Phase I/II multicenter trial of a novel therapeutic cancer vaccine, HepaVac-101, for hepatocellular carcinoma

Advancements in therapeutic peptides: Shaping the future of cancer treatment

In the evolving landscape of cancer treatment, therapeutic peptides are assuming to play an increasingly vital role. Although the number of peptide drugs available for clinical cancer treatment is currently limited, extensive preclinical research is underway, presenting a promising trajectory for the future. The collaborative efforts of natural anti-cancer peptides (ACPs) and synthetic ACPs, propelled by advancements in molecular biology and peptide chemistry, are steering remarkable progress in this domain. We explores the intricate mechanisms underlying the anti-cancer effects of these peptides. The exploration of innovative strategies, including cancer immunotherapy and advanced drug delivery systems, is likely to contribute to the increasing presenceuse of peptide drugs in clinical cancer care. Furthermore, we delve into the potential implications and challenges associated with this anticipated shift, empHasizing the need for continued research and development to unlock the full therapeutic potential of peptide drugs in cancer treatment.

Immune landscape of hepatocellular carcinoma: From dysregulation of the immune responses to the potential immunotherapies

Hepatocellular carcinoma (HCC) presents a considerable global health burden due to its late diagnosis and high morbidity. The liver's specific anatomical and physiological features expose it to various antigens, requiring precise immune regulation. To the best of our knowledge, this is the first time that a comprehensive overview of the interactions between the immune system and gut microbiota in the development of HCC, as well as the relevant therapeutic approaches are discussed. Dysregulation of immune compartments within the liver microenvironment drives HCC pathogenesis, characterized by elevated regulatory cells such as regulatory T cells (Tregs), myeloid-derived suppressor cells, and M2 macrophages as well as suppressive molecules, alongside reduced number of effector cells like T cells, natural killer cells, and M1 macrophages. Dysbiosis of gut microbiota also contributes to HCC by disrupting intestinal barrier integrity and triggering overactivated immune responses. Immunotherapy approaches, particularly immune checkpoint inhibitors, have exhibited promise in HCC management, yet adoptive cell therapy and cancer vaccination research are in the early steps with relatively less favorable outcomes. Further understanding of immune dysregulation, gut microbiota involvement, and therapeutic combination strategies are essential for advancing precision immunotherapy in HCC.

Treatment options for advanced hepatocellular carcinoma: the potential of biologics

INTRODUCTION

Advanced hepatocellular carcinoma (HCC) represents a significant global health burden, whose treatment has been recently revolutionized by the advent of biologic treatments. Despite that, innovative therapeutic regimens and approaches, especially immune-based, remain to be explored aiming at extending the therapeutic benefits to a wider population of patients.

AREAS COVERED

This review comprehensively discusses the evolving landscape of biological treatment modalities for advanced HCC, including immune checkpoint inhibitors, antiangiogenic monoclonal antibodies, tumor-targeting monoclonal antibodies either naked or drug-conjugated, therapeutic vaccines, oncolytic viruses, adoptive cell therapies, and cytokine-based therapies. Key clinical trials and preclinical studies are examined, highlighting the actual or potential impact of these interventions in reshaping treatment paradigms for HCC.

EXPERT OPINION

Tailored and rational combination strategies, leveraging the synergistic effects of different modalities, represent a promising approach to maximize treatment efficacy in advanced HCC, which should aim at conversion endpoints to increase the fraction of patients eligible for curative approaches. The identification of predictive biomarkers holds the key to optimizing patient selection and improving therapeutic outcomes.

Insights in Molecular Therapies for Hepatocellular Carcinoma

We conducted a comprehensive review of the current literature of published data and clinical trials (MEDLINE), as well as published congress contributions and active recruiting clinical trials on targeted therapies in hepatocellular carcinoma. Combinations of different agents and medical therapy along with radiological interventions were analyzed for the setting of advanced HCC. Those settings were also analyzed in combination with adjuvant situations after resection or radiological treatments. We summarized the current knowledge for each therapeutic setting and combination that currently is or has been under clinical evaluation. We further discuss the results in the background of current treatment guidelines. In addition, we review the pathophysiological mechanisms and pathways for each of these investigated targets and drugs to further elucidate the molecular background and underlying mechanisms of action. Established and recommended targeted treatment options that already exist for patients are considered for systemic treatment: atezolizumab/bevacizumab, durvalumab/tremelimumab, sorafenib, lenvatinib, cabozantinib, regorafenib, and ramucirumab. Combination treatment for systemic treatment and local ablative treatment or transarterial chemoembolization and adjuvant and neoadjuvant treatment strategies are under clinical investigation.

