Advances and challenges in anti-cancer vaccines for multiple myeloma.

Multiple myeloma (MM) is a hematological cancer marked by plasma cell accumulation in the bone marrow. Despite treatment advancements, MM remains incurable in most patients. MM-associated immune dysregulation fosters disease progression, prompting research into immunotherapy to combat the disease. An area of immunotherapy investigation is the design of myeloma vaccine therapy to reverse tumor-associated immune suppression and elicit tumor-specific immune responses to effectively target MM cells. This article reviews vaccine immunotherapy for MM, categorizing findings by antigen type and delivery method. Antigens include idiotype (Id), tumor-associated (TAA), tumor-specific (TSA), and whole tumor lysate. Myeloma vaccination has so far shown limited clinical efficacy. However, further studies are essential to optimize various aspects, including antigen and patient selection, vaccine timing and sequencing, and rational combinations with emerging MM treatments.

Immunogenicity of Non-Mutated Ovarian Cancer-Specific Antigens.

Epithelial ovarian cancer (EOC) has not significantly benefited from advances in immunotherapy, mainly because of the lack of well-defined actionable antigen targets. Using proteogenomic analyses of primary EOC tumors, we previously identified 91 aberrantly expressed tumor-specific antigens (TSAs) originating from unmutated genomic sequences. Most of these TSAs derive from non-exonic regions, and their expression results from cancer-specific epigenetic changes. The present study aimed to evaluate the immunogenicity of 48 TSAs selected according to two criteria: presentation by highly prevalent HLA allotypes and expression in a significant fraction of EOC tumors. Using targeted mass spectrometry analyses, we found that pulsing with synthetic TSA peptides leads to a high-level presentation on dendritic cells. TSA abundance correlated with the predicted binding affinity to the HLA allotype. We stimulated naïve CD8 T cells from healthy blood donors with TSA-pulsed dendritic cells and assessed their expansion with two assays: MHC-peptide tetramer staining and TCR Vß CDR3 sequencing. We report that these TSAs can expand sizeable populations of CD8 T cells and, therefore, represent attractive targets for EOC immunotherapy.

HLAIImaster: a deep learning method with adaptive domain knowledge predicts HLA II neoepitope immunogenic responses.

While significant strides have been made in predicting neoepitopes that trigger autologous CD4+ T cell responses, accurately identifying the antigen presentation by human leukocyte antigen (HLA) class II molecules remains a challenge. This identification is critical for developing vaccines and cancer immunotherapies. Current prediction methods are limited, primarily due to a lack of high-quality training epitope datasets and algorithmic constraints. To predict the exogenous HLA class II-restricted peptides across most of the human population, we utilized the mass spectrometry data to profile >223 000 eluted ligands over HLA-DR, -DQ, and -DP alleles. Here, by integrating these data with peptide processing and gene expression, we introduce HLAIImaster, an attention-based deep learning framework with adaptive domain knowledge for predicting neoepitope immunogenicity. Leveraging diverse biological characteristics and our enhanced deep learning framework, HLAIImaster is significantly improved against existing tools in terms of positive predictive value across various neoantigen studies. Robust domain knowledge learning accurately identifies neoepitope immunogenicity, bridging the gap between neoantigen biology and the clinical setting and paving the way for future neoantigen-based therapies to provide greater clinical benefit. In summary, we present a comprehensive exploitation of the immunogenic neoepitope repertoire of cancers, facilitating the effective development of "just-in-time" personalized vaccines.

A new high-throughput screening methodology for the discovery of cancer-testis antigen using multi-omics data.

