The Melanoma-Associated Antigen Family A (MAGE-A): A Promising Target for Cancer Immunotherapy?

Adoptive Cell Therapy for Solid Tumors: Current Status in Melanoma and Next-Generation Therapies

Lifileucel or TIL has recently been FDA approved for metastatic melanoma patients as first cell therapy for a solid tumor. We discuss roll-out of TIL as new SOC and other upcoming new cell therapies.

Melanoma antigens in pediatric medulloblastoma contribute to tumor heterogeneity and species-specificity of group 3 tumors

Background

Medulloblastoma (MB) is the most malignant childhood brain cancer. Group 3 MB subtype accounts for about 25% of MB diagnoses and is associated with the most unfavorable outcomes. Herein, we report that more than half of group 3 MB tumors express melanoma antigens (MAGEs), which are potential prognostic and therapeutic markers. MAGEs are tumor antigens, expressed in several types of adult cancers and associated with poorer prognosis and therapy resistance; however, their expression in pediatric cancers is mostly unknown. The aim of this study was to determine whether MAGEs are activated in pediatric MB.

Methods

To determine MAGE frequency in pediatric MB, we obtained formalin-fixed paraffin-embedded tissue (FFPE) samples of 34 patients, collected between 2008 - 2015, from the Children's Medical Center Dallas pathology archives and applied our validated reverse transcription quantitative PCR (RT-qPCR) assay to measure the relative expression of 23 MAGE cancer-testis antigen genes. To validate our data, we analyzed several published datasets from pediatric MB patients and patient-derived orthotopic xenografts, totaling 860 patients. We then examined how MAGE expression affects the growth and oncogenic potential of medulloblastoma cells by CRISPR-Cas9- and siRNA-mediated gene depletion.

Results

Our RT-qPCR analysis suggested that MAGEs were expressed in group 3/4 medulloblastoma. Further mining of bulk and single-cell RNA-sequencing datasets confirmed that 50-75% of group 3 tumors activate a subset of MAGE genes. Depletion of MAGEAs, B2, and Cs alter MB cell survival, viability, and clonogenic growth due to decreased proliferation and increased apoptosis.

Conclusions

These results indicate that targeting MAGEs in medulloblastoma may be a potential therapeutic option for group 3 medulloblastomas.

Key Points

Several Type I MAGE CTAs are expressed in >60% of group 3 MBs. Type I MAGEs affect MB cell proliferation and apoptosis. MAGEs are potential biomarkers and therapeutic targets for group 3 MBs.

Importance of the Study

This study is the first comprehensive analysis of all Type I MAGE CTAs ( MAGEA , -B , and -C subfamily members) in pediatric MBs. Our results show that more than 60% of group 3 MBs express MAGE genes, which are required for the viability and growth of cells in which they are expressed. Collectively, these data provide novel insights into the antigen landscape of pediatric MBs. The activation of MAGE genes in group 3 MBs presents potential stratifying and therapeutic options.

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Advances in Therapeutic Cancer Vaccines, Their Obstacles, and Prospects Toward Tumor Immunotherapy

Over the past few decades, cancer immunotherapy has experienced a significant revolution due to the advancements in immune checkpoint inhibitors (ICIs) and adoptive cell therapies (ACTs), along with their regulatory approvals. In recent times, there has been hope in the effectiveness of cancer vaccines for therapy as they have been able to stimulate de novo T-cell reactions against tumor antigens. These tumor antigens include both tumor-associated antigen (TAA) and tumor-specific antigen (TSA). Nevertheless, the constant quest to fully achieve these abilities persists. Therefore, this review offers a broad perspective on the existing status of cancer immunizations. Cancer vaccine design has been revolutionized due to the advancements made in antigen selection, the development of antigen delivery systems, and a deeper understanding of the strategic intricacies involved in effective antigen presentation. In addition, this review addresses the present condition of clinical tests and deliberates on their approaches, with a particular emphasis on the immunogenicity specific to tumors and the evaluation of effectiveness against tumors. Nevertheless, the ongoing clinical endeavors to create cancer vaccines have failed to produce remarkable clinical results as a result of substantial obstacles, such as the suppression of the tumor immune microenvironment, the identification of suitable candidates, the assessment of immune responses, and the acceleration of vaccine production. Hence, there are possibilities for the industry to overcome challenges and enhance patient results in the coming years. This can be achieved by recognizing the intricate nature of clinical issues and continuously working toward surpassing existing limitations.

