Background: Epithelial-mesenchymal transition (EMT) has been associated with wound healing, tumorigenesis, and metastasis. Circular RNAs (circRNAs) are functional non-coding RNAs involved in multiple human cancers. However, whether and how circRNAs contribute to the EMT in hepatocellular carcinomas (HCC) remains to be deciphered. In this study, we investigated the regulation and function of hsa_circ_0003288 on programmed death-1 ligand 1 (PD-L1) during EMT and HCC invasiveness. Methods: Hsa_circ_0003288 expression was measured by real-time quantitative reverse transcriptase PCR (qRT-PCR). Luciferase reporter assays, RNA pull-down assay and fluorescence in situ hybridization (FISH) were used to determine the correlation between hsa_circ_0003288 and miR-145 and between miR-145 and PD-L1. Furthermore, ectopic overexpression and siRNA-mediated downregulation of hsa_circ_0003288, transwell assays, and in vivo studies were used to determine the function of hsa_circ_0003288 on the EMT and invasiveness of L02 and HCC cells. Results: miR-145 directly targeted the PD-L1 3′-untranslated region (UTR) region, and hsa_circ_0003288 acted as a miR-145 sponge to regulate PD-L1 expression. Overexpression of hsa_circ_0003288 increased PD-L1 levels and promoted EMT, migration, and invasiveness of L02 cells. These observations were reversed after knockdown of hsa_circ_0003288 in HepG2 and Huh7 cells. Overexpression of PD-L1 rescued EMT, migration, and invasiveness of HepG2 and Huh7 cells after knockdown of hsa_circ_0003288. Furthermore, hsa_circ_0003288 knockdown reduced EMT in in vivo studies. Hsa_circ_0003288/PD-L1 axis was found to mediate the metastatic phenotypes via the PI3K/Akt pathway in HCC. Additionally, expression levels of hsa_circ_0003288 were increased and positively correlated with PD-L1 expression in HCC tissues. Conclusion: Our findings demonstrated that hsa_circ_0003288 promoted EMT and invasion of HCC via the hsa_circ_0003288/miR-145/PD-L1 axis through the PI3K/Akt pathway. Targeting hsa_circ_0003288 may be a therapeutic strategy for the treatment of HCC.

Transarterial chemoembolization (TACE) has been extensively used in clinic to treat unresectable hepatocellular carcinoma (HCC). Herein, magnesium microspheres (Mg MSs) were used as embolic devices to enhance lipiodol-mediated TACE. After being dispersed in lipiodol and injected into tumors, Mg MSs would continuously generate hydrogen and magnesium hydroxide, which could neutralize the acidic tumor microenvironment, restore exhausted CD8 ⁺ T cells, reverse immunosuppression, and trigger specific T cell–mediated antitumor responses, synergistically resulting in inhibited tumor growth. As demonstrated in a rabbit orthotopic liver cancer model, artery infusion of Mg MS–dispersed lipiodol offered greatly enhanced therapeutic outcome compared to lipiodol-based or polymeric-bead–based TACE. In a pilot clinical study, among 15 eligible patients with HCC, 11 patients achieved complete response and 3 patients achieved partial responses without unexpected treatment-related adverse events during the 1 to 3 months’ follow-up. The objective response rate of Mg-enhanced TACE was ~93.3% in this small-scale trial, much higher than that of current TACE therapies.

Purpose: To retrospectively evaluate and compare treatment effectiveness and safety between transarterial chemoembolization (TACE) combined with molecularly targeted agents plus immune checkpoint inhibitors (TACE+T+I) and TACE combined with molecularly targeted agents (TACE+T) for unresectable hepatocellular carcinoma (uHCC).Methods: We retrospectively analyzed the data of patients with unresectable HCC from January 2018 to June 2022. The patients were screened based on the inclusion criteria and were divided into the triple combination group (TACE+T+I) and the double combination group (TACE+T). The primary outcomes were overall survival (OS), progression-free survival (PFS), and adverse events (AEs). The secondary outcomes were objective response rate (ORR) and disease control rate (DCR). Risk factors associated with PFS and OS were determined by Cox regression analysis.Results: A total of 87 patients were enrolled in this study, including 42 patients in the TACE+T+I group and 45 patients in the TACE+T group. Over a median follow-up of 29.00 and 26.70 months, patients who received TACE+T+I therapy achieved a significantly longer median OS (24.00 vs. 21.40 months, p = 0.007) and median PFS (9.70 vs. 7.00 months, p = 0.017); no grade 4 AEs or treatment-related death occurred in the two groups. Grade 3 AEs attributed to systemic agents in the two groups showed no significant difference (19.0% vs. 15.6%, p = 0.667). Patients in the TACE+T+I group demonstrated better tumor response when compared with patients in the TACE+T group, with an ORR of 52.4% vs. 17.8% (p = 0.001). No significant difference was observed in DCR between the two groups (83.3% vs. 77.8%, p = 0.514). Cox regression analysis showed that only the treatment method was an independent factor of OS, and both age and treatment method were independent factors related to PFS.Conclusion: Compared with TACE plus molecularly targeted agents (TACE+T), the triple therapy (TACE+T+I) could improve survival and tumor response in unresectable HCC with manageable toxicities.