Oct4 and Nanog are key regulatory genes that maintain the pluripotency and self-renewal properties of embryonic stem cells. We previously reported that the two stemness markers were tightly associated with cancer progression and poor outcomes of hepatocellular carcinoma. In this study, we demonstrate that coexpression of Oct4/Nanog modulates activation of signal transducer and activator of transcription 3 (Stat3), an oncogenic transcription factor that is activated in many human malignancies including hepatocellular carcinoma (HCC), as well as the expression of Snail, a key regulator implicated in epithelial-mesenchymal transition and tumor metastasis. Oct4 and Nanog were ectopic expressed in MHCC97-L cell lines via lentiviral gene transfection. The stemness characteristics including self-renewal, proliferation, chemoresistance, and tumorigenicity were assessed. The effect of coexpression of Oct4 and Nanog on epithelial-mesenchymal transition change, and the underlying molecular signaling was investigated. Ectopic coexpression of Oct4 and Nanog empowered MHCC97-L cells with cancer stem cell (CSC) properties, including self-renewal, extensive proliferation, drug resistance, and high tumorigenic capacity. Significantly, Oct4 and Nanog encouraged epithelial-mesenchymal transition change contributing to tumor migration, invasion/metastasis in vitro and in vivo. Following molecular mechanism investigation indicated Oct4/Nanog-regulated epithelial-mesenchymal transition change through Stat3-dependent Snail activation. Moreover, silencing Stat3 abrogates Oct4/Nanog-mediated epithelial-mesenchymal transition (EMT) change and invasion/metastasis in HCC. We delineate Oct4 and Nanog initiate stem cell characteristics in hepatocellular carcinoma and promote epithelial-mesenchymal transition through activation of Stat3/Snail signaling. Our findings propose Stat3/Snail pathway as a novel therapeutic target for the treatment of progression and metastasis of HCC with CSC-like signatures and epithelial-mesenchymal transition phenotype.

Background: Emerging evidence indicates that circular RNAs (circRNAs) and m⁶A RNA methylation participate in the pathogenesis and metastasis of multiple malignancies including hepatocellular carcinoma (HCC). However, it remains undocumented how circRNAs form a feedback loop with the m⁶A modification contributing to HCC. Methods: A novel hsa_circ_0017114 (circGPR137B) was identified from three pairs of primary HCC and adjacent normal tissues by circRNA expression profiling. The association of circGPR137B and miR-4739 with clinicopathological parameters and prognosis in patients with HCC was analyzed by RT-qPCR, fluorescence in situ hybridization and TCGA cohorts. The role of circGPR137B in HCC was estimated in vitro and in vivo. RT-qPCR, western blot, m⁶A dot blot, RIP, MeRIP and dual-luciferase reporter assays were used to validate the reciprocal regulation of the feedback loop among circGPR137B, miR-4739 and m⁶A demethylase FTO. Meanwhile, the expression, function and prognosis of FTO in HCC were investigated by RT-qPCR, western blot, TCGA and rescue experiments. Results: We identified a new dramatically downregulated circGPR137B in HCC tissues, and found that downregulation of circGPR137B or upregulation of miR-4739 was associated with poor prognosis in patients with HCC. Ectopic expression of circGPR137B strikingly repressed the proliferation, colony formation and invasion, whereas knockdown of circGPR137B harbored the opposite effects. Moreover, restored expression of circGPR137B inhibited tumor growth and lung metastasis in vivo. Further investigations showed that circGPR137B, co-localized with miR-4739 in the cytoplasm, acted as a sponge for miR-4739 to upregulate its target FTO, which mediated m⁶A demethylation of circGPR137B and promoted its expression. Thus, a feedback loop comprising circGPR137B/miR-4739/FTO axis was formed. FTO suppressed cell growth and indicated favorable survival in patients with HCC. Conclusion: Our results demonstrate that circGPR137B inhibits HCC tumorigenesis and metastasis through the circGPR137B/miR-4739/FTO feedback loop. This positive feedback mechanism executed by functional coupling between a circRNA sponge and an m⁶A modification event suggests a model for epigenetics.

Background: Although transarterial chemoembolization (TACE) has been used extensively for advanced hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT), no consensus has been reached and an evidence base for practice is lacking. This meta-analysis evaluated the efficacy and safety of TACE for treatment of HCC with PVTT. Methods: Ovid Medline, EMBASE, Web of Knowledge, and Cochrane library databases were searched up to August 2012 for controlled trials assessing TACE in patients with PVTT. Data concerning the study design, characteristics of trials, and outcomes were extracted. Hazard ratio (HR) and 95% confidence interval (CI) were calculated using random effects models. Results: Eight controlled trials involving 1601 HCC patients were included. TACE significantly improved the 6-month (HR, 0.41; 95% CI: 0.32–0.53; z, 6.28; p = 0.000) and 1-year (HR, 0.44; 95% CI: 0.34–0.57; z, 6.22; p = 0.000) overall survival of patients with PVTT compared with conservative treatment. Subgroup analyses showed that TACE was significantly effective in HCC patients whether with main portal vein (MPV) obstruction or with segmental PVTT. Fatal complications were rare, even in patients with MPV obstruction. Temporary liver decompensation and postembolization syndrome occurred frequently. However, they could be treated successfully with conservative treatment. Conclusions: TACE, as a safe treatment, has potential for incurring a survival benefit for advanced HCC with PVTT, even with MPV obstruction. Further large randomized controlled trials may be needed to confirm this result.

