The Melanoma-Associated Antigen A3 Mediates Fibronectin-Controlled Cancer Progression and Metastasis

DUB3 is a MAGEA3 deubiquitinase and a potential therapeutic target in hepatocellular carcinoma

Although melanoma-associated antigen A3 and A6 (MAGEA3/6)-specific tumor vaccines have shown antitumor effects in melanoma and non-small cell lung cancer (NSCLC), many cancers do not respond because MAGEA3 can promote cancer without triggering an immune response. Here, we identified DUB3 as the MAGEA3 deubiquitinase. DUB3 interacts with, deubiquitinates and stabilizes MAGEA3. Depletion of DUB3 in hepatocellular carcinoma (HCC) cells results in MAGEA3 degradation and P53-dependent growth inhibition. Moreover, DUB3 knockout attenuates HCC tumorigenesis in vivo, which can be rescued by restoration of MAGEA3. Intriguingly, pharmacological inhibition of DUB3 by palbociclib promotes degradation of MAGEA3 and inhibits tumor growth in preclinical models implanted with parental HCC cells but not with DUB3 knockout HCC cells. In patients with HCC, DUB3 is highly expressed, and its levels positively correlate with MAGEA3 levels. Taken together, DUB3 is a MAGEA3 deubiquitinase, and abrogating DUB3 enzymatic activity by palbociclib is a promising therapeutic strategy for HCC.

How the Intrinsically Disordered N-Terminus of Cancer/Testis Antigen MAGEA10 Is Responsible for Its Expression, Nuclear Localisation and Aberrant Migration

Melanoma-associated antigen A (MAGEA) subfamily proteins are normally expressed in testis and/or placenta. However, aberrant expression is detected in the tumour cells of multiple types of human cancer. MAGEA expression is mainly observed in cancers that have acquired malignant phenotypes, invasiveness and metastasis, and the expression of MAGEA family proteins has been linked to poor prognosis in cancer patients. All MAGE proteins share the common MAGE homology domain (MHD) which encompasses up to 70% of the protein; however, the areas flanking the MHD region vary between family members and are poorly conserved. To investigate the molecular basis of MAGEA10 expression and anomalous mobility in gel, deletion and point-mutation, analyses of the MAGEA10 protein were performed. Our data show that the intrinsically disordered N-terminal domain and, specifically, the first seven amino acids containing a unique linear motif, PRAPKR, are responsible for its expression, aberrant migration in SDS-PAGE and nuclear localisation. The aberrant migration in gel and nuclear localisation are not related to each other. Hiding the N-terminus with an epitope tag strongly affected its mobility in gel and expression in cells. Our results suggest that the intrinsically disordered domains flanking the MHD determine the unique properties of individual MAGEA proteins.

Immunization with a multi-antigen targeted DNA vaccine eliminates chemoresistant pancreatic cancer by disrupting tumor-stromal cell crosstalk

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterised by limited responses to chemoimmunotherapy attributed to highly desmoplastic tumor microenvironment. Disrupting the tumor-stromal cell crosstalk is considered as an improved PDAC treatment strategy, whereas little progress has been made due to poor understanding of its underlying mechanism. Here, we examined the cellular role of melanoma associated antigen A isoforms (MAGEA) in regulating tumor-stromal crosstalk mediated chemoresistance.

METHODS

We used clinical samples to explore the correlation between MAGEA expression and patient prognosis in multiple cancers. We utilized cancer cell lines, patient derived organoids and orthotopic PDAC model to examine the function of MAGEA in chemoresistance. We performed biochemical, proteome profiler array and transcriptional analysis to uncover a mechanism that governs tumor-stromal crosstalk. We developed a multi-MAGEA antigen targeted DNA vaccine and tested its effect on PDAC tumor growth.

RESULTS

We establish MAGEA as a regulator of the tumor-stromal crosstalk in PDAC. We provide strong clinical evidence indicating that high MAGEA expression, including MAGEA2, MAGEA3 and MAGEA10, correlates with worse chemotherapeutic response and poor prognosis in multiple cancers, while their expression is up-regulated in chemoresistant PDAC patient derived organoids and cancer cell lines. Mechanistically, MAGEA2 prohibits gemcitabine-induced JNK-c-Jun-p53 mediated cancer cell apoptosis, while gemcitabine stimulated pancreatic stellate cells secretes GDF15 to further enhance the gemcitabine resistance of MAGEA2 expressing cells by activating GFRAL-RET mediated Akt and ERK1/2 dependent survival pathway. Strikingly, immunization with a DNA vaccine that targeting multiple MAGEA antigens, including MAGEA2, MAGEA3 and MAGEA10, elicits robust immune responses against the growth of gemcitabine resistant tumors.

CONCLUSIONS

These findings suggest that targeting MAGEA-mediated paracrine regulation of chemoresistance by immunotherapy can be an improved pancreatic cancer treatment strategy.

The Extracellular Matrix: Its Composition, Function, Remodeling, and Role in Tumorigenesis

The extracellular matrix (ECM) is a ubiquitous member of the body and is key to the maintenance of tissue and organ integrity. Initially thought to be a bystander in many cellular processes, the extracellular matrix has been shown to have diverse components that regulate and activate many cellular processes and ultimately influence cell phenotype. Importantly, the ECM's composition, architecture, and stiffness/elasticity influence cellular phenotypes. Under normal conditions and during development, the synthesized ECM constantly undergoes degradation and remodeling processes via the action of matrix proteases that maintain tissue homeostasis. In many pathological conditions including fibrosis and cancer, ECM synthesis, remodeling, and degradation is dysregulated, causing its integrity to be altered. Both physical and chemical cues from the ECM are sensed via receptors including integrins and play key roles in driving cellular proliferation and differentiation and in the progression of various diseases such as cancers. Advances in 'omics' technologies have seen an increase in studies focusing on bidirectional cell-matrix interactions, and here, we highlight the emerging knowledge on the role played by the ECM during normal development and in pathological conditions. This review summarizes current ECM-targeted therapies that can modify ECM tumors to overcome drug resistance and better cancer treatment.

MAGE-I proteins and cancer-pathways: A bidirectional relationship

Data emerged from the last 20 years of basic research on tumor antigens positioned the type I MAGE (Melanoma Antigen GEnes - I or MAGE-I) family as cancer driver factors. MAGE-I gene expression is mainly restricted to normal reproductive tissues. However, abnormal re-expression in cancer unbalances the cell status towards enhanced oncogenic activity or reduced tumor suppression. Anomalous MAGE-I gene re-expression in cancer is attributed to altered epigenetic-mediated chromatin silencing. Still, emerging data indicate that MAGE-I can be regulated at protein level. Results from different laboratories suggest that after its anomalous re-expression, specific MAGE-I proteins can be regulated by well-known signaling pathways or key cellular processes that finally potentiate the cancer cell phenotype. Thus, MAGE-I proteins both regulate and are regulated by cancer-related pathways. Here, we present an updated review highlighting the recent findings on the regulation of MAGE-I by oncogenic pathways and the potential consequences in the tumor cell behavior.

DDX17 promotes the growth and metastasis of lung adenocarcinoma

DEAD box RNA helicase 17 (DDX17) has been shown to be an RNA binding protein involved in RNA metabolism and associated with cancer progression. However, the biological role of DDX17 in the pathogenesis of lung adenocarcinoma (LUAD) has not been well characterized. Here, we demonstrated that DDX17 promoted the proliferation, migration and invasion of H1299 and A549 lung adenocarcinoma cells. Analyses of public datasets showed that DDX17 is upregulated in LUAD specimens. Our tumor xenograft models confirmed the in vivo promoting role of DDX17 in the growth and metastasis of LUAD. Mechanistic analyses further revealed that DDX17 protein interacts with the mRNA of MYL9 and MAGEA6 and upregulates their levels. MYL9 could mediate the function of DDX17 to regulate the actin cytoskeleton rearrangement and cell adhesion, particularly by modulating the stress fiber and focal adhesion formation, whereas DDX17 might inhibit the autophagy process through MAGEA6/AMPKα1 axis in LUAD cells. Collectively, our study revealed the oncogenic role and pathways of DDX17 in LUAD.

