Epitope-optimized alpha-fetoprotein genetic vaccines prevent carcinogen-induced murine autochthonous hepatocellular carcinoma

Alpha-fetoprotein: Past, present, and future

Alpha-fetoprotein (AFP) is a glycoprotein that plays an important role in immune regulation with critical involvement in early human development and maintaining the immune balance during pregnancy. Postfetal development, the regulatory mechanisms controlling AFP undergo a shift and AFP gene transcription is suppressed. Instead, these enhancers refocus their activity to maintain albumin gene transcription throughout adulthood. During the postnatal period, AFP expression can increase in the setting of hepatocyte injury, regeneration, and malignant transformation. It is the first oncoprotein discovered and is routinely used as part of a screening strategy for HCC. AFP has been shown to be a powerful prognostic biomarker, and multiple HCC prognosis models confirmed the independent prognostic utility of AFP. AFP is also a useful predictive biomarker for monitoring the treatment response of HCC. In addition to its role as a biomarker, AFP plays important roles in immune modulation to promote tumorigenesis and thus has been investigated as a therapeutic target in HCC. In this review article, we aim to provide an overview of AFP, encompassing the discovery, biological role, and utility as an HCC biomarker in combination with other biomarkers and how it impacts clinical practice and future direction.

Genetic fusion of CCL11 to antigens enhances antigenicity in nucleic acid vaccines and eradicates tumor mass through optimizing T-cell response

Nucleic acid vaccines have shown promising potency and efficacy for cancer treatment with robust and specific T-cell responses. Improving the immunogenicity of delivered antigens helps to extend therapeutic efficacy and reduce dose-dependent toxicity. Here, we systematically evaluated chemokine-fused HPV16 E6/E7 antigen to improve the cellular and humoral immune responses induced by nucleotide vaccines in vivo. We found that fusion with different chemokines shifted the nature of the immune response against the antigens. Although a number of chemokines were able to amplify specific CD8 + T-cell or humoral response alone or simultaneously. CCL11 was identified as the most potent chemokine in improving immunogenicity, promoting specific CD8 + T-cell stemness and generating tumor rejection. Fusing CCL11 with E6/E7 antigen as a therapeutic DNA vaccine significantly improved treatment effectiveness and caused eradication of established large tumors in 92% tumor-bearing mice (n = 25). Fusion antigens with CCL11 expanded the TCR diversity of specific T cells and induced the infiltration of activated specific T cells, neutrophils, macrophages and dendritic cells (DCs) into the tumor, which created a comprehensive immune microenvironment lethal to tumor. Combination of the DNA vaccine with anti-CTLA4 treatment further enhanced the therapeutic effect. In addition, CCL11 could also be used for mRNA vaccine design. To summarize, CCL11 might be a potent T cell enhancer against cancer.

Complete remission of tumors in mice with neoantigen-painted exosomes and anti-PD-1 therapy

Neoantigen-based cancer vaccines are emerging as promising tumor therapies, but enhancement of immunogenicity can further improve therapeutic outcomes. Here, we demonstrate that anchoring different peptide neoantigens on subcutaneously administered serum exosomes promote lymph node homing and dendritic cell uptake, resulting in significantly enhanced antigenicity in vitro and in vivo. Exosomes anchoring of melanoma peptide neoantigens augmented the magnitude and breadth of T cell response in vitro and in vivo, to a greater extent with CD8+ T cell responses. Simultaneous decoration of different peptide neoantigens on serum exosomes induced potent tumor suppression and neoantigen-specific immune responses in mice with melanoma and colon cancer. Complete tumor eradication and sustainable immunological memory were achieved with neoantigen-painted serum exosome vaccines in combination with programmed cell death protein 1 (PD-1) antibodies in mice with colon cancer. Importantly, human serum exosomes loaded with peptide neoantigens elicited significant tumor growth retardation and immune responses in human colon cancer 3-dimensional (3D) multicellular spheroids. Our study demonstrates that serum exosomes direct in vivo localization, increase dendritic cell uptake, and enhance the immunogenicity of antigenic peptides and thus provides a general delivery tool for peptide antigen-based personalized immunotherapy.

The Current Status of the Liver Liquid Biopsy in MASH Related HCC: Overview and Future Directions

Metabolic dysfunction-associated steatohepatitis (MASH) is one of the major risk factors for chronic liver disease and hepatocellular carcinoma (HCC). The incidence of MASH in Western countries continues to rise, driving HCC as the third cause of cancer-related death worldwide. HCC has become a major global health challenge, partly from the obesity epidemic promoting metabolic cellular disturbances but also from the paucity of biomarkers for its early detection. Over 50% of HCC cases are clinically present at a late stage, where curative measures are no longer beneficial. Currently, there is a paucity of both specific and sensitive biological markers for the early-stage detection of HCC. The search for biological markers in the diagnosis of early HCC in high-risk populations is intense. We described the potential role of surrogates for a liver biopsy in the screening and monitoring of patients at risk for nesting HCC.

Combination of AFP vaccine and immune checkpoint inhibitors slows hepatocellular carcinoma progression in preclinical models

Many patients with hepatocellular carcinoma (HCC) do not respond to the first-line immune checkpoint inhibitor treatment. Immunization with effective cancer vaccines is an attractive alternative approach to immunotherapy. However, its efficacy remains insufficiently evaluated in preclinical studies. Here, we investigated HCC-associated self/tumor antigen, α-fetoprotein-based (AFP-based) vaccine immunization for treating AFP (+) HCC mouse models. We found that AFP immunization effectively induced AFP-specific CD8+ T cells in vivo. However, these CD8+ T cells expressed exhaustion markers, including PD1, LAG3, and Tim3. Furthermore, the AFP vaccine effectively prevented c-MYC/Mcl1 HCC initiation when administered before tumor formation, while it was ineffective against full-blown c-MYC/Mcl1 tumors. Similarly, anti-PD1 and anti-PD-L1 monotherapy showed no efficacy in this murine HCC model. In striking contrast, AFP immunization combined with anti-PD-L1 treatment triggered significant inhibition of HCC progression in most liver tumor nodules, while in combination with anti-PD1, it induced slower tumor progression. Mechanistically, we demonstrated that HCC-intrinsic PD-L1 expression was the primary target of anti-PD-L1 in this combination therapy. Notably, the combination therapy had a similar therapeutic effect in the cMet/β-catenin mouse HCC model. These findings suggest that combining the AFP vaccine and immune checkpoint inhibitors may be effective for AFP (+) HCC treatment.