Tumor Antigens beyond the Human Exome

With the advent of immunotherapeutics, a new era in the combat against cancer has begun. Particularly promising are neo-epitope-targeted therapies as the expression of neo-antigens is tumor-specific. In turn, this allows the selective targeting and killing of cancer cells whilst healthy cells remain largely unaffected. So far, many advances have been made in the development of treatment options which are tailored to the individual neo-epitope repertoire. The next big step is the achievement of efficacious "off-the-shelf" immunotherapies. For this, shared neo-epitopes propose an optimal target. Given the tremendous potential, a thorough understanding of the underlying mechanisms which lead to the formation of neo-antigens is of fundamental importance. Here, we review the various processes which result in the formation of neo-epitopes. Broadly, the origin of neo-epitopes can be categorized into three groups: canonical, noncanonical, and viral neo-epitopes. For the canonical neo-antigens that arise in direct consequence of somatic mutations, we summarize past and recent findings. Beyond that, our main focus is put on the discussion of noncanonical and viral neo-epitopes as we believe that targeting those provides an encouraging perspective to shape the future of cancer immunotherapeutics.

Advances and considerations in the use of immunotherapies for primary hepato-biliary malignancies

Hepatocellular carcinoma (HCC) and cholangiocarcinoma (CCA) comprise the two most common primary liver malignancies. Curative treatment options often include hepatectomy or liver transplantation; however, many patients present with advanced disease that is not amenable to surgical management. In turn, many patients are treated with systemic or targeted therapy. The tumor microenvironment (TME) is a complex network of immune cells and somatic cells, which can foster an environment for disease development and progression, as well as susceptibility and resistance to systemic therapeutic agents. In particular, the TME is comprised of both immune and non-immune cells. Immune cells such as T lymphocytes, natural killer (NK) cells, macrophages, and neutrophils reside in the TME and can affect tumorigenesis, disease progression, as well as response to therapy. Given the importance of the immune system, there are many emerging approaches for cancer immunotherapy. We herein provide a review the latest data on immunotherapy for primary HCC and BTC relative to the TME.

The Roles of Myeloid-Derived Suppressor Cells in Liver Disease

Liver disease-related mortality is a major cause of death worldwide. Hepatic innate and adaptive immune cells play diverse roles in liver homeostasis and disease. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immature myeloid cells. MDSCs can be broadly divided into monocytic MDSCs and polymorphonuclear or granulocytic MDSCs, and they functionally interact with both liver parenchymal and nonparenchymal cells, such as hepatocytes and regulatory T cells, to impact liver disease progression. The infiltration and activation of MDSCs in liver disease can be regulated by inflammatory chemokines and cytokines, tumor-associated fibroblasts, epigenetic regulation factors, and gut microbiota during liver injury and cancer. Given the pivotal roles of MDSCs in advanced liver diseases, they can be targeted to treat primary and metastatic liver cancer, liver generation, alcoholic and nonalcoholic liver disease, and autoimmune hepatitis. Currently, several treatments such as the antioxidant and anti-inflammatory agent berberine are under preclinical and clinical investigation to evaluate their therapeutic efficacy on liver disease and their effect on MDSC infiltration and function. Phenotypic alteration of MDSCs in different liver diseases that are in a model-dependent manner and lack special markers for distinct MDSCs are challenges for targeting MDSCs to treat liver disease. Multi-omics study is an option to uncover the features of disease-specific MDSCs and potential gene or protein targets for liver disease treatment. In summary, MDSCs play important roles in the pathogenesis and progression of liver disease by regulating both intrahepatic innate and adaptive immune responses.

Advances, opportunities and challenges in developing therapeutic cancer vaccines

Therapeutic cancer vaccines have shown promising efficacy in helping immunotherapy for cancer patients, but the systematic characterization of the clinical application and the method for improving efficacy is lacking. Here, we mainly summarize the classification of therapeutic cancer vaccines, including protein vaccines, nucleic acid vaccines, cellular vaccines and anti-idiotypic antibody vaccines, and subdivide the above vaccines according to different types and delivery forms. Additionally, we outline the clinical efficacy and safety of vaccines, as well as the combination strategies of therapeutic cancer vaccines with other therapies. This review will provide a detailed overview and rationale for the future clinical application and development of therapeutic cancer vaccines.

Current status of vaccine immunotherapy for gastrointestinal cancers

Recent advances in tumor immunology and molecular drug development have ushered in a new era of cancer immunotherapy. Immunotherapy has shown promising results for several types of tumors, such as advanced melanoma, non-small cell lung cancer, renal cell carcinoma, bladder cancers, and refractory Hodgkin's lymphoma. Similarly, efforts have been made to develop immunotherapies such as adoptive T-cell transplantation, peptide vaccines, and dendritic cell vaccines, specifically for gastrointestinal tumors. However, before the advent of immune checkpoint inhibitors, immunotherapy did not work as well as expected. In this article, we review immunotherapy, focusing on cancer vaccines for gastrointestinal tumors, which generally target eliciting tumor-specific CD8 + cytotoxic T lymphocytes (CTLs). We also review various vaccine therapies and describe the relationship between vaccines and adjuvants. Finally, we discuss prospects for the combination of immunotherapy with immune checkpoint inhibitors.

