Intrahepatic IgA complex induces polarization of cancer-associated fibroblasts to matrix phenotypes in the tumor microenvironment of HCC.

BACKGROUND AND AIMS: Cancer-associated fibroblasts (CAFs) play key roles in the tumor microenvironment. IgA contributes to inflammation and dismantling antitumor immunity in the human liver. In this study, we aimed to elucidate the effects of the IgA complex on CAFs in Pil Soo Sung the tumor microenvironment of HCC. APPROACH AND RESULTS: CAF dynamics in HCC tumor microenvironment were analyzed through single-cell RNA sequencing of HCC samples. CAFs isolated from 50 HCC samples were treated with mock or serum-derived IgA dimers in vitro. Progression-free survival of patients with advanced HCC treated with atezolizumab and bevacizumab was significantly longer in those with low serum IgA levels ( p <0.05). Single-cell analysis showed that subcluster proportions in the CAF-fibroblast activation protein-α matrix were significantly increased in patients with high serum IgA levels. Flow cytometry revealed a significant increase in the mean fluorescence intensity of fibroblast activation protein in the CD68 + cells from patients with high serum IgA levels ( p <0.001). We confirmed CD71 (IgA receptor) expression in CAFs, and IgA-treated CAFs exhibited higher programmed death-ligand 1 expression levels than those in mock-treated CAFs ( p <0.05). Coculture with CAFs attenuated the cytotoxic function of activated CD8 + T cells. Interestingly, activated CD8 + T cells cocultured with IgA-treated CAFs exhibited increased programmed death-1 expression levels than those cocultured with mock-treated CAFs ( p <0.05). CONCLUSIONS: Intrahepatic IgA induced polarization of HCC-CAFs into more malignant matrix phenotypes and attenuates cytotoxic T-cell function. Our study highlighted their potential roles in tumor progression and immune suppression.

Blood-based biomarkers for immune-based therapy in advanced HCC: Promising but a long way to go.

The introduction of immune checkpoint inhibitors (ICIs) represents a key shift in the management strategy for patients with hepatocellular carcinoma (HCC). However, there is a paucity of predictive biomarkers that facilitate the identification of patients that would respond to ICI therapy. Although several researchers have attempted to resolve the issue, the data is insufficient to alter daily clinical practice. The use of minimally invasive procedures to obtain patient-derived specimen, such as using blood-based samples, is increasingly preferred. Circulating tumor DNA (ctDNA) can be isolated from the blood of cancer patients, and liquid biopsies can provide sufficient material to enable ongoing monitoring of HCC. This is particularly significant for patients for whom surgery is not indicated, including those with advanced HCC. In this review, we summarize the current state of understanding of blood-based biomarkers for ICI-based therapy in advanced HCC, which is promising despite there is still a long way to go.

Tenofovir alafenamide alleviates nonalcoholic steatohepatitis in mice by blocking the phosphorylation of AKT in intrahepatic mononuclear phagocytes.

BACKGROUND AND PURPOSE: Although the prevalence of nonalcoholic steatohepatitis (NASH) is rapidly increasing, effective therapy is lacking. Tenofovir alafenamide (TAF) is a widely used antiviral drug for hepatitis B. In this study, we investigated the potential pharmacological effects of TAF on NASH. EXPERIMENTAL APPROACH: Two different NASH mouse models were established: 1) by subcutaneous injection of streptozotocin (0.2 mg) and feeding the mice a high-fat, high-cholesterol (HFHC) diet, and 2) feeding the mice a choline-deficient, L-amino acid-defined, high-fat (CDAHF) diet. KEY RESULTS: Serum alanine aminotransferase and triglyceride levels in TAF-treated NASH mice were significantly lower than those in the mock-treated ones. The livers from the TAF-treated NASH mice showed attenuated mononuclear phagocyte (MP) infiltration compared to those from the mock-treated ones. TAF-treated NASH mice exhibited decreased liver infiltration of activated MPs (IAIE+/PD-L1+/MerTK+). In ex vivo experiments using sorted human CD14+ monocytes treated with lipopolysaccharide (LPS) and/or TAF, we confirmed the decreased level of phosphorylated AKT in TAF-treated LPS-stimulated monocytes compared to that in the mock-treated ones. Mouse liver immunoblotting showed that phosphorylation levels of AKT were significantly lower in the TAF-treated NASH group than in the mock-treated group. CONCLUSION AND IMPLICATIONS: TAF exerts anti-inflammatory effects in NASH livers by attenuating AKT phosphorylation in intrahepatic activated MPs. Therefore, TAF may serve as a new therapeutic option for NASH.

Enhanced Tumoricidal Immune Responses by Transarterial Chemotherapy Using Novel Nanocomplexes in a Rat Liver Cancer Model.