BACKGROUND: Cancer/testis antigens (CTAs), also known as tumor-specific antigens (TSAs) are specifically expressed in cancer cells and exhibit high immunogenicity, making them promising targets for immunotherapy and cancer vaccines. METHODS: A new integrated high-throughput screening methodology for CTAs was proposed in this study through combining DNA methylation and RNA sequencing data. Briefly, the genes with increased transcript level and decreased DNA methylation were identified by multi-omics analysis. RNA sequencing studies in cell lines exposed to DNA methyltransferase (DNMT) inhibitors were performed to validate the inherent causal relationship between DNA hypomethylation and gene expression upregulation. RESULTS: We proposed a new integrated high-throughput screening methodology for identification of CTAs using multi-omics analysis. In addition, we tested the feasibility of this method using gastric cancer (GC) as an example. In GC, we identified over 2000 primary candidate CTAs and ultimately identified 20 CTAs with significant tissue-specificity, including a testis-specific serine protease TESSP1/PRSS41. Integrated analysis confirmed that PRSS41 expression was reactivated in gastrointestinal cancers by promoter DNA hypomethylation at the CpG site (cg08104780). Additionally, DNA hypomethylation of PRSS41 predicted a poor prognosis in GC. CONCLUSION: We propose a new high-throughput screening method for the identification of CTAs in cancer and validate its effectiveness. Our work emphasizes that serine protease PRSS41 is a novel TSA that is reactivated in GC due to promoter DNA hypomethylation.

Antigen-specific T cell activation through targeted delivery of in-situ generated antigen and calcium ionophore to enhance antitumor immunotherapy.

Recent advances in adoptive T-cell therapy have delivered impressive therapeutic outcomes by instigating enduring anti-tumor responses. Nonetheless, achieving specific T-cell activation remains a challenge due to several factors. Some cancer cells evade T-cell recognition due to the scarcity of tumor-specific T cells and deficiencies in antigen processing or major histocompatibility complex (MHC) presentation. Notably underestimated is the impact of waning T-cell receptor (TCR) expression and the constrained formation of immune synapses (IS) between dendritic cells (DCs) and T cells, impairing T-cell activation. Addressing these complexities, we introduce a pioneering approach featuring the deployment of a gel implant. This implant establishes an on-site antigen reservoir, efficiently targets DCs in lymph nodes, and facilitates calcium ion (Ca2+) delivery. Engineered with controlled swelling, poroelasticity, and resilience, the gel is suitable for surgical implantation. Its ample encapsulation capacity accommodates both photosensitizers and nanoparticles. Upon in situ photothermal irradiation, the gel generates tumor-specific antigens. Furthermore, cationic albumin nanoparticles (cNPs) co-loaded with monophosphoryl lipid A (MPLA) and ionomycin are released, guiding antigens to tumor-draining lymph nodes for DCs maturation. This meticulous process fosters the formation of IS thereby amplifying antigen-specific T-cell activation.

Amplifying mRNA vaccines: potential versatile magicians for oncotherapy.

Cancer vaccines drive the activation and proliferation of tumor-reactive immune cells, thereby eliciting tumor-specific immunity that kills tumor cells. Accordingly, they possess immense potential in cancer treatment. However, such vaccines are also faced with challenges related to their design and considerable differences among individual tumors. The success of messenger RNA (mRNA) vaccines against coronavirus disease 2019 has prompted the application of mRNA vaccine technology platforms to the field of oncotherapy. These platforms include linear, circular, and amplifying mRNA vaccines. In particular, amplifying mRNA vaccines are characterized by high-level and prolonged antigen gene expression at low doses. They can also stimulate specific cellular immunity, making them highly promising in cancer vaccine research. In this review, we summarize the research progress in amplifying mRNA vaccines and provide an outlook of their prospects and future directions in oncotherapy.

Topology and adenocarcinoma cell localization dataset on the labyrinthin diapeutic biomarker.