A novel nomogram predicting the early recurrence of hepatocellular carcinoma patients after R0 resection

Background

Early tumor recurrence is one of the most significant poor prognostic factors for patients with HCC after R0 resection. The aim of this study is to identify risk factors of early recurrence, in addition, to develop a nomogram model predicting early recurrence of HCC patients.

Methods

A total of 481 HCC patients after R0 resection were enrolled and divided into a training cohort (n = 337) and a validation cohort (n = 144). Risk factors for early recurrence were determined based on Cox regression analysis in the training cohort. A nomogram incorporating independent risk predictors was established and validated.

Results

Early recurrence occurred in 37.8% of the 481 patients who underwent curative liver resection of HCC. AFP ≥ 400 ng/mL (HR: 1.662; P = 0.008), VEGF-A among 127.8 to 240.3 pg/mL (HR: 1.781, P = 0.012), VEGF-A > 240.3 pg/mL (HR: 2.552, P < 0.001), M1 subgroup of MVI (HR: 2.221, P = 0.002), M2 subgroup of MVI (HR: 3.120, P < 0.001), intratumor necrosis (HR: 1.666, P = 0.011), surgical margin among 5.0 to 10.0 mm (HR: 1.601, P = 0.043) and surgical margin < 5.0 mm (HR: 1.790, P = 0.012) were found to be independent risk factors for recurrence-free survival in the training cohort and were used for constructing the nomogram. The nomogram indicated good predictive performance with an AUC of 0.781 (95% CI: 0.729-0.832) and 0.808 (95% CI: 0.731-0.886) in the training and validation cohorts, respectively.

Conclusions

Elevated serum concentrations of AFP and VEGF-A, microvascular invasion, intratumor necrosis, surgical margin were independent risk factors of early intrahepatic recurrence. A reliable nomogram model which incorporated blood biomarkers and pathological variables was established and validated. The nomogram achieved desirable effectiveness in predicting early recurrence in HCC patients.

Novel low-avidity glypican-3 specific CARTs resist exhaustion and mediate durable antitumor effects against HCC

BACKGROUND AND AIMS

Chimeric antigen receptor engineered T cells (CARTs) for HCC and other solid tumors are not as effective as they are for blood cancers. CARTs may lose function inside tumors due to persistent antigen engagement. The aims of this study are to develop low-affinity monoclonal antibodies (mAbs) and low-avidity CARTs for HCC and to test the hypothesis that low-avidity CARTs can resist exhaustion and maintain functions in solid tumors, generating durable antitumor effects.

METHODS AND RESULTS

New human glypican-3 (hGPC3) mAbs were developed from immunized mice. We obtained three hGPC3-specific mAbs that stained HCC tumors, but not the adjacent normal liver tissues. One of them, 8F8, bound an epitope close to that of GC33, the frequently used high-affinity mAb, but with approximately 17-fold lower affinity. We then compared the 8F8 CARTs to GC33 CARTs for their in vitro function and in vivo antitumor effects. In vitro, low-avidity 8F8 CARTs killed both hGPC3high and hGPC3low HCC tumor cells to the same extent as high-avidity GC33 CARTs. 8F8 CARTs expanded and persisted to a greater extent than GC33 CARTs, resulting in durable responses against HCC xenografts. Importantly, compared with GC33 CARTs, there were 5-fold more of 8F8-BBz CARTs in the tumor mass for a longer period of time. Remarkably, the tumor-infiltrating 8F8 CARTs were less exhausted and apoptotic, and more functional than GC33 CARTs.

CONCLUSION

The low-avidity 8F8-BBz CART resists exhaustion and apoptosis inside tumor lesions, demonstrating a greater therapeutic potential than high-avidity CARTs.

Universal immunotherapeutic strategy for hepatocellular carcinoma with exosome vaccines that engage adaptive and innate immune responses

Background

Personalized immunotherapy utilizing cancer vaccines tailored to the tumors of individual patients holds promise for tumors with high genetic heterogeneity, potentially enabling eradication of the tumor in its entirety.

Methods

Here, we demonstrate a general strategy for biological nanovaccines that trigger tailored tumor-specific immune responses for hepatocellular carcinoma (HCC). Dendritic cell (DC)-derived exosomes (DEX) are painted with a HCC-targeting peptide (P47-P), an α-fetoprotein epitope (AFP212-A2) and a functional domain of high mobility group nucleosome-binding protein 1 (N1ND-N), an immunoadjuvant for DC recruitment and activation, via an exosomal anchor peptide to form a “trigger” DEX vaccine (DEX_P&A2&N).

Results

DEX_P&A2&N specifically promoted recruitment, accumulation and activation of DCs in mice with orthotopic HCC tumor, resulting in enhanced cross-presentation of tumor neoantigens and de novo T cell response. DEX_P&A2&N elicited significant tumor retardation and tumor-specific immune responses in HCC mice with large tumor burdens. Importantly, tumor eradication was achieved in orthotopic HCC mice when antigenic AFP peptide was replaced with the full-length AFP (A) to form DEX_P&A&N. Supplementation of Fms-related tyrosine kinase 3 ligand greatly augmented the antitumor immunity of DEX_P&A&N by increasing immunological memory against tumor re-challenge in orthotopic HCC mice. Depletion of T cells, cross-presenting DCs and other innate immune cells abrogated the functionality of DEX_P&A&N.

