Cancer-testis Antigens Research Articles

Abstract 13: Discovery and development of T cell receptors targeting MAGE family antigens for adoptive T cell therapy against solid tumors

Abstract Background: T cell receptors (TCRs) recognize epitopes from intracellular and cell surface antigens, enabling targeting of diverse tumor antigen classes including overexpressed, differentiation, cancer-testis antigens, as well as those from driver mutations, frameshift mutations, splice variants, and human endogenous retroviral elements (HERV). Melanoma-associated antigens (MAGE) are highly expressed in various solid tumor types, including melanoma, non-small cell lung cancers (NSCLC), bladder, and head and neck cancers, representing promising targets for TCR-T therapy. However, discovering robust and specific MAGE-reactive TCRs remains challenging due to limited throughput of TCR screening methodologies, and the inherently low frequency of tumor-reactive T cells in tumor samples and peripheral blood. Methods: We employ a proprietary mass-cytometry-based multiplexed tetramer staining approach, TargetScape®, to screen and characterize CD8+ T cells in healthy donors and patients’ samples. Our screening panels contain multiple peptides for MAGE family antigens including A1, C2, and A10. Subsequent single cell sequencing or single cell PCR (scPCR) of identified tumor antigen-specific T cells with high sensitivity enables comprehensive analysis of T cell phenotype, transcriptome, TCR specificity, and paired TCR sequence. TCRs identified through this method are transduced for expression in Jurkat reporter cell lines and their reactivity to corresponding peptides is assessed. Selected TCR candidates are then transduced into primary T cells and evaluated for activation and effector function using a variety of cancer cell lines expressing the corresponding endogenous antigens. Specificity assessment is performed through alanine scans and identification of potential off-target peptides and screening for reactivity. Results: We utilized this approach to discover natural TCRs that target several MAGE family antigens. Through Jurkat reporter screening, we observed specific activation of multiple TCRs in the presence of antigen presenting cells and the peptide initially employed to identify the TCRs. Primary T-cells expressing promising TCR candidates exhibited killing activities and cytokine release when confronted with multiple solid tumor cell lines expressing endogenous levels of the MAGE antigen. Specificity assessment is currently in progress, with preliminary data indicating overall favorable specificity profiles for selected TCRs. Conclusions: Our Deep Immunomics platform enables us to detect, characterize, and validate TCR candidates against highly clinically relevant shared cancer antigens. Leveraging this platform, we identified various natural tumor specific TCRs exhibiting activities against a range of solid tumor cell lines expressing MAGE antigens. Promising candidates are currently undergoing in vivo efficacy studies. Citation Format: Juliana Velez Lujan, Hannah Fields, Kan Xing Wu, Yovita Purwanti, Emily Xin Zi Tang, Michael Cordeau, Kathleen Mendez, Melissa Wirawan, Michael Fehlings, Katja Fink, Zilei Liu, Daniel MacLeod. Discovery and development of T cell receptors targeting MAGE family antigens for adoptive T cell therapy against solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 13.

Abstract 7531: Mechanisms of response to anti-PD1 (PD1) combined with Ipilimumab (IPI) in patients (pts) with PD1-resistant metastatic melanoma (MM)