BACKGROUND/AIM: Locoregional treatments for hepatocellular carcinoma (HCC) induce immunogenic cell death and a tumor-specific immune response, but infiltration and activation of immune cells in the liver have not been clearly described. Transarterial chemoembolization (TACE) or transarterial chemotherapy (TAC) without embolization have been used to treat intermediate or advanced stage HCC patients. The identification of intrahepatic immune cell changes after locoregional therapy provides a theoretical basis for the combination with immune checkpoint inhibitors (ICIs) in HCC. This study aimed to determine the anticancer effect and changes in the liver immune cell population and function after direct injection of polymerized phenylboronic acid-conjugated doxorubicin (pPBA-Dox) nanocomplexes into the liver through TAC. MATERIALS AND METHODS: pPBA-Dox nanocomplexes were delivered directly to the liver cancer in a rat model by transarterial methods. Anticancer effect was confirmed by magnetic resonance imaging (MRI), and the immune cell population and functional changes were confirmed by flow cytometry (FACS). RESULTS: We first established a rat liver cancer model by implanting McA-RH7777 into rats and confirmed the formation of liver cancer through MRI, pathological examinations, and biochemical tests. Transarterial injection of pPBA-Dox nanocomplexes had a stronger anticancer effect than conventional Dox alone. Higher numbers of CD8+ and CD4+ T cells with activated phenotypes were infiltrated into the tumor microenvironment after transarterial pPBA-Dox treatments than after Dox alone treatment, suggesting the induction of stronger local immune responses by pPBA-Dox than Dox alone. CONCLUSION: This study provides a theoretical basis for TAC combined with ICIs and insight into novel targeted therapies using nanocomplexes for the treatment of HCC.

Intrahepatic inflammatory IgA+PD-L1high monocytes in hepatocellular carcinoma development and immunotherapy.

BACKGROUND: IgA neutralizes pathogens to prevent infection at mucosal sites. However, emerging evidence shows that IgA contributes to aggravating inflammation or dismantling antitumor immunity in human diseased liver. The aim of this study was to elucidate the roles of inflammation-induced intrahepatic inflammatory IgA+ monocytes in the development of hepatocellular carcinoma (HCC). METHODS: Patient cohorts including steatohepatitis cohort (n=61) and HCC cohort (n=271) were established. Patients' surgical and biopsy specimens were analyzed using immunohistochemistry. Multicolor flow cytometry was performed with a subset of patient samples. Single-cell RNA-Seq analysis was performed using Gene Expression Omnibus (GEO) datasets. Additionally, we performed in vitro differentiation of macrophages, stimulation with coated IgA, and RNA sequencing. Hepa1-6 cells and C57BL/6N mice were used to obtain HCC syngeneic mouse models. RESULTS: Serum IgA levels were associated (p<0.001) with fibrosis progression and HCC development in patients with chronic liver diseases. Additionally, immunohistochemical staining of inflamed livers or HCC revealed IgA positivity in monocytes, with a correlation between IgA+ cell frequency and IgA serum levels. Compared with IgA- monocytes, intrahepatic IgA+ monocytes expressed higher levels of programmed death-ligand 1 (PD-L1) in inflamed livers and in HCC tumor microenvironment. Single-cell RNA sequencing using NCBI GEO database indicated an upregulation in inflammation-associated genes in the monocytes of patients whose plasma cell IGHA1 expression was greater than or equal to the median value. Bulk RNA sequencing demonstrated that in vitro stimulation of M2-polarized macrophages using coated IgA complex induced PD-L1 upregulation via YAP-mediated signaling. In vivo blockade of IgA signaling decreased the number of tumor-infiltrating IgA+PD-L1high macrophages and increased the number of CD69+CD8+ T cells to enhance antitumor effects in HCC mice models. CONCLUSIONS: Overall, the findings of this study showed that serum IgA levels was correlated with intrahepatic and intratumoral infiltration of inflammatory IgA+PD-L1high monocytes in chronic liver diseases and HCC, providing potential therapeutic targets.

Death-Associated Protein 6 (Daxx) Alleviates Liver Fibrosis by Modulating Smad2 Acetylation.

Transforming growth factor-ß (TGF-ß) has been identified as an inducer of hepatocyte epithelial-mesenchymal transition (EMT), which triggers liver fibrosis. Death-associated protein 6 (Daxx) is known to be associated with the TGF-ß-induced apoptotic pathway, but the function of Daxx in liver fibrosis remains unknown. This study aimed to elucidate the role of Daxx in liver fibrosis. We used liver fibrosis tissues from humans and mice to assess Daxx expression. EMT properties and TGF-ß signaling pathway activation were investigated in the Daxx-overexpressing FL83B cell line. The therapeutic effect of Daxx was investigated in a mouse model of liver fibrosis by the hydrodynamic injection of plasmids. The expression of Daxx was markedly decreased in hepatocytes from fibrotic human and mouse livers, as well as in hepatocytes treated with TGF-ß in vitro. The overexpression of Daxx inhibited the EMT process by interfering with the TGF-ß-induced phosphorylation of Smad2. Coimmunoprecipitation analysis confirmed that Daxx reduced the transcriptional activity of Smad2 by binding to its MH1 domain and interfering with Smad2 acetylation. In addition, the therapeutic delivery of Daxx alleviated liver fibrosis in a thioacetamide-induced fibrosis mouse model. Overall, our results indicate that Daxx could be a potential therapeutic target to modulate fibrogenesis, as well as a useful biomarker for liver fibrosis.