Tumor-infiltrating lymphocytes and hepatocellular carcinoma: pathology and clinical management

Harnessing immunotherapy for hepatocellular carcinoma: Principles and emerging promises

HCC is considered as one of the leadin causes of death worldwide, with the ability of resistance towards therapeutics. Immunotherapy, particularly ICIs, have provided siginficant insights towards harnessing the immune system. The present review introduces the concepts and possibilities of immunotherapy for HCC treatment, emphasizing its underlying mechanisms and capacity to enhance patient results, focusing on both pre-clinical and clinical insights. The functions of TME and immune evasion mechanisms typical of HCC would be evaluated along with how contemporary immunotherapeutic approaches are designed to address these challenges. Furthermore, the clinical application of immunotherapy in HCC is discussed, emphasizing recent trial findings demonstrating the effectiveness and safety of drugs. In addition, the problems caused by immune evasion and resistance would be discussed to increase potential of immunotherapy along with combination therapy.

T lymphocyte-based immune response and therapy in hepatocellular carcinoma: focus on TILs and CAR-T cells

Hepatocellular carcinoma (HCC) is among the leading causes of cancer-related death worldwide. The primary therapies for HCC are liver transplantation, hepatic tumor excision, radiofrequency ablation, and molecular-targeted medicines. An unfavorable prognosis marks HCC and has limited pharmacological response in therapeutic studies. The tumor immune microenvironment (TME) imposes significant selection pressure on HCC, resulting in its evolution and recurrence after various treatments. As the principal cellular constituents of tumor-infiltrating lymphocytes (TILs), T cells have shown both anti-tumor and protumor actions in HCC. T cell-mediated immune responses are pivotal in cancer monitoring and elimination. TILs are recognized for their critical involvement in the progression, prognosis, and immunotherapeutic management of HCC. Foxp3 + , CD8 + , CD3 + , and CD4 + T cells are the extensively researched subtypes of TILs. This article examines the functions and processes of several subtypes of TILs in HCC. Emerging T cell-based therapies, including TILs and chimeric antigen receptor (CAR)-T cell therapy, have shown tumor regression in several clinical and preclinical studies. Herein, it also delves into the existing T cell-based immunotherapies in HCC, with emphasis on TILs and CAR-T cells.

Spatial heterogeneity of the hepatocellular carcinoma microenvironment determines the efficacy of immunotherapy

Hepatocellular carcinoma (HCC) remains a global health challenge owing to its widespread incidence and high mortality. HCC has a specific immune tolerance function because of its unique physiological structure, which limits the efficacy of chemotherapy, radiotherapy, and molecular targeting. In recent years, new immune approaches, including adoptive cell therapy, tumor vaccines, and oncolytic virus therapy, have shown great potential. As the efficacy of immunotherapy mainly depends on the spatial heterogeneity of the tumor immune microenvironment, it is necessary to elucidate the crosstalk between the composition of the liver cancer immune environment, from which potential therapeutic targets can be selected to provide more appropriate individualized treatment programs. The role of spatial heterogeneity of immune cells in the microenvironment of HCC in the progression and influence of immunotherapy on improving the treatment and prognosis of HCC were comprehensively analyzed, providing new inspiration for the subsequent clinical treatment of liver cancer.

Characterization of lymphocyte-rich hepatocellular carcinoma and the prognostic role of tertiary lymphoid structures

BACKGROUND & AIMS

Lymphocyte-rich hepatocellular carcinoma (LR-HCC) is largely unknown and a rare subtype of HCC with immune-rich stroma. Tertiary lymphoid structures (TLS), frequently observed in LR-HCC, are known to be prognostically significant in various malignancies; however, their significance in HCC remains unevaluated.

METHODS

Clinicopathologic data of 191 cases of surgically resected conventional HCC (C-HCC, n = 160) and LR-HCC (n = 31) were retrieved. Immunohistochemistry, multiplex immunofluorescence staining, RNA sequencing and proteomic analysis were conducted. Differences between the subtypes were statistically evaluated.

RESULTS

LR-HCC was significantly correlated to larger tumour size, higher Edmondson-Steiner grade, presence of TLS and higher CD3-, CD8- and FOXP3-positive T cell, high PD-1 and PD-L1 expression (p < .001 for all) compared to C-HCC. Patients with LR-HCC exhibited significantly better overall survival (OS) (p = .044) and recurrence-free survival (RFS) (p = .025) than C-HCC. LR-HCC demonstrated TLS signatures with significantly higher proteomic-based immune scores in 14 of 17 types of tumour-infiltrating immune cells. Furthermore, C-HCC with secondary follicles, the most mature form of TLS, exhibited significantly better OS (p = .031) and RFS (p = .033) than those without. Across the global proteome, LR-HCC was well-differentiated from C-HCC and a map of protein-protein interactions between tumour-infiltrating lymphocytes and HCC in tumour microenvironment was completed.

CONCLUSION

LR-HCC is clinicopathologically and molecularly distinct and shows better prognosis compared to C-HCC. Also, the presence of secondary follicle can be an important prognostic marker for better prognosis in both LR-HCC and C-HCC.

Comprehensive characterization of Fidgetin on tumor immune microenvironment evaluation and immunotherapy in human hepatocellular carcinoma

Most cancers have a downregulation of Fidgetin (FIGN), which has been linked to tumor growth. However, there aren't many papers that mention FIGN's connection to hepatocellular carcinoma (HCC). Here, FIGN expression in HCC tissues was markedly reduced as compared to nearby normal liver tissues. According to univariate and multivariate Cox regression, it served as an independent predictor of survival outcomes. Patients with high levels of FIGN expression had a worse outcome. FIGN was shown to be engaged in immune-related pathways and to have a positive correlation with immunological score and immune cells according to KEGG pathway analysis. In HCC patients, FIGN was substantially linked with immunological checkpoints and the hot tumor state. Additionally, immunotherapy and chemotherapy showed a significant therapeutic response in HCC patients with low FIGN expression. This research revealed that FIGN expression was tightly related to hepatoma immunity and might be employed as a biomarker to predict patient prognosis and guide medication.

Identification of immune cell-related prognostic genes characterized by a distinct microenvironment in hepatocellular carcinoma

BACKGROUND

The development and progression of hepatocellular carcinoma (HCC) have been reported to be associated with immune-related genes and the tumor microenvironment. Nevertheless, there are not enough prognostic biomarkers and models available for clinical use. Based on seven prognostic genes, this study calculated overall survival in patients with HCC using a prognostic survival model and revealed the immune status of the tumor microenvironment (TME).

AIM

To develop a novel immune cell-related prognostic model of HCC and depict the basic profile of the immune response in HCC.

METHODS

We obtained clinical information and gene expression data of HCC from The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) datasets. TCGA and ICGC datasets were used for screening prognostic genes along with developing and validating a seven-gene prognostic survival model by weighted gene coexpression network analysis and least absolute shrinkage and selection operator regression with Cox regression. The relative analysis of tumor mutation burden (TMB), TME cell infiltration, immune checkpoints, immune therapy, and functional pathways was also performed based on prognostic genes.