AMPK signaling and its targeting in cancer progression and treatment

The intrinsic mechanisms sensing the imbalance of energy in cells are pivotal for cell survival under various environmental insults. AMP-activated protein kinase (AMPK) serves as a central guardian maintaining energy homeostasis by orchestrating diverse cellular processes, such as lipogenesis, glycolysis, TCA cycle, cell cycle progression and mitochondrial dynamics. Given that AMPK plays an essential role in the maintenance of energy balance and metabolism, managing AMPK activation is considered as a promising strategy for the treatment of metabolic disorders such as type 2 diabetes and obesity. Since AMPK has been attributed to aberrant activation of metabolic pathways, mitochondrial dynamics and functions, and epigenetic regulation, which are hallmarks of cancer, targeting AMPK may open up a new avenue for cancer therapies. Although AMPK is previously thought to be involved in tumor suppression, several recent studies have unraveled its tumor promoting activity. The double-edged sword characteristics for AMPK as a tumor suppressor or an oncogene are determined by distinct cellular contexts. In this review, we will summarize recent progress in dissecting the upstream regulators and downstream effectors for AMPK, discuss the distinct roles of AMPK in cancer regulation and finally offer potential strategies with AMPK targeting in cancer therapy.

Quantitative Biophysical Metrics for Rapid Evaluation of Ovarian Cancer Metastatic Potential

Ovarian cancer is routinely diagnosed long after the disease has metastasized through the fibrous sub-mesothelium. Despite extensive research in the field linking ovarian cancer progression to increasingly poor prognosis, there are currently no validated cellular markers or hallmarks of ovarian cancer that can predict metastatic potential. To discern disease progression across a syngeneic mouse ovarian cancer progression model, here, we fabricated extracellular-matrix mimicking suspended fiber networks: crosshatches of mismatch diameters for studying protrusion dynamics, aligned same diameter networks of varying inter-fiber spacing for studying migration, and aligned nanonets for measuring cell forces. We found that migration correlated with disease, while force-disease biphasic relationship exhibited f-actin stress-fiber network dependence. However, unique to suspended fibers, coiling occurring at tips of protrusions and not the length or breadth of protrusions displayed strongest correlation with metastatic potential. To confirm that our findings were more broadly applicable beyond the mouse model, we repeated our studies in human ovarian cancer cell lines and found that the biophysical trends were consistent with our mouse model results. Altogether, we report complementary high throughput and high content biophysical metrics capable of identifying ovarian cancer metastatic potential on time scale of hours. [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text] [Media: see text].

Role and Clinical Utility of Cancer/Testis Antigens in Head and Neck Squamous Cell Carcinoma

Cancer/testis (CT) antigens exhibit selective expression predominantly in immunoprivileged tissues in non-pathological contexts but are aberrantly expressed in diverse cancers. Due to their expression pattern, they have historically been attractive targets for immunotherapies. A growing number of studies implicate CT antigens in almost all hallmarks of cancer, suggesting that they may act as cancer drivers. CT antigens are expressed in head and neck squamous cell carcinomas. However, their role in the pathogenesis of these cancers remains poorly studied. Given that CT antigens hold intriguing potential as therapeutic targets and as biomarkers for prognosis and that they can provide novel insights into oncogenic mechanisms, their further study in the context of head and squamous cell carcinoma is warranted.

Integration Analysis of m6A Related Genes in Skin Cutaneous Melanoma and the Biological Function Research of the SPRR1B

Melanoma has gradually entered the public view because of its high morbidity and rising prevalence rate, which is a serious threat to human life and health. Recently, N6-methyladenine (m6A) modification has been increasingly confirmed as a potential role in the development of tumogenesis. The purpose of this study is to explore the role and function of m6a-related regulators in the development of melanoma disease at the molecular, cellular and clinical levels through bioinformatics and traditional experiments. We screened and validated differential expression genes (DEGs) in m6A regulators via the GEO, GTEx, TCGA database. The biological processes and signaling pathway involved by DEGs were improved by constructing bioinformational methods such as PPI, GO enrichment, KEGG enrichment, GSEA enrichment, and immune infiltration analysis. And then, we explored the biological function of the key gene, SPRR1B, through cell invasion, migration, infiltration, and tissue chips. The gene IGF2BP3 which was differentially expressed in m6A regulatory factor gene was screened. The results of the enrichment analysis are significantly enriched in the biological processes and pathways of the skin barrier, epidermal differentiation, cytoskeleton, lymphocyte migration and other pathways, pointing to the direction of tumor immunity and tumor metastasis. Tumor immune-related genes YTHDC1, YTHDC2 and ALKBH5 were found. Knock SPRR1B reduction group had a significantly lower invasive ability, the ability to migrate. Nomogram prediction model shows that SPRR1B increased, expressing a worse prognosis. For this purpose, the relationship between m6A regulatory factor and melanoma progression was explored. At the same time, it was found that the abnormal up-regulated expression of SPRR1B before metastasis would lead to poor prognosis of melanoma. SPRR1B promotes the proliferation, invasion and migration of human melanoma cells.

Prognostic Value of Melanoma-Associated Antigen-A (MAGE-A) Gene Expression in Various Human Cancers: A Systematic Review and Meta-analysis of 7428 Patients and 44 Studies

Background

Members of the melanoma-associated antigen-A (MAGE-A) subfamily are overexpressed in many cancers and can drive cancer progression, metastasis, and therapeutic recurrence.

Objective

This study is the first comprehensive meta-analysis evaluating the prognostic utility of MAGE-A members in different cancers.

Methods

A systematic literature search was conducted in PubMed, Google Scholar, Science Direct, and Web of Science. The pooled hazard ratios with 95% confidence intervals were estimated to evaluate the prognostic significance of MAGE-A expression in various cancers.

Results

In total, 44 eligible studies consisting of 7428 patients from 11 countries were analysed. Univariate and multivariate analysis for overall survival, progression-free survival, and disease-free survival showed a significant association between high MAGE-A expression and various cancers (P < 0.00001). Additionally, subgroup analysis demonstrated that high MAGE-A expression was significantly associated with poor prognosis for lung, gastrointestinal, breast, and ovarian cancer in both univariate and multivariate analysis for overall survival.

Conclusion

Overexpression of MAGE-A subfamily members is linked to poor prognosis in multiple cancers. Therefore, it could serve as a potential prognostic marker of poor prognosis in cancers.

Electronic supplementary material

The online version of this article (10.1007/s40291-020-00476-5) contains supplementary material, which is available to authorized users.

Oncogenic activity and cellular functionality of melanoma associated antigen A3

Cancer testis antigen Melanoma associated antigen A3 (MAGE-A3) has been subject of research for many years. Being expressed in various tumor types and influencing proliferation, metastasis, and tumor pathogenicity, MAGE-A3 is an attractive target for cancer therapy, particularly because in healthy tissues, MAGE-A3 is only expressed in testes and placenta. MAGE-A3 acts as a cellular master regulator by stimulating E3 ubiquitin ligase tripartite motif-containing protein 28 (TRIM28), resulting in regulation of various cellular targets. These include tumor suppressor protein p53 and cellular energy sensor AMP-activated protein kinase (AMPK). The restricted expression of MAGE-A3 in tumor cells makes MAGE-A3 an attractive target for vaccine-based immune therapy. However, although phase I and phase II clinical trials involving MAGE-A3-specific immunotherapeutic interventions were promising, large phase III studies failed. This article gives an overview about the role of MAGE-A3 as a cellular master switch and discusses approaches to improve MAGE-A3-based immunotherapies.