OBJECTIVE: The discovery and characterization of tumor associated antigens is increasingly important to advance the field of immuno-oncology. In this regard, labyrinthin has been implicated as a neoantigen found on the cell surface of adenocarcinomas. Data on the (1) topology, (2) amino acid (a.a.) homology analyses and (3) cell surface localization of labyrinthin by fluorescent activated cell sorter (FACS) are studied in support of labyrinthin as a novel, pan-adenocarcinoma marker. RESULTS: Bioinformatics analyses predict labyrinthin as a type II protein with calcium binding domain(s), N-myristoylation sites, and kinase II phosphorylation sites. Sequence homologies for labyrinthin (255 a.a.) were found vs. the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH; 758 a.a.) and the ASPH-gene related protein junctate (299 a.a.), which are both type II proteins. Labyrinthin was detected by FACS on only non-permeablized A549 human lung adenocarcinoma cells, but not on normal WI-38 human lung fibroblasts nor primary cultures of normal human glandular-related cells. Microscopic images of immunofluorescent labelled MCA 44-3A6 binding to A549 cells at random cell cycle stages complement the FACS results by further showing that labyrinthin persisted on the cell surfaces along with some cell internalization for greater than 20 min.

Current status and progress of the development of prostate cancer vaccines.

At present, common treatments of prostate cancer mainly include surgery, radiotherapy, chemotherapy and hormone therapy. However, patients have high recurrence rate after treatment, and are prone to castration-resistant prostate cancer. Tumor vaccine is based on tumor specific antigen (TSA) and tumor associated antigen (TAA) to activate specific immune response of the body to cancer cells. With continuous maturity of tumor vaccine technology, different forms of prostate cancer vaccines have been developed, such as cellular vaccines, extracellular-based anti-tumor vaccines, polypeptide vaccines, and nucleic acid vaccines. In this review, we summarize current status and progress in the development of prostate cancer vaccines.

An update on the use of cryoablation and immunotherapy for breast cancer.

The use of cryoablation, a minimally-invasive image-guided technique to target and kill cancer cells, continues to gain traction within the medical field and with patients. This includes the use of cryoablation for the treatment of small breast cancers and focal sites of metastatic disease. In comparison to open surgical approaches, length of hospital stay and recovery time are decreased with the use of cryoablation. Research studies have also found that cryoablation may actually enhance tumor susceptibility to immunotherapy agents. Immunotherapy enhances a person's own immune system to identify and attack cancer cells. It is proposed that after cryoablation there is increased expression of tumor specific antigens which the body can recognize as foreign invaders and with the combination of immunotherapy, result in an even more robust and efficient attack on the cancer cells. In this review we aim to highlight some of the recent advances in cryoablation which support the potential for cryoablation to induce these tumor-specific immune responses and thus supporting the use of combining cryoablation and immunotherapy for the treatment of breast cancer.

Novel Antibody-Peptide Binding Assay Indicates Presence of Immunoglobulins against EGFR Phospho-Site S1166 in High-Grade Glioma.

We investigated the feasibility of detecting the presence of specific autoantibodies against potential tumor-associated peptide antigens by enriching these antibody-peptide complexes using Melon Gel resin and mass spectrometry. Our goal was to find tumor-associated phospho-sites that trigger immunoreactions and raise autoantibodies that are detectable in plasma of glioma patients. Such immunoglobulins can potentially be used as targets in immunotherapy. To that aim, we describe a method to detect the presence of antibodies in biological samples that are specific to selected clinically relevant peptides. The method is based on the formation of antibody-peptide complexes by mixing patient plasma with a glioblastoma multiforme (GBM) derived peptide library, enrichment of antibodies and antibody-peptide complexes, the separation of peptides after they are released from immunoglobulins by molecular weight filtration and finally mass spectrometric quantification of these peptides. As proof of concept, we successfully applied the method to dinitrophenyl (DNP)-labeled α-casein peptides mixed with anti-DNP. Further, we incubated human plasma with a phospho-peptide library and conducted targeted analysis on EGFR and GFAP phospho-peptides. As a result, immunoaffinity against phospho-peptide GSHQIS[+80]LDNPDYQQDFFPK (EGFR phospho-site S1166) was detected in high-grade glioma (HGG) patient plasma but not in healthy donor plasma. For the GFAP phospho-sites selected, such immunoaffinity was not observed.

