Expansion of anti-AFP Th1 and Tc1 responses in hepatocellular carcinoma occur in different stages of disease

Differential Virus-Specific IFN-Gamma Producing T Cell Responses to Marek's Disease Virus in Chickens With B19 and B21 MHC Haplotypes

Marek’s disease virus (MDV), the etiologic agent for Marek’s disease (MD), causes a deadly lymphoproliferative disease in chickens. Causes of the well-documented association between genetically defined lines of chicken and resistance to MD remain unknown. Here, the frequencies of IFN-gamma producing pp38 and MEQ-specific T cell responses were determined in line N (B21 haplotype; MD-resistant) and line P2a (B19 haplotype, MD-susceptible) chickens after infection with vaccine and/or virulent (RB1B) strains of MDV using both standard ex vivo and cultured chIFN-gamma ELISPOT assays. Notably, MDV infection of naïve and vaccinated MD-resistant chickens induced higher frequencies of IFN-gamma producing MDV-specific T cell responses using the cultured and ex vivo ELISPOT assay, respectively. Remarkably, vaccination did not induce or boost MEQ-specific effector T cells in the susceptible chickens, while it boosted both pp38-and MEQ-specific response in resistant line. Taken together, our results revealed that there is a direct association between the magnitude of T cell responses to pp38 and MEQ of MDV antigens and resistance to the disease.

Alternative Splicing-Based Differences Between Hepatocellular Carcinoma and Intrahepatic Cholangiocarcinoma: Genes, Immune Microenvironment, and Survival Prognosis

Alternative splicing (AS) event is a novel biomarker of tumor tumorigenesis and progression. However, the comprehensive analysis of hepatocellular carcinoma (HCC) and intrahepatic cholangiocarcinoma (ICC) is lacking. Differentially expressed analysis was used to identify the differentially expressed alternative splicing (DEAS) events between HCC or ICC tissues and their normal tissues. The correlation between DEAS events and functional analyses or immune features was evaluated. The cluster analysis based on DEAS can accurately reflect the differences in the immune microenvironment between HCC and ICC. Forty-five immune checkpoints and 23 immune features were considered statistically significant in HCC, while only seven immune checkpoints and one immune feature in ICC. Then, the prognostic value of DEAS events was studied, and two transcripts with different basic cell functions (proliferation, cell cycle, invasion, and migration) were produced by ADHFE1 through alternative splicing. Moreover, four nomograms were established in conjunction with relevant clinicopathological factors. Finally, we found two most significant splicing factors and further showed their protein crystal structure. The joint analysis of the AS events in HCC and ICC revealed novel insights into immune features and clinical prognosis, which might provide positive implications in HCC and ICC treatment.

The Landscape of Immune Cells Indicates Prognosis and Applicability of Checkpoint Therapy in Hepatocellular Carcinoma

Background

Tumor-infiltrating immune cells are important components of tumor microenvironment (TME), and their composition reflects the confrontation between host immune system and tumor cells. However, the relationship between the composition of infiltrating immune cells, prognosis, and the applicability of anti-PD-1/PD-L1 therapy in hepatocellular carcinoma (HCC) needs systematic examination.

Methods

Cell-Type Identification by Estimating Relative Subsets of RNA Transcripts (CIBERSORT) was applied to evaluate the infiltration of immune cells based on The Cancer Genome Atlas (TCGA) liver hepatocellular carcinoma (LIHC) cohort. Diagnostic and prognostic models were constructed based on immune cells, and the models were validated by two external cohorts. The relationship between immune cells and PD-L1 was evaluated by Spearman correlation, and the finding was validated in our in-house HCC sample.

Result

Patients in TCGA LIHC cohort were classified into six subtypes with different prognosis based on the proportion of tumor-infiltrating immune cells simulated via CIBERSORT. Among 22 types of immune cells, intratumoral PD-L1 mRNA level exhibited linear relationship with the fraction of five types of immune cells (M1 macrophages, plasma cells, CD8⁺ T cells, resting mast cells, and regulatory T cells), and M1 macrophages showed the strongest relevance (R = 0.26, p < 0.001). Immunohistochemistry of our in-house HCC specimens verified this conclusion. Moreover, intratumoral mRNA levels of M1 macrophage-associated cytokines were positively correlated with PD-L1 level.