MAGE-A3 is a prognostic biomarker for poor clinical outcome in cutaneous squamous cell carcinoma with perineural invasion via modulation of cell proliferation

Perineural invasion is a pathologic process of neoplastic dissemination along and invading into the nerves. Perineural invasion is associated with aggressive disease and a greater likelihood of poor outcomes. In this study, 3 of 9 patients with cutaneous squamous cell carcinoma and perineural invasion exhibited poor clinical outcomes. Tumors from these patients expressed high levels of MAGE-A3, a cancer testis antigen that may contribute to key processes of tumor development. In addition to perineural invasion, the tumors exhibited poor differentiation and deep invasion and were subsequently classified as Brigham and Women's Hospital tumor stage 3. Cyclin E, A and B mRNA levels were increased in these tumors compared with normal skin tissues (102.93±15.03 vs. 27.15±4.59, 36.83±19.41 vs. 11.59±5.83, 343.77±86.49 vs. 95.65±29.25, respectively; p<0.05). A431 cutaneous squamous cell carcinoma cells pretreated with MAGE-A3 antibody exhibited a decreased percentage S-phase cells (14.13±2.8% vs. 33.97±1.1%; p<0.05) and reduced closure in scratch assays (43.88±5.49% vs. 61.17±3.97%; p = 0.0058). In a syngeneic animal model of squamous cell carcinoma, immunoblots revealed overexpression of MAGE-A3 and cyclin E, A, and B protein in tumors at 6 weeks. However, knockout of MAGE-A3 expression caused a reduction in tumor growth (mean tumor volume 155.3 mm3 vs. 3.2 mm3) compared with parental cells. These results suggest that MAGE-A3 is a key mediator in cancer progression. Moreover, elevated collagen XI and matrix metalloproteases 3, 10, 11, and 13 mRNA levels were observed in poorly differentiated cutaneous squamous cell carcinoma with perineural invasion compared with normal skin tissue (1132.56±882.7 vs. 107.62±183.62, 1118.15±1109.49 vs. 9.5±5, 2603.87±2385.26 vs. 5.29±3, 957.95±627.14 vs. 400.42±967.66, 1149.13±832.18 vs. 19.41±35.62, respectively; p<0.05). In summary, this study highlights the potential prognostic value of MAGE-A3 in clinical outcomes of cutaneous squamous cell carcinoma patients.

Emerging roles of the MAGE protein family in stress response pathways

The melanoma antigen (MAGE) proteins all contain a MAGE homology domain. MAGE genes are conserved in all eukaryotes and have expanded from a single gene in lower eukaryotes to ∼40 genes in humans and mice. Whereas some MAGEs are ubiquitously expressed in tissues, others are expressed in only germ cells with aberrant reactivation in multiple cancers. Much of the initial research on MAGEs focused on exploiting their antigenicity and restricted expression pattern to target them with cancer immunotherapy. Beyond their potential clinical application and role in tumorigenesis, recent studies have shown that MAGE proteins regulate diverse cellular and developmental pathways, implicating them in many diseases besides cancer, including lung, renal, and neurodevelopmental disorders. At the molecular level, many MAGEs bind to E3 RING ubiquitin ligases and, thus, regulate their substrate specificity, ligase activity, and subcellular localization. On a broader scale, the MAGE genes likely expanded in eutherian mammals to protect the germline from environmental stress and aid in stress adaptation, and this stress tolerance may explain why many cancers aberrantly express MAGEs Here, we present an updated, comprehensive review on the MAGE family that highlights general characteristics, emphasizes recent comparative studies in mice, and describes the diverse functions exerted by individual MAGEs.

Depleting RhoA/Stress Fiber-Organized Fibronectin Matrices on Tumor Cells Non-Autonomously Aggravates Fibroblast-Driven Tumor Cell Growth

Fibronectin (FN) expressed by tumor cells has been known to be tumor suppressive but the pericellular FN (periFN) assembled on circulating tumor cells appears to evidently promote distant metastasis. Whereas the regulation of periFN assembly in suspended cells has currently been under investigation, how it is regulated in adherent tumor cells and the role of periFN in primary tumor growth remain elusive. Techniques of RNAi, plasmid transfections, immunoblotting, fluorescence/immunohistochemistry staining, cell proliferation assays, and primary tumor growth in C57BL6 mice and Fischer 344 rats were employed in this study. We found that endogenously synthesized FN in adherent tumor cells was required for periFN assembly which was aligned by RhoA-organized actin stress fiber (SF). Depleting periFN on adherent tumor cells congruently promoted in vivo tumor growth but surprisingly did not autonomously impact on in vitro tumor cell proliferation and apoptosis, suggestive of a non-autonomous role of periFN in in vivo tumor growth. We showed that the proliferative ability of shFN-expressing tumor cells was higher than shScramble cells did in the presence of fibroblasts. Altogether, these results suggested that depriving RhoA/SF-regulated periFN matrices non-autonomously promotes fibroblast-mediated tumor cell growth.

Immunological and functional aspects of MAGEA3 cancer/testis antigen

Identification of ectopic gene activation in cancer cells serves as a basis for both gene signature-guided tumor targeting and unearthing of oncogenic mechanisms to expand the understanding of tumor biology/oncogenic process. Proteins expressed only in germ cells of testis and/or placenta (immunoprivileged organs) and in malignancies are called cancer testis antigens; they are antigenic because of the lack of antigen presentation by those specific cell types (germ cells), which limits the exposure of the proteins to the immune cells. Since the Cancer Testis Antigens (CTAs) are immunogenic and expressed in a wide variety of cancer types, CT antigens have become interesting target for immunotherapy against cancer. Among CT antigens MAGEA family is reported to have 12 members (MAGEA1 to MAGEA12). The current review highlights the studies on MAGEA3 which is a CT antigen and reported in almost all types of cancer. MAGEA3 is well tried for cancer immunotherapy. Recent advances on its functional and immunological aspect warranted much deliberation on effective therapeutic approach, thus making it a more interesting target for cancer therapy.

Next-Generation Cancer-Specific Hybrid Theranostic Nanomaterials: MAGE-A3 NIR Persistent Luminescence Nanoparticles Conjugated to Afatinib for In Situ Suppression of Lung Adenocarcinoma Growth and Metastasis

The rate of lung cancer has gradually increased in recent years, with an average annual increase of 15%. Afatinib (AFT) plays a key role in preventing non-small cell lung carcinoma (NSCLC) growth and spread. To increase the efficiency of drug loading and NSCLC cell tracking, near infrared-persistent luminescence nanomaterials (NIR PLNs), a silica shell-assisted synthetic route for mono-dispersal, are developed and used in the nanovehicle. After optimizing their physical and chemical properties, the NIR PLNs are able to absorb light energy and emit NIR luminescence for several hours. In this research, NIR PLNs are functionalized for drug-carrying capabilities. Effective accumulation of target drugs, such as AFT, using PLN nanomaterials can lead to unique anticancer therapeutic benefits (AFT-PLN). To minimize side effects and increase drug accumulation, nanomaterials with targeting abilities are used instead of simple drugs to inhibit the growth of tumor cells. Thus, the specific targeting aptamer, MAGE-A3 (MAp) is identified, and the PLN to increase its targeting ability (AFT-PLN@MAp) accordingly modified. The advancement of nanoscale techniques in the field of lung cancer is urgently needed; this research presents a plausible diagnostic strategy and a novel method for therapeutic administration.

