MAGED4B is a Poor Prognostic Marker of Stomach Adenocarcinoma and a Potential Therapeutic Target for Stomach Adenocarcinoma Tumorigenesis

Background

Gastric cancer is the second most common cause of cancer death worldwide with poor overall prognosis. It is important to study the molecular mechanism of stomach adenocarcinoma (STAD). MAGED4B, a member of the melanoma antigen gene (MAGE) family, is highly expressed in many tumor cells and is associated with tumor progression. Its prognostic value in and the function of the encoded protein are still unclear.

Methods

The data of 415 STAD tissues was retrieved from TCGA database, and the expression level of MAGED4B mRNA was evaluated. The correlation between the expression of MAGED4B mRNA and the progression free survival (PFS) time of STAD patients was evaluated by Kaplan Meier analysis. The STAD cell lines with overexpressed and silent MAGED4B were constructed, and the effects of MAGED4B on the viability, migration and proliferation were evaluated by the CCK-8, scratch test and EDU test. The flow cytometry was used to detect apoptosis with overexpressed and silent MAGED4B under the cisplatin treatment, and WB was used to detect the expressions of related proteins, such as TNF-α.

Results

The expression level of MAGED4B mRNA in the STAD tissues was higher than that in the normal tissues, and its high expression was related to poor PFS. The overexpression of MAGED4B in the STAD cell lines can promote the vitality, motility and proliferation of the STAD cells, while the silencing of MAGED4B can inhibit the above three cell functions of the STAD cells. The overexpression of MAGED4B can reduce the cisplatin induced apoptosis and increase the cisplatin IC₅₀; the silencing of MAGED4B can promote the cisplatin induced apoptosis and reduce the cisplatin IC₅₀. The overexpression of MAGED4B reduced the protein levels of TRIM27 and TNF- α.

Conclusion

MAGED4B could be a valuable prognostic biomarker and a therapeutic target for gastric adenocarcinoma of great interest.

DNA Vaccines Targeting Novel Cancer-Associated Antigens Frequently Expressed in Head and Neck Cancer Enhance the Efficacy of Checkpoint Inhibitor

HPV-independent head and neck squamous cell carcinoma (HNSCC) is a common cancer globally. The overall response rate to anti-PD1 checkpoint inhibitors (CPIs) in HNSCC is ~16%. One major factor influencing the effectiveness of CPI is the level of tumor infiltrating T cells (TILs). Converting TILlow tumors to TILhigh tumors is thus critical to improve clinical outcome. Here we describe a novel DNA vaccines to facilitate the T-cell infiltration and control tumor growth. We evaluated the expression of target antigens and their respective immunogenicity in HNSCC patients. The efficacy of DNA vaccines targeting two novel antigens were evaluated with or without CPI using a syngeneic model. Most HNSCC patients (43/44) co-expressed MAGED4B and FJX1 and their respective tetramer-specific T cells were in the range of 0.06-0.12%. In a preclinical model, antigen-specific T cells were induced by DNA vaccines and increased T cell infiltration into the tumor, but not MDSC or regulatory T cells. The vaccines inhibited tumor growth and improved the outcome alone and upon combination with anti-PD1 and resulted in tumor clearance in approximately 75% of mice. Pre-existence of MAGED4B and FJX1-reactive T cells in HNSCC patients suggests that these widely expressed antigens are highly immunogenic and could be further expanded by vaccination. The DNA vaccines targeting these antigens induced robust T cell responses and with the anti-PD1 antibody conferring excellent tumor control. This opens up an opportunity for combination immunotherapy that might benefit a wider population of HNSCC patients in an antigen-specific manner.

In vitro evaluation of dual-antigenic PV1 peptide vaccine in head and neck cancer patients

Peptide vaccines derived from tumour-associated antigens have been used as an immunotherapeutic approach to induce specific cytotoxic immune response against tumour. We previously identified that MAGED4B and FJX1 proteins are overexpressed in HNSCC patients; and further demonstrated that two HLA-A2-restricted 9-11 amino acid peptides derived from these proteins were able to induce anti-tumour immune responses in vitro independently using PBMCs isolated from these patients. In this study, we evaluated the immunogenicity and efficacy of a dual-antigenic peptide vaccine (PV1), comprised of MAGED4B and FJX1 peptides in HNSCC patients. We first demonstrated that 94.8% of HNSCC patients expressed MAGED4B and/or FJX1 by immunohistochemistry, suggesting that PV1 could benefit the majority of HNSCC patients. The presence of pre-existing MAGED4B and FJX1-specific T-cells was detected using a HLA-A2 dimer assay and efficacy of PV1 to induce T-cell to secrete cytotoxic cytokine was evaluated using ELISPOT assay. Pre-existing PV1-specific T-cells were detected in all patients. Notably, we demonstrated that patients' T-cells were able to secrete cytotoxic cytokines upon exposure to target cells expressing the respective antigen post PV1 stimulation. Furthermore, patients with high expression of MAGED4B and FJX1 in their tumours were more responsive to PV1 stimulation, demonstrating the specificity of the PV1 peptide vaccine. Additionally, we also demonstrated the expression of MAGED4B and FJX1 in breast, lung, colon, prostate and rectal cancer suggesting the potential use of PV1 in these cancers. In summary, PV1 could be a good vaccine candidate for the treatment of HNSCC patients and other cancers expressing these antigens.

Identification of immunogenic MAGED4B peptides for vaccine development in oral cancer immunotherapy

The ever-increasing number of tumor-associated antigens has provided a major stimulus for the development of therapeutic peptides vaccines. Tumor-associated peptides can induce high immune response rates and have been developed as vaccines for several types of solid tumors, and many are at various stages of clinical testing. MAGED4B, a melanoma antigen, is overexpressed in oral squamous cell carcinoma (OSCC) and this expression promotes proliferation and cell migration. In this study, we have identified 9 short peptides derived from MAGED4B protein that are restricted in binding to the HLA subtypes common in the Asian population (HLA-A2, A11, and A24). The peptides had good binding affinity with the MHC-Class I molecules and stimulated ex-vivo IFN-gamma and Granzyme-B production in blood samples from OSCC patients, suggesting that they are immunogenic. Further, T cells stimulated with peptide-pulsed dendritic cells showed enhanced T-cell cytotoxic activity against MAGED4B-overexpressing OSCC cell lines. In summary, we have identified MAGED4B peptides that induce anti-tumor immune responses advocating that they could be further developed as vaccine candidates for the treatment of OSCC.