Conclusions

Our study demonstrated that the prognosis of HCC patients was associated with the pattern of infiltrating immune cells in TME, and macrophage-associated cytokines might be a potential non-invasive marker for predicting the PD-L1 level for HCC patients.

Immune Checkpoint Inhibitors as Monotherapy or Within a Combinatorial Strategy in Advanced Hepatocellular Carcinoma

In advanced-stage hepatocellular carcinoma (HCC), systemic treatment represents the standard therapy. Target therapy has marked a new era based on a greater knowledge of molecular disease signaling. Nonetheless, survival outcomes and long-term response remain unsatisfactory, mostly because of the onset of primary or acquired resistance. More recently, results from clinical trials with immune targeting agents, such as the immune checkpoint inhibitors (ICIs), have shown a promising role for these drugs in the treatment of advanced HCC. In the context of an intrinsic tolerogenic liver environment, since HCC-induced immune tolerance, it is supported by multiple immunosuppressive mechanisms and several clinical trials are now underway to evaluate ICI-based combinations, including their associations with antiangiogenic agents or multikinase kinase inhibitors and multiple ICIs combinations. In this review, we will first discuss the basic principles of hepatic immunogenic tolerance and the evasive mechanism of antitumor immunity in HCC; furthermore we will elucidate the consistent biological rationale for immunotherapy in HCC even in the presence of an intrinsic tolerogenic environment. Subsequently, we will critically report and discuss current literature on ICIs in the treatment of advanced HCC, including a focus on the currently explored combinatorial strategies and their rationales. Finally, we will consider both challenges and future directions in this field.

HCC Immune Surveillance and Antiviral Therapy of Hepatitis C Virus Infection

OBJECTIVE

HCV clearance by current antiviral therapies improves clinical outcomes but falls short in eliminating the risk for hepatocellular carcinoma (HCC) emergence. As the HCC immune surveillance establishment is vital for the control of neoplastic development and growth, we investigated its correlation with on-/post-treatment HCC emergence, and further analyzed the influence of viral eradication on this setup in patients with HCV-related liver cirrhosis.

DESIGN

PBMC isolated at baseline and longitudinally during therapy were analyzed for tumor-associated antigen (TAA)-specific CD8+ T cell responses against glypican-3 overlapping peptides in vitro using high-definition flow cytometry. Multianalyte profiling of fifty soluble inflammatory mediators (SIM) in the plasma was also performed using Luminex-based multiplex technology.

RESULTS

Cirrhosis patients were characterized by an altered profile of distinct SIMs at baseline. At this time point, immune-surveilling T cells targeting specific HCC-associated antigens were readily detectable in HCV-free cirrhosis patients whilst being rather weak in such patients who further developed HCC upon virus eradication. Therapy-induced cure of HCV infection analogously reduced the strength of the prevailing HCC immune surveillance machinery, particularly by CD8+ T cells in cirrhosis patients. These results were further validated by T cell reactivities to six immuno-dominant HCC-associated HLA-A2-restricted epi-topes. Further, we demonstrated that this phenomenon was likely orchestrated by alterations in SIMs - with evidence of IL-12 being a major culprit.

CONCLUSION

Given the relationship between the baseline HCC-specific immune surveilling T cell responses and therapy-associated HCC emergence, and the impact of HCV clearance on its strength and magnitude, we recommend a continued HCC screening in cirrhotic HCV patients despite HCV resolution.