Differential expression of MAGEA6 toggles autophagy to promote pancreatic cancer progression

The melanoma-associated antigen family A (MAGEA) antigens are expressed in a wide variety of malignant tumors but not in adult somatic cells, rendering them attractive targets for cancer immunotherapy. Here we show that a number of cancer-associated MAGEA mutants that undergo proteasome-dependent degradation in vitro could negatively impact their utility as immunotherapeutic targets. Importantly, in pancreatic ductal adenocarcinoma cell models, MAGEA6 suppresses macroautophagy (autophagy). The inhibition of autophagy is released upon MAGEA6 degradation, which can be induced by nutrient deficiency or by acquisition of cancer-associated mutations. Using xenograft mouse models, we demonstrated that inhibition of autophagy is critical for tumor initiation whereas reinstitution of autophagy as a consequence of MAGEA6 degradation contributes to tumor progression. These findings could inform cancer immunotherapeutic strategies for targeting MAGEA antigens and provide mechanistic insight into the divergent roles of MAGEA6 during pancreatic cancer initiation and progression.

Aberrantly enhanced melanoma-associated antigen (MAGE)-A3 expression facilitates cervical cancer cell proliferation and metastasis via actuating Wnt signaling pathway

BACKGROUND

The over-expression of melanoma-associated antigen (MAGE)-A3 in cervical cancer (CC) has been observed in our previous study, suggesting that it possibly take a vital role during the development and metastasis of CC. The present study aimed to investigate the biological function of MAGE-A3 in the progression of CC and explore how it executes its roles.

METHODS

The mRNA expression of MAGE-A3 in End1/E6E7 and CC cell lines (HeLa, SiHa and C33A) was measured by real-time quantitative reverse transcription PCR (qRT-PCR). Loss- and gain-of-function methods were used to assess the effect of MAGE-A3 on the proliferative, migratory and invasive abilities of HeLa and SiHa cells. Western blot was performed to measure the expression levels of proteins related to epithelial-mesenchymal transition (EMT) and proteins in the Wnt signaling pathway. In vivo tumorigenesis assay was conducted to evaluate the effect of MAGE-A3 on tumor growth.

RESULTS

MAGE-A3 expression was significantly up-regulated in CC cell lines (HeLa, SiHa and C33A) compared with that in End1/E6E7 cell line. Knockdown of MAGE-A3 could significantly suppress migration, invasion and proliferation in HeLa cells; whereas, overexpression of MAGE-A3 in SiHa cells presented the opposite results. Moreover, knockdown of MAGE-A3 presented a suppressive effect on the activation of EMT and Wnt signaling pathway in HeLa cells, whilst up-regulation of MAGE-A3 exhibited the opponent outcomes in SiHa cells. Through in vivo tumorigenesis assay, we further verified that MAGE-A3 acted as a facilitator in tumor growth.

CONCLUSIONS

MAGE-A3 is overexpressed in CC cells and possibly facilitates the viability and motility of CC cells via modulating EMT and Wnt signaling. This study implied that MAGE-A3 might be a potential therapeutic target as well as a prognosis predictor for patients with CC.

Fibronectin in Cancer: Friend or Foe

The role of fibronectin (FN) in tumorigenesis and malignant progression has been highly controversial. Cancerous FN plays a tumor-suppressive role, whereas it is pro-metastatic and associated with poor prognosis. Interestingly, FN matrix deposited in the tumor microenvironments (TMEs) promotes tumor progression but is paradoxically related to a better prognosis. Here, we justify how FN impacts tumor transformation and subsequently metastatic progression. Next, we try to reconcile and rationalize the seemingly conflicting roles of FN in cancer and TMEs. Finally, we propose future perspectives for potential FN-based therapeutic strategies.

Expression of cancer/testis antigens in cutaneous melanoma: a systematic review

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.

Functional and mechanistic studies reveal MAGEA3 as a pro-survival factor in pancreatic cancer cells

Background

In the era of personalized therapy, functional annotation of less frequent genetic aberrations will be instrumental in adapting effective therapeutic in clinic. Overexpression of Melanoma associated antigen A3 (MAGEA3) is reported in certain pancreatic cancer (PCA) patients. The major objective of the current study was to investigate the functional role of MAGEA3 in pancreatic cancer cells (PCCs) growth and survival.

Methods

Using overexpression (tet-on regulated system and constitutive expression system) and knockdown (by siRNA and shRNA) approach, we dissected the mechanistic role of MAGEA3 in pancreatic cancer pathogenesis. We generated MAGEA3 expressing stable PCA cell lines and mouse primary pancreatic epithelial cells. MAGEA3 was also depleted in certain MAGEA3 positive PCCs by siRNA or shRNA. The stable cells were subjected to in vitro assays like proliferation and survival assays under growth factor deprivation or in the presence of cytotoxic drugs. The MAGEA3 overexpressing or depleted stable PCCs were evaluated in vivo using xenograft model to check the role of MAGEA3 in tumor progression. We also dissected the mechanism behind the MAGEA3 role in tumor progression using western blot analysis and CCL2 neutralization.

Results

MAGEA3 overexpression in PCA cells did not alter the cell proliferation but protected the cells during growth factor deprivation and also in the presence of cytotoxic drugs. However, depletion of MAGEA3 in MAGEA3 positive cells resulted in reduced cell proliferation and increased apoptosis upon growth factor deprivation and also in response to cytotoxic drugs. The in vivo xenograft study revealed that overexpression of MAGEA3 promoted tumor growth however depleting the same hindered the tumor progression. Mechanistically, our in vitro and in vivo study revealed that MAGEA3 has tumor-promoting role by reducing macro-autophagy and overexpressing pro-survival molecules like CCL2 and survivin.

Conclusion

Our data proves tumor-promoting role of MAGEA3 and provides the rationale to target MAGEA3 and/or its functional mediators like CCL2 for PCA, which may have a better impact in PCA therapy.

Electronic supplementary material

The online version of this article (10.1186/s13046-019-1272-2) contains supplementary material, which is available to authorized users.

Regulation of MAGE-A3/6 by the CRL4-DCAF12 ubiquitin ligase and nutrient availability

Melanoma antigen genes (MAGEs) are emerging as important oncogenic drivers that are normally restricted to expression in male germ cells but are aberrantly expressed in cancers and promote tumorigenesis. Mechanistically, MAGEs function as substrate specifying subunits of E3 ubiquitin ligases. Thus, the activation of germline-specific genes in cancer can drive metabolic and signaling pathways through altered ubiquitination to promote tumorigenesis. However, the mechanisms regulating MAGE expression and activity are unclear. Here, we describe how the MAGE-A3/6 proteins that function as repressors of autophagy are downregulated in response to nutrient deprivation. Short-term cellular starvation promotes rapid MAGE-A3/6 degradation in a proteasome-dependent manner. Proteomic analysis reveals that degradation of MAGE-A3/6 is controlled by the CRL4-DCAF12 E3 ubiquitin ligase. Importantly, the degradation of MAGE-A3/6 by CRL4-DCAF12 is required for starvation-induced autophagy. These findings suggest that oncogenic MAGEs can be dynamically controlled in response to stress to allow cellular adaptation, autophagy regulation, and tumor growth and that CRL4-DCAF12 activity is responsive to nutrient status.

Cancer-testis antigens MAGEA proteins are incorporated into extracellular vesicles released by cells

Melanoma-associated antigen A (MAGEA) family proteins represent a class of tumor antigens that are expressed in a variety of malignant tumors, but their expression in normal tissues is restricted to germ cells. MAGEA family consists of eleven proteins that are highly conserved sharing the common MAGE homology domain (MHD). In the current study, we show that MAGEA4 and MAGEA10 proteins are incorporated into extracellular vesicles released by mouse fibroblast and human osteosarcoma U2OS cells and are expressed, at least partly, on the surface of released EVs. The C-terminal part of the protein containing MHD domain is required for this activity. Expression of MAGEA proteins induced the budding of cells and formation of extracellular vesicles with 150 to 1500 nm in diameter. Our data suggest that the release of MAGEA-positive EVs is at least to some extent induced by the expression of MAGEA proteins itself. This may be one of the mechanisms of MAGEA proteins to induce cancer formation and progression.