Abstract Background: Approximately 1 in 3 pts with PD1-resistant MM will benefit from IPI+PD1, but the role of adding IPI in this context is unclear. We sought to (a) identify biomarkers and (b) determine mechanisms of response to IPI+PD1 in PD1 resistant pts. Methods: Pts with PD1-resistant MM subsequently treated with IPI+PD1 were included. We performed multiplex immunofluorescence (mIF), imaging mass cytometry (IMC) and RNA sequencing (RNAseq) on melanoma samples, and cytometry by time of flight (CYTOF) on peripheral blood mononuclear cells (PBMCs), at 3 timepoints (before PD1 [T1], before IPI+PD1 [T2], and after IPI+PD1 [T3]). Results: 34 pts with PD1-resistant MM (82% innate resistance) who received IPI+PD1 were included: 16 (47%) responders and 18 (53%) non-responders to IPI+PD1. Median age was 66yo (37-86) and 19 (56%) were male. Six pts (18%) were ECOG PS ≥1, 18 (53%) were stage M1C/D and 11 (32%) had elevated LDH at the start of IPI+PD1.Gene expression analysis (RNAseq) on T1 and T2 tumor samples revealed higher expression of cancer testis antigens (CTA; MAGE-A3 and MAGE-C1; p<0.05) and immune regulatory genes (ILR2; p<0.2), but lower expression of fibrosis regulation genes (FABP3 and MMP7; p < 0.2) in responders vs non-responders. We then examined whether the addition of IPI led to expansion of CTA-specific T cells, and CyTOF analysis of MAGE-A3 tetramers on PBMCs showed a decrease in peripheral MAGE-A3-specific CD8+ T cells with PD1 (T1 to T2; p=0.03); and expansion of this T-cell subset with subsequent IPI+PD1 (T2 to T3) was seen in 7/12 HLA-A2+ pts. Further analysis on PBMC longitudinal samples showed an increase in regulatory T cells (Tregs) in responders (p=0.04), between T1 and T3, and a decrease in % of TCF7+ CD8+ & CD4+ T cells in non-responders (p<0.05) with the addition of IPI (T2 to T3). On baseline (T1) tumor samples (mIF), IPI+PD1 responders had a higher % of stem cell-like TCF7+ CD8+ T cells (p=0.0004), lower % of well-differentiated Tbet+ CD8+ T cells (p=0.07), and higher % of CD4+ T cells (p=0.006), compared with non-responders; but no difference in Tregs. On longitudinal tumor samples, there was a decrease in the % of stem cell-like TCF7+ CD8+ T cells but an increase in the % of tumor-reactive CD39+ CD103+ CD8+ T cells with PD1 (T1 to T2; p<0.05), mainly seen in responders (p=0.06). There were only 3 T2 to T3 IHC paired samples, precluding further analysis. IMC analysis on longitudinal samples (T1, T2 and T3) is underway to characterize the interaction between Tregs and T effector cells. Conclusions: We identified potential mechanisms of response to IPI+PD1 in PD1-resistant MM pts. Our data suggests that response to IPI+PD1 requires baseline stem cell-like TCF7+ T cells with the potential to differentiate to an effector phase (CD39+ CD103+ CD8+ T cells), and that IPI facilitated expansion of antigen-specific T cells in a CTA-expression context, that PD1 alone is unable to do. Citation Format: Ines Pires da Silva, Jordan Conway, Jarem Edwards, Felix Marsh-Wakefield, Camelia Quek, Angela Ferguson, Peter Johnansson, Matteo Carlino, Alexander Menzies, James Wilmott, Umaimainthan Palendira, Richard Scolyer, Georgina Long. Mechanisms of response to anti-PD1 (PD1) combined with Ipilimumab (IPI) in patients (pts) with PD1-resistant metastatic melanoma (MM) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7531.

Abstract 2513: MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder cancer

Abstract PD-L1 programmed death ligand 1/CD274 has been shown to be an excellent immune therapy target for many tumors. Currently, studies have shown PD-L1in combination with other immune therapy targets can improve patient outcomes generating the need for new targets. One candidate is the cancer testis antigen Melanoma Antigen Gene Family (MAGE-A) because these genes have limited expression in normal tissues and high expression in cancer. Clinical trials have already begun targeting MAGE-A3 and MAGE-A4 proteins in multiple tumor types. Protein assessment of individual MAGE-A family members has been challenging due to sequence homology as high as ninety-five percent between members. Previously, with the use of CytoSections two highly specific antibodies for immunohistochemistry to MAGE-A3 (clone OTI1H1) and MAGE-A4 (clone OTI2C1) were found. In this study, the MAGE-A3 and MAGE-A4 antibodies were screened with PD-L1 on colon, lung, and bladder cancers. Results show detection of both MAGE-A3 and MAGE-A4 in 25% of colon; 30% of lung; and 20% of bladder cancers. More than 70% of the lung and bladder cancers were positive for MAGE-A4 but only six of twenty-four colon cancers were positive for MAGE-A4. The results show 60 percent of the positive for MAGEA3 or MAGEA4 in colon, lung, and bladder cancers were also positive for PD-L1. This study suggests that MAGE-A3 and MAGE-A4 have tumor specific expression patterns and a potential to be a co-immunotherapy target with PD-L1. Citation Format: Rachel Gonzalez, YiChen Guo, Jina Yom, Bailey Gilmore, Eden Zewdu, Xi-Andy Han, Dehe Kong, Tianli Qu, Qi Ren, Xiaomin Hu, Ranran Zhang, Zhaohui Wu, Alex Strom, Xuan Liu, Wei Fu. MAGE-A3, MAGE-A4, and PD-L1 protein show co-expression in colon, lung and bladder cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2513.

Abstract 6845: MAGEA3 expression and secretion in MMR-MSH6 and MMR-PMS2 microsatellite-stable colorectal cancer

Abstract Despite the breakthrough of PD-1/PD-L1 blockade therapy in the recent years, mixed responses have been shown across multiple tumor types, including in colorectal cancer (CRC), the second leading cause of death worldwide. This immunotherapy has proven to be successful for a subtype of CRC that carries mismatch repair deficiency (dMMR) and high microsatellite instability (MSI-H), despite a lack of response by microsatellite-stable CRC. For these types of non-responsive cancers, new immunotherapy targets are currently being investigated for alternative therapy such as the MAGE-A cancer testis antigen family whose expression is restricted to germline cells in normal tissue but is overexpressed in many cancer cells. In this study, we examine the relationship between MAGEA3 and MMR proteins MSH6 and PMS2. Immunohistochemical staining of CRC tissues demonstrated co-expression between MAGEA3 with both MSH6 and PMS2. Immune cells were observed to express MAGEA3 in CRC as well. To investigate the possibility of secreted MAGEA3 from tumor cells, we performed western blot analysis of CRC cell lines, ELISA, and binding assay on cell lines and the positive results suggest that MAGEA3 protein is secreted. The results suggest that MAGE-A3 may be a promising target for microsatellite-stable colorectal cancer immunotherapy. Citation Format: Jina Yom, Rachel Gonzalez, Bailey Gilmore, Zhaoying Guo, Andy Han, Eden Zewdu, Dehe Kong, Tianli Qu, Hailey Guo, Alex Strom, Zoe Zhao, Xiaomin Hu, Qi Ren, Yan Ma, Ranran Zhang, Zhaohui Wu, Xuan Liu, Wei Fu. MAGEA3 expression and secretion in MMR-MSH6 and MMR-PMS2 microsatellite-stable colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6845.