Molecular Targets in Hepatocarcinogenesis and Implications for Therapy

Hepatocarcinogenesis comprises of multiple, complex steps that occur after liver injury and usually involve several pathways, including telomere dysfunction, cell cycle, WNT/β-catenin signaling, oxidative stress and mitochondria dysfunction, autophagy, apoptosis, and AKT/mTOR signaling. Following liver injury, gene mutations, accumulation of oxidative stress, and local inflammation lead to cell proliferation, differentiation, apoptosis, and necrosis. The persistence of this vicious cycle in turn leads to further gene mutation and dysregulation of pro- and anti-inflammatory cytokines, such as interleukin (IL)-1β, IL-6, IL-10, IL-12, IL-13, IL-18, and transforming growth factor (TGF)-β, resulting in immune escape by means of the NF-κB and inflammasome signaling pathways. In this review, we summarize studies focusing on the roles of hepatocarcinogenesis and the immune system in liver cancer. In addition, we furnish an overview of recent basic and clinical studies to provide a strong foundation to develop novel anti-carcinogenesis targets for further treatment interventions.

Effect of dendritic cell-based immunotherapy on hepatocellular carcinoma: A systematic review and meta-analysis

BACKGROUND AIMS

Dendritic cell (DC)-based immunotherapy has recently been reported frequently in the treatment of hepatocellular carcinoma (HCC); however, its efficacy remains controversial. In this study, we aimed to evaluate the clinical efficacy of DC-based immunotherapy on HCC by conducting a systematic review and meta-analysis.

METHODS

PubMed, Cochrane Library, Embase and Web of Science were searched to identify clinical trials on DC-based immunotherapy for HCC published up to January 31, 2018. The articles were selected according to pre-established inclusion criteria and methodologic quality, and publication bias were evaluated.

RESULTS

A total of 1276 cases from 19 clinical trials were included. Compared with traditional treatment, further DC-based therapy enhanced the CD4⁺ T/CD8⁺ T ratio (standardized mean difference: 0.68, 95% confidence interval [CI] 0.46-0.89, P < 0.001); increased the 1-year, 18-month and 5-year progression-free survival (PFS) rate and the 1-year, 18-month and 2-year overall survival (OS) rate (relative risk > 1, P < 0.05), prolonged the median PFS time (median survival ratio [MSR]: 1.98, 95% CI: 1.60-2.46, P < 0.001) and median OS time (MSR: 1.72, 95% CI: 1.51-1.96, P < 0.001). Adverse reactions were mild.

CONCLUSIONS

DC-based therapy not only enhanced anti-tumor immunity, improved the survival rate and prolonged the survival time of HCC patients, but it was also safe. These findings will provide encouraging information for further development of DC-based immunotherapy as an adjuvant treatment for HCC. However, the results must be interpreted with caution because of the small study numbers, publication bias and the various of study designs, pre-treatment and therapeutic processes of DCs.

Cancer vaccines and immunotherapeutic approaches in hepatobiliary and pancreatic cancers

Hepatobiliary and pancreatic cancers along with other gastrointestinal malignancies remain the leading cause of cancer-related deaths worldwide. Strategies developed in the recent years on immunotherapy and cancer vaccines in the setting of primary liver cancer as well as in pancreatic cancer are the scope of this review. Significance of orthotopic and autochthonous animal models which mimic and/or closely reflect human malignancies allowing for a prompt and trustworthy analysis of new therapeutics is underlined. Combinational approaches that on one hand, specifically target a defined cancer-driving pathway, and on the other hand, restore the functions of immune cells, which effector functions are often suppressed by a tumor milieu, are shown to have the strongest perspectives and future directions. Among combinational immunotherapeutic approaches a personalized- and individual cancer case-based therapy is of special importance.