Old age as a risk factor for liver diseases: Modern therapeutic approaches

Recent scientific interest has been directed towards age-related diseases, driven by the significant increase in global life expectancy and the growing population of individuals aged 65 and above. The ageing process encompasses various biological, physiological, environmental, psychological, behavioural, and social changes, leading to an augmented susceptibility to chronic illnesses. Cardiovascular, neurological, musculoskeletal, liver and oncological diseases are prevalent in the elderly. Moreover, ageing individuals demonstrate reduced regenerative capacity and decreased tolerance towards therapeutic interventions, including organ transplantation. Liver diseases, such as non-alcoholic fatty liver disease, alcoholic liver disease, hepatitis, fibrosis, and cirrhosis, have emerged as significant public health concerns. Paradoxically, these conditions remain underestimated despite their substantial global impact. Age-related factors are closely associated with the severity and unfavorable prognosis of various liver diseases, warranting further investigation to enhance clinical management and develop novel therapeutic strategies. This comprehensive review focuses specifically on age-related liver diseases, their treatment strategies, and contemporary practices. It provides a detailed account of the global burden, types, molecular mechanisms, and epigenetic alterations underlying these liver pathologies.

Identification of tumor antigens and immune subtypes of hepatocellular carcinoma for mRNA vaccine development

BACKGROUND

mRNA vaccines have been investigated in multiple tumors, but limited studies have been conducted on their use for hepatocellular carcinoma (HCC).

AIM

To identify candidate mRNA vaccine antigens for HCC and suitable subpopulations for mRNA vaccination.

METHODS

Gene expression profiles and clinical information of HCC datasets were obtained from International Cancer Genome Consortium and The Cancer Genome Atlas. Genes with somatic mutations and copy number variations were identified by cBioPortal analysis. The differentially expressed genes with significant prognostic value were identified by Gene Expression Profiling Interactive Analysis 2 website analysis. The Tumor Immune Estimation Resource database was used to assess the correlation between candidate antigens and the abundance of antigen-presenting cells (APCs). Tumor-associated antigens were overexpressed in tumors and associated with prognosis, genomic alterations, and APC infiltration. A consensus cluster analysis was performed with the Consensus Cluster Plus package to identify the immune subtypes. The weighted gene coexpression network analysis (WGCNA) was used to determine the candidate biomarker molecules for appropriate populations for mRNA vaccines.

RESULTS

AURKA, CCNB1, CDC25C, CDK1, TRIP13, PES1, MCM3, PPM1G, NEK2, KIF2C, PTTG1, KPNA2, and PRC1 were identified as candidate HCC antigens for mRNA vaccine development. Four immune subtypes (IS1-IS4) and five immune gene modules of HCC were identified that were consistent in both patient cohorts. The immune subtypes showed distinct cellular and clinical characteristics. The IS1 and IS3 immune subtypes were immunologically "cold". The IS2 and IS4 immune subtypes were immunologically "hot", and the immune checkpoint genes and immunogenic cell death genes were upregulated in these subtypes. IS1-related modules were identified with the WGCNA algorithm. Ultimately, five hub genes (RBP4, KNG1, METTL7A, F12, and ABAT) were identified, and they might be potential biomarkers for mRNA vaccines.

CONCLUSION

AURKA, CCNB1, CDC25C, CDK1, TRIP13, PES1, MCM3, PPM1G, NEK2, KIF2C, PTTG1, KPNA2, and PRC1 have been identified as candidate HCC antigens for mRNA vaccine development. The IS1 and IS3 immune subtypes are suitable populations for mRNA vaccination. RBP4, KNG1, METTL7A, F12, and ABAT are potential biomarkers for mRNA vaccines.

The NLR member CIITA: Master controller of adaptive and intrinsic immunity and unexpected tool in cancer immunotherapy

Human nucleotide-binding oligomerization domain (NOD)-like receptors (NLR) include a large family of proteins that have important functions in basic physio-pathological processes like inflammation, cell death and regulation of transcription of key molecules for the homeostasis of the immune system. They are all characterized by a common backbone structure (the STAND ATPase module consisting in a nucleotide-binding domain (NBD), an helical domain 1 (HD1) and a winged helix domain (WHD), used by both prokaryotes and eukaryotes as defense mechanism. In this review, we will focus on the MHC class II transactivator (CIITA), the master regulator of MHC class II (MHC-II) gene expression and the founding member of NLR. Although a consistent part of the described NLR family components is often recalled as innate or intrinsic immune sensors, CIITA in fact occupies a special place as a unique example of regulator of both intrinsic and adaptive immunity. The description of the discovery of CIITA and the genetic and molecular characterization of its expression will be followed by the most recent studies that have unveiled this dual role of CIITA, key molecule in intrinsic immunity as restriction factor for human retroviruses and precious tool to induce the expression of MHC-II molecules in cancer cells, rendering them potent surrogate antigen presenting cells (APC) for their own tumor antigens.

Engineered macromolecular Toll-like receptor agents and assemblies

Macromolecular Toll-like receptor (TLR) agents have been utilized as agonists and inhibitors in preclinical and clinical settings. These agents interface with the TLR class of innate immune receptors which recognize macromolecular ligands that are characteristic of pathogenic material. As such, many agents that have been historically investigated are derived from the natural macromolecules which activate or inhibit TLRs. This review covers recent research and clinically available TLR agents that are macromolecular or polymeric. Synthetic materials that have been found to interface with TLRs are also discussed. Assemblies of these materials are investigated in the context of improving stability or efficacy of ligands. Attention is given to strategies which modify or enhance the current agents and to future outlooks on the development of these agents.