An Engineered M13 Filamentous Nanoparticle as an Antigen Carrier for a Malignant Melanoma Immunotherapeutic Strategy

Bacteriophages, prokaryotic viruses, hold great potential in genetic engineering to open up new avenues for vaccine development. Our study aimed to establish engineered M13 bacteriophages expressing MAGE-A1 tumor peptides as a vaccine for melanoma treatment. Through in vivo experiments, we sought to assess their ability to induce robust immune responses. Using phage display technology, we engineered two M13 bacteriophages expressing MAGE-A1 peptides as fusion proteins with either pVIII or pIIII coat proteins. Mice were intraperitoneally vaccinated three times, two weeks apart, using two different engineered bacteriophages; control groups received a wild-type bacteriophage. Serum samples taken seven days after each vaccination were analyzed by ELISA assay, while splenocytes harvested seven days following the second boost were evaluated by ex vivo cytotoxicity assay. Fusion proteins were confirmed by Western blot and nano-LC-MS/MS. The application of bacteriophages was safe, with no adverse effects on mice. Engineered bacteriophages effectively triggered immune responses, leading to increased levels of anti-MAGE-A1 antibodies in proportion to the administered bacteriophage dosage. Anti-MAGE-A1 antibodies also exhibited a binding capability to B16F10 tumor cells in vitro, as opposed to control samples. Splenocytes demonstrated enhanced CTL cytotoxicity against B16F10 cells. We have demonstrated the immunogenic capabilities of engineered M13 bacteriophages, emphasizing their potential for melanoma immunotherapy.

Melanoma Antigen Family A (MAGE A) as Promising Biomarkers and Therapeutic Targets in Bladder Cancer

The Melanoma Antigen Gene (MAGE) is a large family of highly conserved proteins that share a common MAGE homology domain. Interestingly, many MAGE family members exhibit restricted expression in reproductive tissues but are abnormally expressed in various human malignancies, including bladder cancer, which is a common urinary malignancy associated with high morbidity and mortality rates. The recent literature suggests a more prominent role for MAGEA family members in driving bladder tumorigenesis. This review highlights the role of MAGEA proteins, the potential for them to serve as diagnostic or prognostic biomarker(s), and as therapeutic targets for bladder cancer.

Therapeutic cancer vaccines: advancements, challenges, and prospects

With the development and regulatory approval of immune checkpoint inhibitors and adoptive cell therapies, cancer immunotherapy has undergone a profound transformation over the past decades. Recently, therapeutic cancer vaccines have shown promise by eliciting de novo T cell responses targeting tumor antigens, including tumor-associated antigens and tumor-specific antigens. The objective was to amplify and diversify the intrinsic repertoire of tumor-specific T cells. However, the complete realization of these capabilities remains an ongoing pursuit. Therefore, we provide an overview of the current landscape of cancer vaccines in this review. The range of antigen selection, antigen delivery systems development the strategic nuances underlying effective antigen presentation have pioneered cancer vaccine design. Furthermore, this review addresses the current status of clinical trials and discusses their strategies, focusing on tumor-specific immunogenicity and anti-tumor efficacy assessment. However, current clinical attempts toward developing cancer vaccines have not yielded breakthrough clinical outcomes due to significant challenges, including tumor immune microenvironment suppression, optimal candidate identification, immune response evaluation, and vaccine manufacturing acceleration. Therefore, the field is poised to overcome hurdles and improve patient outcomes in the future by acknowledging these clinical complexities and persistently striving to surmount inherent constraints.

Development of dendritic cell loaded MAGE-A2 long peptide; a potential target for tumor-specific T cell-mediated prostate cancer immunotherapy

BACKGROUND

Prostate cancer (PCa) is the second leading cause of cancer-related deaths among men worldwide. Immunotherapy is an emerging treatment modality for cancers that harnesses the immune system's ability to eliminate tumor cells. In particular, dendritic cell (DC) vaccines, have demonstrated promise in eliciting a tumor-specific immune response. In this study, we investigated the potential of using DCs loaded with the MAGE-A2 long peptide to activate T cell cytotoxicity toward PCa cell lines.

METHODS

Here, we generated DCs from monocytes and thoroughly characterized their phenotypic and functional properties. Then, DCs were pulsed with MAGE-A2 long peptide (LP) as an antigen source, and monitored for their transition from immature to mature DCs by assessing the expression levels of several costimulatory and maturation molecules like CD14, HLA-DR, CD40, CD11c, CD80, CD83, CD86, and CCR7. Furthermore, the ability of MAGE-A2 -LP pulsed DCs to stimulate T cell proliferation in a mixed lymphocyte reaction (MLR) setting and induction of cytotoxic T cells (CTLs) in coculture with autologous T cells were examined. Finally, CTLs were evaluated for their capacity to produce interferon-gamma (IFN-γ) and kill PCa cell lines (PC3 and LNCaP).

RESULTS

The results demonstrated that the antigen-pulsed DCs exhibited a strong ability to stimulate the expansion of T cells. Moreover, the induced CTLs displayed substantial cytotoxicity against the target cells and exhibited increased IFN-γ production during activation compared to the controls.