Current immunotherapeutic strategies in hepatocellular carcinoma: recent advances and future directions

Hepatocellular carcinoma (HCC) is a common and serious health problem with high mortality. Treatment for HCC remains largely unsatisfactory owing to its high recurrence rates and frequent accompanying cirrhosis. In addition, the unique immune environment of the liver promotes tolerance, which, in conjunction with immune evasion by the disease, makes HCC a less promising target for conventional immunotherapy. However, recent advances in the immunotherapy have led to novel approaches to overcome these obstacles by manipulating and enhancing tumor-specific immune responses against HCC by using various modalities, such as cancer vaccines and immune checkpoint blockade. These treatments have shown both safety and promising outcomes in patients with HCC of various etiologies and tumor stages. Furthermore, combined strategies have been assessed to achieve optimal outcomes, by using immunotherapies with or without conventional treatments. This review briefly covers the background, recent advances, current issues, and future perspectives on immunotherapy in the field of HCC treatment.

Promising new strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common causes of cancer death worldwide. It usually arises based on a background of chronic liver diseases, defined as the hypercarcinogenic state. The current treatment options for HCC ranging from locoregional treatments to chemotherapies, including sorafenib, effectively regulate the limited sizes and numbers of the nodules. However, these treatments remain unsatisfactory because they have insufficient antitumor effects on the large and numerous nodules associated with HCC and because of a high recurrence rate in the surrounding inflamed liver. To develop novel and promising therapies with higher antitumor effects, recent progress in identifying molecular targets and developing immunological procedures for HCC are reviewed. The molecular targets discussed include the intracellular signaling pathways of protein kinase B/mammalian target of rapamycin and RAS/RAF/mitogen-activated protein kinase, Wnt/β-catenin and glutamine synthetase, insulin-like growth factor, signal transducer and activator of transcription 3, nuclear factor-κB and telomerase reverse transcriptase, and c-MET. Immunological studies have focused mainly on target identification, T cells, natural killer cells, dendritic cells, natural killer T cells, and vaccine development.

T cell inflammation profile after surgical resection may predict tumor recurrence in HBV-related hepatocellular carcinoma

The most effective treatment for HBV-related hepatocellular carcinoma (HCC) is surgical removal of the tumor in early stage patients. But many such patients will develop recurrent tumor within the first 24months, which is the major cause of death. To enable the prevention and earlier detection of recurrent HCC, we investigated the T cell responses that were potentially involved in HCC recurrence. We found that patients with recurrent HCC presented significantly lower frequencies of interferon gamma (IFNγ)-expressing Th1 cells and Tc1 cells, as well as significantly elevated Foxp3⁺ Treg cells, in the peripheral blood and the resected primary tumor. The peripheral blood and tumor-infiltrating T cells from patients with recurrent HCC also presented higher PD-1 and TIM-3 expression than patients without recurrent HCC. Interestingly, we observed a loss of IFNγ-expressing T cells and an increase in exhausted T cells in the peripheral blood after the removal of the HCC tumor. Furthermore, the T cell specificity in the HLA-A*02-positive patients in our cohort was examined. HBsAg-specific T cell responses could be observed in a subset of patients without HCC recurrence but not in patients with recurrent HCC, while NY-ESO-1-specific T cell responses were observed in a subset of both recurrent and non-recurrent groups. Together, these data indicated that HCC recurrence was associated with the type and robustness of T cell responses.

The yin and yang of evasion and immune activation in HCC

Current systemic treatment options for patients with hepatocellular carcinoma (HCC) are limited to sorafenib. With the recent FDA approval of the second PD1-PD-L1 pathway inhibitor, immunotherapy has gained even more interest as a potential novel treatment option for patients with HCC. This is due not only because of the failure of other treatment approaches in the past, but also because immunological mechanisms have been shown to play an important role during tumor development, growth, and treatment. Here we present a review of immunological mechanisms in the liver relevant for tumor progression and treatment. We summarize our current knowledge on immune activating and immune suppressing mechanisms during tumor initiation, development, and treatment. We try to explain the paradox of how inflammatory responses in a setting of chronic infection promote tumor development, while the primary aim of immunotherapy is to activate immunity. Finally we summarize recent advances in addition to providing an outlook for the immunotherapy of HCC.