Peptide-based vaccine for cancer therapies

Different strategies based on peptides are available for cancer treatment, in particular to counter-act the progression of tumor growth and disease relapse. In the last decade, in the context of therapeutic strategies against cancer, peptide-based vaccines have been evaluated in different tumor models. The peptides selected for cancer vaccine development can be classified in two main type: tumor-associated antigens (TAAs) and tumor-specific antigens (TSAs), which are captured, internalized, processed and presented by antigen-presenting cells (APCs) to cell-mediated immunity. Peptides loaded onto MHC class I are recognized by a specific TCR of CD8+ T cells, which are activated to exert their cytotoxic activity against tumor cells presenting the same peptide-MHC-I complex. This process is defined as active immunotherapy as the host's immune system is either de novo activated or restimulated to mount an effective, tumor-specific immune reaction that may ultimately lead to tu-mor regression. However, while the preclinical data have frequently shown encouraging results, therapeutic cancer vaccines clinical trials, including those based on peptides have not provided satisfactory data to date. The limited efficacy of peptide-based cancer vaccines is the consequence of several factors, including the identification of specific target tumor antigens, the limited immunogenicity of peptides and the highly immunosuppressive tumor microenvironment (TME). An effective cancer vaccine can be developed only by addressing all such different aspects. The present review describes the state of the art for each of such factors.

A Comprehensive Review on Cancer Vaccines and Vaccine Strategies in Hepatocellular Carcinoma

HCC, the most prevalent form of primary liver cancer, presents a substantial global health challenge due to its high mortality and limited therapeutic options. This review delves into the potential of cancer vaccines as a novel therapeutic avenue for HCC. We examine the various categories of cancer vaccines, including peptide-based, dendritic cell-based, viral vector-based, DNA, and mRNA vaccines, and their potential application in HCC management. This review also addresses the inherent challenges in vaccine development, such as tumor heterogeneity and the need for identifying tumor-specific antigens. We underscore the role of cancer vaccines in reshaping the immune environment within HCC, fostering durable immune memory, and their potential in combination therapies. The review also evaluates clinical trials and emphasizes the necessity for more extensive research to optimize vaccine design and patient selection criteria. We conclude with future perspectives, highlighting the significance of personalized therapies, innovative antigen delivery platforms, immune modulatory agents, and predictive biomarkers in revolutionizing HCC treatment. Simple Summary: This review explores the potential of cancer vaccines as a promising therapeutic strategy for hepatocellular carcinoma (HCC), a prevalent and deadly liver cancer. The authors discuss various types of cancer vaccines, their challenges, and their role in modulating the immune response within HCC. They also highlight clinical trials and future perspectives, emphasizing the importance of personalized therapies, novel antigen delivery platforms, and predictive biomarkers. The findings from this research could significantly impact the research community by providing a comprehensive understanding of the current state of cancer vaccines for HCC, thereby guiding future research and potentially transforming HCC treatment strategies.

Rethinking Antigen Source: Cancer Vaccines Based on Whole Tumor Cell/tissue Lysate or Whole Tumor Cell

Cancer immunotherapies have improved human health, and one among the important technologies for cancer immunotherapy is cancer vaccine. Antigens are the most important components in cancer vaccines. Generally, antigens in cancer vaccines can be divided into two categories: pre-defined antigens and unidentified antigens. Although, cancer vaccines loaded with predefined antigens are commonly used, cancer vaccine loaded with mixed unidentified antigens, especially whole cancer cells or cancer cell lysates, is a very promising approach, and such vaccine can obviate some limitations in cancer vaccines. Their advantages include, but are not limited to, the inclusion of pan-spectra (all or most kinds of) antigens, inducing pan-clones specific T cells, and overcoming the heterogeneity of cancer cells. In this review, the recent advances in cancer vaccines based on whole-tumor antigens, either based on whole cancer cells or whole cancer cell lysates, are summarized. In terms of whole cancer cell lysates, the focus is on applying whole water-soluble cell lysates as antigens. Recently, utilizing the whole cancer cell lysates as antigens in cancer vaccines has become feasible. Considering that pre-determined antigen-based cancer vaccines (mainly peptide-based or mRNA-based) have various limitations, developing cancer vaccines based on whole-tumor antigens is a promising alternative.

