Exosomes are nano-sized vesicles that serve as mediators for intercellular communication through the delivery of cargo, including protein, lipids, nucleic acids or other cellular components, to neighboring or distant cells. Exosomal cargo may vary in response to different physiological or pathological conditions. The endosomal sorting complex required for transport (ESCRT) family has been widely accepted as a key mechanism in biogenesis and cargo sorting. On the other hand, accumulating evidence show that ESCRT-independent pathways exist. Due to the critical role of exosomes in intercellular communications in delivering cargo to recipient cells, exosomes have been investigated as a vector for the delivery of endogenous or exogenous cargo for therapeutic purposes. But the number of exosomes produced by cells is limited, which hampers their application. Synthetic exosome-mimics have been fabricated and investigated as a therapeutic tool for drug delivery. This review focuses on ESCRT-independent regulation of cargo loading into exosomes, including lipid raft and ceramide-mediated mechanisms, and reported exosomes or exosome-mimics with therapeutic effects.

Background: The propensity of the activated neutrophils to form extracellular traps (NETs) is demonstrated in multiple inflammatory conditions. In this study, we investigated the roles of NETs in metastasis of hepatocellular carcinoma (HCC) and further explored the underlying mechanism of how NETs affect metastasis as well as the therapeutic value. Methods: The neutrophils were isolated from the blood of human HCC patients and used to evaluate the formation of NETs. The expression of NET markers was detected in tumor specimens. A LPS-induced NET model was used to investigate the role of NETs on HCC metastasis. RNA-seq was performed to identify the key molecular event triggered by NETs, and their underlying mechanism and therapeutic significance were explored using both in vitro and in vivo assays.Results: NET formation was enhanced in neutrophils derived from HCC patients, especially those with metastatic HCCs. NETs trapped HCC cells and subsequently induced cell-death resistance and enhanced invasiveness to trigger their metastatic potential, which was mediated by internalization of NETs into trapped HCC cells and activation of Toll-like receptors TLR4/9-COX2 signaling. Inhibition of TLR4/9-COX2 signaling abrogated the NET-aroused metastatic potential. A combination of DNase 1 directly wrecking NETs with anti-inflammation drugs aspirin/hydroxychloroquine effectively reduced HCC metastasis in mice model. Conclusions:NETs trigger tumorous inflammatory response and fuel HCC metastasis. Targeting NETs rather than neutrophils themselves can be a practice strategy against HCC metastasis.

BaCKgRoUND aND aIMS:Recently, clinical trials of lenvatinib plus pembrolizumab in HCC have displayed an impressive objective response rate. This study aimed to clarify the mechanism for optimal patient selection.appRoaCH aND ReSUltS: First, in patients with HCC, lenvatinib-treated recurrent tumors had lower programmed death ligand 1 (PD-L1) expression and regulatory T cell (Treg) infiltration compared with matched primary tumors. Consistently, in C57BL/6 wild-type mice receiving antiprogrammed cell death 1 (PD-1) therapy, PD-L1 expression and Treg infiltration in s.c. tumors were reduced when adding lenvatinib to the scheme. Mechanistically, on the one hand, FGF receptor 4 (FGFR4) was the most pivotal target in PD-L1 down-regulation by lenvatinib in vitro. Furthermore, lenvatinib reinforced the proteasomal degradation of PD-L1 by blocking the FGFR4-glycogen synthase kinase 3β axis and rescued the sensitivity of interferonγ-pretreated HCC cells to T-cell killing by targeting FGFR4. On the other hand, the level of IL-2 increased after anti-PD-1 treatment, but IL-2-mediated Treg differentiation was blocked by lenvatinib through targeting FGFR4 to restrain signal transducer and activator of transcription 5 (STAT5) phosphorylation. By regulating the variations in the number of Tregs and the tumor FGFR4 level in C57BL/6-forkhead box protein P3 (Foxp3 DTR ) mice, we found that high levels of FGFR4 and Treg infiltration sensitized tumors to the combination treatment. Finally, high levels of FGFR4 and Foxp3 conferred immune tolerance but better response to the combined therapy in patient cohorts.CoNClUSIoNS: Lenvatinib reduced tumor PD-L1 level and Treg differentiation to improve anti-PD-1 efficacy by blocking FGFR4. Levels of FGFR4 expression and Treg infiltration in tumor could serve as biomarkers for screening patients with HCC using lenvatinib plus anti-PD-1 combination therapy. (Hepatology 2021;74:2544-2560). H CC, the major primary liver cancer, is the fourth most common cause of cancer-related deaths worldwide. (1) HCC is usually diagnosed in advanced stages, resulting in limited treatment options. (2) Recently, the clinical success of immune checkpoint blockade (ICB) has been encouraging for patients with cancer. ICB works primarily by targeting cytotoxic lymphocyte antigen 4, programmed cell death protein 1 (PD-1), or programmed death ligand 1 (PD-L1). Anti-PD-1, as the most promising immunotherapy strategy, has the potential to elicit durable control and even cure of some treatment-refractory cancers,