Abstract 1329: Development of the first optimised “off the shelf” MAGE-A4 targeting TCR-NK cells for advancement into the clinic for the treatment of solid tumors

Abstract T cell receptor (TCR)-T based therapies, such as MAGE-A4 TCR-T cells, have shown compelling data demonstrating effective infiltration into and targeting of solid tumors with clinical responses across various solid cancers. However, heterogeneity and down-regulation of target antigen and HLA expression limit the durability and curative potential of these types of treatments. On the other hand, owing to their clinical potency, favorable safety profile and applicability as “off the shelf” therapy, natural killer (NK) cells have emerged as promising modalities in recent years. Unguided NK cells have shown limited potential against solid cancers, due to lacking infiltration into tumors. With our proprietary TCR-NK platform, we combine the solid tumor targeting capabilities of TCRs with the pan-cancer sensing and cytotoxic potential of highly potent killer cells, redirecting and arming NK cells with a fully functional TCR-CD3 complex. Here we present our lead product, an optimized TCR-NK cell product, ZI-MA4-1a, expressing an affinity enhanced TCR (KVL-a) directed to the HLA class I-restricted clinically validated cancer-testis antigen MAGE-A4, that is broadly expressed across solid tumors. The KVL-a TCR was successfully engineered from a naturally occurring wild-type TCR, increasing the affinity to MAGE-A4-peptide-HLA complex and resulting in enhanced recognition of tumor cells expressing the target antigen. ZI-MA4-1a is produced by transducing healthy peripheral blood derived NK cells with the full CD3 complex, the KVL-a TCR and a CD8 coreceptor. The process has been optimized to enrich TCR-NK cells, increasing process robustness, diminishing the impact of donor variability, and producing a higher performing TCR-NK cell product. We show the dual functionality of ZI-MA4-1a: TCR driven cytotoxicity as well as innate NK sensing of antigen knockout or HLA negative cancers. We demonstrate killing of heterogenous tumor cell models in vitro, as well as the multifunctionality of ZI-MA4-1a with killing, degranulation and multicytokine secretion. Interestingly, we observe enhanced proliferation of ZI-MA4-1a cells after activation by MAGE-A4 expressing tumor cells, indicating that TCR-NK cells acquire further proliferative capacity when the TCR is triggered. Finally, we demonstrate higher activity of ZI-MA4-1a compared to KVL-a and benchmark TCR transduced T cells against antigen positive targets, and activity against antigen negative tumor cells escaping TCR-T cell recognition. Citation Format: Sarah Vollmers, Artur Cieslar-Pobuda, Justyna Kmiecik, Giulia Malachin, Michelle L. Sætersmoen, Frida Høsøien Haugen, Margherita Boieri, Maja Sandve, Dennis Clement, Ines Cardoso, Pimthanya Wanichawan, Martha E. Haugstøyl, Anja Oldenburg, Liliane Christ, Pranav Oberoi, Luz Mora-Velandia, Anders Holm, Namir J. Hassan, Emilie Gauthy, Julia Ino, Sylvie Pollmann, Luise U. Weigand. Development of the first optimised “off the shelf” MAGE-A4 targeting TCR-NK cells for advancement into the clinic for the treatment of solid tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1329.

Expression of Immunotherapy Target PRAME in Cancer Correlates with Histone H3 Acetylation and Is Unrelated to Expression of Methylating (DMNT3A/3B) and Demethylating (TET1) Enzymes.

Background/Objectives: Preferentially expressed antigen in melanoma (PRAME), a member of the cancer testis antigen family, is a promising target for cancer immunotherapy. Understanding the epigenetic mechanisms involved in the regulation of PRAME expression might be crucial for optimizing anti-PRAME treatments. Methods: Three malignancies of different lineages (sinonasal melanoma, testicular seminoma, and synovial sarcoma), in which immunohistochemical (IHC) reactivity for PRAME is a common yet variable feature, were studied. The expression of PRAME, ten-eleven translocation demethylase 1 (TET1), and DNA methyltransferase (DNMT) 3A and 3B were evaluated using immunohistochemistry. Moreover, the expression of two epigenetic marks, 5-hydroxymethylcytosine (5hmC) and histone 3 acetylation (H3ac), was tested. Results: All PRAME-positive tumors expressed medium-to-high levels of H3ac but differed considerably with respect to other markers. In seminomas, PRAME expression correlated with TET1, but in melanomas and synovial sarcomas, it correlated with both DNMTs and DNMT3A, respectively. Conclusions: PRAME expression was not determined by a balance between the global expression of DNA methylating/demethylating enzymes. However, histone acetylation may be one of the epigenetic mechanisms involved in PRAME regulation. Thus, the therapeutic combination of histone deacetylase inhibitors and PRAME immunotherapy merits further investigation.