Hepatocellular carcinoma: novel molecular targets in carcinogenesis for future therapies

BACKGROUND

Hepatocellular carcinoma is one of the most common and lethal malignant tumors worldwide. Over the past 15 years, the incidence of HCC has more than doubled. Due to late diagnosis and/or advanced underlying liver cirrhosis, only limited treatment options with marginal clinical benefit are available in up to 70% of patients. During the last decades, no effective conventional cytotoxic systemic therapy was available contributing to the dismal prognosis in patients with HCC. A better knowledge of molecular hepatocarcinogenesis provides today the opportunity for targeted therapy.

MATERIALS AND METHODS

A search of the literature was made using cancer literature, the PubMed, Scopus, and Web of Science (WOS) database for the following keywords: "hepatocellular carcinoma," "molecular hepatocarcinogenesis," "targeted therapy," and "immunotherapy."

DISCUSSION AND CONCLUSION

Treatment decisions are complex and dependent upon tumor staging, presence of portal hypertension, and the underlying degree of liver dysfunction. The knowledge of molecular hepatocarcinogenesis broadened the horizon for patients with advanced HCC. During the last years, several molecular targeted agents have been evaluated in clinical trials in advanced HCC. In the future, new therapeutic options will be represented by a blend of immunotherapy-like vaccines and T-cell modulators, supplemented by molecularly targeted inhibitors of tumor signaling pathways.

Role of lymphocytes in liver cancer

Hepatocellular carcinoma (HCC) typically occurs in patients with chronic inflammatory liver diseases, such as viral hepatitis or (non-)alcoholic steatohepatitis. Inflammation appears indeed as a crucial factor in hepatocarcinogenesis. Nevertheless, sophisticated animal models and studies of human samples revealed that the HCC also elicits antitumor immune responses. Patrolling and infiltrating lymphocytes (e.g., NKT and T cells, respectively) can exert decisive functions in the transition from chronic hepatic inflammation to cancer as well as in antitumor immune responses. An improved understanding of the cellular and molecular mechanisms whereby inflammation promotes or restricts hepatocarcinogenesis will open new avenues for therapeutic approaches to liver cancer.

Alpha-fetoprotein: a renaissance

Alpha-fetoprotein (AFP) is a major mammalian embryo-specific and tumor-associated protein that is also present in small quantities in adults at normal conditions. Discovery of the phenomenon of AFP biosynthesis in carcinogenesis by G. Abelev and Yu. Tatarinov 50 years ago, in 1963, provoked intensive studies of this protein. AFPs of some mammalian species were isolated, purified and physico-chemically and immunochemically characterized. Despite the significant success in study of AFP, its three-dimensional structure, mechanisms of receptor binding along with a structure of the receptor itself and, what is the most important, its biological role in embryo- and carcinogenesis remain still obscure. Due to difficulties linked with methodological limitations, research of AFP was to some extent extinguished by the 1990 s. However, over the last decade a growing number of investigations of AFP and its usage as a tumor-specific biomarker have been observed. This was caused by the use of new technologies, primarily, computer-based and genetic engineering approaches in studying of this very important oncodevelopmental protein. Our review summarizes efforts of different scientific groups throughout the world in studying AFP for 50 years with emphasis on detailed description of recent achievements in this field.

Immunobiology of hepatocellular carcinoma

INTRODUCTION

Hepatocellular carcinoma (HCC) is a tumor of increasing incidence and high mortality worldwide. Diagnosis of HCC is often difficult, especially at early stages of disease. Additionally, current treatment options are limited. HCC usually develops in an environment of chronic liver disease. The immune system has an important role in shaping this environment, especially in chronic viral hepatitis, the leading cause of HCC. However, the immune system also plays a role in natural immunity against HCC although this is apparently not sufficient to control the majority of tumors. This failure in tumor control is due to multiple immunomodulatory mechanisms employed by HCC to subvert the immune system. In this review, we will summarize the current knowledge about the role of the immune system in hepatocarcinogenesis. Additionally, we will describe the mechanisms used by the immune system to control established lesions and the reasons why these immune responses apparently fail so often. Finally, possible implications for the design of novel immunotherapeutic strategies will be discussed.