RESULTS

Seven prognostic genes were identified for signature construction. Survival receiver operating characteristic curve analysis showed the good performance of survival prediction. TMB could be regarded as an independent factor in HCC survival prediction. There was a significant difference in stromal score, immune score, and estimate score between the high-risk and low-risk groups stratified based on the risk score derived from the seven-gene prognostic model. Several immune checkpoints, including VTCN1 and TNFSF9, were found to be associated with the seven prognostic genes and risk score. Different combinations of checkpoint blockade targeting inhibitory CTLA4 and PD1 receptors and potential chemotherapy drugs hold great promise for specific HCC therapies. Potential pathways, such as cell cycle regulation and metabolism of some amino acids, were also identified and analyzed.

CONCLUSION

The novel seven-gene (CYTH3, ENG, HTRA3, PDZD4, SAMD14, PGF, and PLN) prognostic model showed high predictive efficiency. The TMB analysis based on the seven genes could depict the basic profile of the immune response in HCC, which might be worthy of clinical application.

Clinical impact of sarcopenia in early-stage intrahepatic recurrent hepatocellular carcinoma: an association with impaired host immunity

PURPOSE

This study investigated the role of sarcopenia in the long-term outcomes of patients with early-stage intrahepatic recurrent hepatocellular carcinoma (HCC).

METHODS

The study included 136 patients with intrahepatic recurrent Barcelona Clinic Liver Cancer (BCLC) stage 0/A HCC following liver resection diagnosed between 2006 and 2020 and underwent surgery, radiofrequency ablation (RFA), or transcatheter arterial chemoembolization (TACE). Sarcopenia was defined based on the skeletal muscle index using computed tomography at the time of recurrence, and its association with long-term outcomes was evaluated. Tumor-infiltrating lymphocytes (CD4 + , CD8 + , and CD45RO + T cells) were assayed using immunohistochemistry on specimens obtained from repeat hepatectomies, and their association with sarcopenia was evaluated.

RESULTS

The overall survival (OS) and recurrence-free survival (RFS) rates after initial recurrence of patients with sarcopenia were significantly lower than those without sarcopenia (p < 0.001 and p < 0.001, respectively). Multivariate analysis identified sarcopenia as an independent prognostic factor for RFS (p < 0.001). In patients without sarcopenia, surgery resulted in better RFS than RFA or TACE. Contrastingly, in patients with sarcopenia, the RFS was extremely poor regardless of the treatment type: surgery, RFA, or TACE (median RFS, 11.7, 12.7, and 10.1 months). Significantly low levels of tumor-infiltrating CD4 + , CD8 + , and CD45RO + lymphocytes were observed in patients with sarcopenia (p = 0.001, p = 0.001, and p = 0.001, respectively).

CONCLUSIONS

This study suggests that patients with sarcopenia have poor RFS regardless of the treatment type for early-stage intrahepatic recurrent HCC. Impaired host immunity might be one of the underlying mechanisms.

Detection of fibrotic changes in the progression of liver diseases by label-free multiphoton imaging

Collagen fibers play an important role in the progression of liver diseases. The formation and progression of liver fibrosis is a dynamic pathological process accompanied by morphological changes in collagen fibers. In this study, we used multiphoton microscopy for label-free imaging of liver tissues, allowing direct detection of various components including collagen fibers, tumors, blood vessels, and lymphocytes. Then, we developed a deep learning classification model to automatically identify tumor regions, and the accuracy reaches 0.998. We introduced an automated image processing method to extract eight collagen morphological features from various stages of liver diseases. Statistical analysis showed significant differences between them, indicating the potential use of these quantitative features for monitoring fibrotic changes during the progression of liver diseases. Therefore, multiphoton imaging combined with automatic image processing method would hold a promising future in rapid and label-free diagnosis of liver diseases.

Immune-Based Combination Therapies for Advanced Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the fourth most frequent cause of cancer-related death worldwide. HCC frequently presents as advanced disease at diagnosis, and disease relapse following radical surgery is frequent. In recent years, immune checkpoint inhibitors (ICIs) have revolutionized the treatment of advanced HCC, particularly with the introduction of atezolizumab/bevacizumab as the new standard of care for first-line treatment. Recently, dual immune checkpoint blockade with durvalumab plus tremelimumab has also emerged as an effective first-line treatment for advanced HCC and most of the research is currently focused on developing combination treatments based mainly on ICIs. In this review, we will discuss the rationale and ongoing clinical trials of immune-based combination therapies for the treatment of advanced HCC, also focusing on new immunotherapy strategies such as chimeric antigen receptor T cells (CAR-T) and anti-cancer vaccines.

Lymphopenia predicts reduced survival in canine hepatocellular carcinoma

Platelet to lymphocyte ratio (PLR) is a prognostic marker in human hepatocellular carcinoma (HCC) however, its utility in canine HCC has not been explored. The aim of the study was to determine if PLR could predict survival outcomes in 42 dogs with HCC. PLR was not a significant predictive factor (p = 0.15) but lymphopenia alone was significantly correlated with a reduced probability of survival (p = 0.024). Further studies are needed to evaluate if peripheral lymphocyte count mirrors that of the tumor microenvironment in canine HCC.

Tumor cell density dependent IL-8 secretion induces the fluctuation of tregs/CD8 + T cells infiltration in hepatocellular carcinoma: one prompt for the existence of density checkpoint

BACKGROUND

Tumor cell density is a basic pathological feature of solid tumors. Chemotherapy, radiotherapy, and targeted therapy reduce tumor cell density, whereas unrestricted tumor cell proliferation promotes this feature. The impact of tumor cells on the microenvironment following changes in tumor cell density is still unclear. In this study, we focused on the response of key immune cell subsets to tumor cell density in hepatocellular carcinoma (HCC).

METHODS

We determined the density of tumor and immune cells in the same area by section staining. We then identified potential mediators using polymerase chain reaction (PCR), enzyme-linked immunofluorescence assay (ELISA), 3D and co-culture, flow cytometry, and lentivirus intervention. The mechanism of lactate promotion was verified using lactate tests, bioinformatics, western blotting, and the above methods. The IL-8/DAPK1/lactate/regulatory T cell (Treg) axis was verified using a mouse liver cancer model. Tumor mutation burden was calculated using maftools in R.

RESULTS

We found that the Treg/CD8 + T cell ratio is not consistent with tumor cell density in HCC, and a decreased Treg/CD8 + T cell ratio in the range of 5000-6000 cells/mm² may elicit the possibility for immunotherapy in an immunosuppressive microenvironment. We showed that IL-8 mediates this immune fluctuation and promotes the infiltration of Tregs through the DAPK1/pyruvate kinase activity/lactate axis in HCC. Based on tumor ploidy and mutation burden data, we discussed the potential significance of immune fluctuation in the homeostasis of HCC mutation burden and proposed a "density checkpoint" and "entropy model" to describe this phenomenon.

CONCLUSIONS

In summary, we report the mode of infiltration of Tregs/CD8 + T cells in response to tumor cell density and provide a new theoretical basis for IL-8 as a therapeutic target and the selection of an immunotherapy window in HCC.