CONCLUSIONS

Overall, this innovative approach proved efficacious in targeting PCa cell lines, showcasing its potential as a foundation for the development and improved PCa cancer immunotherapy.

Exploring TCR-like CAR-Engineered Lymphocyte Cytotoxicity against MAGE-A4

TCR-like chimeric antigen receptor (CAR-T) cell therapy has emerged as a game-changing strategy in cancer immunotherapy, offering a broad spectrum of potential antigen targets, particularly in solid tumors containing intracellular antigens. In this study, we investigated the cytotoxicity and functional attributes of in vitro-generated T-lymphocytes, engineered with a TCR-like CAR receptor precisely targeting the cancer testis antigen MAGE-A4. Through viral transduction, T-cells were genetically modified to express the TCR-like CAR receptor and co-cultured with MAGE-A4-expressing tumor cells. Flow cytometry analysis revealed a significant surge in cells expressing activation markers CD69, CD107a, and FasL upon encountering tumor cells, indicating robust T-cell activation and cytotoxicity. Moreover, immune transcriptome profiling unveiled heightened expression of pivotal T-effector genes involved in immune response and cell proliferation regulation. Additionally, multiplex assays also revealed increased cytokine production and cytotoxicity driven by granzymes and soluble Fas ligand (sFasL), suggesting enhanced anti-tumor immune responses. Preliminary in vivo investigations revealed a significant deceleration in tumor growth, highlighting the therapeutic potential of these TCR-like CAR-T cells. Further investigations are warranted to validate these revelations fully and harness the complete potential of TCR-like CAR-T cells in overcoming cancer's resilient defenses.

Cancer/Testis Antigens as Targets for RNA-Based Anticancer Therapy

In the last few decades, RNA-based drugs have emerged as a promising candidate in the treatment of various diseases. The introduction of messenger RNA (mRNA) as a vaccine or therapeutic agent enables the production of almost any functional protein/peptide. The key to applying RNA therapy in clinical trials is developing safe and effective delivery systems. Exosomes and lipid nanoparticles (LNPs) have been exploited as promising vehicles for drug delivery. This review discusses the feasibility of exosomes and LNPs as vehicles for mRNA delivery. Cancer/testis antigens (CTAs) show restricted expression in normal tissues and widespread expression in cancer tissues. Many of these CTAs show expression in the sera of patients with cancers. These characteristics of CTAs make them excellent targets for cancer immunotherapy. This review summarizes the roles of CTAs in various life processes and current studies on mRNAs encoding CTAs. Clinical studies present the beneficial effects of mRNAs encoding CTAs in patients with cancers. This review highlight clinical studies employing mRNA-LNPs encoding CTAs.

MAGE-A10 Protein Expression in Advanced High Grade Serous Ovarian Cancer Is Associated with Resistance to First-Line Platinum-Based Chemotherapy

Ovarian cancer has a dismal prognosis. Standard treatment following surgery relies on platinum-based chemotherapy. However, sizeable percentages of patients are unresponsive. Identification of markers predicting the response to chemotherapy might help select eligible patients and spare non-responding patients from treatment-associated toxicity. Cancer/testis antigens (CTAs) are expressed by healthy germ cells and malignant cells of diverse histological origin. This expression profile identifies them as attractive targets for cancer immunotherapies. We analyzed the correlations between expression of MAGE-A10 and New York esophageal-1 cancer (NY-ESO-1) CTAs at the protein level and the effectiveness of platinum-based chemotherapy in patients with advanced-stage high-grade serous ovarian carcinoma (HGSOC). MAGE-A10 and NY-ESO-1 protein expression was analyzed by immunohistochemistry (IHC) in formalin-fixed, paraffin-embedded samples from 93 patients with advanced-stage HGSOC treated at our institutions between January 1996 and December 2013. The correlation between the expression of these markers and response to platinum-based chemotherapy, evaluated according to RECIST 1.1 criteria and platinum sensitivity, measured as platinum-free interval (PFI), progression free (PFS), and overall survival (OS) was explored. The MAGE-A10 protein expression predicted unresponsiveness to platinum-based chemotherapy (p = 0.005), poor platinum sensitivity (p < 0.001), poor PFS (p < 0.001), and OS (p < 0.001). Multivariate analysis identified MAGE-A10 protein expression as an independent predictor of poor platinum sensitivity (p = 0.005) and shorter OS (p < 0.001). Instead, no correlation was observed between the NY-ESO-1 protein expression and response to platinum-based chemotherapy (p = 0.832), platinum sensitivity (p = 0.168), PFS (p = 0.126), and OS (p = 0.335). The MAGE-A10 protein expression reliably identified advanced-stage HGSOC unresponsive to platinum-based chemotherapy. Targeted immunotherapy could represent an important alternative therapeutic option in these cancers.