Potential of immunotherapy for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies worldwide with limited therapeutic options. Since HCC has been shown to be immunogenic, T cell-based immunotherapy is considered a promising treatment. In this review, we summarize current knowledge of T cell responses against tumour-associated antigens, as well as the mechanisms underlying the poor quality of these responses in patients with HCC. Insights into these important aspects of HCC immunology are crucial for the further development of novel immunotherapies.

Lack of ex vivo peripheral and intrahepatic α-fetoprotein-specific CD4+ responses in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignancies with a poor prognosis and limited therapeutic options that is often characterized by the expression of the tumor-associated antigen α-fetoprotein (AFP). CD4+ helper T cells are important in generating potent anticancer immunity as they prime and expand CD8+ T-cell memory and may also have direct antitumor activity. However, very little information is currently available about the relative frequency, immunodominance and peripheral versus intratumoral distribution of AFP-specific CD4+ T-cell responses in patients with HCC. We, therefore, analyzed AFP-specific CD4+ responses in blood and tumor tissue of patients with HCC by using overlapping peptides spanning the entire AFP protein and novel sensitive approaches such as antigen-specific upregulation of CD154. We found that AFP-specific CD4+ T-cell responses were not detectable in the peripheral blood ex vivo. However, after in vitro stimulation, AFP-specific CD4+ T-cell responses were detectable in a large fraction of patients targeting different previously unreported epitopes with no clear immunodominance. These results indicate that AFP-specific CD4+ T-cell responses are not completely deleted but only present at very low frequencies. Importantly, AFP-specific CD4+ T-cell responses were also rarely detectable in tumor tissue, suggesting that the relative absence of these cells in the circulation ex vivo is not due to a rapid accumulation to the tumor side. Taken together, these results suggest that the lack of sufficient CD4+ T-cell help, especially within the tumor tissue, may be one central mechanism responsible for the failure of AFP-specific immune responses to control HCC progression.

Expansion of interferon-gamma-producing multifunctional CD4+ T-cells and dysfunctional CD8+ T-cells by glypican-3 peptide library in hepatocellular carcinoma patients

Glypican-3 is a promising target for immunotherapy for hepatocellular carcinoma, but limited data exist regarding its immunogenicity in patients with diverse HLA types, immunogenicity for CD4(+) T-cells, and the impact of inhibitory co-stimulation on glypican-3-specific T-cells. Using a 15mer overlapping peptide library for glypican-3, PBMC from patients with HCC were assessed ex vivo and after short-term in vitro expansion for tumor antigen-specific T-cell responses with and without blockade of PD-1/PD-L1 and CTLA-4 signaling. Glypican-3-specific T-cells were undetectable ex vivo, but primarily IFNγ(+)TNFα(+) CD4(+) T-cells expanded with short-term in vitro stimulation in 10/19 (52%) patients. Glypican-3-specific CD8(+) T-cells predominantly produced TNFα, but did not secrete IFNγ nor degranulate. CTLA-4 and PD-1 blockade minimally impacted the cytokine secretion and proliferation of glypican-3-specific T-cells. These data suggest that CD8(+) T-cell-directed tumor vaccines in HCC may have limited potential for efficacy unless optimal co-stimulation conditions can be identified but CD4(+)-directed vaccines merit consideration.

Alpha-fetoprotein specific CD4 and CD8 T cell responses in patients with hepatocellular carcinoma

The presence of CD8 T cell responses to tumor associated antigens have been reported in patients with different malignancies. However, there is very little information on a comparable CD8 and CD4 T cell response to a tumor antigen in liver cancer patients. Here, we re-examine the kinetic and the pattern of T helper 1 and cytotoxic T lymphocyte responses to alpha-fetoprotein (AFP), a tumor rejection antigen in hepatocellular carcinoma (HCC). Then, we discuss the possibility of using AFP-based immunotherapy in combination with necrotizing treatments in HCC patients.