Anti-neoplastic sulfonamides alter the metabolic homeostasis and disrupt the suppressor activity of regulatory T cells

Regulatory T cells (Tregs) are essential to maintain self-tolerance and immune homeostasis but, as components of the tumor microenvironment (TME), are also a major barrier to effective cancer immunosurveillance and immunotherapy. FH535 and its derivative Y3 are two N-aryl-benzene-sulfonamides (NABs) that inhibit HCC cell proliferation and tumor progression. However, the impact of NABs on the immune cells in the TME is not yet known. Analyses of explanted livers from patients with hepatocellular carcinoma (HCC) showed that high levels of tumor-infiltrating Tregs were associated with poor tumor differentiation. These results lead us to investigate the immunomodulatory effects of NABs in regulatory and effector T cells. Exposure of primary human Tregs to NABs induced a rapid but temporary increase of cell expansion, a gradual disruption of suppressor activity, and concomitant bioenergetics and autophagic flux dysregulations. In contrast to Tregs, no gross effects were observed in effector T cells. Addition of Rapamycin prevented the functional decay of Tregs and restored their metabolic profile, suggesting that NAB effects require the integrity of the mTOR pathway. This study revealed the immunomodulatory properties of NABs with a preferential impact on Treg activity and provided novel insights into the anti-tumor potential of sulfonamides.

The role of peritumoral CD8 + /TIA1 + lymphocytes in hepatocellular carcinoma aggressiveness and recurrence after surgical resection

Hepatocellular carcinoma (HCC) is characterized by a low mutation burden and a relatively low number of tumor-infiltrating lymphocytes (TILs), making still difficult to identify targets for specific therapies. The aim of this study was the identification of the prognostic role of TILs in HCC, focusing on their distribution and status of activation. We retrospectively enrolled 41 patients, undergone to liver resection for HCC. A significant increase of CD8 + intratumoral lymphocytes was observed in HCCs with prevalent solid architecture, but with a higher PD-1/TIA1 ratio, suggesting that HCCs with solid architecture have more peri-tumoral lymphocytes, but with minor functionality. At multivariate and univariate analyses, TIA1/CD8 ratio correlated with tumor recurrence, meaning that HCC with more activated TILs are characterized by a higher tumor aggressiveness. The use of a feasible and cheap immunohistochemical panel can help in post-surgical prognostic stratification, focusing not only in the raw number and density of TILs, but more on their state of activation and morphology.

The combination of PD-1 blockade with interferon-α has a synergistic effect on hepatocellular carcinoma

BACKGROUND

The efficacy of immune checkpoint inhibitors (ICIs), such as programmed cell death protein-1 (PD-1) or its ligand 1 (PD-L1) antibody, in hepatocellular carcinoma (HCC) is limited, and it is recommended that they be combined with other therapies. We evaluated the combination of pegylated interferon-α (Peg-IFNα) with PD-1 blockade in HCC mouse models.

METHODS

We analyzed the effects of Peg-IFNα on tumor-infiltrating immune cells and PD-1 expression in the HCC immune microenvironment and examined the underlying mechanism of its unique effect on the PD-1 pathway. The in vivo efficacy of anti-PD-1 and Peg-IFNα was evaluated in both subcutaneous and orthotopic mouse models of HCC.

RESULTS

The combination of Peg-IFNα with PD-1 blockade dramatically enhanced T-cell infiltration, improved the efficacy of PD-1 antibody and prolonged mouse survival compared with PD-1 antibody monotherapy. Mechanistically, Peg-IFNα could recruit cytotoxic CD8+ T cells to infiltrate the HCC microenvironment by inducing tumor cells to secrete the chemokine CCL4. Nevertheless, the HCC microenvironment quickly overcame the immune responses by upregulating PD-1 expression in CD8+ T cells via the IFNα-IFNAR1-JAK1-STAT3 signaling pathway. The combination of PD-1 blockade with Peg-IFNα could restore the cytotoxic capacity of CD8+ T cells and exerted a significant synergistic effect on HCC.

CONCLUSION

These results indicate that in addition to initiating the antitumor immune response itself, Peg-IFNα can also generate a microenvironment favoring PD-1 blockade. Thus, the combination of Peg-IFNα and PD-1 blockade can be a promising strategy for HCC.

A simple CD4+ T cells to FIB-4 ratio for evaluating prognosis of BCLC-B hepatocellular carcinoma: a retrospective cohort study

Introduction

Immunotherapy has become a new therapy for advanced hepatocellular carcinoma (HCC); however, its treatment results are considerably different. CD4+ T cells (CD4+) are the key to immunotherapy, but patients with HCC that have low CD4+ are rarely observed for clinical evidence. Hepatitis B virus-related HCC is often accompanied by cirrhosis and portal hypertension; therefore, CD4+ tend to be relatively low in number. TACE is the standard treatment for Barcelona Clinic Liver Cancer (BCLC)-B HCC, which may further reduce the number of CD4 + .

Methods

This retrospective cohort study further reduced CD4+ by including patients with human immunodeficiency virus (HIV) to observe the relationship between CD4+ and Chronic hepatitis B virus (CHB) induced HCC. A total of 170 BCLC-B HCC patients (42 HIV+) were included. Univariate and multivariate analyses, and artificial neural networks (ANNs) were used to evaluate the independent risk factors for the two-year survival.

Results

The statistical analysis of the two-year survival rate showed that the main factors influencing survival were liver function and immune indices, including CD4+, platelet, alanine aminotransferase, aspartate aminotransferase, aspartate aminotransferase-to-platelet ratio index, and fibrosis-4 (FIB-4) (P < 0.05). Compared with that in other indices, in logistic and ANN multivariate analysis, CD4 + -to-FIB-4 ratio (CD4+/FIB-4) had the highest importance with 0.716 C-statistic and 145.93 cut-off value. In terms of overall survival rate, HIV infection was not a risk factor (P = 0.589); however, CD4+/FIB-4 ≤ 145.93 significantly affected patient prognosis (P = 0.002).

Conclusion

HIV infection does not affect the prognosis of BCLC-B HCC, but CD4+ have a significant predictive value. CD4+ played a vital role in HCC and this deserves the attention from physicians. Further, the CD4+/FIB-4 is a clinically valuable effective prognostic indicator for these patients.

Radiation Therapy Promotes Hepatocellular Carcinoma Immune Cloaking via PD-L1 Upregulation Induced by cGAS-STING Activation

PURPOSE

Radiation therapy (RT) is one of the main treatments for patients with unresectable hepatocellular carcinoma (HCC). Emerging evidence indicates that the cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS) stimulator of interferon gene (STING) pathway is crucial in RT-induced antitumor immune responses. Here, we discovered that activation of the cancer cell-intrinsic cGAS-STING pathway mediated immune cloaking after RT-induced DNA damage.

METHODS AND MATERIALS

Key regulatory proteins in the cGAS-STING signaling pathway in human and murine HCC cell lines were knocked out or down using CRISPR and CRISPR-associated protein 9 or small interfering RNA. The underlying mechanism of immune cloaking and clinical significance of cGAS-STING-induced programmed cell death ligand 1 (PD-L1) expression were studied with both ex vivo analyses and in vitro experiments.