Stromal fibronectin expression in patients with resected pancreatic ductal adenocarcinoma

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an extremely dense stroma, which has a fundamental role in tumor progression. Fibronectin (FN1) is the main constituent of the tumor stroma in pancreatic cancer. This study aimed to explore the association between FN1 and clinicopathological characteristics and disease survival.

METHODS

Formalin-fixed paraffin-embedded tissue samples from 138 patients with PDAC were constructed into a tissue microarray, followed by immunohistochemical analysis with a recombinant monoclonal FN1 antibody. Chi-square test or Fisher's exact test were used for comparison of FN1 expression and relevant clinicopathological parameters. Kaplan-Meier survival curves and Cox regression analyses were used to assess the association between FN1 and survival.

RESULTS

FN1 was detected in the stromal compartment in most cases (117/138, 84.8%). Compared to the low FN1 expression group, the high FN1 expression group had significantly larger tumor size (P = 0.002), more advanced T stage (P = 0.039) and N stage (P = 0.009), and also worse AJCC stage (P = 0.003). However, stromal FN1 expression was not associated with disease-free survival or overall survival.

CONCLUSIONS

This study suggests that high stromal FN1 expression is associated with aggressive tumor characteristics in patients with resected PDAC. However, no association between FN1 expression and survival was found.

A Designer Cross-reactive DNA Immunotherapeutic Vaccine that Targets Multiple MAGE-A Family Members Simultaneously for Cancer Therapy

PURPOSE

Cancer/testis antigens have emerged as attractive targets for cancer immunotherapy. Clinical studies have targeted MAGE-A3, a prototype antigen that is a member of the MAGE-A family of antigens, in melanoma and lung carcinoma. However, these studies have not yet had a significant impact due to poor CD8⁺ T-cell immunogenicity, platform toxicity, or perhaps limited target antigen availability. In this study, we develop an improved MAGE-A immunogen with cross-reactivity to multiple family members.

EXPERIMENTAL DESIGN

In this study, we analyzed MAGE-A expression in The Cancer Genome Atlas and observed that many patients express multiple MAGE-A isoforms, not limited to MAGE-A3, simultaneously in diverse tumors. On the basis of this, we designed an optimized consensus MAGE-A DNA vaccine capable of cross-reacting with many MAGE-A isoforms, and tested immunogenicity and antitumor activity of this vaccine in a relevant autochthonous melanoma model.

RESULTS

Immunization of this MAGE-A vaccine by electroporation in C57Bl/6 mice generated robust IFNγ and TNFα CD8⁺ T-cell responses as well as cytotoxic CD107a/IFNγ/T-bet triple-positive responses against multiple isoforms. Furthermore, this MAGE-A DNA immunogen generated a cross-reactive immune response in 14 of 15 genetically diverse, outbred mice. We tested the antitumor activity of this MAGE-A DNA vaccine in Tyr::CreER;BRAF^Ca/+;Pten^lox/lox transgenic mice that develop melanoma upon tamoxifen induction. The MAGE-A DNA therapeutic vaccine significantly slowed tumor growth and doubled median mouse survival.

CONCLUSIONS

These results support the clinical use of consensus MAGE-A immunogens with the capacity to target multiple MAGE-A family members to prevent tumor immune escape.

Epigenetic regulation of MAGE family in human cancer progression-DNA methylation, histone modification, and non-coding RNAs

The melanoma antigen gene (MAGE) proteins are a group of highly conserved family members that contain a common MAGE homology domain. Type I MAGEs are relevant cancer-testis antigens (CTAs), and originally considered as attractive targets for cancer immunotherapy due to their typically high expression in tumor tissues but restricted expression in normal adult tissues. Here, we reviewed the recent discoveries and ideas that illustrate the biological functions of MAGE family in cancer progression. Furthermore, we also highlighted the current understanding of the epigenetic mechanism of MAGE family expression in human cancers.

Cancer-testis antigens: Unique cancer stem cell biomarkers and targets for cancer therapy

Cancer-testis antigens (CTAs) are considered as unique and promising cancer biomarkers and targets for cancer therapy. CTAs are multifunctional protein group with specific expression patterns in normal embryonic and adult cells and various types of cancer cells. CTAs are involved in regulating of the basic cellular processes during development, stem cell differentiation and carcinogenesis though the biological roles and cell functions of CTA families remain largely unclear. Analysis of CTA expression patterns in embryonic germ and somatic cells, pluripotent and multipotent stem cells, cancer stem cells and their cell descendants indicates that rearrangements of characteristic CTA profiles (aberrant expression) could be associated with cancer transformation and failure of the developmental program of cell lineage specification and germ line restriction. Therefore, aberrant CTA profiles can be used as panels of biomarkers for diagnoses and the selection of cancer treatment strategies. Moreover, immunogenic CTAs are prospective targets for cancer immunotherapy. Clinical trials testing broad range of cancer therapeutic vaccines against antigens of MAGEA and NY-ESO-1 families for treating various cancers have shown mixed clinical efficiency, safety and tolerability, suggesting the requirement of in-depth research of CTA expression in normal and cancer stem cells and extensive clinical trials for improving cancer immunotherapy technologies. This review focuses on recent advancement in study of CTAs in normal and cancer cells, particularly in normal and cancer stem cells, and provides a new insight into CTA expression patterns during normal and cancer stem cell lineage development. Additionally, new approaches in development of effective CTA-based therapies exclusively targeting cancer stem cells will be discussed.

New Job for NK Cells: Architects of the Tumor Microenvironment

NK cells control tumor growth directly through targeted cytotoxic granule release or cytokine secretion and indirectly by orchestrating anti-tumor immune responses. In this issue of Immunity, Glasner et al. (2018) now reveal a new role for NK cells in preventing metastatic spread through controlling tumor architecture.

The epigenetic landscape of differentiated thyroid cancer

Differentiated thyroid carcinoma of follicular cell-derivation is the most common endocrine neoplasm with a rapidly increasing incidence. The majority represent papillary carcinomas; more rarely, they are follicular carcinomas. The vast majority have indolent behavior, however a significant proportion progress to develop lymph node metastases and a smaller proportion disseminate systemically. While common and frequent genetic events have been described to underlie the development of these neoplasms, the factors contributing to differing behaviors among tumors with similar genetic alterations remain unclear. This review focuses on epigenetic mechanisms targeting major signaling pathways that underlie the spectrum of biological behaviors and that may have potential diagnostic, prognostic and therapeutic value.

Immunohistochemical Biomarkers in Thyroid Pathology

The application of immunohistochemistry to the diagnosis of thyroid lesions has increased as new biomarkers have emerged. In this review, we discuss the biomarkers that are critical for accurate diagnosis, prognosis, and management. Immunohistochemical markers are used to confirm that an unusual tumor in the thyroid is indeed of thyroid origin, either of follicular epithelial or C-cell differentiation; the various mimics include nonthyroidal lesions such as parathyroid tumors, paragangliomas, thymic neoplasms, and metastatic malignancies. Tumors of thyroid follicular epithelial cells can be further subclassified using a number of immunohistochemical biomarkers that can distinguish follicular-derived from C-cell lesions and others that support malignancy in borderline cases. The use of mutation-specific antibodies can distinguish papillary carcinomas harboring a BRAF^V600E mutation from RAS-like neoplasms. Immunostains have been developed to further identify molecular alterations underlying tumor development, including some rearrangements. Altered expression of several biomarkers that are known to be epigenetically modified in thyroid cancer can be used to assist in predicting more aggressive behavior such as a propensity to develop locoregional lymphatic spread. Immunohistochemistry can assist in identifying lymphatic and vascular invasion. Biomarkers can be applied to determine dedifferentiation and to further classify poorly differentiated and anaplastic carcinomas. The rare tumors associated with genetic predisposition to endocrine neoplasia can also be identified using some immunohistochemical stains. The application of these ancillary tools allows more accurate diagnosis and better understanding of pathogenesis while improving prediction and prognosis for patients with thyroid neoplasms.