Structural basis for RAD18 regulation by MAGEA4 and its implications for RING ubiquitin ligase binding by MAGE family proteins

MAGEA4 is a cancer-testis antigen primarily expressed in the testes but aberrantly overexpressed in several cancers. MAGEA4 interacts with the RING ubiquitin ligase RAD18 and activates trans-lesion DNA synthesis (TLS), potentially favouring tumour evolution. Here, we employed NMR and AlphaFold2 (AF) to elucidate the interaction mode between RAD18 and MAGEA4, and reveal that the RAD6-binding domain (R6BD) of RAD18 occupies a groove in the C-terminal winged-helix subdomain of MAGEA4. We found that MAGEA4 partially displaces RAD6 from the RAD18 R6BD and inhibits degradative RAD18 autoubiquitination, which could be countered by a competing peptide of the RAD18 R6BD. AlphaFold2 and cross-linking mass spectrometry (XL-MS) also revealed an evolutionary invariant intramolecular interaction between the catalytic RING and the DNA-binding SAP domains of RAD18, which is essential for PCNA mono-ubiquitination. Using interaction proteomics, we found that another Type-I MAGE, MAGE-C2, interacts with the RING ubiquitin ligase TRIM28 in a manner similar to the MAGEA4/RAD18 complex, suggesting that the MAGEA4 peptide-binding groove also serves as a ligase-binding cleft in other type-I MAGEs. Our data provide new insights into the mechanism and regulation of RAD18-mediated PCNA mono-ubiquitination.

Abstract P25: Identification of biological components and novel clinical subsets of NPM1-mutated AML using an integrated, multi-omics approach

Abstract P25: Identification of biological components and novel clinical subsets of <i>NPM1</i>-mutated AML using an integrated, multi-omics approach

Synergistic enhancement of the mouse Pramex1 and Pramel1 in repressing retinoic acid (RA) signaling during gametogenesis

BackgroundPRAME constitutes one of the largest multi-copy gene families in Eutherians, encoding cancer-testis antigens (CTAs) with leucine-rich repeats (LRR) domains, highly expressed in cancer cells and gametogenic germ cells. This study aims to elucidate genetic interactions between two members, Pramex1 and Pramel1, in the mouse Prame family during gametogenesis using a gene knockout approach.ResultSingle-gene knockout (sKO) of either Pramex1 or Pramel1 resulted in approximately 7% of abnormal seminiferous tubules, characterized by a Sertoli-cell only (SCO) phenotype, impacting sperm count and fecundity significantly. Remarkably, sKO female mice displayed normal reproductive functions. In contrast, Pramex1/Pramel1 double knockout (dKO) mice exhibited reduced fecundity in both sexes. In dKO females, ovarian primary follicle count decreased by 50% compared to sKO and WT mice, correlating with a 50% fecundity decrease. This suggested compensatory roles during oogenesis in Pramex1 or Pramel1 sKO females. Conversely, dKO males showed an 18% frequency of SCO tubules, increased apoptotic germ cells, and decreased undifferentiated spermatogonia compared to sKO and WT testes. Western blot analysis with PRAMEX1- or PRAMEL1-specific antibodies on sKO testes revealed compensatory upregulation of each protein (30–50%) in response to the other gene’s deletion. Double KO males exhibited more severe defects in sperm count and litter size, surpassing Pramex1 and Pramel1 sKO accumulative effects, indicating a synergistic enhancement interaction during spermatogenesis. Additional experiments administering trans-retinoic acid (RA) and its inhibitor (WIN18,446) in sKO, dKO, and WT mice suggested that PRAMEX1 and PRAMEL1 synergistically repress the RA signaling pathway during spermatogenesis.ConclusionData from sKO and dKO mice unveil a synergistic interaction via the RA signaling pathway between Pramex1 and Pramel1 genes during gametogenesis. This discovery sets the stage for investigating interactions among other members within the Prame family, advancing our understanding of multi-copy gene families involved in germ cell formation and function.

Humoral immunoprofiling identifies novel biomarkers and an immune suppressive autoantibody phenotype at the site of disease in pancreatic ductal adenocarcinoma.