Proceedings of the Online Conference "Vaccines and Vaccination during and Post COVID Pandemics" (7-9 December 2022)

The COVID-19 pandemic put focus on various aspects of vaccine research and development. These include mass vaccination strategies, vaccination compliance and hesitancy, acceptance of novel vaccine approaches, preclinical and animal models used to assess vaccine safety and efficacy, and many other related issues. These issues were addressed by the international online conference "Vaccines and Vaccination During and Post COVID Pandemics" (VAC&VAC 2022) held on the platform of Riga Stradins University, Riga, Latvia. Conference was supported by the International Society for Vaccines, the National Cancer Institute "Fondazione Pascale" (Naples, Italy), and the scientific journal VACCINES (mdpi). VAC&VAC 2022 attracted nearly 150 participants from 14 countries. This report summarizes conference presentations and their discussion. Sessions covered the topics of (1) COVID-19 vaccine development, evaluation, and attitude towards these vaccines, (2) HPV and cancer vaccines, (3) progress and challenges of HIV vaccine development, (4) new and re-emerging infectious threats, and (5) novel vaccine vehicles, adjuvants, and carriers. Each session was introduced by a plenary lecture from renowned experts from leading research institutions worldwide. The conference also included sessions on research funding and grant writing and an early career researcher contest in which the winners received monetary awards and a chance to publish their results free of charge in the special issue of VACCINES covering the meeting.

Emergence of Small Interfering RNA-Based Gene Drugs for Various Diseases

Small molecule, peptide, and protein-based drugs have been developed over decades to treat various diseases. The importance of gene therapy as an alternative to traditional drugs has increased after the discovery of gene-based drugs such as Gendicine for cancer and Neovasculgen for peripheral artery disease. Since then, the pharma sector is focusing on developing gene-based drugs for various diseases. After the discovery of the RNA interference (RNAi) mechanism, the development of siRNA-based gene therapy has been accelerated immensely. siRNA-based treatment for hereditary transthyretin-mediated amyloidosis (hATTR) using Onpattro and acute hepatic porphyria (AHP) by Givlaari and three more FDA-approved siRNA drugs has set up a milestone and further improved the confidence for the development of gene therapeutics for a spectrum of diseases. siRNA-based gene drugs have more advantages over other gene therapies and are under study to treat different types of diseases such as viral infections, cardiovascular diseases, cancer, and many more. However, there are a few bottlenecks to realizing the full potential of siRNA-based gene therapy. They include chemical instability, nontargeted biodistribution, undesirable innate immune responses, and off-target effects. This review provides a comprehensive view of siRNA-based gene drugs: challenges associated with siRNA delivery, their potential, and future prospects.

Immunotherapy of hepatocellular carcinoma: recent progress and new strategy

Due to its widespread occurrence and high mortality rate, hepatocellular carcinoma (HCC) is an abhorrent kind of cancer. Immunotherapy is a hot spot in the field of cancer treatment, represented by immune checkpoint inhibitors (ICIs), which aim to improve the immune system's ability to recognize, target and eliminate cancer cells. The composition of the HCC immune microenvironment is the result of the interaction of immunosuppressive cells, immune effector cells, cytokine environment, and tumor cell intrinsic signaling pathway, and immunotherapy with strong anti-tumor immunity has received more and more research attention due to the limited responsiveness of HCC to ICI monotherapy. There is evidence of an organic combination of radiotherapy, chemotherapy, anti-angiogenic agents and ICI catering to the unmet medical needs of HCC. Moreover, immunotherapies such as adoptive cellular therapy (ACT), cancer vaccines and cytokines also show encouraging efficacy. It can significantly improve the ability of the immune system to eradicate tumor cells. This article reviews the role of immunotherapy in HCC, hoping to improve the effect of immunotherapy and develop personalized treatment regimens.

Novel strategies for cancer immunotherapy: counter-immunoediting therapy

The advent of immunotherapy has made an indelible mark on the field of cancer therapy, especially the application of immune checkpoint inhibitors in clinical practice. Although immunotherapy has proven its efficacy and safety in some tumors, many patients still have innate or acquired resistance to immunotherapy. The emergence of this phenomenon is closely related to the highly heterogeneous immune microenvironment formed by tumor cells after undergoing cancer immunoediting. The process of cancer immunoediting refers to the cooperative interaction between tumor cells and the immune system that involves three phases: elimination, equilibrium, and escape. During these phases, conflicting interactions between the immune system and tumor cells result in the formation of a complex immune microenvironment, which contributes to the acquisition of different levels of immunotherapy resistance in tumor cells. In this review, we summarize the characteristics of different phases of cancer immunoediting and the corresponding therapeutic tools, and we propose normalized therapeutic strategies based on immunophenotyping. The process of cancer immunoediting is retrograded through targeted interventions in different phases of cancer immunoediting, making immunotherapy in the context of precision therapy the most promising therapy to cure cancer.