Antibody response against cancer-testis antigens MAGEA4 and MAGEA10 in patients with melanoma

Melanoma-associated antigen A (MAGEA) represent a class of tumor antigens that are expressed in a variety of malignant tumors, however, their expression in healthy normal tissues is restricted to germ cells of testis, fetal ovary and placenta. The restricted expression and immunogenicity of these antigens make them ideal targets for immunotherapy in human cancer. In the present study the presence of naturally occurring antibodies against two MAGEA subfamily proteins, MAGEA4 and MAGEA10, was analyzed in patients with melanoma at different stages of disease. Results indicated that the anti-MAGEA4/MAGEA10 immune response in melanoma patients was heterogeneous, with only ~8% of patients having a strong response. Comparing the number of strongly responding patients between different stages of disease revealed that the highest number of strong responses was detected among stage II melanoma patients. These findings support the model that the immune system is involved in the control of melanoma in the early stages of disease.

hMAGEA2 promotes progression of breast cancer by regulating Akt and Erk1/2 pathways

Breast cancer is the most abundant cancer worldwide and a severe problem for women. Notably, breast cancer has a high mortality rate, mainly because of tumor progression and metastasis. Triple-negative breast cancer (TNBC) is highly progressive and lacks the expression of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). Therefore, there are no established therapeutic targets against TNBC. In this study, we investigated whether the expression of human melanoma-associated antigen A2 (MAGEA2) is associated with TNBC. We found that hMAGEA2 is significantly overexpressed in human TNBC tissues; we also observed oncogenic properties using TNBC cell lines (MDA-MB-231 and MDA-MB-468). The overexpression of hMAGEA2 in MDA-MB-231 cell line showed dramatically increased cellular proliferation, colony formation, invasion, and xenograft tumor formation and growth. Conversely, knockdown of hMAEGA2 in MDA-MB-468 cell line suppressed cellular proliferation, colony formation, and xenograft tumor formation. Additionally, we showed that hMAGEA2 regulated the activation of Akt and Erk1/2 signaling pathways. These data indicate that hMAGEA2 is important for progression of TNBC and may serve as a novel molecular therapeutic target.

Isolation and Characterization of an HLA-DPB1*04: 01-restricted MAGE-A3 T-Cell Receptor for Cancer Immunotherapy

Long-term tumor regressions have been observed in patients following the adoptive transfer of autologous tumor-infiltrating lymphocytes or genetically modified T cells expressing MHC class I-restricted T-cell receptors (TCRs), but clinical trials have not evaluated responses to genetically modified T cells expressing antitumor MHC class II-restricted TCRs. As studies carried out in a murine tumor model system have demonstrated that the adoptive transfer of CD4 T cells could lead to the regression of established tumors, we plan to test the hypothesis that CD4 T cells can also induce tumor regressions in cancer patients. In this study, 2 MAGE-A3-specific TCRs were isolated from a regulatory T-cell clone (6F9) and an effector clone (R12C9), generated from the peripheral blood of 2 melanoma patients after MAGE-A3 vaccination. The results indicated that T cells transduced with 6F9 TCR mediated stronger effector functions than R12C9 TCR. The 6F9 TCR specifically recognized MAGE-A3 and the closely related MAGE-A6 gene product, but not other members of the MAGE-A family in the context of HLA-DPB1*04:01. To test the feasibility of a potential clinical trial using this TCR, a clinical-scale procedure was developed to obtain a large number of purified CD4 T cells transduced with 6F9 TCR. Because HLA-DPB1*04:01 is present in ∼60% of the Caucasian population and MAGE-A3 is frequently expressed in a variety of cancer types, this TCR immunotherapy could potentially be applicable for a significant portion of cancer patients.

Cancer/testis Antigen MAGEA3 Interacts with STAT1 and Remodels the Tumor Microenvironment

Cancer-testis antigen MAGEA3, being restrictedly expressed in testis and various kinds of tumors, has long been considered as an ideal target for immunotherapy. In this study, we report that MAGEA3 interacts with STAT1 and regulates the expression of tyrosine phosphorylated STAT1 (pY-STAT1) in tumor cells. We show that pY-STAT1 is significantly up-regulated when MAGEA3 is silenced by MAGEA3-specific siRNA. RNA sequencing analysis identified 274 STAT1-related genes to be significantly altered in expression level in MAGEA3 knockdown cells. Further analysis of these differentially expressed genes with GO enrichment and KEGG pathway revealed that they are mainly enriched in plasma membrane, extracellular region and MHC class I protein complex, and involved in the interferon signaling pathways, immune response, antigen presentation and cell chemotaxis. The differentially expressed genes associated with chemokines, antigen presentation and vasculogenic mimicry formation were validated by biological experiments. Matrigel matrix-based tube formation assay showed that silencing MAGEA3 in tumor cells impairs tumor vasculogenic mimicry formation. These data indicate that MAGEA3 expression in tumor cells is associated with immune cells infiltration into tumor microenvironment and anti-tumor immune responses, implying that it may play an important role in tumor immune escape. Our findings reveal the potential impact of MAGEA3 on the immunosuppressive tumor microenvironment and will provide promising strategies for improving the efficacy of MAGEA3-targeted immunotherapy.

MAGE-A11 is activated through TFCP2/ZEB1 binding sites de-methylation as well as histone modification and facilitates ESCC tumor growth

Recently, we have reported that the product of Melanoma Antigens Genes (MAGE) family member MAGE-A11 is an independent poor prognostic marker for esophageal squamous cell carcinoma (ESCC). However, the reason how MAGE-A11 is activated in ESCC progression still remains unclear. In the current study, we demonstrated that DNA methylation and the subsequent histone posttranslational modifications play crucial roles in the regulation of MAGE-A11 in ESCC progression. We found that the methylation rate of TFCP2/ZEB1 binding site on MAGE-A11 promoter in ESCC tissues and cells is higher than the normal esophageal epithelial tissues and cells. Transcription factors TFCP2 and ZEB1 directly bind MAGE-A11 promoter and regulate the endogenous MAGE-A11 expression in a methylation-dependent manner in ESCC cells. Following MAGE-A11 promoter methylation, the methyl-CpG-binding protein MeCP2 was found to bind the methylated MAGE-A11 promoter to mediate histone deactylation by recruiting HDAC1 and HDAC2. Simultaneously, histone inactivation marks including H3K27me3 as well as H3K9me3 were increased, whereas histone activation mark H3K4me3 was decreased. HDAC inhibitor Trichostatin A (TSA) increased DNA methylase inhibitor Decitabine (DAC)-induced MAGE-A11 expression. siRNA-mediated knockdown of histone methltransferase EZH2 or DZNep (a EZH2 inhibitor) treatment increased DAC-induced MAGE-A11 expression. Our results indicate that MAGE-A11 is activated through DNA demethylation, histone acetylation and histone methylation in ESCC, and its activation promotes ESCC tumor growth.

