The cancer/testis antigen (CTA) family is a group of antigens whose expression is restricted to male germline cells of the testis and various malignancies. This expression pattern makes this group of ...antigens potential targets for immunotherapy. The aim of this study was to create an overview of CTA expressed by melanoma cells at mRNA and protein level. A systematic literature search was performed in Medline (PubMed) and Embase from inception up to and including February 2018. Studies were screened for eligibility by two independent reviewers. A total of 65 full-text articles were included in the final analysis. A total of 48 CTA have been studied in melanoma. Various CTA show different expression rates in primary and metastatic tumours. Of the 48 CTA, the most studied were MAGE-A3, MAGE-A1, NY-ESO-1, MAGE-A4, SSX2, MAGE-A2, MAGE-C1/CT7, SSX1, MAGE-C2/CT10 and MAGE-A12. On average, MAGE-A3 mRNA is present in 36% of primary tumours, whereas metastatic tumours have an expression rate of 55-81%. The same applies to the protein expression rate of MAGE-A3 in primary tumours, which is reported to be at 15-37%, whereas metastatic tumours have a higher expression rate of 25-70%. This trend of increased expression in metastases compared with primary tumours is observed with MAGE-A1, MAGE-A2, MAGE-A4, MAGE-A12 and NY-ESO-1. Many CTA are expressed on melanoma. This review provides an overview of the expression frequency of CTAs in melanoma and may aid in identifying CTA as the therapeutic target for immunotherapy.
Despite the revolutionary success of chimeric antigen receptor (CAR)-T therapy for hematological malignancies, successful CAR-T therapies for solid tumors remain limited. One major obstacle is the ...scarcity of tumor-specific cell-surface molecules. One potential solution to overcome this barrier is to utilize antibodies that recognize peptide/major histocompatibility complex (MHCs) in a T cell receptor (TCR)-like fashion, allowing CAR-T cells to recognize intracellular tumor antigens. This study reports a highly specific single-chain variable fragment (scFv) antibody against the MAGE-A4p230-239/human leukocyte antigen (HLA)-A∗02:01 complex (MAGE-A4 pMHC), screened from a human scFv phage display library. Indeed, retroviral vectors encoding CAR, utilizing this scFv antibody as a recognition component, efficiently recognized and lysed MAGA-A4+ tumor cells in an HLA-A∗02:01-restricted manner. Additionally, the adoptive transfer of T cells modified by the CAR-containing glucocorticoid-induced tumor necrosis factor receptor (TNFR)-related receptor (GITR) intracellular domain (ICD), but not CD28 or 4-1BB ICD, significantly suppressed the growth of MAGE-A4+ HLA-A∗02:01+ tumors in an immunocompromised mouse model. Of note, a comprehensive analysis revealed that a broad range of amino acid sequences of the MAGE-A4p230-239 peptide were critical for the recognition of MAGE-A4 pMHC by these CAR-T cells, and no cross-reactivity to analogous peptides was observed. Thus, MAGE-A4-targeted CAR-T therapy using this scFv antibody may be a promising and safe treatment for solid tumors.
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Miyahara and colleagues reported that the intracellular tumor antigen MAGE-A4 could be targeted by a novel CAR-T cell therapy utilizing an antibody with high affinity and specificity for the MAGE-A4p230-239/HLA-A∗02:01 complex. Additionally, the intracellular domain of GITR in CAR constructs enhanced in vivo function compared with CD28 and 4-1BB.
PD‐1 is highly expressed on tumor‐infiltrated antigen‐specific T cells and limit the antitumor function. Blocking of PD‐1/PD‐L1 signaling has shown unprecedented curative efficacies in patients with ...advanced cancer. However, only a limited population of patients benefited from such therapies. Our study aimed to explore biological properties, functional regulation and reversal of MAGE‐A3‐specific CD8+ T cells in patients with esophageal squamous cell carcinoma (ESCC). The underlying principle of deficiency and restoring MAGE‐A3‐specific CD8+ T cells function in tumor microenvironment (TME) was evaluated. MAGE‐A3‐specific CD8+ T cells could lyse HLA‐A2+/MAGE‐A3+ tumor cells. Tetramer+ T cell frequency was higher in elder patients, but lower in patients with lymph node metastasis and late tumor stage (p < 0.05). CD107ahigh expression on functional T cells was an independent prognostic factor in Cox regression analysis. PD‐1 was highly expressed on dysfunctional antigen‐specific CD8+ T cells and tumor infiltrating T lymphocytes (p < 0.05). Myeloid‐derived suppressor cells (MDSCs) derived‐TGF‐β mediated PD‐1high expression on CD8+ T cells, which led to be resistance to PD‐1/PD‐L1 blockade in TME. Dual PD‐1/PD‐L1 and TGF‐β signaling pathway blockades synergistically restored the function and antitumor ability of antigen‐specific CD8+ T cells in vitro/vivo assay. The presence of functional MAGE‐A3‐specific CD8+ T cells had an independent prognostic impact on survival of patients with ESCC. Furthermore, MDSCs‐derived TGF‐β increased PD‐1 expression on T cells and decreased the sensitivity to PD‐1/PD‐L1 blockade. Combining T cell‐based therapy with dual PD‐1/PD‐L1 and TGF‐β signaling pathway blockade could be considered a promising strategy for cancer treatment.