Neoantigens - the next frontier in precision immunotherapy for B-cell lymphoproliferative disorders.

Broad activation of host T-cell immunity by immune checkpoint blockade, has revolutionized the treatment of some but not all B-cell lymphoproliferative disorders (LPDs). The challenge for next generation immunotherapeutics, is to successfully induce anti-tumor specific T-cell immunity across a range of B-LPDs, without provoking immune-related adverse events. An emerging strategy is to target neoantigens. Neoantigens are immunogenic peptides, unique to malignant cells, that are presented to T-cells via human leukocyte antigens. Neoantigens most commonly arise from non-synonymous mutations but can also be derived from tumor specific alterations along the protein biosynthesis pathway. B-cell LPDs uniquely express a clonal B-cell receptor (BCR) idiotype, consisting of immunoglobulin genes that undergo recombination and somatic hypermutation. Notably, the BCR idiotype can also give rise to 'immunoglobulin neoantigens'. Here, we provide an overview of current strategies to identify and validate immunoglobulin and non-immunoglobulin neoantigens as well as summarizing studies investigating neoantigens within B-cell LPDs.

Immunopeptidomic analyses of colorectal cancers with and without microsatellite instability.

Colorectal cancer is the second leading cause of cancer death worldwide, and the incidence of this disease is expected to increase as global socioeconomic changes occur. Immune checkpoint inhibition therapy is effective in treating a minority of colorectal cancer tumors; however, microsatellite stable tumors do not respond well to this treatment. Emerging cancer immunotherapeutic strategies aim to activate a cytotoxic T cell response against tumor-specific antigens, presented exclusively at the cell surface of cancer cells. These antigens are rare and are most effectively identified with a mass spectrometry-based approach, which allows the direct sampling and sequencing of these peptides. Although the few tumor-specific antigens identified to date are derived from coding regions of the genome, recent findings indicate that a large proportion of tumor-specific antigens originate from allegedly noncoding regions. Here, we employed a novel proteogenomic approach to identify tumor antigens in a collection of colorectal cancer-derived cell lines and biopsy samples consisting of matched tumor and normal adjacent tissue. The generation of personalized cancer databases paired with mass spectrometry analyses permitted the identification of more than 30,000 unique MHC I-associated peptides. We identified 19 tumor-specific antigens in both microsatellite stable and unstable tumors, over two-thirds of which were derived from noncoding regions. Many of these peptides were derived from source genes known to be involved in colorectal cancer progression, suggesting that antigens from these genes could have therapeutic potential in a wide range of tumors. These findings could benefit the development of T cell-based vaccines, in which T cells are primed against these antigens to target and eradicate tumors. Such a vaccine could be used in tandem with existing immune checkpoint inhibition therapies, to bridge the gap in treatment efficacy across subtypes of colorectal cancer with varying prognoses. Data are available via ProteomeXchange with identifier PXD028309.

Emerging Novel Combined CAR-T Cell Therapies.

Chimeric antigen receptors (CAR) T cells are T cells engineered to express membrane receptors with high specificity to recognize specific target antigens presented by cancer cells and are co-stimulated with intracellular signals to increase the T cell response. CAR-T cell therapy is emerging as a novel therapeutic approach to improve T cell specificity that will lead to advances in precision medicine. CAR-T cells have had impressive outcomes in hematological malignancies. However, there continue to be significant limitations of these therapeutic responses in targeting solid malignancies such as heterogeneous antigens in solid tumors, tumor immunosuppressive microenvironment, risk of on-target/off-tumor, infiltrating CAR-T cells, immunosuppressive checkpoint molecules, and cytokines. This review paper summarizes recent approaches and innovations through combination therapies of CAR-T cells and other immunotherapy or small molecule drugs to counter the above disadvantages to potentiate the activity of CAR-T cells.