Integrating immunopeptidome analysis for the design and development of cancer vaccines

The repertoire of naturally presented peptides within the MHC (major histocompatibility complex) or HLA (human leukocyte antigens) system on the cellular surface of every mammalian cell is referred to as ligandome or immunopeptidome. This later gained momentum upon the discovery of CD8 + T cells able to recognize and kill cancer cells in an MHC-I antigen-restricted manner. Indeed, cancer immune surveillance relies on T cell recognition of MHC-I-restricted peptides, making the identification of those peptides the core for designing T cell-based cancer vaccines. Moreover, the breakthrough of antibodies targeting immune checkpoint molecules has led to a new and strong interest in discovering suitable targets for CD8 +T cells. Therapeutic cancer vaccines are designed for the artificial generation and/or stimulation of CD8 +T cells; thus, their combination with ICIs to unleash the breaks of the immune system comes as a natural consequence to enhance anti-tumor efficacy. In this context, the identification and knowledge of peptide candidates take advantage of the fast technology updates in immunopeptidome and mass spectrometric methodologies, paying the way to the rational design of vaccines for immunotherapeutic approaches. In this review, we discuss mainly the role of immunopeptidome analysis and its application for the generation of therapeutic cancer vaccines with main focus on HLA-I peptides. Here, we review cancer vaccine platforms based on two different preparation methods: pathogens (viruses and bacteria) and not (VLPs, nanoparticles, subunits vaccines) that exploit discoveries in the ligandome field to generate and/or enhance anti-tumor specific response. Finally, we discuss possible drawbacks and future challenges in the field that remain still to be addressed.

Natural peptides for immunological regulation in cancer therapy: Mechanism, facts and perspectives

Cancer incidence and mortality rates are increasing annually. Treatment with surgery, chemotherapy and radiation therapy (RT) is unsatisfactory because many patients have advanced disease at the initial diagnosis. However, the emergence of immunotherapy promises to be an effective strategy to improve the outcome of advanced tumors. Immune checkpoint antibodies, which are at the forefront of immunotherapy, have had significant success but still leave some cancer patients without benefit. For more cancer patients to benefit from immunotherapy, it is necessary to find new drugs and combination therapeutic strategies to improve the outcome of advanced cancer patients and achieve long-term tumor control or even eradication. Peptides are promising choices for tumor immunotherapy drugs because they have the advantages of low production cost, high sequence selectivity, high tissue permeability, low toxicity and low immunogenicity etc., and the adjuvant matching and technologies like nanotechnology can further optimize the effects of peptides. In this review, we present the current status and mechanisms of research on peptides targeting multiple immune cells (T cells, natural killer (NK) cells, dendritic cells (DCs), tumor-associated macrophages (TAMs), regulatory T cells (Tregs)) and immune checkpoints in tumor immunotherapy; and we summarize the current status of research on peptide-based tumor immunotherapy in combination with other therapies including RT, chemotherapy, surgery, targeted therapy, cytokine therapy, adoptive cell therapy (ACT) and cancer vaccines. Finally, we discuss the current status of peptide applications in mRNA vaccine delivery.

mRNA-Based Therapeutics in Cancer Treatment

Over the past two decades, significant technological innovations have led to messenger RNA (mRNA) becoming a promising option for developing prophylactic and therapeutic vaccines, protein replacement therapies, and genome engineering. The success of the two COVID-19 mRNA vaccines has sparked new enthusiasm for other medical applications, particularly in cancer treatment. In vitro-transcribed (IVT) mRNAs are structurally designed to resemble naturally occurring mature mRNA. Delivery of IVT mRNA via delivery platforms such as lipid nanoparticles allows host cells to produce many copies of encoded proteins, which can serve as antigens to stimulate immune responses or as additional beneficial proteins for supplements. mRNA-based cancer therapeutics include mRNA cancer vaccines, mRNA encoding cytokines, chimeric antigen receptors, tumor suppressors, and other combination therapies. To better understand the current development and research status of mRNA therapies for cancer treatment, this review focused on the molecular design, delivery systems, and clinical indications of mRNA therapies in cancer.

Exploiting RIG-I-like receptor pathway for cancer immunotherapy

RIG-I-like receptors (RLRs) are intracellular pattern recognition receptors that detect viral or bacterial infection and induce host innate immune responses. The RLRs family comprises retinoic acid-inducible gene 1 (RIG-I), melanoma differentiation-associated gene 5 (MDA5) and laboratory of genetics and physiology 2 (LGP2) that have distinctive features. These receptors not only recognize RNA intermediates from viruses and bacteria, but also interact with endogenous RNA such as the mislocalized mitochondrial RNA, the aberrantly reactivated repetitive or transposable elements in the human genome. Evasion of RLRs-mediated immune response may lead to sustained infection, defective host immunity and carcinogenesis. Therapeutic targeting RLRs may not only provoke anti-infection effects, but also induce anticancer immunity or sensitize "immune-cold" tumors to immune checkpoint blockade. In this review, we summarize the current knowledge of RLRs signaling and discuss the rationale for therapeutic targeting RLRs in cancer. We describe how RLRs can be activated by synthetic RNA, oncolytic viruses, viral mimicry and radio-chemotherapy, and how the RNA agonists of RLRs can be systemically delivered in vivo. The integration of RLRs agonism with RNA interference or CAR-T cells provides new dimensions that complement cancer immunotherapy. Moreover, we update the progress of recent clinical trials for cancer therapy involving RLRs activation and immune modulation. Further studies of the mechanisms underlying RLRs signaling will shed new light on the development of cancer therapeutics. Manipulation of RLRs signaling represents an opportunity for clinically relevant cancer therapy. Addressing the challenges in this field will help develop future generations of cancer immunotherapy.