RESULTS

RT upregulated PD-L1 in patients with HCC, which correlated with poor survival. RT activated cGAS-STING, increasing immune-checkpoint PD-L1 expression in human and mouse liver cancer cells. Ionizing radiation activated the STING-TANK-binding kinase 1 (TBK1)-interferon regulatory factor 3 (IRF3) innate immune pathway, leading to PD-L1 upregulation in HCC cells and inhibiting cytotoxic T-lymphocyte activity and protecting tumor cells from immune-mediated eradication. Knockdown of cGAS, STING, TBK1, and IRF3 reversed the antitumor effect of cytotoxic T-lymphocyte-mediated cytotoxicity after ionizing radiation in vitro or in vivo. RT potentiated the antitumor effect of programmed cell death protein 1 and PD-L1 axis blockade and augmented cytotoxic T-cell (CTL) infiltration in HCC tumors in immunocompetent mice. CD8 depletion compromised the synergetic antitumor effect of combined RT and anti-PD-L1 blockade, demonstrating that CD8⁺ CTLs are required for antitumor immunity induced by combination therapy.

CONCLUSIONS

Our results identified an immune-cloaking mechanism for RT-activated, innate immune cGAS-STING and suggested that RT enhances HCC immunotherapy.

Changes in immune profile affect disease progression in hepatocellular carcinoma

Objective: Hepatocellular carcinoma (HCC) as a chronic liver condition is largely associated with immune responses. Previous studies have revealed that different subsets of lymphocytes play fundamental roles in controlling or improving the development and outcome of solid tumors like HCC. Hence, this study aimed to investigate whether immune system changes were related to disease development in HCC patients. Methods: Peripheral blood mononuclear cells were isolated from 30 HCC patients and 30 healthy volunteers using Ficoll density centrifugation. The isolated cells were stained with different primary antibodies and percentages of different immune cells were determined by flow cytometry. Results: HCC patients indicated significant reductions in the numbers of CD4⁺ cells, Tbet+IFNγ+cells, and GATA+IL-4+cells in peripheral blood in comparison with healthy individuals (p < 0.05). There was no significant change in IL-17+RORγt+cells between patient and healthy groups. In contrast, Foxp3+CD127^lowcell frequency was significantly higher in patients than healthy subjects (p < 0.0001). The numbers of Th1, Th2, and Th17 cells were significantly lower in HCC patients than healthy control (p < 0.0001), although the reduction in Th2 cell numbers was not statistically significant. On the contrary, Treg percentage showed a significant increase in patients compared to healthy subjects (p < 0.0001). Other data revealed that Th1, Th2, and Th17 cell frequencies were significantly higher in healthy individuals than patients with different TNM stages of HCC, with the exception of Th2 in patients with stage II HCC (p < 0.01-0.05). Treg percentage was significantly increased in patients with different TNM stages (p < 0.0001). Among all CD4⁺ T cells, the frequency of Th2 cell was significantly associated with TNM stages of HCC (p < 0.05). Conclusion: Our data provide further evidence to show that immune changes may participate in determining HCC progression and disease outcome. However, it should be mentioned that more investigations are needed to clarify our results and explain possible impacts of other immune cells on the pathogenesis of HCC.

Progression on the Roles and Mechanisms of Tumor-Infiltrating T Lymphocytes in Patients With Hepatocellular Carcinoma

Primary liver cancer (PLC) is one of the most common malignancies in China, where it ranks second in mortality and fifth in morbidity. Currently, liver transplantation, hepatic tumor resection, radiofrequency ablation, and molecular-targeted agents are the major treatments for hepatocellular carcinoma (HCC). Overall, HCC has a poor survival rate and a high recurrence rate. Tumor-infiltrating lymphocytes (TILs) have been discovered to play essential roles in the development, prognosis, and immunotherapy treatment of HCC. As the major component cells of TILs, T cells are also proved to show antitumor and protumor effects in HCC. Foxp3+, CD8+, CD3+, and CD4+ T lymphocytes are the broadly studied subgroups of TILs. This article reviews the roles and mechanisms of different tumor-infiltrating T lymphocyte subtypes in HCC.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Immunotherapy of hepatocellular carcinoma: Unique challenges and clinical opportunities

Current therapies for advanced hepatocellular carcinoma (HCC) are marginally effective and exacerbate underlying liver disease. The ability of immunotherapy to elicit nontoxic, systemic, long-lived anti-tumor activity makes it particularly well-suited for use in the setting of HCC. While therapeutic benefit has been achieved in early clinical trials, the efficacy of immune-based therapies is limited by several unique properties of HCC, most notably the inherently tolerogenic character of the liver in both healthy and diseased (chronically-infected or tumor-bearing) states. Therapeutic regimens that both counteract these immunosuppressive mechanisms and amplify tumor-specific immunity are expected to profoundly improve clinical outcomes for HCC patients.

Identification of immune landscape signatures associated with clinical and prognostic features of hepatocellular carcinoma

While cancer immunotherapy has been remarkably successful in some malignancies, some cancers derive limited benefit from current immunotherapies. Here, we combined immune landscape signatures with hepatocellular carcinoma clinical and prognostic features to classify them into distinct subtypes. The immunogenomic profiles, stromal cell features and immune cell composition of the subtypes were then systematically analyzed. Two independent prognostic indexes were established based on 6 immune-related genes and 17 differentially expressed genes associated with stromal cell content. These indexes were significantly correlated with tumor mutation burden, deficient DNA mismatch repair and microsatellite instability. In addition, tumor-infiltrating lymphocytes, including activated NK cells, resting memory CD4 T-cells, eosinophils, and activated mast cells were significantly correlated with hepatocellular carcinoma survival. In conclusion, we have comprehensively described the immune landscape signatures and identified prognostic immune-associated biomarkers of hepatocellular carcinoma. Our findings highlight potential novel avenues for improving responses to immunotherapy.

Immunotherapy for advanced hepatocellular carcinoma, where are we?

A couple of molecular-targeting medications, such as Lenvatinib, are available for the treatment of hepatocellular carcinoma (HCC) in addition to Sorafenib in an advanced stage. Approval for the use of immune check-point inhibitors, such as Nivolumab and Pembrolizumab has shifted the paradigm of current HCC treatment, and the monotherapy or in combination with Lenvatinib or Sorafenib has significantly extended overall survival or progression-free survival in a large portion of patients. A combination of programmed cell death ligand-1 (PD-L1) inhibitor Atezolizumab with a vascular endothelial growth factor (VEGF) inhibitor, Bevacizumab, has recently achieved promising outcome in unresectable HCC patients. Other immunotherapy, such as chimeric antigen receptor T (CAR-T) cell therapy has achieved an evolutional success in hematologic malignancies, and has extended its use in deadly solid tumors, such as HCC. Although there exist various barriers, novel approaches are developed to move potential adoptive T cell therapy strategies, including cytokine-induced killer (CIK) cells, tumor-infiltrating lymphocytes (TIL), T cell receptor (TCR) T cells, CAR-T cells, to clinical application.

Hepatocellular Carcinoma-The Influence of Immunoanatomy and the Role of Immunotherapy

Hepatocellular carcinoma (HCC) is a leading cause of cancer-related morbidity and mortality worldwide. Most patients are diagnosed with advanced disease, limiting their options for treatment. While current treatments are adequate for lower staged disease, available systemic treatments are limited, with marginal benefit at best. Chimeric antigen receptor (CAR) T cell therapy, effective in treating liquid tumors such as B-cell lymphoma, presents a potentially promising treatment option for advanced HCC. However, new challenges specific to solid tumors, such as tumor immunoanatomy or the immune cell presence and position anatomically and the tumor microenvironment, need to be defined and overcome. Immunotherapy currently in use must be re-engineered and re-envisioned to treat HCC with the hopes of ushering in an answer to advanced stage solid tumor disease processes. Future therapy options must address the uniqueness of the tumors under the umbrella of HCC. This review strives to summarize HCC, its staging system, current therapy and immunotherapy medications currently being utilized or studied in the treatment of HCC with the hopes of highlighting what is being done and suggesting what needs to be done in the future to champion this therapy as an effective option.