Conclusions

These findings demonstrate the capacity of universal DEX vaccines to induce tumor-specific immune responses by triggering an immune response tailored to the tumors of each individual, thus presenting a generalizable approach for personalized immunotherapy of HCC, by extension of other tumors, without the need to identify tumor antigens.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13045-022-01266-8.

Research Progress in Alpha-Fetoprotein-Induced Immunosuppression of Liver Cancer

Abstract:

Liver cancer is one of the most common malignant tumors, with limited treatment and 8.2% high mortality. Liver cancer is the fourth leading cause of cancer-related deaths, which seriously endangers human life and health. Approximately 70% of liver cancer patients show increased serum alpha-fetoprotein (AFP) levels. AFP is the main diagnostic and prognostic indicator of liver cancer. AFP, a key marker of liver cancer, plays a crucial role in regulating the proliferation of tumor cells, apoptosis, and induction of cellular immune escape. High levels of AFP during embryonic development protect the embryos from maternal immune attack. AFP also promotes immune escape of liver cancer cells by inhibiting tumor-infiltrating lymphocytes (TILs), natural killer cells (NK), dendritic cells (DC), and macrophages; thus, it is also used as a target antigen in immunotherapy for liver cancer. AFP is highly expressed in liver cancer cells. In addition to being used in the diagnosis of liver cancer, it has become a target of immunotherapy for liver cancer as a tumor-associated antigen. In immunotherapy, it was also confirmed that early AFP response was positively correlated with the efficacy of immunotherapy. Early AFP responders had longer PFS and OS than non-responders. At present, the methods of immunotherapy for liver cancer mainly include Adoptive Cell Transfer Therapy (ACT), tumor vaccine therapy, immune checkpoint inhibitors (ICIs) therapy and so on. A large number of studies have shown that AFP mainly plays a role in ACT and liver cancer vaccines. This review presents the research progress of AFP and immunosuppression of liver cancer.

Molecular classification of hepatocellular carcinoma: prognostic importance and clinical applications

Hepatocellular carcinoma (HCC) is a lethal human malignancy with a very low overall and long-term survival rate. Poor prognostic outcomes are predominantly associated with HCC due to a huge landscape of heterogeneity found in the deadliest disease. However, molecular subtyping of HCC has significantly improved the knowledge of the underlying mechanisms that contribute towards the heterogeneity and progression of the disease. In this review, we have extensively summarized the current information available about molecular classification of HCC. This review can be of great significance for providing the insight information needed for development of novel, efficient and personalized therapeutic options for the treatment of HCC patients globally.

Hepatocellular carcinoma (HCC): the most promising therapeutic targets in the preclinical arena based on tumor biology characteristics

INTRODUCTION

: Hepatocellular carcinoma (HCC) is a malignant liver tumor characterized by high molecular heterogeneity, which has hampered the development of effective targeted therapies severely. Recent experimental data have unraveled novel promising targets for HCC treatment.

AREAS COVERED

: Eligible articles were retrieved from PubMed and Web of Science databases up to July 2021. This review summarizes the established targeted therapies for advanced HCC, focusing on the strategies to overcome drug resistance and the search for combinational treatments. In addition, conventional biomarkers holding the promises for HCC treatments and novel therapeutic targets from the research field are discussed.

EXPERT OPINION

: HCC is a molecularly complex disease, with several and distinct pathways playing critical roles in different tumor subtypes. Experimental models recapitulating the features of each tumor subset would be highly beneficial to design novel and more effective therapies against this disease. Furthermore, a deeper understanding of combinatorial drug synergism and the role of the tumor microenvironment in HCC will lead to improved therapeutic outcomes.

Towards customized cancer vaccines: a promising filed in personalized cancer medicine

INTRODUCTION

Cancer remains a major source of disease burden worldwide. Although cancer vaccines have been developed, most currently available cancer vaccines have limited therapeutic efficacy. Recent research using novel sequencing and bioinformatic tools has led scientists to realize that each tumor harbors a unique set of genetic mutations that can manifest as tumor-specific neoantigens. Therefore, it would be useful to develop personalized cancer vaccines that target neoantigens, which might improve the efficacy of these cancer treatments.

AREAS COVERED

This review covers cancer vaccine development and the emerging field of personalized cancer vaccines, with a discussion of future clinical trials for this promising treatment strategy.

EXPERT OPINION

Developing vaccines to treat tumors is one of the most promising and exciting fields in cancer research. However, cancer vaccines have shown limited efficacy in clinical trials for several decades, which may be related to the unique and complex processes underlying tumor development and progression. Recent studies have indicated that tumors express highly specific neoantigens, which are distinct from self-antigens. Thus, developing cancer vaccines that target these tumor-specific neoantigens is a promising strategy for developing personalized cancer vaccines.

In Silico Design of a Novel Multi-Epitope Peptide Vaccine Against Hepatocellular Carcinoma

Background:

Hepatocellular Carcinoma (HCC) is a prevalent cancer in the world. As yet, there is no medication for complete treatment of HCC.

Objective:

There is a critical need to search for an innovative therapy for HCC. Recently, multiepitope vaccines have been introduced as effective immunotherapy approach against HCC.

Methods:

In this research, several immunoinformatics methods were applied to create an original multi-epitope vaccine against HCC consisting of CD8+ cytolytic T lymphocytes (CTLs) epitopes selected from α- fetoprotein (AFP), glypican-3 (GPC3), aspartyl-β-hydroxylase (ASPH); CD4+ helper T lymphocytes (HTLs) epitopes from tetanus toxin fragment C (TTFC), and finally, two tandem repeats of HSP70407-426 were used which stimulated strong innate and adaptive immune responses. All the mentioned parts were connected together by relevant linkers.