The protective effect and antitumor activity of Aconiti Lateralis Radix Praeparata (Fuzi) polysaccharide on cyclophosphamide-induced immunosuppression in H22 tumor-bearing mice

Background: Aconiti Lateralis Radix Praeparata, also known as Fuzi in Chinese, has been used in Traditional Chinese Medicine for more than 2,000 years. In recent years, some traditional herbal compounds containing Fuzi have achieved positive clinical results in tumor treatment. And the polysaccharide isolated from Fuzi has attracted much attention as a potential immunomodulator. However, its immunomodulatory mechanism remains to be further studied. Aim of the study. Fuzi neutral polysaccharide (FNPS) and cyclophosphamide (CTX) were combined to treat Hepatoma 22 (H22) tumor-bearing mice, and its mechanism of ameliorating immunosuppression caused by CTX was studied. Methods: FNPS was isolated and purified. The molecular weight, functional groups, monosaccharide composition, and apparent morphology were characterized by gel permeation chromatography, Fourier transform infrared spectrometer, ion chromatography and scanning electron microscope, respectively. Through the analysis of tumor, immune organs, and serum cytokine levels of H22 tumor-bearing mice, the immunomodulatory effect and the protective effect on immunosuppressive mice induced by CTX was evaluated. And the immunomodulatory activity of FNPS was further verified by macrophage functional experiments. Results: FNPS was composed of rhamnose, arabinose, galactose, glucose, and mannose in a molar ratio of 0.008:0.017:0.018:0.908:0.048. Its molecular weight was 94 kDa. In vivo experiments showed that 200 mg mL^-1 FNPS could alleviate the suppression of immune organs and immune cells caused by CTX treatment, enhance the antitumor effect of CTX, increase the serum levels of Th1 immune-related pro-inflammatory cytokines (IL-1β and IL-6), and decrease Th2 immune-related anti-inflammatory cytokine (IL-10) and tumor-related pro-inflammatory cytokine (TNF-α) in the chemotherapy mice. Functional experiments revealed that 25 μg mL^-1 FNPS could promote phagocytosis and proliferation of macrophages. When the concentration reached 50 μg mL^-1, it enhanced the migration activity. Conclusion: FNPS has the potential to alleviate the immunosuppressive effect of CTX by activating immune cells and promoting inflammation. It could be used as a potential auxiliary medication for liver cancer treatment.

Systemic T-cell and humoral responses against cancer testis antigens in hepatocellular carcinoma patients

Hepatocellular carcinoma (HCC) is the fourth leading cause of cancer-related deaths worldwide due to high recurrence rates after curative treatment and being frequently diagnosed at an advanced stage. Immune-checkpoint inhibition (ICPI) has yielded impressive clinical successes in a variety of solid cancers, however results in treatment of HCC have been modest. Vaccination could be a promising treatment to synergize with ICPI and enhance response rates. Cancer testis antigens (CTAs) were recently discovered to be widely expressed in HCC and expression in macroscopically tumor-free tissues correlated with recurrence, implying the presence of micro-satellites. To determine whether CTAs are immunogenic in HCC patients, we analyzed systemic T-cell and humoral responses against seven CTAs in 38 HCC patients using a multitude of techniques; flowcytometry, ELISA and whole antigen and peptide stimulation assays. CTA-specific T-cells were detected in all (25/25) analyzed patients, of which most had a memory phenotype but did not exhibit unequivocal signs of chronic stimulation or recent antigen encounter. Proliferative CD4⁺ and CD8⁺ T-cell responses against these CTAs were found in 14/16 analyzed HCC patients. CTA-peptide stimulation-induced granzyme B, IL2, and TNFa in 8/8 analyzed patients, including two MAGEA1 peptides included based on in silico prediction. Finally, IgG responses were observed in 13/32 patients, albeit with low titers. The presence of CD4⁺ and CD8⁺ T-cells and IgG responses shows the immunogenicity of these CTAs in HCC-patients. We hypothesize that vaccines based on these tumor-specific antigens may boost preexisting CTA-specific immunity and could enhance therapeutic efficacy of ICPI in advanced HCC.

Expert Insights on Current Treatments for Hepatocellular Carcinoma: Clinical and Molecular Approaches and Bottlenecks to Progress

Hepatocellular carcinoma (HCC) is a primary liver tumor that typically occurs in the setting of chronic liver disease/cirrhosis. Treatment modalities for HCC have evolved and given the variety of treatment options, a multi-disciplinary approach requiring input from surgical, medical, and radiation oncology, hepatology, and interventional radiology is necessary. Multiple advances have been made over the last decade regarding treatment of HCC, especially advanced disease. Resection and transplantation remain as cornerstone curative-intent treatment options. For patients who are not candidates for curative-intent therapy, exciting progress has been made in molecular and cellular approaches to systemic therapy for HCC including immunotherapies and tyrosine kinase inhibitors. Although the prognosis for advanced HCC remains poor, the armamentarium of therapies has increased, and valuable years of life can be gained with these therapies. While the main therapeutic modality for early-stage disease remains resection, multimodal immunotherapy has emerged as first-line treatment for advanced disease. We herein review different clinical and molecular treatment modalities related to the treatment of HCC, as well as provide insights into future directions for HCC treatment. We highlight how research and progress are needed to move into a new era of molecular and cellular treatments.