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MAGE‐A3 is one of the most frequently expressed cancer germline genes and a potential target for cancer immunotherapy. Here the authors show that the frequency of functional MAGE‐A3‐specific CD8+ T cells is an independent prognostic factor in patients with esophageal squamous cell carcinoma. The exhaustion marker PD‐1 was highly expressed on dysfunctional antigen‐specific CD8+ T cells and tumor‐infiltrating T lymphocytes but anti‐tumor function was restored upon dual blockade of PD‐1/PD‐L1 and TGF‐β signaling pathways, a strategy the authors recommend to explore further in esophageal cancer immunotherapy.
Primary σ70 factors are key conserved bacterial regulatory proteins that interact with regulatory DNA to control gene expression. It is, however, poorly understood whether σ70 sequence diversity in ...different bacteria reflects functional differences. Here, we employ comparative and functional genomics to explore the sequence and function relationship of primary σ70. Using multiplex automated genome engineering and deep sequencing (MAGE-seq), we generate a saturation mutagenesis library and high-resolution fitness map of E. coli σ70 in domains 2–4. Mapping natural σ70 sequence diversity to the E. coli σ70 fitness landscape reveals significant predicted fitness deficits across σ70 orthologs. Interestingly, these predicted deficits are larger than observed fitness changes for 15 σ70 orthologs introduced into E. coli. Finally, we use a multiplexed transcriptional reporter assay and RNA sequencing (RNA-seq) to explore functional differences of several σ70 orthologs. This work provides an in-depth analysis of σ70 sequence and function to improve efforts to understand the evolution and engineering potential of this global regulator.
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•Evolutionary sequence diversity of bacterial primary σ70 factors•High-resolution fitness landscape map of E. coli σ70•Mapping natural diversity to fitness map predicts varying fitness deficits•σ70 replacement in E. coli with natural orthologs elicits transcriptional changes
Through comparative and functional genomics, Park and Wang dissect the sequence and function relationship of the bacterial σ70 factor. MAGE-seq generates a saturation mutagenesis library and a high-resolution fitness map of E. coli σ70. Replacement of endogenous E.coli σ70 with natural orthologs elicits transcriptional changes.
Cancer-testis antigens of the Mage family (Melanoma antigens) are expressed predominantly in the spermatogenic and cancer cells, but some genes of this family are expressed ubiquitously. Expression ...patterns and functional role of Mage family antigens in the regulation of cellular processes in normal embryonic and definitive cells are virtually unknown. Comparative immunofluorescent analysis of Mage expression in mouse oocytes and early embryos identified the expression of Mage antigens at all stages studied. The greatest intensity of the fluorescent staining was detected in the epiblasts and the extraembryonic structures of the egg cylinder at E6.5 stage. At all studied developmental stages of the mouse oocyte and the early embryo, the localization of Mage antigens was found predominantly in the cytoplasm. Quantitative real-time PCR showed that expression levels of most
Mage
genes in cells of the epiblast and ectoplacental cone were similar, while the gene expression levels of
Mage-a10
,
Mage-b16
, and
Mage-b18
were higher in cells of the ectoplacental cone than in epiblast cells. Thus, for the first time, our analysis has shown that the Mage family antigens are expressed at the early stages of mouse development and may be involved in the regulation of earliest events of embryogenesis.
Vaccines based on tumour‐specific antigens are a promising approach for immunotherapy. However, the clinical efficacy of tumour‐specific antigens is still challenging. Twelve conjugates with ...self‐assembly properties were designed and synthesized using MAGE‐A1 peptide and TLR2 agonist, combined with different covalent bonds. All the developed conjugates formed spherical nanoparticles with a diameter of approximately 150 nm, and enhanced the efficacy of the peptide vaccines with the better targeting of lymph nodes. All the conjugates could well bind to serum albumin and improve the plasma stability of the individual antigenic peptides. In particular, conjugate 6 (N‐Ac PamCS‐M‐6) had a more significant ability to promote dendritic cell maturation, CD8+ T cell activation, and subsequent killing of tumour cells, with an in vivo tumour inhibition rate of 70 ± 2.9%. The interaction between specific response and the different conjugation modes was further explored, thereby providing a fundamental basis for novel immune anti‐tumour molecular platforms.
self‐assembled vaccines for breast cancer immunotherapy
Twelve conjugates with self‐assembly properties were designed and synthesized using MAGE‐A1 peptide and TLR2 agonist.
Conjugate 6 (N‐Ac PamCS‐M‐6) had a more significant ability to promote dendritic cell maturation, CD8+ T cell activation, and subsequent killing of tumour cells.
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