Results:

According to physicochemical, structural, and immunological results, the designed vaccine is stable, non-allergen, antigen; it also has a high-quality 3D structure, and numerous linear and conformational B cell epitopes, whereby this vaccine may stimulate efficient humoral immunity.

Conclusion:

Center on the collected results, the designed vaccine potentially can induce cellular and humoral immune responses in HCC cases; nonetheless, the efficiency of vaccine must be approved within in vitro and in vivo immunological analyzes.

Translational Considerations to Improve Response and Overcome Therapy Resistance in Immunotherapy for Hepatocellular Carcinoma

Over the last decade, progress in systemic therapies significantly improved the outcome of primary liver cancer. More recently, precision oncological and immunotherapeutic approaches became the focus of intense scientific and clinical research. Herein, preclinical studies showed promising results with high response rates and improvement of overall survival. However, results of phase III clinical trials revealed that only a subfraction of hepatocellular carcinoma (HCC) patients respond to therapy and display only moderate objective response rates. Further, predictive molecular characteristics are largely missing. In consequence, suitable trial design has emerged as a crucial factor for the success of a novel compound. In addition, increasing knowledge from translational studies indicate the importance of targeting the tumor immune environment to overcome resistance to immunotherapy. Thus, combination of different immunotherapies with other treatment modalities including antibodies, tyrosine kinase inhibitors, or local therapies is highly promising. However, the mechanisms of failure to respond to immunotherapy in liver cancer are still not fully understood and the modulation of the immune system and cellular tumor composition is particularly relevant in this context. Altogether, it is increasingly clear that tailoring of immunotherapy and individualized approaches are required to improve efficacy and patient outcome in liver cancer. This review provides an overview of the current knowledge as well as translational considerations to overcome therapy resistance in immunotherapy of primary liver cancer.

Alarmin-painted exosomes elicit persistent antitumor immunity in large established tumors in mice

Treating large established tumors is challenging for dendritic cell (DC)-based immunotherapy. DC activation with tumor cell-derived exosomes (TEXs) carrying multiple tumor-associated antigen can enhance tumor recognition. Adding a potent adjuvant, high mobility group nucleosome-binding protein 1 (HMGN1), boosts DCs’ ability to activate T cells and improves vaccine efficiency. Here, we demonstrate that TEXs painted with the functional domain of HMGN1 (TEX-N1ND) via an exosomal anchor peptide potentiates DC immunogenicity. TEX-N1ND pulsed DCs (DC_TEX-N1ND) elicit long-lasting antitumor immunity and tumor suppression in different syngeneic mouse models with large tumor burdens, most notably large, poorly immunogenic orthotopic hepatocellular carcinoma (HCC). DC_TEX-N1ND show increased homing to lymphoid tissues and contribute to augmented memory T cells. Importantly, N1ND-painted serum exosomes from cancer patients also promote DC activation. Our study demonstrates the potency of TEX-N1ND to strengthen DC immunogenicity and to suppress large established tumors, and thus provides an avenue to improve DC-based immunotherapy.

The use of tumour exosome-activated dendritic cell (DC) immunotherapy shows promise for the treatment of large established tumours. Here, the authors generate alarmin HMGN1-attached tumour exosomes which significantly improve therapy efficacy by boosting DC activation in several preclinical mouse models.

Engineering T cells for immunotherapy of primary human hepatocellular carcinoma

Liver cancers, majority of which are primary hepatocellular carcinoma (HCC), continue to be on the rise in the world. Furthermore, due to the lack of effective treatments, liver cancer ranks the 4^th most common cause of male cancer deaths. Novel therapies are urgently needed. Over the last few years, immunotherapies, especially the checkpoint blockades and adoptive cell therapies of engineered T cells, have demonstrated a great potential for treating malignant tumors including HCC. In this review, we summarize the current ongoing research of antigen-specific immunotherapies including cancer vaccines and adoptive cell therapies for HCC. We briefly discuss the HCC cancer vaccine and then focus on the antigen-specific T cells genetically engineered with the T cell receptor genes (TCRTs) and the chimeric antigen receptor genes (CARTs). We first review the current options of TCRTs and CARTs immunotherapies for HCC, and then analyze the factors and parameters that may help to improve the design of TCRTs and CARTs to enhance their antitumor efficacy and safety. Our goals are to render readers a panoramic view of the current stand of HCC immunotherapies and provide some strategies to design better TCRTs and CARTs to achieve more effective and durable antitumor effects.

The immunobiology of hepatocellular carcinoma in humans and mice: Basic concepts and therapeutic implications

Basic and clinical studies have demonstrated the efficacy of immunotherapy, a technical and conceptual breakthrough that has revolutionised cancer treatment. Hepatocellular carcinoma (HCC), a deadly malignancy with aetiologic diversity and a chronic course, is strongly influenced by the immune system, and was recently found to partially benefit from immune-checkpoint inhibitor therapy. Notably, HCC onco-immunology depends on diverse genetic and environmental factors that together shape cancer-promoting inflammation and immune dysfunction - critical processes that control HCC malignant progression and response to therapy. Herein, we summarise the current understanding of liver and HCC onco-immunology obtained through basic studies with mouse models and clinical practice in humans. In particular, we discuss preclinical and clinical findings that implicate immunomodulation as a major factor in HCC development and explain the basis for HCC-targeting immunotherapy.