Pancreatic ductal adenocarcinoma (PDAC) is a heterogeneous cancer, with minimal response to therapeutic intervention and with 85% of cases diagnosed at an advanced stage due to lack of early symptoms, highlighting the importance of understanding PDAC immunology in greater detail. Here, we applied an immunoproteomic approach to investigate autoantibody responses against cancer-testis and tumor-associated antigens in PDAC using a high-throughput multiplexed protein microarray platform, comparing humoral immune responses in serum and at the site of disease in order to shed new light on immune responses in the tumor microenvironment. We simultaneously quantified serum or tissue IgG and IgA antibody isotypes and subclasses in a cohort of PDAC, disease control and healthy patients, observing inter alia that subclass utilization in tumor tissue samples was predominantly immune suppressive IgG4 and inflammatory IgA2, contrasting with predominant IgG3 and IgA1 subclass utilization in matched sera and implying local autoantibody production at the site of disease in an immune-tolerant environment. By comparison, serum autoantibody subclass profiling for the disease controls identified IgG4, IgG1, and IgA1 as the abundant subclasses. Combinatorial analysis of serum autoantibody responses identified panels of candidate biomarkers. The top IgG panel included ACVR2B, GAGE1, LEMD1, MAGEB1 and PAGE1 (sensitivity, specificity and AUC values of 0.933, 0.767 and 0.906). Conversely, the top IgA panel included AURKA, GAGE1, MAGEA10, PLEKHA5 and XAGE3aV1 (sensitivity, specificity, and AUC values of 1.000, 0.800, and 0.954). Assessment of antigen-specific serum autoantibody glycoforms revealed abundant sialylation on IgA in PDAC, consistent with an immune suppressive IgA response to disease.

Cancer testis antigen burden (CTAB): a novel biomarker of tumor-associated antigens in lung cancer

BackgroundCancer-testis antigens (CTAs) are tumor antigens that are normally expressed in the testes but are aberrantly expressed in several cancers. CTA overexpression drives the metastasis and progression of lung cancer, and is associated with poor prognosis. To improve lung cancer diagnosis, prognostic prediction, and drug discovery, robust CTA identification and quantitation is needed. In this study, we examined and quantified the co-expression of CTAs in lung cancer to derive cancer testis antigen burden (CTAB), a novel biomarker of immunotherapy response.MethodsFormalin fixed paraffin embedded (FFPE) tumor samples in discovery cohort (n = 5250) and immunotherapy and combination therapy treated non-small cell lung cancer (NSCLC) retrospective (n = 250) cohorts were tested by comprehensive genomic and immune profiling (CGIP), including tumor mutational burden (TMB) and the mRNA expression of 17 CTAs. PD-L1 expression was evaluated by IHC. CTA expression was summed to derive the CTAB score. The median CTAB score for the discovery cohort of 170 was applied to the retrospective cohort as cutoff for CTAB “high” and “low”. Biomarker and gene expression correlation was measured by Spearman correlation. Kaplan–Meier survival analyses were used to detect overall survival (OS) differences, and objective response rate (ORR) based on RECIST criteria was compared using Fisher’s exact test.ResultsThe CTAs were highly co-expressed (p < 0.05) in the discovery cohort. There was no correlation between CTAB and PD-L1 expression (R = 0.011, p = 0.45) but some correlation with TMB (R = 0.11, p = 9.2 × 10–14). Kaplan–Meier survival analysis of the immunotherapy-treated NSCLC cohort revealed better OS for the pembrolizumab monotherapy treated patients with high CTAB (p = 0.027). The combination group demonstrated improved OS compared to pembrolizumab monotherapy group (p = 0.04). The pembrolizumab monotherapy patients with high CTAB had a greater ORR than the combination therapy group (p = 0.02).ConclusionsCTA co-expression can be reliably measured using CGIP in solid tumors. As a biomarker, CTAB appears to be independent from PD-L1 expression, suggesting that CTAB represents aspects of tumor immunogenicity not measured by current standard of care testing. Improved OS and ORR for high CTAB NSCLC patients treated with pembrolizumab monotherapy suggests a unique underlying aspect of immune response to these tumor antigens that needs further investigation.

Silver nanoparticles enhanced enzyme-linked immunosorbent assay (ELISA) detection of cancer testis antigens (CTAs).

The Enzyme-Linked Immunosorbent Assay (ELISA) has been a cornerstone technique in laboratory medicine for over 55 years, relying on the specific binding of antibodies to antigens. ELISA's widespread use stems from its ability to detect low concentrations, its specificity, reproducibility, and potential for high-throughput screening. However, its sensitivity has limitations, prompting the exploration of innovative methods to improve the limit of detection (LOD). Nanoparticles provide a promising platform for enhancing ELISA sensitivity. Due to their high surface-to-volume ratio, they offer increased binding sites for capture elements and reporting tags, leading to amplified analytical signals. Recent studies have demonstrated improved sensitivity in ELISA through nanoparticle application, yielding faster detection times and enhanced sensitivities. This study investigates the potential of 50 nm citrate-capped silver nanoparticles to enhance ELISA's performance in quantifying cancer testis antigens (CTAs). In our study, we used the Human NY-ESO-1 ELISA kit (for research purposes) to determine the concentration of CTAs in randomly selected samples from healthy (n=89) and oncological (n=80) subjects, aged 18-75. We employed 50 nm citrate-capped silver nanoparticles (AGCB50-1M, BioPure Silver Nanoparticles - bare citrate, nano-Composix, San Diego, CA, USA). ELISA reactions followed the manufacturer's instructions, and data processing aligned with the same guidelines. Absorbance (OD) measurements occurred at 450 nm, influencing nanoparticle selection. Each ELISA well contained 5 ml of nanoparticles' stock solution with specified concentrations. CTAs concentrations were derived from the standard curve through CurveExpert Basic software. Statistical analysis was performed using SPSS v. 27 software, with p-values indicating significance if <0.03. The study adhered to Helsinki Declaration principles and received ethical approval. Participants provided informed written consent. The increased concentration values of CTAs for healthy individuals and cancer patients were determined in the case of the application of silver nanoparticles. The usage of nanoparticles can enhance the sensitivity of the ELISA method and positively influence its specific detection limit.

