Purpose: Recombinant tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising antitumor agent. However, many hepatocellular carcinoma (HCC) cells show resistance to TRAILinduced 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. Clin Cancer Res; 16(21); 5189-99. ©2010 AACR.

<b><i>Background and Aims:</i></b> 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. <b><i>Methods:</i></b> 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. <b><i>Results:</i></b> 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 (<i>p</i> = 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 (<i>p</i> = 0.005). <b><i>Conclusions:</i></b> 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.

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.

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