinical trial, and variable response to the treatment. In addition, methodological heterogeneity also exists in designing trial protocol and response evaluation. All these factors may eventually lead to conflicting results among clinical trials. Accounting for these heterogeneities is important to foster the success of future trials. In recent years, significant progress with molecular targeted agents and immune checkpoint inhibitors was made in advanced HCC. These new agents are also being tested in clinical trials involving earlier stage HCC and will also face the challenge of these issues.

Increased Expression of Programmed Death-Ligand 1 in Infiltrating Immune Cells in Hepatocellular Carcinoma Tissues after Sorafenib Treatment.

OBJECTIVE: Programmed death-ligand 1 (PD-L1) expression in the tumor microenvironment (TME) has been reported to be related to prognosis in patients with hepatocellular carcinoma (HCC) after hepatectomy. The impact of sorafenib on PD-L1 expression in the TME of advanced HCC is unclear. PATIENTS AND METHODS: Patients with HCC who received sorafenib for advanced disease at National Taiwan University Hospital, Taipei, Taiwan, and who had paired HCC tissues obtained before and after sorafenib treatment were included in the study group. HCC patients not treated with sorafenib who had paired primary and recurrent or metastatic tissues were identified as the reference group. The membrane PD-L1 staining, detected by immunohistochemistry (IHC) using SP142 antibody, was semiquantitatively scored in tumor cells (TCs) or tumor-infiltrating immune cells (ICs). Additional IHC assays were employed to characterize the PD-L1-expressing ICs. RESULTS: Twenty-three advanced HCC patients with pre- and post-sorafenib paired HCC tissues were included in the study group. The median duration of sorafenib treatment was 4.3 months (range: 1.3-18.7). PD-L1 expression in ICs was significantly higher in post-sorafenib HCC tissues than in pre-sorafenib HCC tissues (pre-sorafenib vs. post-sorafenib IHC 0/1/2/3: 11/5/5/2 vs. 5/5/2/11, p = 0.016). However, PD-L1 expression in TCs was not significantly different between pre- and post-sorafenib tissues (IHC 0/1/2/3: 19/2/0/2 vs. 14/5/0/4, p = 0.094). In the reference group of 44 patients not treated with sorafenib, PD-L1 expression in ICs and TCs was not significantly different between the paired primary and metastatic HCC tissues. By performing IHC double staining with PD-L1 and CD68, we found the PD-L1-expressing ICs were mainly CD68-positive macrophages. PD-L1 expression levels of pre- and post-sorafenib tissues were not associated with patients' overall survival or duration of sorafenib treatment. CONCLUSIONS: PD-L1 expression in ICs was significantly increased in post-sorafenib HCC tissues. The mechanisms and clinical significance of this observation warrants further investigation.

Modified CLIP with objective liver reserve assessment retains prognosis prediction for patients with advanced hepatocellular carcinoma.

BACKGROUND AND AIM: The Cancer of the Liver Italian Program (CLIP) score is a commonly used staging system for hepatocellular carcinoma (HCC) helpful with predicting prognosis of advanced HCC. CLIP uses the Child-Turcotte-Pugh (CTP) score to evaluate liver reserve. A new scoring system, the albumin-bilirubin (ALBI) grade, has been proposed as they objectively evaluate liver reserve. We examined whether the modification of CLIP with ALBI retained its prognosis prediction for patients with advanced HCC. METHODS: We included patients who received first-line antiangiogenic therapy for advanced HCC. Liver reserve was assessed using CTP and ALBI scores, which were then incorporated into CLIP and ALBI-CLIP, respectively. To assess their efficacies of prognostic prediction, the Cox's proportional hazard model and concordance indexes were used. RESULTS: A total of 142 patients were included; 137 of them were classified CTP A and 5 patients CTP B. Patients could be divided into four or five groups with different prognosis according to CLIP and ALBI-CLIP, respectively. Higher R(2) (0.249 vs 0.216) and lower Akaike information criterion (995.0 vs 1001.1) were observed for ALBI-CLIP than for CLIP in the Cox's model predicting overall survival. ALBI-CLIP remained an independent predictor for overall survival when CLIP and ALBI-CLIP were simultaneously incorporated in Cox's models allowing variable selection with adjustment for hepatitis etiology, treatment, and performance status. The concordance index was also higher for ALBI-CLIP than for CLIP (0.724 vs 0.703). CONCLUSIONS: Modification of CLIP scoring with ALBI, which objectively assesses liver reserve, retains and might have improved prognosis prediction for advanced HCC.