From bench to bed: the tumor immune microenvironment and current immunotherapeutic strategies for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) ranks the most common primary liver malignancy and the third leading cause of tumor-related mortality worldwide. Unfortunately, despite advances in HCC treatment, less than 40% of HCC patients are eligible for potentially curative therapies. Recently, cancer immunotherapy has emerged as one of the most promising approaches for cancer treatment. It has been proven therapeutically effective in many types of solid tumors, such as non-small cell lung cancer and melanoma. As an inflammation-associated tumor, it's well-evidenced that the immunosuppressive microenvironment of HCC can promote immune tolerance and evasion by various mechanisms. Triggering more vigorous HCC-specific immune response represents a novel strategy for its management. Pre-clinical and clinical investigations have revealed that various immunotherapies might extend current options for needed HCC treatment. In this review, we provide the recent progress on HCC immunology from both basic and clinical perspectives, and discuss potential advances and challenges of immunotherapy in HCC.

Alarmin augments the antitumor immunity of lentiviral vaccine in ectopic, orthotopic and autochthonous hepatocellular carcinoma mice

It is a daunting therapeutic challenge to completely eradicate hepatocellular carcinoma (HCC) from patients. Alpha-fetoprotein (AFP) -based vaccines appear promising, however the efficacy needs to be improved.

Methods: Here, we explore if fusing high-mobility group nucleosome binding protein 1 (HMGN1), a potent immunoadjuvant, to AFP (lenti-HA) can augment the antitumor immunity of AFP-expressing lentiviral vector (lenti-AFP), a vehicle extensively employed for genetic immunization with high transduction efficacy and good safety profiles. The antitumor immunity of Lenti-HA was systemically assessed in ectopic, orthotopic and autochthonous HCC models.

Results: Lenti-HA elicited strong anti-HCC effects in mice and amplified the antitumor immunity of lenti-AFP by reducing effective dose 6-fold. Importantly, lenti-HA induced a robust antitumor immune response with prolonged survival rate and improved the immune and tumor microenvironment in mice with carcinogen-induced autochthonous HCC. Lenti-HA localized primarily to lymphoid organs with no preference for specific immune cell types. Activated dendritic cells (DCs), particularly CD103⁺CD11b^- DCs, were also actively recruited to lymph nodes in lenti-HA-treated HCC mice. Moreover, lenti-HA-transduced human DCs elicited stronger immune response than lenti-AFP against HCC cells in vitro.

Conclusion: Our study demonstrates that HMGN1 augments the antitumor immunity of AFP-expressing lentiviral vaccines in HCC mice and human cells in vitro and thus provides a new therapeutic strategy for HCC.

Down-regulation of siglec-2 (CD22) predicts worse overall survival from HBV-related early-stage hepatocellular carcinoma: a preliminary analysis from Gene Expression Omnibus

Sialic-acid-binding immunoglobulin-like lectin (siglec) regulates cell death, anti-proliferative effects and mediates a variety of cellular activities. Little was known about the relationship between siglecs and hepatocellular carcinoma (HCC) prognosis. Siglec gene expression between tumor and non-tumor tissues were compared and correlated with overall survival (OS) from HCC patients in GSE14520 microarray expression profile. Siglec-1 to siglec-9 were all down-regulated in tumor tissues compared with those in non-tumor tissues in HCC patients (all P < 0.05). Univariate and multivariate Cox regression analysis revealed that siglec-2 overexpression could predict better OS (HR = 0.883, 95%CI = 0.806-0.966, P = 0.007). Patients with higher siglec-2 levels achieved longer OS months than those with lower siglec-2 levels in the Kaplan-Meier event analysis both in training and validation sets (P < 0.05). Alpha-fetoprotein (AFP) levels in siglec-2 low expression group were significantly higher than those in siglec-2 high expression group using Chi-square analysis (P = 0.043). In addition, both logistic regression analysis and ROC curve method showed that siglec-2 down-regulation in tumor tissues was significantly associated with AFP elevation over 300 ng/ml (P < 0.05). In conclusion, up-regulation of siglec-2 in tumor tissues could predict better OS in HCC patients. Mechanisms of siglec-2 in HCC development need further research.

Identification of α-fetoprotein-specific T-cell receptors for hepatocellular carcinoma immunotherapy

Hepatocellular carcinoma (HCC) is the major form of liver cancer for which there is no effective therapy. Genetic modification with T-cell receptors (TCRs) specific for HCC-associated antigens, such as α-fetoprotein (AFP), can potentially redirect human T cells to specifically recognize and kill HCC tumor cells to achieve antitumor effects. In this study, using lentivector and peptide immunization, we identified a population of cluster of differentiation 8 (CD8) T cells in human leukocyte antigen (HLA)-A2 transgenic AAD mice that recognized AFP₁₅₈ epitope on human HCC cells. Adoptive transfer of the AFP₁₅₈ -specific mouse CD8 T cells eradicated HepG2 tumor xenografts as large as 2 cm in diameter in immunocompromised nonobese diabetic severe combined immunodeficient gamma knockout (NSG) mice. We then established T-cell hybridoma clones from the AFP₁₅₈ -specific mouse CD8 T cells and identified three sets of paired TCR genes out of five hybridomas. Expression of the murine TCR genes redirected primary human T cells to bind HLA-A2/AFP₁₅₈ tetramer. TCR gene-engineered human T (TCR-T) cells also specifically recognized HLA-A2⁺ AFP⁺ HepG2 HCC tumor cells and produced effector cytokines. Importantly, the TCR-T cells could specifically kill HLA-A2⁺ AFP⁺ HepG2 tumor cells without significant toxicity to normal primary hepatocytes in vitro. Adoptive transfer of the AFP-specific TCR-T cells could eradicate HepG2 tumors in NSG mice.

CONCLUSION

We have identified AFP-specific murine TCR genes that can redirect human T cells to specifically recognize and kill HCC tumor cells, and those AFP₁₅₈ -specific TCRs have a great potential to engineer a patient's autologous T cells to treat HCC tumors. (Hepatology 2018).