Background: This study was designed to evaluate the effectiveness of radiofrequency ablation in patients with intermediate (BCLC B) stage hepatocellular carcinoma who underwent transcatheter arterial chemoembolization. Methods: Included in this study were 211 patients with intermediate stage HCC who underwent initial transcatheter arterial chemoembolization and were potentially amendable for radiofrequency ablation (single tumor with diameter 5-8 cm, median 6.0 cm; 2–5 multiple nodules with diameter less than 5 cm) between January 2005 and December 2011. According to the inclusion and exclusion criteria, 55 patients were treated with following radiofrequency ablation, and the remaining 156 patients were treated with transcatheter arterial chemoembolization alone. The treatment effectiveness, local tumor control and survival outcome between the two groups were compared. Results: The complete tumor necrosis rate after treatment was 76.9% in combination group vs. 46.5% in transcatheter arterial chemoembolization alone group (P = 0.02). The major complication rate was 1.8% in combination group vs. 2.6% in transcatheter arterial chemoembolization alone group. Follow-up observation showed that the total tumor control rate was 74.5% in combination group versus 54.5% in transcatheter arterial chemoembolization alone group (P < 0.001). The 1-, 3- and 5-year survival rates in combination group were significantly higher than those in TACE alone group (P = 0.01). Conclusions: Radiofrequency ablation following initial transcatheter arterial chemoembolization delays tumor progression and prolongs overall survival of patients with intermediate stage HCC tumors.

Previously, we showed the inhibitor of differentiation or DNA binding 1 (ID1)/Myc signaling is highly expressed in oxaliplatin-resistant hepatocellular carcinoma (HCC). This study sought to investigate the role of ID1/Myc signaling on immune evasion in oxaliplatin-resistant HCC. The oxaliplatin (OXA)-resistant HCC cell lines (Hepa 1-6–OXA, 97H-OXA, and 3B-OXA) were established and their oxaliplatin tolerance was confirmed in vitro and in vivo. The relationship between ID1/Myc and programmed death-ligand 1 (PD-L1) up-regulation and polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) accumulation was explored. The underlying mechanism in which ID1/Myc signaling regulated PD-L1 expression and PMN-MDSC accumulation was investigated in vitro and vivo. Increased ID1/Myc expression was identified in oxaliplatin-resistant HCC and correlated with PD-L1 up-regulation and PMN-MDSC accumulation. The knockdown of Myc sensitized oxaliplatin-resistant HCC cells to oxaliplatin and resulted in a decrease of PMN-MDSCs and an increase of interferon-γ⁺ CD8⁺ T cells in a tumor microenvironment. Polymerase chain reaction array, enzyme-linked immunosorbent assay, and MDSC Transwell migration assay indicated that oxaliplatin-resistant HCC cells recruited PMN-MDSCs through chemokine (C-C motif) ligand 5 (CCL5). The dual luciferase reporter assay and chromatin immunoprecipitation assay indicated that Myc could directly increase the transcriptions of PD-L1 and CCL5. Furthermore, anti–PD-L1 antibody combined with CCL5 blockade showed significant antitumor effects in oxaliplatin-resistant HCC. ID1/Myc signaling drives immune evasion in oxaliplatin-resistant HCC via PD-L1 up-regulation and PMN-MDSC recruitment. Blocking the ID1/Myc-induced immune tolerance represents a promising treatment target to conquer chemoresistance in HCC.

Objective: Several new first-line treatments were recently approved for unresectable hepatocellular carcinoma (HCC). In this meta-analysis, we compare the efficacy and safety of first-line systemic treatments to provide information for clinical decision making in unresectable HCC.Methods: Pubmed, Science Direct, Web of Science, Scopus, Ovid MEDLINE, Embase, Google Scholar, the Cochrane Library, EMbase, CNKI, CBM, VIP, and the Wanfang databases, as well as the Cochrane Central Register of Controlled Trails were searched for randomized clinical trials evaluating the efficacy of first-line chemotherapy, molecular targeted therapy, or immunotherapy for unresectable HCC. Hazard ratios with 95% confidence intervals (CIs) were calculated to explore the effects of various treatment options on overall survival (OS) and progression-free survival (PFS), whereas odd ratios with 95% CIs were used for adverse events (AEs) and serious adverse events (SAEs). A network meta-analysis was performed to synthesize data and for direct and indirect comparisons between treatments. The cumulative ranking curve (SUCRA) and P score were used to rank treatments. The risk of bias across studies was assessed graphically and numerically using the funnel plot and Egger’s regression test.Results: Fifteen studies including 9005 patients were analyzed. Sintilimab plus bevacizumab, atezolizumab plus bevacizumab, and donafenib had better OS outcomes than sorafenib. Sintilimab plus bevacizumab, atezolizumab plus bevacizumab, lenvatinib, and linifanib had better PFS outcomes than sorafenib. The results of network meta-analysis showed that sintilimab plus bevacizumab was associated with the best OS and PFS. Egger’s tests indicated that none of the included studies had obvious publication deviation.Conclusion: Sintilimab plus bevacizumab showed the best OS and PFS outcomes with no additional AEs or SAEs. Thus, sintilimab plus bevacizumab may be a better first line choice for the treatment of patients with unresectable HCC.Systematic Review Registration: PROSPEROI [https://www.crd.york.ac.uk/PROSPERO/index.php], identifier CRD42021269734.