Chronic Viral Liver Diseases: Approaching the Liver Using T Cell Receptor-Mediated Gene Technologies

Chronic infection with viral hepatitis is a major risk factor for liver injury and hepatocellular carcinoma (HCC). One major contributing factor to the chronicity is the dysfunction of virus-specific T cell immunity. T cells engineered to express virus-specific T cell receptors (TCRs) may be a therapeutic option to improve host antiviral responses and have demonstrated clinical success against virus-associated tumours. This review aims to give an overview of TCRs identified from viral hepatitis research and discuss how translational lessons learned from cancer immunotherapy can be applied to the field. TCR isolation pipelines, liver homing signals, cell type options, as well as safety considerations will be discussed herein.

Emerging role of Immune Checkpoint Inhibitors in Hepatocellular Carcinoma

Hepatocellular carcinoma is the most common primary liver cancer and the fourth leading cause of cancer death worldwide. A total of 70–80% of patients are diagnosed at an advanced stage with a dismal prognosis. Sorafenib had been the standard care for almost a decade until 2018 when the Food and Drug Administration approved an alternative first-line agent namely lenvatinib. Cabozantinib, regorafenib, and ramucirumab also displayed promising results in second line settings. FOLFOX4, however, results in an alternative first-line treatment for the Chinese clinical oncology guidelines. Moreover, nivolumab and pembrolizumab, two therapeutics against the Programmed death (PD)-ligand 1 (PD-L1)/PD1 axis have been recently approved for subsequent-line therapy. However, similar to other solid tumors, the response rate of single agent targeting PD-L1/PD1 axis is low. Therefore, a lot of combinatory approaches are under investigation, including the combination of different immune checkpoint inhibitors (ICIs), the addition of ICIs after resection or during loco-regional therapy, ICIs in addition to kinase inhibitors, anti-angiogenic therapeutics, and others. This review focuses on the use of ICIs for the hepatocellular carcinoma with a careful assessment of new ICIs-based combinatory approaches.

MET Inhibitors Promote Liver Tumor Evasion of the Immune Response by Stabilizing PDL1

BACKGROUND & AIMS

Inhibitors of MET have not produced satisfactory outcomes in trials of patients with liver cancer. We investigated the mechanisms of liver tumor resistance to MET inhibitors in mice.

METHODS

We tested the effects of MET inhibitors tivantinib and capmatinib in the mouse hepatocellular carcinoma (HCC) cell line HCA-1 and in immune-competent and immunodeficient mice with subcutaneous tumors grown from this cell line. Tumors were collected from mice and tumor cells were analyzed by time-of-flight mass cytometry. We used short hairpin RNAs to weaken expression of MET in Hep3B, SK-HEP-1, HA59T, and HA22T liver cancer cell lines and analyzed cells by immunoblot, immunofluorescence, and immunoprecipitation assays. Mass spectrometry was used to assess interactions between MET and glycogen synthase kinase 3β (GSK3B), and GSK3B phosphorylation, in liver cancer cell lines. C57/BL6 mice with orthotopic tumors grown from Hep1-6 cells were given combinations of capmatinib or tivantinib and antibodies against programmed cell death 1 (PDCD1; also called PD1); tumors were collected and analyzed by immunofluorescence. We analyzed 268 HCCsamples in a tissue microarray by immunohistochemistry.

RESULTS

Exposure of liver cancer cell lines to MET inhibitors increased their expression of PD ligand 1 (PDL1) and inactivated cocultured T cells. MET phosphorylated and activated GSK3B at tyrosine 56, which decreased the expression of PDL1 by liver cancer cells. In orthotopic tumors grown in immune-competent mice, MET inhibitors decreased the antitumor activity of T cells. However, addition of anti-PD1 decreased orthotopic tumor growth and prolonged survival of mice compared with anti-PD1 or MET inhibitors alone. Tissue microarray analysis of HCC samples showed an inverse correlation between levels of MET and PDL1 and a positive correlation between levels of MET and phosphorylated GSK3B.

CONCLUSIONS

In studies of liver cancer cell lines and mice with orthotopic tumors, MET mediated phosphorylation and activated GSK3B, leading to decreased expression of PDL1. Combined with a MET inhibitor, anti-PD1 and anti-PDL1 produced additive effect to slow growth of HCCs in mice.

Anti-tumor activity and mechanism of oligoclonal hepatocellular carcinoma tumor-infiltrating lymphocytes in vivo and in vitro

Objective: To explore a method for culturing hepatocellular carcinoma and tumor-infiltrating lymphocytes (HCC-TIL) and investigate the mechanism of TIL in killing tumors. Methods: The distribution of regulatory T cells (Treg) in HCC was detected by immunohistochemistry. Conventional TIL and oligoclonal TIL were isolated by the traditional method of enzyme digestion combined with mechanical treatment for whole HCC and micro HCC tissue block culturing method. MTT was used to compare the killing activity of TIL. Flow cytometry was used to analyze the proportion of CD8+ T cells and Treg cells in TIL. Tumor-bearing mice were established, and TIL adoptive immunotherapy was performed. Results: Treg cells were mainly distributed in the stroma of HCC. In vitro experiments showed oligoclonal TIL had higher cytotoxicity to tumor cells which negatively correlated with the proportion of Treg cells. In vivo experiments showed oligoclonal TIL had a higher anti-tumor effect. IFN-γ in peripheral blood and the positive rate of intratumoral lymphocytic infiltration in oligoclonal TIL group were both higher. TGF-β and IL-10 in peripheral blood and the positive rate of intratumoral FoxP3 and IL-17 were both lower than those in conventional TIL group. Conclusion: The oligoclonal TIL culture method could obtain TIL with higher purity, and cytotoxicity to tumor cells was associated with Treg cells. The oligoclonal TIL had cytotoxicity to autologous HCC cells and significant inhibitory effect on the growth of transplanted tumors. The mechanism might be associated with the inhibition of Treg cells proliferation, increase of IFN-γ secretion, and decrease of TGF-β, IL-10, and IL-17 secretion.

CD73 expression in normal and pathological human hepatobiliopancreatic tissues

BACKGROUND

The tumor-expressed CD73 ectonucleotidase generates immune tolerance and promotes invasiveness via adenosine production from degradation of AMP. While anti-CD73 blockade treatment is a promising tool in cancer immunotherapy, a characterization of CD73 expression in human hepatobiliopancreatic system is lacking.

PATIENTS AND METHODS

CD73 expression was investigated by immunohistochemistry in a variety of non-neoplastic and neoplastic conditions of the liver, pancreas, and biliary tract.