High expression of MAGE-A9 contributes to stemness and malignancy of human hepatocellular carcinoma

MAGE-A9, a well-characterized cancer testis antigen (CTA), belongs to a member of melanoma antigen gene (MAGE) family. In human malignancies, aberrant expression of MAGE genes correlated with poor clinical prognosis, increased tumor growth, metastases, and enrichment in stem cell populations of certain cancers. Cancer stem cells (CSCs) have been proposed to contribute to the major malignant phenotypes of liver cancer, including recurrence, metastasis and chemoresistance. However, expression and potential role of MAGE-A9 in liver cancer stem cells (LCSCs) still remain unclear. In the present study, we first analyzed the expression profiling of MAGE family genes in EpCAM+ and EpCAM- human hepatocellular carcinoma (HCC), based on public Gene Expression Omnibus (GEO) database. Among these examined MAGE members, MAGE-A9 is the only one with significantly higher expression in EpCAM+ HCC specimens as compared with EpCAM- HCC. Quantitative PCR analysis further confirmed that MAGE-A9 expression significantly elevated in a subtype of HCC patients that had features of hepatic stem/progenitor cells with high-level expression of EpCAM and α-fetoprotein (AFP). Moreover, MAGE-A9 displayed remarkably enriched expression in EpCAM+ HCC cells that were sorted by fluorescence-activated cell sorting and cultured HCC cell spheroids with characteristics of stem/progenitor cells. Functional experiments further revealed that MAGE-A9 overexpression promoted cell proliferation, colony formation, migration, chemoresistance, and tumorigenicity in the context of EpCAM+ HCC cells, whereas MAGE-A9 knockdown significantly inhibited anchorage-dependent and spheroid colony formation and in vivo tumorigenicity. Collectively, these data demonstrate that MAGE-A9 functions as an important regulator of LCSCs, and MAGE-A9 may serve as a potential therapeutic target against HCC stem/progenitor cells.

A novel electrochemical immunosensor based on ITO modified by carboxyl-ended silane agent for ultrasensitive detection of MAGE-1 in human serum

A new, low-cost electrochemical immunosensor was developed for rapid detection of Melanoma-associated antigen 1 (MAGE-1), a cancer biomarker. The fabrication procedure of immunosensor was based on the covalent immobilization of anti-MAGE-1, biorecognition molecule, on ITO electrode by carboxyethylsilanetriol (CTES) monolayer. The biosensing MAGE-1 antigen was monitored by using electrochemical impedance spectroscopy (EIS) and cyclic voltammetry (CV) technique. Apart from these techniques, single frequency impedance (SFI) was used for investigation of antibody-antigen interactions. Scanning electron microscopy (SEM), fourier transform infrared spectroscopy (FTIR), atomic force microscopy (AFM) were utilized for characterization of the proposed biosensor. To fabricate highly sensitive, good stability immunosensor, some parameters were optimized. Under optimal conditions, the developed electrochemical immunosensor for MAGE-1 exhibited a dynamic range of 4 fg/mL and 200 fg/mL with a low detection limit of 1.30 fg/mL. It had acceptable repeatability (5.05%, n = 20) and good storage stability (3.58% loss after 10 weeks). Moreover, this electrochemical immunosensor has been successfully applied to the determination of MAGE-1 in human serum samples.

Spontaneous CD4+ and CD8+ T-cell responses directed against cancer testis antigens are present in the peripheral blood of testicular cancer patients

Cancer/testis antigen (CTAg) expression is restricted to spermatogenic cells in an immune‐privileged site within the testis. However, these proteins are expressed aberrantly by malignant cells and T‐cell responses against CTAgs develop in many cancer patients. We investigated the prevalence, magnitude and phenotype of CTAg‐specific T cells in the blood of patients with testicular germ cell tumors (TGCTs). CD8⁺ and CD4⁺ T‐cell responses against MAGE‐A family antigens were present in 44% (20/45) of patients’ samples assayed by ex vivo IFN‐γ ELISPOT. The presence of MAGE‐specific CD8⁺ T cells was further determined following short‐term in vitro expansion through the use of pMHC‐I multimers containing known immunogenic peptides. Longitudinal analysis revealed that the frequency of MAGE‐specific T cells decreased by 89% following orchidectomy suggesting that persistence of tumor antigen is required to sustain CTAg‐specific T‐cell immunity. Notably, this decrease correlated with a decline in the global effector/memory T‐cell pool following treatment. Spontaneous T‐cell immunity against CTAg proteins therefore develops in many patients with testicular cancer and may play an important role in the excellent clinical outcome of patients with this tumor subtype.

Suppression of MAGE-A10 alters the metastatic phenotype of tongue squamous cell carcinoma cells

MAGE-A10 is a member of the MAGE protein family (melanoma associated antigen) which is overexpressed in cancer cells. Although MAGE-A10 has been characterized for some time and is generally associated to metastasis its function remains unknown. Here we describe experiments using as models oral squamous cell carcinoma (OSCC) cell lines displaying increasing metastatic potential (LN1 and LN2). These cell lines were transduced with lentivirus particles coding for short hairpin against MAGE-A10 mRNA. Repression of MAGE-A10 expression in LN2 cells altered their morphology and impaired growth of LN1 and LN2 cell lines. Furthermore, repression of MAGE-A10 expression increased cell-cell and cell matrix adhesion. Furthermore shMAGEA10 cells were shown to assemble aberrantly on a 3D culture system (microspheroids) when compared to cells transduced with the control scrambled construct. Cell migration was inhibited in knocked down cells as revealed by two different migration assays, wound healing and a phagokinetic track motility assay. In vitro invasion assay using a leiomyoma tissue derived matrix (myogel) showed that shMAGEA10 LN1 and shMAGEA10 LN2 cells displayed a significantly diminished ability to penetrate the matrices. Concomitantly, the expression of E-cadherin, N-cadherin and vimentin genes was analyzed. shMAGEA10 activated the expression of E-cadherin and repression N-cadherin and vimentin transcription.

Taken together the results indicate that MAGE-A10 exerts its effects at the level of the epithelial-mesenchymal transition (EMT) presumably by regulating the expression of adhesion molecules.

Fibronectin 1 promotes migration and invasion of papillary thyroid cancer and predicts papillary thyroid cancer lymph node metastasis

Lymph node metastasis (LNM) is common in papillary thyroid cancer (PTC), and is an indicator of recurrence. The detailed molecular mechanism of LNM in PTC has not been well described. This study aimed to investigate the role of fibronectin 1 in PTC LNM and its clinical relevance. The expression of fibronectin 1 was confirmed in PTC tissues and cell lines. A correlation analysis was conducted and a receiver-operating characteristic curve obtained. The effect of fibronectin 1 on the proliferation of PTC cell lines was performed using a colony-formation assay and Cell Counting Kit 8. Cell-cycle analysis was performed with a flow-cytometry assay. Migration and invasion ability were evaluated by transwell and wound-healing assays. Fibronectin 1 was overexpressed in metastasized PTC. Overexpressed fibronectin 1 was positively correlated with PTC LNM. Receiver-operating characteristic analysis showed that the diagnostic accuracy of fibronectin 1 was 81.1%, with sensitivity of 80% and specificity of 82%. Overexpression of fibronectin 1 promoted proliferation, migration, and invasion in PTC. Fibronectin 1 plays a critical role in PTC metastasis by modulating the proliferation, migration, and invasion ability of PTC cells, and it is a valuable diagnostic biomarker for predicting PTC LNM.