Immunization with glypican-3 nanovaccine containing TLR7 agonist prevents the development of carcinogen-induced precancerous hepatic lesions to cancer in a murine model

BACKGROUND

Glypican-3 (GPC3) is one of the key tissue markers that could discriminate malignant precancerous lesions from benign hepatic lesions in cirrhotic patients. We aimed to develop a GPC3 cancer vaccine to induce specific T cells to intervene in hepatocellular carcinoma (HCC) development.

METHODS

Synthesizing mannosylated liposomes (LPMan) as vaccine delivery system, incorporating one Toll-like receptor (TLR)-7/8 agonist CL097 as adjuvant, we prepared a GPC3 nanovaccine, LPMan-GPC3/CL097. We injected 25 mg/kg diethylnitrosamine intraperitoneally to induce autochthonous HCC in HBV-transgenic mice, which persistently express hepatitis B surface antigen in hepatocytes. Starting from week 8 after diethylnitrosamine injection when malignant hepatocytes generated, we immunized the mice subcutaneously every 2 weeks 4 times with LPMan-GPC3/CL097 containing 5 µg of GPC3 plus 5 µg of CL097.

RESULTS

The vaccine efficiently targeted draining lymph nodes where naïve T cells reside and enhanced the expression of molecules involved in antigen presentation in migratory dendritic cells (DCs). Antigen was professionally processed in endoplasmic reticulum-Golgi system of DCs, subsequently priming both CD4⁺ and CD8⁺ T cells. The LPMan-GPC3/CL097 immunization generated significantly more GPC3-specific CD4⁺ IFNγ- and CD8⁺ IFNγ-producing T cells in mice spleens and livers, which specifically eliminated GPC3-expressing tumor cells. One week after last immunization (week 15 after diethylnitrosamine), 5/5 un-immunized, 5/5 sham (LPMan-CL097) and 1/5 LPMan-GPC3/CL097-immunized mice developed HCC. By week 20 after diethylnitrosamine, significantly less HCC developed in LPMan-GPC3/CL097-immunized mice than in sham-immunized mice (P<0.01).

CONCLUSIONS

LPMan-GPC3/CL097 immunization induced de novo generation of specific T cells against tumor-associated antigen GPC3 that could prevent HCC development in cirrhotic liver.

In vitro modeling of hepatocellular carcinoma molecular subtypes for anti-cancer drug assessment

Tractable experimental model that accounts for inter-tumor molecular heterogeneity is a key element of anti-cancer drug development. Hepatocellular carcinoma is known to exhibit highly heterogeneous molecular aberrations across the tumors, including somatic genetic and epigenetic alterations. Previous studies showed that molecular tumor subtypes determined by transcriptome, as a comprehensive functional readout, are reproducibly observed across global patient populations irrespective of geographic and etiological variations. Here we demonstrate that transcriptomic hepatocellular carcinoma subtypes, S1 and S2, determined by our previous transcriptome meta-analysis of multiple clinical hepatocellular carcinoma cohorts, are presented in a panel of hepatoma cell lines widely used by the research community. Interestingly, cell line that resembles gene expression pattern of S3 subtype, representing less aggressive tumors, was not identified in the panel. MYC pathway-activated S2-like cell lines showed higher sensitivity to a small molecule BET bromodomain inhibitor, (+)-JQ1, which has anti-MYC activity. These results support the use of hepatoma cell lines as models to evaluate molecular subtype-specific drug response, which is expected to lead to development of tailored, precision care of the patients with hepatocellular carcinoma.

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.

Dendritic cell-derived exosomes elicit tumor regression in autochthonous hepatocellular carcinoma mouse models

BACKGROUND & AIMS

Dendritic cell (DC)-derived exosomes (DEXs) form a new class of vaccines for cancer immunotherapy. However, their potency in hepatocellular carcinoma (HCC), a life-threatening malignancy with limited treatment options in the clinic that responds poorly to immunotherapy, remains to be investigated.

METHODS

Exosomes derived from α-fetoprotein (AFP)-expressing DCs (DEX_AFP) were investigated in three different HCC mouse models systemically. Tumor growth and microenvironment were monitored.

RESULTS

DEX_AFP elicited strong antigen-specific immune responses and resulted in significant tumor growth retardation and prolonged survival rates in mice with ectopic, orthotopic and carcinogen-induced HCC tumors that displayed antigenic and pathological heterogeneity. The tumor microenvironment was improved in DEX_AFP-treated HCC mice, demonstrated by significantly more γ-interferon (IFN-γ)-expressing CD8⁺ T lymphocytes, elevated levels of IFN-γ and interleukin-2, and fewer CD25⁺Foxp3⁺ regulatory T (Treg) cells and decreased levels of interleukin-10 and transforming growth factor-β in tumor sites. Lack of efficacy in athymic nude mice and CD8⁺ T cell-depleted mice showed that T cells contribute to DEX_AFP-mediated antitumor function. Dynamic examination of the antitumor efficacy and the immune microenvironment in DEX_AFP-treated orthotopic HCC mice at different time-points revealed a positive correlation between tumor suppression and immune microenvironment.

CONCLUSIONS

Our findings provide evidence that AFP-enriched DEXs can trigger potent antigen-specific antitumor immune responses and reshape the tumor microenvironment in HCC mice and thus provide a cell-free vaccine option for HCC immunotherapy. Lay summary: Dendritic cell (DC)-derived exosomes (DEXs) form a new class of vaccines for cancer immunotherapy. However, their potency in hepatocellular carcinoma (HCC) remains unknown. Here, we investigated exosomes from HCC antigen-expressing DCs in three different HCC mouse models and proved their feasibility and capability of treating HCC, and thus provide a cell-free vaccine for HCC immunotherapy.