AIM high: Epigenetic modulation and immune stimulation in bladder cancer.

648 Background: Immune-checkpoint inhibitors (ICI) have emerged as valuable treatment options for patients with bladder cancer, particularly those who are ineligible for other therapies or have experienced disease progression on treatment. Response rates are only 20-30%, highlighting the need for biomarkers to predict treatment response and strategies to overcome resistance. Epigenetic modulators including the DNA methyltransferase (DNMT) inhibitor 5-azacitidine (AZA) and histone deacetylase inhibitors (HDACi) may represent co-targeting therapies in combination with ICI to enhance antitumor immunity. AZA has been demonstrated to increase the expression of a panel of immunomodulatory genes termed the “AZA Immune gene panel (AIM)” in breast, colorectal, and ovarian cancer cell lines. We hypothesized that bladder cancer with low AIM expression can be therapeutically converted by epigenetic modulation to “AIM-high” for future combination with ICI. Methods: Five human bladder cancer cell lines were selected: SCaBER, SW780, T24, RT4 and one developed at our institution (CoCaB1). The Cancer Cell Line Encyclopedia (CCLE) was used to screen the four included lines for intrinsic AIM expression, which were predicted to be AIM-high (n=1) and AIM-low (n=3). A cell viability assay was performed to screen for AZA and HDACi toxicity. Cells were treated with drug or vehicle for 72 hours and harvested at day 6, 14, and 21. RNA was extracted for RNA sequencing (RNA-seq) analyses. For analysis of AIM gene expression in clinical specimens, RNA-seq data was obtained from primary (n=6) and metastatic (n=83) bladder cancer specimens for 20 patients participating in the University of Washington Bladder Cancer Rapid Autopsy Program. Results: RNA-seq analyses of 5 cell lines demonstrated increased expression (&gt;log 2-fold change, p&lt;0.05) of a subset of AIM genes involved in inflammation, interferon, cytokine/chemokine signaling, and cancer testis antigens (CTA, a family of immunogenic proteins) with AZA treatment. Co-treatment with HDACi showed additional upregulation of AIM genes. Gene set enrichment analyses uncovered enrichment in T-cell pathway activation. In metastatic bladder cancer tissues, interferon, cytokine/chemokine, inflammation, and CTA AIM gene set categories were upregulated in a subset of patients. AIM gene enrichment displayed a patient-dependent pattern and was consistent across metastatic sites within a patient. Conclusions: Epigenetic priming therapy increases the expression of immunomodulatory and T-cell related genes in bladder cancer cell lines with low baseline AIM expression. Additional correlative studies in the rapid autopsy series will further determine clinical- and treatment-related factors contributing to intrinsic immune-related gene expression. Building on this paradigm, future in vivo and clinical studies could lead to novel combination therapies for patients with bladder cancer.

Correlation of cancer testis antigen expression with high type-I interferon signal and prognosis in small bowel neuroendocrine tumors.