RESULTS

CD73 was expressed in normal hepatobiliopancreatic tissues with subcellular-specific patterns of staining: canalicular in hepatocytes, and apical in cholangiocytes and pancreatic ducts. CD73 was present in all hepatocellular carcinoma (HCC), in all pancreatic ductal adenocarcinoma (PDAC), and in the majority of intra and extrahepatic cholangiocellular carcinomas, whereas it was detected only in a subset of pancreatic neuroendocrine neoplasms and almost absent in acinar cell carcinoma. In addition to the canonical pattern of staining, an aberrant membranous and/or cytoplasmic expression was observed in invasive lesions, especially in HCC and PDAC. These two entities were also characterized by a higher extent and intensity of staining as compared to other hepatobiliopancreatic neoplasms. In PDAC, aberrant CD73 expression was inversely correlated with differentiation (p < 0.01) and was helpful to identify isolated discohesive tumor cells. In addition, increased CD73 expression was associated with reduced overall survival (HR 1.013) and loss of E-Cadherin.

CONCLUSIONS

Consistent CD73 expression supports the rationale for testing anti-CD73 therapies in patients with hepatobiliopancreatic malignancies. Specific patterns of expression could also be of help in the routine diagnostic workup.

Prognostic value of tumor-infiltrating lymphocytes in hepatocellular carcinoma: A meta-analysis

BACKGROUND

In patients with hepatocellular carcinoma (HCC), the prognostic role of tumor-infiltrating lymphocytes (TILs) for survival is still controversial. A meta-analysis was performed to investigate the prognostic effect of TILs in HCC.

METHODS

We identify studies from PubMed, Embase, and the Cochrane Library to evaluate the prognostic value of TILs in patients with HCC. A meta-analysis was conducted to estimate overall survival and disease-free survival. The hazard ratio (HR) and 95% confidence interval (CI) were calculated employing fixed-effect or random-effect models depending on the heterogeneity of the included trials.

RESULTS

A total of 7905 patients from 46 observational studies were enrolled. For TILs subsets, the density of CD8+, FOXP3+, CD3+, and Granzyme B+ lymphocytes was significantly associated with improved survival (P < .05). The density of FOXP3+ TILs in intratumor (IT) was the most significant prognostic marker (pooled HR = 1.894; 95% CI = 1.659-2.164; P < .001). Patients with high infiltration of CD8+ TILs in IT (pooled HR = 0.676; 95% CI = 0.540-0.845; P = .001) or in margin of tumor (MT) (pooled HR = 0.577; 95% CI = 0.437-0.760; P < .001) had better OS. The pooled analysis revealed that high density of Granzyme B+ T-lymphocytes in IT was statistically significant associated with better OS (pooled HR = 0.621; 95% CI = 0.516-0.748; P < .001) and DFS (pooled HR = 0.678; 95% CI = 0.563-0.815; P < .001). It was interesting that high density of CD3+ in IT foreboded worse OS (pooled HR = 1.008; 95% CI = 1.000-1.015; P = .037), but better DFS (pooled HR = 0.596; 95% CI = 0.374-0.948; P = .029).

CONCLUSION

Our findings suggested that some TIL subsets could serve as prognostic biomarkers in HCC. High-quality randomized controlled trials are needed to determine if these TILs could serve as targets for immunotherapy in HCC.

Chimeric antigen receptor-engineered T-cell therapy for liver cancer

BACKGROUND

Chimeric antigen receptor-engineered T-cell (CAR-T) therapy is a newly developed immunotherapy used in the treatment of cancers. Because CAR-T therapy has shown great success in treating CD19-positive hematological malignancies, its application has been explored in the treatment of solid tumors, such as liver cancer. In this review, we discuss the immune characteristics of liver cancer, the obstacles encountered during the application of CAR-T therapy, and preclinical and clinical progress in the use of CAR-T therapy in patients with liver cancer.

DATA SOURCES

The data on CAR-T therapy related to liver cancers were collected by searching PubMed and the Web of Science databases prior to December 2017 with the keywords "chimeric antigen receptor", "CAR-T", "liver cancer", "hepatocellular carcinoma", and "solid tumor". Additional articles were identified by manual search of references found in the primary articles. The data for clinical trials were collected by searching ClinicalTrials.gov.

RESULTS

The liver has a tolerogenic nature in the intrahepatic milieu and its tumor microenvironment significantly affects tumor progression. The obstacles that reduce the efficacy of CAR-T therapy in solid tumors include a lack of specific tumor antigens, limited trafficking and penetration of CAR-T cells to tumor sites, and an immunosuppressive tumor microenvironment. To overcome these obstacles, several strategies have emerged. In addition, several strategies have been developed to manage the side effects of CAR-T, including enhancing the selectivity of CARs and controlling CAR-T activity. To date, no clinical trials of CAR-T therapy against HCC have been completed. However, preclinical studies in vitro and in vivo have shown potent antitumor efficacy. Glypican-3, mucin-1, epithelial cell adhesion molecule, carcinoembryonic antigen, and other targets are currently being studied.

CONCLUSIONS

The application of CAR-T therapy for liver cancer is just beginning to be explored and more research is needed. However, we are optimistic that CAR-T therapy will offer a new approach for the treatment of liver cancers in the future.

T cell receptor repertoire profiling predicts the prognosis of HBV-associated hepatocellular carcinoma

Tumor‐infiltrating T cell repertoire has been demonstrated to be closely associated with anti‐tumor immune response. However, the relationship between T cell repertoire in tumor tissue and prognosis has never been reported in Hepatocellular carcinoma (HCC). We performed the high‐throughput T cell receptor (TCR) sequencing to systematically characterize the infiltrating T cell repertoires of tumor and matched adjacent normal tissues from 23 HBV‐associated HCC patients. Significant differences on usage frequencies of some Vβ, Jβ, and Vβ‐Jβ paired genes have been found between the 2 groups of tissue samples, but no significant difference of TCR repertoire diversity could be found. Interestingly, the similarity of TCR repertoires between paired samples or the TNM stage alone could not be helpful to evaluate the prognosis of patients very well, but their combination could serve as an efficient prognostic indicator that the patients with early stage and high similarity showed a better prognosis. This is the first attempt to assess the potential value of TCR repertoire in HCC prognosis, and our findings could serve as a complement for the characterization of TCR repertoire in HCC.

Isolation and Characterization of Mouse Intrahepatic Lymphocytes by Flow Cytometry

In the field of cellular immunology multicolor flow cytometry is a frequently applied method that allows for the simultaneously detection of multiple parameters on an individual cell basis. Flow cytometry can be used to characterize a wide range of immune cell subsets using fluorophore-conjugated antibodies to a wide range of cellular antigens. The isolation of immune cells from nonlymphoid tissue and their preparation for flow cytometry can be a challenging process with respect to immune cell yields and viability. Here we describe a method for the efficient isolation of viable mouse intrahepatic lymphocytes (IHL) from normal liver tissue and liver cancer and their subsequent characterization by multicolor flow cytometry.

Immune-Mediated Therapies for Liver Cancer

In recent years, immunotherapy has gained renewed interest as an alternative therapeutic approach for solid tumors. Its premise is based on harnessing the power of the host immune system to destroy tumor cells. Development of immune-mediated therapies, such as vaccines, adoptive transfer of autologous immune cells, and stimulation of host immunity by targeting tumor-evasive mechanisms have advanced cancer immunotherapy. In addition, studies on innate immunity and mechanisms of immune evasion have enhanced our understanding on the immunology of liver cancer. Preclinical and clinical studies with immune-mediated therapies have shown potential benefits in patients with liver cancer. In this review, we summarize current knowledge and recent developments in tumor immunology by focusing on two main primary liver cancers: hepatocellular carcinoma and cholangiocarcinoma.