Advances in Targeted Immunotherapy for Hepatobiliary Cancers

Cancer of the hepatobiliary system can be divided into primary liver cancer and biliary tract cancer (BTC), which includes hepatocellular carcinoma (HCC), cholangiocarcinoma (CCA), and gallbladder cancer (GBC). These aggressive cancers often present at an advanced stage or among patients with poorly preserved liver function. The primary treatment for HCC and BTC when diagnosed early is surgical resection, but given the high rate of recurrence and often advanced stage at diagnosis, many patients will require systemic therapy. Unfortunately, even with systemic therapy, long-term survival is poor. The immune system plays an important role in preventing cancer progression. The unique immune environment of the liver and subsequent alterations to the immune microenvironment by tumor cells to create a favorable microenvironment plays a key role in the progression of HCC and BTC. Due to the paucity of effective systemic therapies and distinctive immune environment of the liver, research and clinical trials are investigating the use of immunotherapy in HCC and BTC. This review will focus on current immunotherapies and emerging data for the treatment of HCC and BTC.

Local immunotherapy with the RNA-based immune stimulator CV8102 induces substantial anti-tumor responses and enhances checkpoint inhibitor activity

Immunotherapy has revolutionized cancer treatment in recent years. Although currently approved checkpoint inhibitors (CPIs) yield remarkable anti-tumoral responses in several cancer types, a substantial proportion of patients do not benefit from such therapies. Local activation of innate immune signaling pathways is a promising approach to overcome the immunosuppressive tumor microenvironment, induce anti-tumor immunity, and improve the efficacy of CPI therapies. Here, we assessed the mode of action and efficacy of the RNA-based innate immune stimulator CV8102 for local immunotherapy in preclinical models. Intratumoral (i.t.) administration of CV8102 activated innate immune responses in the tumor microenvironment and draining lymph nodes, resulting in a dose-dependent anti-tumoral response. Combining i.t. CV8102 with systemic anti-programmed death protein 1 (PD-1) treatment further enhanced anti-tumoral responses, inducing tumor infiltration and activation of CD8+ T cells. The resulting memory response prevented tumor growth in rechallenged animals and impaired the growth of non-injected distal tumors. Therefore, i.t. CV8102 delivery is a promising approach for local cancer immunotherapy, especially in combination with CPIs. Clinical testing of CV8102 is ongoing (NCT03291002).

The oncogenic gamma herpesviruses Epstein-Barr virus (EBV) and Kaposi's sarcoma-associated herpesvirus (KSHV) hijack retinoic acid-inducible gene I (RIG-I) facilitating both viral and tumour immune evasion

Herpesviruses evade host immunity to establish persistent lifelong infection with dormant latent and replicative lytic phases. Epstein-Barr virus (EBV) and Kaposi's Sarcoma-associated virus (KSHV) are double-stranded DNA herpesviruses that encode components to activate RNA sensors, (Retinoic acid-inducible gene I (RIG-I) and melanoma differentiation-associated protein 5 (MDA5). Yet both viruses can effectively evade the antiviral immune response. The ability of these viruses to disarm RIG-I to evade immunity allowing viral persistency can contribute to the creation of a protected niche that facilitates tumour growth and immune evasion. Alternatively, viral nucleic acids present in the cytosol during the replicative phase of the viral lifecycle can activate pro-inflammatory signaling downstream of RIG-I augmenting tumour promoting inflammation. Understanding how these viral proteins disrupt innate immune pathways could help identify mechanisms to boost immunity, clearing viral infection and enhancing the efficacy of immunotherapy for virally induced cancers. Here we review literature on the strategies EBV and KSHV use to either enhance or inhibit RLR signaling.

Perspectives in Immunotherapy: meeting report from the Immunotherapy Bridge, December 1st-2nd, 2021

Over the past decade, immunotherapy has become an increasingly fundamental modality in the treatment of cancer. The positive impact of immune checkpoint inhibition, especially anti-programmed death (PD)-1/PD-ligand (L)1 blockade, in patients with different cancers has focused attention on the potential for other immunotherapeutic approaches. These include inhibitors of additional immune checkpoints, adoptive cell transfer (ACT), and therapeutic vaccines. Patients with advanced cancers who previously had limited treatment options available may now benefit from immunotherapies that can offer durable responses and improved survival outcomes. However, despite this, a significant proportion of patients fail to respond to immunotherapy, especially those with less immunoresponsive cancer types, and there remains a need for new treatment strategies.The virtual Immunotherapy Bridge (December 1st-2nd, 2021), organized by the Fondazione Melanoma Onlus, Naples, Italy in collaboration with the Society for Immunotherapy of Cancer addressed several areas of current research in immunotherapy, including lessons learned from cell therapies, drivers of immune response, and trends in immunotherapy across different cancers, and these are summarised here.