596 Background: Patients with small bowel neuroendocrine tumors (SBNET) frequently present with metastatic disease, and efficacy of available therapies, including immune checkpoint inhibitors (ICI), is limited. Toward developing novel immunomodulatory strategies, we evaluated the tumor immune microenvironment of SBNETs using bulk transcriptional and digital spatial profiling (DSP). Methods: Patients with SBNET who underwent surgical resection at MD Anderson Cancer Center from 2003-2016 were retrospectively analyzed. Overall survival (OS) was assessed using the Kaplan-Meier method and Cox proportional hazards model was used for multivariate analysis (MVA). Bulk transcriptional profiling was performed using the Nanostring PanCancer-Immune Panel. DSP was performed with whole human transcriptome using PanCK to segment tumor and adjacent stroma; 88 distinct regions were analyzed using differential gene expression and Reactome pathway enrichment pipelines. Results: Resected SBNETs from 42 patients were selected for transcriptional analysis. Unsupervised clustering of gene expression demonstrated dichotomization into high and low cancer testis antigen (CTA) expression. CTA-high patients (n=12) demonstrated elevated expression of type-I interferons (IFN) and CTAs such as PRAME, GAGE1, and MAGEA3 and had significantly longer OS compared to CTA-low patients (n=30; median OS not reached vs 1975 days, p=0.008). MVA controlling for age, sex, metastatic disease, and Ki-67% confirmed CTA-high status as an independent predictor of longer OS (hazard ratio [HR] 0.2, 95% confidence interval [CI] 0.05-0.83). A pilot DSP experiment with 4 CTA-high and 4 CTA-low tumors revealed higher expression of epigenetic modification genes (e.g., H3C1, H2BC8, p&lt;0.001) in CTA-high tumors with significant enrichment in epigenetic pathways (e.g., histone acetylation, DNA methylation). CTA-high tumors exhibited increased M2 macrophage presence (p=0.025) and increased stromal compartment NK cell activation (p=0.001). Conclusions: High expression of CTA and type-I IFN in resected SBNET is associated with longer survival, agnostic of stage or grade. While CTA expression has been implicated in tumor immunogenicity, this is the first work to identify a clinical signal in SBNET. Increased IFN in CTA-high tumors, corroborated by increased stromal NK cell activation, suggests an immune-mediated component of improved survival. Spatial transcriptomic analysis reveals epigenetic differences in CTA-high tumors and highlights the potential for combination epigenetic modifiers and immunotherapy in future trials.

MAGE-A11 is a potential prognostic biomarker and immunotherapeutic target in gastric cancer.

Gastric cancer poses a serious threat to human health and affects the digestive system. The lack of early symptoms and a dearth of effective identification methods make diagnosis difficult, with many patients only receiving a definitive diagnosis at a malignant stage, causing them to miss out on optimal therapeutic interventions. Melanoma-associated antigen-A (MAGE-A) is part of the MAGE family and falls under the cancer/testis antigen (CTA) category. The MAGE-A subfamily plays a significant role in tumorigenesis, proliferation and migration. The expression, prognosis and function of MAGE-A family members in GC, however, remain unclear. Our research and screening have shown that MAGE-A11 was highly expressed in GC tissues and was associated with poor patient prognosis. Additionally, MAGE-A11 functioned as an independent prognostic factor in GC through Cox regression analysis, and its expression showed significant correlation with both tumour immune cell infiltration and responsiveness to immunotherapy. Our data further indicated that MAGE-A11 regulated GC cell proliferation and migration. Subsequently, our findings propose that MAGE-A11 may operate as a prognostic factor, having potential as an immunotherapy target for GC.

Multi-omics analysis of overexpressed tumor-associated proteins: gene expression, immunopeptide presentation, and antibody response in oropharyngeal squamous cell carcinoma, with a focus on cancer-testis antigens.

The human leukocyte antigen complex (HLA) is essential for inducing specific immune responses to cancer by presenting tumor-associated peptides (TAP) to T cells. Overexpressed tumor associated antigens, mainly cancer-testis antigens (CTA), are outlined as essential targets for immunotherapy in oropharyngeal squamous cell carcinoma (OPSCC). This study assessed the degree to which presentation, gene expression, and antibody response (AR) of TAP, mainly CTA, are correlated in OPSCC patients to evaluate their potential as immunotherapy targets. Snap-frozen tumor (NLigand/RNA=40), healthy mucosa (NRNA=6), and healthy tonsils (NLigand=5) samples were obtained. RNA-Seq was performed using Illumina HiSeq 2500/NovaSeq 6000 and whole exome sequencing (WES) utilizing NextSeq500. HLA ligands were isolated from tumor tissue using immunoaffinity purification, UHPLC, and analyzed by tandem MS. Antibodies were measured in serum (NAb=27) utilizing the KREX™ CT262 protein array. Data analysis focused on 312 proteins (KREX™ CT262 panel + overexpressed self-proteins). 183 and 94 of HLA class I and II TAP were identified by comparative profiling with healthy tonsils. Genes from 26 TAP were overexpressed in tumors compared to healthy mucosa (LFC>1; FDR<0.05). Low concordance (r=0.25; p<0.0001) was found between upregulated mRNA and class I TAP. The specific mode of correlation of TAP was found to be dependent on clinical parameters. A lack of correlation was observed both between mRNA and class II TAP, as well as between class II tumor-unique TAP (TAP-U) presentation and antibody response (AR) levels. This study demonstrates that focusing exclusively on gene transcript levels fails to capture the full extent of TAP presentation in OPSCC. Furthermore, our findings reveal that although CTA are presented at relatively low levels, a few CTA TAP-U show potential as targets for immunotherapy.

Identification and Validation of a Cancer-Testis Antigen-Related Signature to Predict the Prognosis in Stomach Adenocarcinoma.