The Antitumor Effects of Vaccine-Activated CD8+ T Cells Associate with Weak TCR Signaling and Induction of Stem-Like Memory T Cells

To understand why vaccine-activated tumor-specific T cells often fail to generate antitumor effects, we studied two α-fetoprotein-specific CD8⁺ T cells (Tet₄₉₉ and Tet₂₁₂) that had different antitumor effects. We found that Tet₄₉₉ required high antigen doses for reactivation, but could survive persistent antigen stimulation and maintain their effector functions. In contrast, Tet₂₁₂ had a low threshold of reactivation, but underwent exhaustion and apoptosis in the presence of persistent antigen. In vivo, Tet₄₉₉ cells expanded more than Tet₂₁₂ upon reencountering antigen and generated stronger antitumor effects. The different antigen responsiveness and antitumor effects of Tet₂₁₂ and Tet₄₉₉ cells correlated with their activation and differentiation states. Compared with Tet₂₁₂, the population of Tet₄₉₉ cells was less activated and contained more stem-like memory T cells (Tscm) that could undergo expansion in vivo The TCR signaling strength on Tet₄₉₉ was weaker than Tet₂₁₂, correlating with more severe Tet₄₉₉ TCR downregulation. Weak TCR signaling may halt T-cell differentiation at the Tscm stage during immune priming and also explains why Tet₄₉₉ reactivation requires a high antigen dose. Weak TCR signaling of Tet₄₉₉ cells in the effector stage will also protect them from exhaustion and apoptosis when they reencounter persistent antigen in tumor lesion, which generates antitumor effects. Further investigation of TCR downregulation and manipulation of TCR signaling strength may help design cancer vaccines to elicit a mix of tumor-specific CD8⁺ T cells, including Tscm, capable of surviving antigen restimulation to generate antitumor effects. Cancer Immunol Res; 5(10); 908-19. ©2017 AACR.

Prediction and preliminary screening of HLA-A*0201-restricted epitope peptides of human GPC3

In response to the limited therapeutic option for hepatocellular carcinoma (HCC), immunotherapy as a promising approach points out a new direction to the cure of tumours through specific recognition and elimination of tumour cells by the immunity-enhanced autologous immunocytes of patients. Few effective tumour antigens, however, are alternative in addition to alpha fetoprotein or tumour cell lysates. Recent studies have demonstrated that glypican-3 (GPC3) is not only a promising diagnostic marker, but also ideal therapeutic target to HCC. In this study, potential HLA-A*0201 GPC3 peptides were screened with three epitope prediction software, the binding affinity of 13 predicted epitopes with high scores was determined by T2 cells binding assay and four optimal epitopes were identified. This is the first study in which the optimal HLA-A*0201 GPC3 epitopes were screened from a large number of candidates predicted by three software. The optimized HLA-A*0201 GPC3 peptides will provide new epitope candidates for HCC immunotherapy.

Clinical implications of basic research in hepatocellular carcinoma

A 58-year old Caucasian female has compensated hepatitis C related cirrhosis. Her surveillance ultrasound showed hypodense liver nodules and subsequent triple phase CT scan showed five tumor nodules with diameters ranging from 3-5cms involving both hepatic lobes. The nodules showed characteristic radiologic findings on the CT scan and she was diagnosed with hepatocellular carcinoma (HCC) based on non-invasive criteria. There was also associated right portal vein tumor thrombosis. Her functional capacity at diagnosis was slightly limited, but she was capable of performing all activities of daily living and self-care. Her laboratory tests at diagnosis were as follows: sodium 129mmol/L, potassium 3.6mmol/L, blood urea nitrogen 22mg/dL, creatinine 1.0mg/dL, albumin 2.9g/dl, bilirubin 1.8mg/dl, alanine aminotransferase 87U/L, aspartate aminotransferase 68U/L, alkaline phosphatase 139U/L, white blood cell 3.5x10(9)/L, hemoglobin 10.4, platelet count 73x10(9)/L, international normalized ratio 1.9 and alpha-fetoprotein 5200ng/ml. An upper endoscopy was negative for esophageal or gastric varices. Based on the tumor burden, presence of macrovascular invasion, ECOG performance status of 1 and Child-Pugh class A she was classified to have BCLC stage C HCC. She was started on sorafenib therapy at 400mg oral twice daily but unfortunately this had to be discontinued since she experienced severe diarrhea and skin rash. She now returns for follow-up and requests information on the available therapeutic options. This particular case scenario is not uncommon and does raise several clinically relevant questions: This review provides a comprehensive overview of the current state of HCC management and also examines the clinical implications of recent basic research in HCC.

Clinicopathological indices to predict hepatocellular carcinoma molecular classification

BACKGROUND & AIMS

Hepatocellular carcinoma (HCC) is the second most lethal cancer caused by lack of effective therapies. Although promising, HCC molecular classification, which enriches potential responders to specific therapies, has not yet been assessed in clinical trials of anti-HCC drugs. We aimed to overcome these challenges by developing clinicopathological surrogate indices of HCC molecular classification.

METHODS

Hepatocellular carcinoma classification defined in our previous transcriptome meta-analysis (S1, S2 and S3 subclasses) was implemented in an FDA-approved diagnostic platform (Elements assay, NanoString). Ninety-six HCC tumours (training set) were assayed to develop molecular subclass-predictive indices based on clinicopathological features, which were independently validated in 99 HCC tumours (validation set). Molecular deregulations associated with the histopathological features were determined by pathway analysis. Sample sizes for HCC clinical trials enriched with specific molecular subclasses were determined.

