In hepatocellular carcinoma (HCC), the clinical significance of soluble immune checkpoint protein levels as predictors of patient outcomes or therapeutic responses has yet to be defined. This study profiled the baseline levels of sixteen soluble checkpoint proteins and their changes following sorafenib treatment for HCC. Plasma samples were obtained from 53 patients with advanced HCC at baseline, week 1, 2 and 4 of sorafenib treatment and tested the concentrations of 16 soluble checkpoint proteins using multiplexed fluorescent bead-based immunoassays. Multivariate analysis showed high sBTLA levels at baseline were an independent predictor of poor overall survival (p = 0.038). BTLA was highly expressed in T cells and macrophages in peritumoral areas. At week 2, sCD27 levels were decreased compared to baseline. By contrast, the concentrations of most inhibitory proteins, including sBTLA, sLAG-3, sCTLA-4, sPD-1, sCD80, sCD86 and sPD-L1, had significantly increased. The fold-changes of soluble checkpoint receptors and their ligands, including sCTLA-4 with sCD80/sCD86, sPD-1 with sPD-L1; and the foldchanges of sCTLA-4 with sBTLA or sPD-1 were positively correlated. sBTLA may be a good biomarker for predicting overall survival in HCC patients. Sorafenib treatment in patients with advanced HCC revealed dynamic changes of soluble checkpoint protein levels.

Immune checkpoint inhibitors, combined with anti-angiogenic agents or locoregional treatments (e.g., transarterial chemoembolization (TACE)), are expected to become standard-of-care for unresectable hepatocellular carcinoma (HCC). We measured the plasma levels of 16 soluble checkpoint proteins using multiplexed fluorescent bead-based immunoassays in patients with HCC who underwent lenvatinib (n = 24) or TACE (n = 22) treatment. In lenvatinib-treated patients, plasma levels of sCD27 (soluble cluster of differentiation 27) decreased (p = 0.040) and levels of sCD40 (p = 0.014) and sTIM-3 (p < 0.001) were increased at Week 1, while levels of sCD27 (p < 0.001) were increased significantly at Weeks 2 through 4. At Week 1 of TACE, in addition to sCD27 (p = 0.028), sCD40 (p < 0.001), and sTIM-3 (soluble T-cell immunoglobulin and mucin domain–3) (p < 0.001), levels of sHVEM (soluble herpesvirus entry mediator) (p = 0.003), sTLR-2 (soluble Toll-like receptor 2) (p = 0.009), sCD80 (p = 0.036), sCTLA-4 (soluble cytotoxic T-lymphocyte antigen 4) (p = 0.005), sGITR (soluble glucocorticoid-induced tumor necrosis factor receptor) (p = 0.030), sGITRL (soluble glucocorticoid-induced TNFR-related ligand) (p = 0.090), and sPD-L1 (soluble programmed death-ligand 1) (p = 0.070) also increased. The fold-changes in soluble checkpoint receptors and their ligands, including sCTLA-4 with sCD80/sCD86 and sPD-1 (soluble programmed cell death domain–1) with sPD-L1 were positively correlated in both the lenvatinib and TACE treatment groups. Our results suggest that there are some limited differences in immunomodulatory effects between anti-angiogenic agents and TACE. Further studies from multicenters may help to identify an effective combination therapy.

Background and Aims Antifibrotic therapy remains an unmet medical need in human chronic liver disease. We report the antifibrotic properties of cytoglobin (CYGB), a respiratory protein expressed in hepatic stellate cells (HSCs), the main cell type involved in liver fibrosis. Approach and Results Cygb‐deficient mice that had bile duct ligation–induced liver cholestasis or choline‐deficient amino acid–defined diet–induced steatohepatitis significantly exacerbated liver damage, fibrosis, and reactive oxygen species (ROS) formation. All of these manifestations were attenuated in Cygb‐overexpressing mice. We produced hexa histidine–tagged recombinant human CYGB (His‐CYGB), traced its biodistribution, and assessed its function in HSCs or in mice with advanced liver cirrhosis using thioacetamide (TAA) or 3,5‐diethoxycarbonyl‐1,4‐dihydrocollidine (DDC). In cultured HSCs, extracellular His‐CYGB was endocytosed and accumulated in endosomes through a clathrin‐mediated pathway. His‐CYGB significantly impeded ROS formation spontaneously or in the presence of ROS inducers in HSCs, thus leading to the attenuation of collagen type 1 alpha 1 production and α‐smooth muscle actin expression. Replacement the iron center of the heme group with cobalt nullified the effect of His‐CYGB. In addition, His‐CYGB induced interferon‐β secretion by HSCs that partly contributed to its antifibrotic function. Momelotinib incompletely reversed the effect of His‐CYGB. Intravenously injected His‐CYGB markedly suppressed liver inflammation, fibrosis, and oxidative cell damage in mice administered TAA or DDC mice without adverse effects. RNA‐sequencing analysis revealed the down‐regulation of inflammation‐ and fibrosis‐related genes and the up‐regulation of antioxidant genes in both cell culture and liver tissues. The injected His‐CYGB predominantly localized to HSCs but not to macrophages, suggesting specific targeting effects. His‐CYGB exhibited no toxicity in chimeric mice with humanized livers. Conclusions His‐CYGB could have antifibrotic clinical applications for human chronic liver diseases.

Intracellular gap (iGap) formation in liver sinusoidal endothelial cells (LSECs) is caused by the destruction of fenestrae and appears under pathological conditions; nevertheless, their role in metastasis of cancer cells to the liver remained unexplored. We elucidated that hepatotoxin-damaged and fibrotic livers gave rise to LSECs-iGap formation, which was positively correlated with increased numbers of metastatic liver foci after intrasplenic injection of Hepa1-6 cells. Hepa1-6 cells induced interleukin-23–dependent tumor necrosis factor–α (TNF-α) secretion by LSECs and triggered LSECs-iGap formation, toward which their processes protruded to transmigrate into the liver parenchyma. TNF-α triggered depolymerization of F-actin and induced matrix metalloproteinase 9 (MMP9), intracellular adhesion molecule 1, and CXCL expression in LSECs. Blocking MMP9 activity by doxycycline or an MMP2/9 inhibitor eliminated LSECs-iGap formation and attenuated liver metastasis of Hepa1-6 cells. Overall, this study revealed that cancer cells induced LSEC-iGap formation via proinflammatory paracrine mechanisms and proposed MMP9 as a favorable target for blocking cancer cell metastasis to the liver.

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