Regulatory T-cells promote hepatitis B virus infection and hepatocellular carcinoma progression

Regulatory T-cells (Tregs), known for their immune suppressive function, have been reported in higher numbers, with activated phenotypes and greater potency, in hepatitis B virus (HBV)-related liver diseases than in normal conditions. The numbers, phenotypes, and function of intrahepatic and/or tumor-infiltrating Tregs in HBV-related liver diseases also differ from those of Tregs in the peripheral blood. By inhibiting the function of effector T-cells (Teffs), Tregs play a substantial role in the formation and maintenance of the liver's suppressive microenvironment, which might account for the progression of HBV-related hepatitis and hepatocellular carcinoma (HCC). In acute hepatitis B virus infection, Tregs can safeguard the liver from damage at the cost of prolonged antiviral processes, which results in chronic HBV infection in the liver. Furthermore, Tregs play a role in the development of cirrhosis, the transformation of cirrhosis to HCC, and the progression and metastasis of HCC. Higher levels of Tregs in the peripheral blood and/or tumor sites signify a poorer prognosis in HBV-related liver conditions, and observational data from mouse models and human patients support the theory that depleting Tregs may be therapeutic in HBV-related liver diseases by inducing antiviral and antitumor immunity.

Protective Effect of Boiled and Freeze-dried Mature Silkworm Larval Powder Against Diethylnitrosamine-induced Hepatotoxicity in Mice

Background

Hepatocellular carcinoma (HCC) is a representative inflammation-associated cancer and known to be the most frequent tumors. HCC may also induce important pro- and anti-tumor immune reactions. However, the underlying mechanisms are unsatisfactorily identified. We investigated the protective effect of boiled and freeze-dried mature silkworm larval powder (BMSP) on diethylnitrosamine (DEN)-induced hepatotoxicity in mice.

Methods

Mice were fed with diet containing BMSP (0.1, 1, and 10 g/kg) for two weeks and DEN (100 mg/kg, intraperitoneally) was injected 18 hours before the end of this experiment. Liver toxicity was determined in serum and histopathological examination was assessed in the liver tissues. Infiltration of immune cells and expressions of inflammatory cytokines and chemokines were also examined.

Results

Pretreatment with BMSP reduced necrotic and histopathological changes induced by DEN in the liver. Measurement of serum biochemical indicators, the levels of alkaline phosphatase, alanine aminotransferase, and aspartate aminotransferase, showed that pretreatment with BMSP also decreased DEN-induced hepatotoxicity. In addition, BMSP inhibited the macrophage and CD31 infiltration in a dose-dependent manner. The expressions of interleukin-1β, IFN-γ and chemokines for T cell activation were decreased in BMSP pretreatment groups.

Conclusions

BMSP may have a protective effect against acute liver injury by inhibiting necrosis and inflammatory response in DEN-treated mice.

Identification of Recurrence-Related microRNAs from Bone Marrow in Hepatocellular Carcinoma Patients

Hepatocellular carcinoma (HCC) is a poor-prognosis cancer due to its high rate of recurrence. microRNAs (miRNAs) are a class of small non-coding RNA molecules that affect crucial processes in cancer development. The objective of this study is to identify the role of miRNAs in patient bone marrow (BM) and explore the function of these molecules during HCC progression. We purified miRNAs from bone marrow cells of seven HCC patients, and divided them into three fractions by cell surface markers as follows: CD14(+) (macrophage), CD14(-)/CD45(+) (lymphocyte), and CD14(-)/CD45(-)/EpCAM(+) (epithelial cell). We employed microarray-based profiling to analyze miRNA expression in the bone marrow of patients with HCC. Differentially expressed miRNAs were significantly different between fractions from whole bone marrow, macrophages, and lymphocytes, and depended on stages in tumor progression. Differences in expression of miRNAs associated with cell proliferation also varied significantly between HCC patients with recurrence, multiple tumors, and advanced clinical stages. These results suggest that miRNA profiles in separated fractions of BM cells are associated with HCC progression.

Potential immunotherapeutic role of interleukin-2 and interleukin-12 combination in patients with hepatocellular carcinoma

Background

Many recent therapeutic interventions are necessary to improve the treatment of hepatocellular carcinoma (HCC), including immunotherapy, which seems to offer one of the new realistic therapeutic modalities. This study aims to investigate the optimization of immunotherapy for HCC patients by appraisal of both interferon (IFN)-γ levels and phenotyping of lymphocytes obtained from peripheral blood and fine-needle aspirates.

Methods

The isolated lymphocytes were cultured in the presence of interleukins (IL)-2, IL-4, and IL-12. Enzyme-linked immunosorbent assay and flow cytometric techniques were used for the assessment of human IFN-γ production and the studied T-cell subpopulations, respectively.

Results

Mixed cell populations of peripheral blood lymphocytes and tumor infiltrating lymphocytes treated with IL-2 plus IL-12 showed a marked and significant elevation in IFN-γ levels in their culture media, a significant decrease in the percentage of cluster of differentiation (CD)4⁺CD25⁺ regulatory T-cells, and a nonsignificant increase in the percentage of CD8⁺ cytotoxic T-cells. Meanwhile, IL-2 plus IL-4 treatment demonstrated nonsignificant effects.

Conclusion

Our data suggested that IL-12 together with IL-2 caused a suppression of CD4⁺CD25⁺ regulatory T-cells and an elevation of IFN-γ levels, which play a crucial immunotherapeutic role in the management of HCC patients.

Novel aspects of the liver microenvironment in hepatocellular carcinoma pathogenesis and development

Hepatocellular carcinoma (HCC) is a prevalent primary liver cancer that is derived from hepatocytes and is characterised by high mortality rate and poor prognosis. While HCC is driven by cumulative changes in the hepatocyte genome, it is increasingly recognised that the liver microenvironment plays a pivotal role in HCC propensity, progression and treatment response. The microenvironmental stimuli that have been recognised as being involved in HCC pathogenesis are diverse and include intrahepatic cell subpopulations, such as immune and stellate cells, pathogens, such as hepatitis viruses, and non-cellular factors, such as abnormal extracellular matrix (ECM) and tissue hypoxia. Recently, a number of novel environmental influences have been shown to have an equally dramatic, but previously unrecognized, role in HCC progression. Novel aspects, including diet, gastrointestinal tract (GIT) microflora and circulating microvesicles, are now being recognized as increasingly important in HCC pathogenesis. This review will outline aspects of the HCC microenvironment, including the potential role of GIT microflora and microvesicles, in providing new insights into tumourigenesis and identifying potential novel targets in the treatment of HCC.