RESULTS

Hepatocellular carcinoma subclass-predictive indices were steatohepatitic (SH)-HCC variant and immune cell infiltrate for S1 subclass, macrotrabecular/compact pattern, lack of pseudoglandular pattern, and high serum alpha-foetoprotein (>400 ng/ml) for S2 subclass, and microtrabecular pattern, lack of SH-HCC and clear cell variants, and lower histological grade for S3 subclass. Macrotrabecular/compact pattern, a predictor of S2 subclass, was associated with the activation of therapeutically targetable oncogene YAP and stemness markers EPCAM/KRT19. BMP4 was associated with pseudoglandular pattern. Subclass-predictive indices-based patient enrichment reduced clinical trial sample sizes from 121, 184 and 53 to 30, 43 and 22 for S1, S2 and S3 subclass-targeting therapies respectively.

CONCLUSIONS

Hepatocellular carcinoma molecular subclasses can be enriched by clinicopathological indices tightly associated with deregulation of therapeutically targetable molecular pathways.

Molecular classification of hepatocellular carcinoma: potential therapeutic implications

Genomic profiling of hepatocellular carcinoma (HCC) tumors has elucidated recurrent molecular aberrations common or specific to disease etiology, patient race or geographic regions, allowing the classification of HCC tumors into subclasses sharing similar molecular and clinical characteristics. Previously reported transcriptome-based molecular subclasses have highlighted several common themes. Aggressive tumors are characterized by TP53 inactivation mutations and activation of pro-oncogenic signaling pathways, and further subclassified according to expression of stemness markers. The stemness marker-negative aggressive tumors display preferential TGF-β activation. Another group of less aggressive tumors contains a subclass characterized by CTNNB1 mutations accompanied with overexpression of liver-specific WNT targets such as GLUL. Molecular therapies selectively targeting features of the HCC subclasses have suggested their utility in enriching potential responders in clinical trials and guiding therapeutic decision-making for HCC patients.

Role of chemokine pathways in hepatobiliary cancer

Persistent hepatic inflammation resulting from hepatitis B or C virus infections (HBV or HCV, respectively), obesity-associated non-alcoholic steatohepatitis (NASH) or alcohol abuse is a hallmark feature of chronic liver diseases and appears to be an essential prerequisite of hepatocarcinogenesis. The inflammatory processes in the liver are regulated by various chemokines, which orchestrate the interaction between parenchymal liver cells, Kupffer cells (resident macrophages), hepatic stellate cells (HSC), endothelial cells, and infiltrating immune cells. In consequence, these cellular interactions result in the re-modeling of the hepatic microenvironment toward a pro-inflammatory, pro-fibrotic, pro-angiogenic and thus pre-neoplastic milieu. Once developed, liver neoplasms provoke pro- and anti-tumor immune responses that are also critically regulated through differential activation of chemokine pathways. With respect to hepatobiliary cancers, including hepatocellular carcinoma (HCC), gallbladder cancer and cholangiocellular carcinoma (cholangiocarcinoma), together belonging to the highest causes of cancer-related deaths worldwide, this review article will give an overview of chemokine pathways involved in both the establishment of a pro-tumorigenic microenvironment as well as the development and progression of hepatobiliary cancer. Pharmaceutical targeting of chemokine pathways is a promising approach to treat or even prevent hepatobiliary cancer.

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.

Immunotherapy for hepatocellular carcinoma: From basic research to clinical use

Hepatocellular carcinoma (HCC) is a common cancer worldwide with a poor prognosis. Few strategies have been proven efficient in HCC treatment, particularly for those patients not indicated for curative resection or transplantation. Immunotherapy has been developed for decades for cancer control and is attaining more attention as a result of encouraging outcomes of new strategies such as chimeric antigen receptor T cells and immune checkpoint blockade. Right at the front of the new era of immunotherapy, we review the immunotherapy in HCC treatment, from basic research to clinical trials, covering anything from immunomodulators, tumor vaccines and adoptive immunotherapy. The mechanisms, efficacy and safety as well as the approach particulars are unveiled to assist readers to gain a concise but extensive understanding of immunotherapy of HCC.

Current concepts of immune based treatments for patients with HCC: from basic science to novel treatment approaches

The recent approval of two immune checkpoint inhibitors for the treatment of malignant melanoma has sparked great interest by physicians and basic scientists searching for novel therapeutics for GI cancer. Chronic inflammation is recognised as a major risk factor for the development of hepatocellular carcinoma (HCC) and makes this type of cancer a potentially ideal target for an immune based treatment approach. Further evidence for a critical role of immune responses in patients with HCC is derived from the fact that immune signatures and profiles predict patients' outcome as well as the fact that tumour-induced spontaneous antitumour immunity can be detected. In addition ablative therapies can lead to changes in the number, phenotype and function of different immune cell subsets, which correlate with patients' survival. Various HCC-specific mouse models have been developed, which improve our understanding of hepatocarcinogenesis and tumour-immune cell interactions, and lead to the development of novel immune based treatment approaches, which are currently being evaluated in preclinical and in early clinical settings. Immune checkpoint blockade along with adoptive immune cell therapy and vaccine approaches are currently being evaluated either alone or in combination with other treatments. Here, we provide an overview for the rationale of immunotherapy in HCC, summarise ongoing studies and provide a perspective for immune based approaches in patients with HCC.

Engineering α-fetoprotein-based gene vaccines to prevent and treat hepatocellular carcinoma: review and future prospects

Activation of a patient's immune system offers an attractive approach to prevent and treat hepatocellular carcinoma (HCC). However, the antitumor efficacy of current HCC vaccines was weak owing to insufficient immune activation of targeting self/tumor antigens. We recently found that epitope-optimized α-fetoprotein effectively activated CD8 T cells and generated potent antitumor effects in the carcinogen-induced autochthonous HCC mouse model. We predict that the same antigen engineering approach of epitope-optimization will enable us to develop effective human vaccines to prevent HCC recurrence after liver resection. The engineered human HCC vaccines may also allow us to identify high-affinity T-cell receptors and antibodies that can be used to reprogram T cells to treat HCC tumors via adoptive transfer.