Sorafenib overcomes TRAIL resistance of hepatocellular carcinoma cells through the inhibition of STAT3.

PURPOSE: Recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising antitumor agent. However, many hepatocellular carcinoma (HCC) cells show resistance to TRAIL-induced apoptosis. Here, we report that sorafenib improves the antitumor effect of TRAIL-related agents in resistant HCC. EXPERIMENTAL DESIGN: HCC cell lines (PLC5, Huh-7, Hep3B, and Sk-Hep1) were treated with sorafenib and/or TRAIL-related agents (TRAIL or LBY135) and analyzed in terms of apoptosis and signal transduction. In vivo efficacy was determined in nude mice with PLC5 xenografts. RESULTS: Sorafenib, the only approved drug for HCC, sensitizes resistant HCC cells to an agonistic DR5 antibody (LBY135) and TRAIL-induced apoptosis in TRAIL-resistant HCC cells. We found that STAT3 played a significant role in mediating TRAIL sensitization. Our data showed that sorafenib downregulated phospho-STAT3 (pSTAT3) and subsequently reduced the expression levels of STAT3-related proteins (Mcl-1, survivin, and cyclin D1) in a dose- and time-dependent manner in TRAIL-treated HCC cells. Knockdown of STAT3 by RNA interference overcame apoptotic resistance to TRAIL in HCC cells, and ectopic expression of STAT3 in HCC cells abolished the TRAIL-sensitizing effect of sorafenib. Moreover, SHP-1 inhibitor reversed downregulation of pSTAT3 and apoptosis induced by sorafenib, and silencing of SHP-1 by RNA interference abolished the effects of sorafenib on pSTAT3. Notably, sorafenib increased SHP-1 activity in PLC5 cells. Finally, sorafenib plus LBY135 significantly suppressed PLC5 xenograft tumor growth. CONCLUSIONS: Sorafenib sensitizes resistant HCC cells to TRAIL-induced apoptosis at clinical achievable concentrations, and this effect is mediated via the inhibition of STAT3.

Synergistic interactions between sorafenib and bortezomib in hepatocellular carcinoma involve PP2A-dependent Akt inactivation.

BACKGROUND & AIMS: Previously we reported that Akt inactivation determines the sensitivity of hepatocellular carcinoma (HCC) cells to bortezomib. Here we report that combined treatment with sorafenib and bortezomib shows synergistic effects in HCC. METHODS: HCC cell lines (PLC/PRF/5, Huh-7, and Hep3B) were treated with sorafenib and/or bortezomib and analyzed in terms of apoptosis signal transduction. In vivo efficacy was determined in nude mice with PLC/PRF/5 xenografts. RESULTS: Pretreatment with sorafenib enhanced bortezomib-induced apoptotic cell death by restoring bortezomib's ability to inactivate Akt in PLC/PRF/5 cells. Knocking down Akt1 by RNA-interference overcame apoptotic resistance to bortezomib in PLC/PRF/5 cells and ectopic expression of active Akt in HCC cells abolished the bortezomib sensitizing effect of sorafenib, indicating Akt inactivation plays a key role in mediating the combinational effects. Moreover, okadaic acid, a protein phosphatase 2A (PP2A) inhibitor, reversed down-regulation of phospho-Akt (P-Akt) expression induced by co-treatment with sorafenib and bortezomib, and 1, 9 di-deoxy-forskolin, a PP2A agonist, restored bortezomib's effect on P-Akt and apoptosis. Importantly, silencing of PP2A by RNA-interference reduced the apoptotic effect induced by sorafenib-bortezomib co-treatment, indicating that PP2A is indispensable for mediating the effects of these drugs. Notably, sorafenib with bortezomib increased PP2A activity in PLC/PRF/5 cells without altering protein levels of PP2A complex or the interaction between PP2A and Akt proteins. Finally, sorafenib plus bortezomib significantly suppressed PLC/PRF/5 xenograft tumor growth, down-regulated P-Akt expression, and up-regulated PP2A activity. CONCLUSIONS: The combination of sorafenib and bortezomib shows synergy in HCC through PP2A-dependent Akt inactivation.