Labyrinthin: A distinct pan-adenocarcinoma diagnostic and immunotherapeutic tumor specific antigen.

Structural analysis and detection of optimal cell surface localization of labyrinthin, a pan-adenocarcinoma target, was studied with respect to adenocarcinoma specificity vs. normal and non-adenocarcinoma cells. Patient-derived tissue microarray immunohistochemistry (IHC) was performed on 729 commercially prepared tissue blocks of lung, colon, breast, pancreas, prostate, and ovary cancers combined, plus a National Cancer Institute (NCI) tissue microarray derived from another 236 cases. The results confirmed that anti-labyrinthin mouse monoclonal MCA 44-3A6 antibody recognized adenocarcinomas, but not normal or non-adenocarcinoma cancer cells. The consensus of multiple topology analysis programs on labyrinthin (255 amino acids) estimate a type II cell membrane associated protein with an N-terminus signal peptide. However, because the labyrinthin sequence is enveloped within the 758 amino acids of the intracellular aspartyl/asparaginyl beta-hydroxylase (ASPH), a purported tumor associated antigen, standard IHC methods that permeabilize cells can expose common epitopes. To circumvent antibody cross-reactivity, cell surface labyrinthin was distinguished from intracellular ASPH by FACS analysis of permeabilized vs non-permeabilized cells. All permeabilized normal, adeno-and non-adenocarcinoma cells produced a strong MCA 44-3A6 binding signal, likely reflecting co-recognition of intracellular ASPH proteins along with internalized labyrinthin, but in non-permeabilized cells only adenocarcinoma cells were positive for labyrinthin. Confocal microscopy confirmed the FACS results. Labyrinthin as a functional cell-surface marker was suggested when: 1) WI-38 normal lung fibroblasts transfected with labyrinthin sense cDNA displayed a cancerous phenotype; 2) antisense transfection of A549 human lung adenocarcinoma cells appeared more normal; and 3) MCA44-3A6 suppressed A549 cell proliferation. Collectively, the data indicate that labyrinthin is a unique, promising adenocarcinoma tumor-specific antigen and therapeutic target. The study also raises a controversial issue on the extent, specificity, and usefulness of ASPH as an adenocarcinoma tumor-associated antigen.

The state of the art of bispecific antibodies for treating human malignancies.

Bispecific antibodies (bsAb) that target two independent epitopes or antigens have been extensively explored in translational and clinical studies since they were first developed in the 1960s. Many bsAbs are being tested in clinical trials for treating a variety of diseases, mostly cancer. Here, we provide an overview of various types of bsAbs in clinical studies and discuss their targets, safety profiles, and efficacy. We also highlight the current challenges, potential solutions, and future directions of bsAb development for cancer treatment.

T-cell-based immunotherapy in colorectal cancer.

Colorectal cancer (CRC) is the leading cause of cancer death worldwide. CRC therapeutic strategies include surgical resection, chemotherapy, radiotherapy, and other approaches. However, patients with metastatic CRC have worse prognoses. In recent years, T-cell-based immunotherapy has elicited promising responses in B-cell malignancies, melanoma, and lung cancer, but most CRC patients are resistant to immunotherapy, chemotherapy, and targeted therapy. Immune checkpoint inhibitors have shown encouraging results in non-small cell lung cancer, melanoma, and other cancers, but immune checkpoint blockade is only effective for CRC subset with microsatellite instability. Other immunotherapies, such as cytokines, cancer vaccines, small molecules, oncolytic viruses, and chimeric antigen-receptor therapy, are currently in use against CRC. This review analyzes recent developments in immunotherapy for CRC treatment as well as the challenges in overcoming resistance.

Targeted drug delivery using an aptamer against shared tumor-specific peptide antigen of MAGE-A3.