Increased circulating Th17 cells after transarterial chemoembolization correlate with improved survival in stage III hepatocellular carcinoma: a prospective study

Transarterial chemoembolization (TACE) has therapeutic effects in patients with unresectable hepatocellular carcinoma (HCC), but its impact on the cellular immune response during disease progression is largely unknown. Here we conducted a prospective study to evaluate the effect of TACE on immune status and to identify prognostic immune markers governing treatment success. In this study, 51 stage III HCC patients, 28 stage I HCC patients (TNM classification) and 20 healthy donors were enrolled. Flow cytometry and cytometric bead array were used to evaluate the circulating immune cell subsets, including CD4⁺ T cells (Th1, Th17 and Treg cells), CD8⁺ T cells, NK cells, and NKT cells, and plasma cytokines before TACE and 30 days after TACE. Interestingly, among those immune parameters, the frequency of circulating Th17 cells was higher in stage III HCC patients than in stage I HCC patients (P = 0.015) and healthy donors (P<0.001). Moreover, an increased frequency of circulating Th17 cells was observed 30 days after TACE (Th17_D30) compared with the baseline level (P = 0.036). Kaplan-Meier analysis demonstrated that Th17_D30 was positively associated with overall survival (OS; P = 0.007) and time to progression (TTP; P = 0.009). Multivariate Cox analysis revealed that Th17_D30 was an independent prognostic factor for OS (HR = 0.317, P = 0.032) and TTP (HR = 0.304, P = 0.010). These results provide a potential prognostic marker for stage III HCC patients undergoing TACE and may be useful for identifying patients who can benefit from adjuvant immunotherapies.

Hepatitis B surface antigen could contribute to the immunopathogenesis of hepatitis B virus infection

Various findings concerning the clinical significance of quantitative changes in hepatitis B surface antigen (HBsAg) during the acute and chronic phase of hepatitis B virus (HBV) infection have been reported. In addition to being a biomarker of HBV-replication activity, it has been reported that HBsAg could contribute to the immunopathogenesis of HBV persistent infection. Moreover, HBsAg could become an attractive target for immune therapy, since the cellular and humeral immune response against HBsAg might be able to control the HBV replication and life cycle. However, several reports have described the immune suppressive function of HBsAg. HBsAg might suppress monocytes, dendritic cells (DCs), natural killer (NK), and natural killer T (NK-T) cells by direct interaction. On the other hand, cytotoxic T lymphocytes (CTLs) and helper T (Th) cells were exhausted by high amounts of HBsAg. In this paper, we focused on the immunological aspects of HBsAg, since better understanding of the interaction between HBsAg and immune cells could contribute to the development of an immune therapy as well as a biomarker of the state of HBV persistent infection.

Tim-3/galectin-9 signaling pathway mediates T-cell dysfunction and predicts poor prognosis in patients with hepatitis B virus-associated hepatocellular carcinoma

The interaction between T cell immunoglobulin- and mucin-domain-containing molecule (Tim-3) expressed on T helper 1 (Th1) cells, and its ligand, galectin-9, negatively regulates Th1-mediated immune responses. However, it is poorly understood if and how the Tim-3/galectin-9 signaling pathway is involved in immune escape in patients with hepatocellular carcinoma (HCC). Here we studied the expression, function, and regulation of the Tim-3/galectin-9 pathway in patients with hepatitis B virus (HBV)-associated HCC. We detected different levels of galectin-9 expression on antigen-presenting cell (APC) subsets including Kupffer cells (KCs), myeloid dendritic cells (DCs), and plasmacytoid DCs in HCC. The highest galectin-9 expression was on KCs in HCC islets, not in the adjacent tissues. Furthermore, Tim-3 expression was increased on CD4(+) and CD8(+) T cells in HCC as compared to the adjacent tissues, and Tim-3(+) T cells were replicative senescent and expressed surface and genetic markers for senescence. Interestingly, tumor-infiltrating T-cell-derived interferon (IFN)-γ stimulated the expression of galectin-9 on APCs in the HCC microenvironment. Immunofluorescence staining revealed a colocalization of Tim-3(+) T cells and galectin-9(+) KCs in HCC. Functional studies demonstrated that blockade of the Tim-3/galectin-9 signaling pathway importantly increased the functionality of tumor-infiltrating Tim-3(+) T cells as shown by increased T-cell proliferation and effector cytokine production. Finally, we show that the numbers of Tim-3(+) tumor-infiltrating cells were negatively associated with patient survival.

CONCLUSION

Our work demonstrates that the Tim-3/galectin-9 signaling pathway mediates T-cell senescence in HBV-associated HCC. The data suggest that this pathway could be an immunotherapeutic target in patients with HBV-associated HCC.

Hepatocellular carcinoma-specific immunotherapy with synthesized α1,3- galactosyl epitope-pulsed dendritic cells and cytokine-induced killer cells

AIM: To evaluate the safety and clinical efficacy of a new immunotherapy using both α-Gal epitope-pulsed dendritic cells (DCs) and cytokine-induced killer cells.

METHODS: Freshly collected hepatocellular carcinoma (HCC) tumor tissues were incubated with a mixture of neuraminidase and recombinant α1,3-galactosyltransferase (α1,3GT) to synthesize α-Gal epitopes on carbohydrate chains of the glycoproteins of tumor membranes. The subsequent incubation of the processed membranes in the presence of human natural anti-Gal IgG resulted in the effective phagocytosis to the tumor membrane by DCs. Eighteen patients aged 38-78 years with stage III primary HCC were randomLy chosen for the study; 9 patients served as controls, and 9 patients were enrolled in the study group.

RESULTS: The evaluation demonstrated that the procedure was safe; no serious side effects or autoimmune diseases were observed. The therapy significantly prolonged the survival of treated patients as compared with the controls (17.1 ± 2.01 mo vs 10.1 ± 4.5 mo, P = 0.00121). After treatment, all patients in the study group had positive delayed hypersensitivity and robust systemic cytotoxicity in response to tumor lysate as measured by interferon-γ-expression in peripheral blood mononuclear cells using enzyme-linked immunosorbent spot assay. They also displayed increased numbers of CD8-, CD45RO- and CD56-positive cells in the peripheral blood and decreased α-fetoprotein level in the serum.

CONCLUSION: This new tumor-specific immunotherapy is safe, effective and has a great potential for the treatment of tumors.

Characterization of diethylnitrosamine-induced liver carcinogenesis in Syrian golden hamsters

The aim of this study was to characterize hepatocarcinogenesis in diethylnitrosamine (DEN)-treated hamsters. Syrian golden hamsters (n=36) were administered DEN by hypodermic injection and addition to drinking water. Morphological analyses, including light microscopy and immunohistochemistry of α-fetal protein (AFP), were performed on liver and lung tissues. Primary cell culture and tumor transplantation were carried out to evaluate the potential application in hepatocellular carcinoma (HCC) research. From 25 to 50 weeks of treatment, liver tumors, including macronodular HCC and ascites, were found in one-third (4/12) of the animals treated with DEN. HCC was characterized by poor differentiation, frequent mitosis, AFP reaction, vessel invasion and potential application in primary cell culture and xenotransplantation. Pre-neoplastic lesions were hyperplastic nodules comprised of clear cells, bile duct proliferation, fatty metamorphosis and multilocular cysts. The DEN-treated hamsters also showed lung tumors consisting of AFP-negative, well-differentiated neoplastic cells. Characterization of DEN-induced HCC in hamsters provides insights into human hepatocarcinogenesis. This animal model has potential applications in HCC research.