A Comprehensive Guide to the MAGE Family of Ubiquitin Ligases

Melanoma antigen (MAGE) genes are conserved in all eukaryotes and encode for proteins sharing a common MAGE homology domain. Although only a single MAGE gene exists in lower eukaryotes, the MAGE family rapidly expanded in eutherians and consists of more than 50 highly conserved genes in humans. A subset of MAGEs initially garnered interest as cancer biomarkers and immunotherapeutic targets due to their antigenic properties and unique expression pattern that is primary restricted to germ cells and aberrantly reactivated in various cancers. However, further investigation revealed that MAGEs not only drive tumorigenesis but also regulate pathways essential for diverse cellular and developmental processes. Therefore, MAGEs are implicated in a broad range of diseases including neurodevelopmental, renal, and lung disorders, and cancer. Recent biochemical and biophysical studies indicate that MAGEs assemble with E3 RING ubiquitin ligases to form MAGE-RING ligases (MRLs) and act as regulators of ubiquitination by modulating ligase activity, substrate specification, and subcellular localization. Here, we present a comprehensive guide to MAGEs highlighting the molecular mechanisms of MRLs and their physiological roles in germ cell and neural development, oncogenic functions in cancer, and potential as therapeutic targets in disease.

Cancer-testis antigen MAGE-C2 binds Rbx1 and inhibits ubiquitin ligase-mediated turnover of cyclin E

Cancer-testis antigen MAGE-C2 is normally expressed in testis but aberrantly expressed in various kinds of tumors. Its functions in tumor cells are mostly unknown. Here, we show that MAGE-C2 binds directly to the RING domain protein Rbx1, and participates in Skp1-Cullin1-F box protein (SCF) complex. Furthermore, MAGE-C2 can inhibit the E3 ubiquitin ligase activity of SCF complex. Ablation of endogenous MAGE-C2 decreases the level of cyclin E and accelerates cyclin E turnover by inhibiting ubiquitin-mediated proteasome degradation. Overexpression of MAGE-C2 increases the level of cyclin E and promotes G1-S transition and cell proliferation, and the results are further confirmed by knockdown of MAGE-C2. Overall, the study indicates that MAGE-C2 is involved in SCF complex and increases the stability of cyclin E in tumor cells.

Snail and serpinA1 promote tumor progression and predict prognosis in colorectal cancer

The role of Snail and serpin peptidase inhibitor clade A member 1 (serpinA1) in tumorigenesis has been previously identified. However, the exact role and mechanism of these proteins in progression of colorectal cancer (CRC) are controversial. In this study, we investigated the role of Snail and serpinA1 in colorectal cancer (CRC) and examined the mechanisms through which these proteins mediate CRC progression. Immunohistochemical analysis of 528 samples from patients with CRC showed that elevated expression of Snail or serpinA1 was correlated with advanced stage, lymph node metastasis, and poor prognosis. Moreover, we detected a correlation between Snail and serpinA1 expression. Functional studies performed using the CRC cell lines DLD-1 and SW-480 showed that overexpression of Snail or serpinA1 significantly increased CRC cell invasion and migration. Conversely, knockdown of Snail or serpinA1 expression suppressed CRC cell invasion and migration. ChIP analysis revealed that Snail regulated serpinA1 by binding to its promoter. In addition, fibronectin mediated Snail and serpinA1 signaling was involved in CRC cell invasion and migration. Taken together, our data showed that Snail and serpinA1 promoted CRC progression through fibronectin. These findings suggested that Snail and serpinA1 were novel prognostic biomarkers and candidate therapeutic targets in CRC.

In vivo enhancement of the MAGE-specific cellular immune response by a recombinant MAGE1-MAGE3-TBHSP70 tumor vaccine

Background

Since cytotoxic T cell (CTL) response is the major cellular type in attacking tumor cells, most immunotherapy targets to manipulate the CTL response. Immunotherapies targeting melanoma-specific antigens (MAGEs), a group of tumor-specific shared antigen, have shown to be promising. Our previous study has shown that MAGE1/TBHSP70 and MAGE3/TBHSP70 could induce a robust immune response against B-16 melanoma cells in C57BL/6 mice. In this study, we used an animal model to further demonstrate MAGEs as a potential immunotherapy target for tumorigenesis in vivo.

Methods

In the current study, we developed a MAGE1/MAGE3/TBHSP70 recombinant protein vaccine and evaluated its protective efficacy against tumor development by challenge vaccine-immunized mice with MAGE-expressing human tumor cell lines in a Hu-PBL-SCID mouse model. The cellular immune reactions were monitored by ELISPOT and cytotoxicity assays.

Results

Splenocytes isolated from vaccine-immunized mice presented potent cytokine secretion capacity and CTL-specific cytotoxic. Vaccine-immunized mice had a significant tumor regression and prolonged survival compared with controls (both p < 0.05). In vitro, rMAGE1-MAGE3-TBHSP70 showed a potent tumor-antigen-specific immune response in both hepatocellular carcinoma and pulmonary carcinoma cell lines.

Conclusion

This newly-developed recombinant protein vaccine may serve as a new immunotherapy for cancer.

Musashi-2 (MSI2) supports TGF-β signaling and inhibits claudins to promote non-small cell lung cancer (NSCLC) metastasis

Non-small cell lung cancer (NSCLC) has a 5-y survival rate of ∼16%, with most deaths associated with uncontrolled metastasis. We screened for stem cell identity-related genes preferentially expressed in a panel of cell lines with high versus low metastatic potential, derived from NSCLC tumors of Kras(LA1/+);P53(R172HΔG/+) (KP) mice. The Musashi-2 (MSI2) protein, a regulator of mRNA translation, was consistently elevated in metastasis-competent cell lines. MSI2 was overexpressed in 123 human NSCLC tumor specimens versus normal lung, whereas higher expression was associated with disease progression in an independent set of matched normal/primary tumor/lymph node specimens. Depletion of MSI2 in multiple independent metastatic murine and human NSCLC cell lines reduced invasion and metastatic potential, independent of an effect on proliferation. MSI2 depletion significantly induced expression of proteins associated with epithelial identity, including tight junction proteins [claudin 3 (CLDN3), claudin 5 (CLDN5), and claudin 7 (CLDN7)] and down-regulated direct translational targets associated with epithelial-mesenchymal transition, including the TGF-β receptor 1 (TGFβR1), the small mothers against decapentaplegic homolog 3 (SMAD3), and the zinc finger proteins SNAI1 (SNAIL) and SNAI2 (SLUG). Overexpression of TGFβRI reversed the loss of invasion associated with MSI2 depletion, whereas overexpression of CLDN7 inhibited MSI2-dependent invasion. Unexpectedly, MSI2 depletion reduced E-cadherin expression, reflecting a mixed epithelial-mesenchymal phenotype. Based on this work, we propose that MSI2 provides essential support for TGFβR1/SMAD3 signaling and contributes to invasive adenocarcinoma of the lung and may serve as a predictive biomarker of NSCLC aggressiveness.

Oncogenic cancer/testis antigens: prime candidates for immunotherapy

Recent developments have set the stage for immunotherapy as a supplement to conventional cancer treatment. Consequently, a significant effort is required to further improve efficacy and specificity, particularly the identification of optimal therapeutic targets for clinical testing. Cancer/testis antigens are immunogenic, highly cancer-specific, and frequently expressed in various types of cancer, which make them promising candidate targets for cancer immunotherapy, including cancer vaccination and adoptive T-cell transfer with chimeric T-cell receptors. Our current understanding of tumor immunology and immune escape suggests that targeting oncogenic antigens may be beneficial, meaning that identification of cancer/testis antigens with oncogenic properties is of high priority. Recent work from our lab and others provide evidence that many cancer/testis antigens, in fact, have oncogenic functions, including support of growth, survival and metastasis. This novel insight into the function of cancer/testis antigens has the potential to deliver more effective cancer vaccines. Moreover, immune targeting of oncogenic cancer/testis antigens in combination with conventional cytotoxic therapies or novel immunotherapies such as checkpoint blockade or adoptive transfer, represents a highly synergistic approach with the potential to improve patient survival.