We developed a DNA aptamer, Ap52, against the shared tumor-specific MAGE-A3111-125 peptide antigen that was used to target multiple types of cancer cells. Here we report the in vivo study of mice implanted with pancreatic tumor cells AsPC-1, which demonstrates accumulation of phosphorothioate-modified Ap52 (ThioAp52) at the xenograft tumor following either intravenous or in situ injection. When complexed with antitumor drug doxorubicin (Dox), ThioAp52 achieves targeted delivery to four types of cancer cells, including breast, oral, pancreatic, and skin. Image analysis shows that ThioAp52-Dox complex selectively enters cancer cells, while free Dox is taken up by all cell lines. The cytotoxicity of ThioAp52-Dox for cancer cells is enhanced as compared to that for the corresponding normal/noncancerous cells. These results indicate that this aptamer against shared tumor-specific antigen can be a potential delivery vehicle for therapeutics to treat multiple cancers.

Personalized cancer vaccination in head and neck cancer.

Cancer is characterized by an accumulation of somatic mutations that represent a source of neoantigens for targeting by antigen-specific T cells. Head and neck squamous cell carcinoma (HNSCC) has a relatively high mutation burden across all cancer types, and cellular immunity to neoantigens likely plays a key role in HNSCC clinical outcomes. Immune checkpoint inhibitors (CPIs) have brought new treatment options and hopes to patients with recurrent and/or metastatic HNSCC. However, many patients do not benefit from CPI therapies, highlighting the need for novel immunotherapy or combinatorial strategies. One such approach is personalized cancer vaccination targeting tumor-associated antigens and tumor-specific antigens, either as single agents or in combination with other therapies. Recent advances in next-generation genomic sequencing technologies and computational algorithms have enabled efficient identification of somatic mutation-derived neoantigens and are anticipated to facilitate the development of cancer vaccine strategies. Here, we review cancer vaccine approaches against HNSCC, including fundamental mechanisms of a cancer vaccine, considerations for selecting appropriate antigens, and combination therapies.

The Origin and Immune Recognition of Tumor-Specific Antigens.

The dominant paradigm holds that spontaneous and therapeutically induced anti-tumor responses are mediated mainly by CD8 T cells and directed against tumor-specific antigens (TSAs). The presence of specific TSAs on cancer cells can only be proven by mass spectrometry analyses. Bioinformatic predictions and reverse immunology studies cannot provide this type of conclusive evidence. Most TSAs are coded by unmutated non-canonical transcripts that arise from cancer-specific epigenetic and splicing aberrations. When searching for TSAs, it is therefore important to perform mass spectrometry analyses that interrogate not only the canonical reading frame of annotated exome but all reading frames of the entire translatome. The majority of aberrantly expressed TSAs (aeTSAs) derive from unstable short-lived proteins that are good substrates for direct major histocompatibility complex (MHC) I presentation but poor substrates for cross-presentation. This is an important caveat, because cancer cells are poor antigen-presenting cells, and the immune system, therefore, depends on cross-presentation by dendritic cells (DCs) to detect the presence of TSAs. We, therefore, postulate that, in the untreated host, most aeTSAs are undetected by the immune system. We present evidence suggesting that vaccines inducing direct aeTSA presentation by DCs may represent an attractive strategy for cancer treatment.

Podoplanin as an Attractive Target of CAR T Cell Therapy.

To date, various kinds of cancer immunotherapy methods have been developed, but T cell immunotherapy is one of the most promising strategies. In general, T cell receptor (TCR) or chimeric antigen receptor (CAR) is used to modify the antigen specificity of T cells. CARs possess an underlying potential with treatment efficacy to treat a broad range of cancer patients compared with TCRs. Although a variety of CAR molecules have been developed so far, the clinical application for solid tumors is limited partly due to its adverse effect known as "on-target off-tumor toxicity". Therefore, it is very important for CAR T cell therapy to target specific antigens exclusively expressed by malignant cells. Here, we review the application of T cell immunotherapy using specific antigen receptor molecules and discuss the possibility of the clinical application of podoplanin-targeted CAR derived from a cancer-specific monoclonal antibody (CasMab).