Background: Stomach adenocarcinoma (STAD) is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. Cancer-testis antigens (CTAs) participate in the pathogenesis and development of multiple cancers and are aberrantly overexpressed in various types of cancer. This study aimed to develop a CTA-related gene signature (CTARSig) to predict prognosis in STAD patients and explore its underlying mechanisms. Methods: We performed differential and prognostic analyses of CTA-related genes and constructed a CTA-related signature (CTARSig) along with a novel nomogram to predict the prognosis of patients with STAD based on the Cox and The Least Absolute Shrinkage and Selection Operator. CTARSig was further validated in an external cohort (GSE84437). Additionally, univariate and multivariate Cox regression, as well as receiver operating characteristic (ROC) analyses, were performed to assess the CTARSig systematically. Single-sample gene set enrichment analysis and ESTIMATE were used to characterise the Tumor Immune Microenvironment (TIME) in patients with STAD. Furthermore, Gene Set Variation Analysis, Kyoto Encyclopedia of Genes and Genomes, and Gene Ontology analyses revealed the biological functions and signalling pathways associated with CTARSig. Finally, the human gastric cancer cell lines, HCG-27 and AGS, were used for in vitro and in vivo experiments, respectively, to further validate the role of ELOVL4. Results: Eleven CTA-related genes were identified to construct the CTARSig. Kaplan-Meier curves, independent prognostic analysis, and ROC curves revealed that CTARSig could better predict survival in patients with STAD. Moreover, in our study, we demonstrated that ELOVL4 is upregulated in gastric cancer tissues and that its high expression is associated with poor survival. Additionally, in vitro and in vivo experiments demonstrated that ELOVL4 promotes the metastatic and invasive potential of STAD cells, suggesting it may be a potential therapeutic target for STAD. Conclusion: In this study, a novel signature associated with CTAs was constructed for STAD, which may be a good predictor of patient prognosis. Thus, ELOVL4 may be a potential therapeutic target for gastric cancer. This study provides new insights into the potential roles of CTAs in gastric cancer.

Modified Dendritic cell-based T-cell expansion protocol and single-cell multi-omics allow for the selection of the most expanded and in vitro-effective clonotype via profiling of thousands of MAGE-A3-specific T-cells.

Adoptive cell therapy using TCR-engineered T-cells is one of the most effective strategies against tumor cells. The TCR T-cell approach has been well tested against a variety of blood neoplasms but is yet to be deeply tested against solid tumors. Among solid tumors, cancer-testis antigens are the most prominent targets for tumor-specific therapy, as they are usually found on cells that lie behind blood-tissue barriers. We have employed a novel efficient protocol for MAGE-A3-specific T-cell clonal expansion, performed single-cell multi-omic analysis of the expanded T-cells via BD Rhapsody, engineered a selected T-cell receptor into a lentiviral construct, and tested it in an in vitro LDH-cytotoxicity test. We have observed a 191-fold increase in the MAGE-A3-specific T-cell abundance, obtained a dominant T-cell receptor via single-cell multi-omic BD Rhapsody data analysis in the TCRscape bioinformatics tool, and observed potent cytotoxicity of the dominant-clonotype transduced TCR T-cells against a MAGE-A3-positive tumor. We have demonstrated the efficiency of our T-cell enrichment protocol in obtaining potent anti-tumor T-cells and their T-cell receptors, especially when paired with the modern single-cell analysis methods.

Detecting Predicted Cancer-Testis Antigens in Proteomics Datasets of Healthy and Tumoral Samples

Detecting Predicted Cancer-Testis Antigens in Proteomics Datasets of Healthy and Tumoral Samples

The role of the NY-ESO-1 in the prognosis of gastric cancer.

Gastric cancer (GC) is one of the most common malignancies worldwide and the fourth leading cause of cancer-related deaths. GC is a multifactorial disease influenced by both environmental and genetic factors. Its most critical features include invasiveness and high metastatic potential. Metastasis is a complex process, and our understanding of the mechanisms involved remains incomplete. Growing evidence suggests that cancer-testis antigens (CTAs) play a crucial role in the metastatic potential of various tumors. Several studies have linked CTA expression with lower tumor differentiation, higher metastatic potential, and poor chemotherapy response. New York esophageal squamous cell carcinoma-1 (NY-ESO-1) antigen, part of the CTA group, is expressed in tumor tissues, while its expression in normal tissues is restricted to spermatogonia. This study aimed to determine the expression of NY-ESO-1 in primary adenocarcinoma of the stomach, both with and without metastasis in regional lymph nodes, and to compare it with TNM stage, age, gender, and survival. We analyzed GC tissue from 53 node-negative and 55 node-positive primary gastric carcinoma patients for NY-ESO-1 expression using immunohistochemical assay. The results were correlated with clinicopathological parameters and survival. Patients with positive NY-ESO-1 expression in primary tumors had a median survival of 19.0 months (range 14.1-24.0), in contrast to those with negative expression, who had a median survival of 52.0 months (range 0.0-133.3) (chi-square 7.99, P=0.005). T status, N status, and NY-ESO-1 expression were all independently associated with shorter survival. No significant difference in NY-ESO-1 expression in primary tumors was observed concerning lymph node metastasis status. In summary, our findings suggest that increased expression of NY-ESO-1 could potentially serve as a prognostic biomarker for GC.