Expression of cancer-testis antigens in the immune microenvironment of non-small cell lung cancer

The antigenic repertoire of tumors is critical for successful anti-cancer immune response and the efficacy of immunotherapy. Cancer-testis antigens (CTAs) are targets of humoral and cellular immune reactions. We aimed to characterize CTA expression in non-small cell lung cancer (NSCLC) in the context of the immune microenvironment. Of 90 CTAs validated by RNA sequencing, eight CTAs (DPEP3, EZHIP, MAGEA4, MAGEB2, MAGEC2, PAGE1, PRAME, and TKTL1) were selected for immunohistochemical profiling in cancer tissues from 328 NSCLC patients. CTA expression was compared with immune cell densities in the tumor environment and with genomic, transcriptomic, and clinical data. Most NSCLC cases (79%) expressed at least one of the analyzed CTAs, and CTA protein expression correlated generally with RNA expression. CTA profiles were associated with immune profiles: high MAGEA4 expression was related to M2 macrophages (CD163) and regulatory T cells (FOXP3), low MAGEA4 was associated with T cells (CD3), and high EZHIP was associated with plasma cell infiltration (adj. P-value < 0.05). None of the CTAs correlated with clinical outcomes. The current study provides a comprehensive evaluation of CTAs and suggests that their association with immune cells may indicate in situ immunogenic effects. The findings support the rationale to harness CTAs as targets for immunotherapy.

Characterization of Cancer/Testis Antigens as Prognostic Markers of Ovarian Cancer

The main goal of this study was to characterize cancer/testis antigens (CTAs) as potential molecular markers of ovarian cancer. First, we gathered and analyzed a significantly large dataset of 21 selected CTAs that are encoded by 32 genes; the dataset consisted of the mutation data, expression data, and survival data of patients with ovarian cancer (n = 15,665). The 19 functionally significant missense mutations were identified in 9 CTA genes: ACRBP, CCT4, KDM5B, MAGEA1, MAGEA4, PIWIL1, PIWIL2, PRAME, and SPA17. The analysis of the mRNA expression levels of 21 CTAs in healthy and tumor ovarian tissue showed an up-regulation in the expression level of AKAP3, MAGEA4, PIWIL1, and PRAME in tumor samples and a down-regulation in the expression level of CTAG1A, CTAG1B, MAGEC1, and PIWIL2. The CCT4 up-regulation and PRAME mutations were correlated with a good prognosis for ovarian cancer, while higher levels of GAGE2A and CT45A1 mRNAs were correlated with a poor prognosis for ovarian cancer patients. Thus, GAGE2, CT45, CCT4, and PRAME cancer/testis antigens can be considered as potential prognostic markers for ovarian tumors, and GAGE2, CCT4, and PRAME were revealed to be correlated with the prognosis for ovarian cancer patients for the first time.

The Price of Human Evolution: Cancer-Testis Antigens, the Decline in Male Fertility and the Increase in Cancer

The increasing frequency of general and particularly male cancer coupled with the reduction in male fertility seen worldwide motivated us to seek a potential evolutionary link between these two phenomena, concerning the reproductive transcriptional modules observed in cancer and the expression of cancer-testis antigens (CTA). The phylostratigraphy analysis of the human genome allowed us to link the early evolutionary origin of cancer via the reproductive life cycles of the unicellulars and early multicellulars, potentially driving soma-germ transition, female meiosis, and the parthenogenesis of polyploid giant cancer cells (PGCCs), with the expansion of the CTA multi-families, very late during their evolution. CTA adaptation was aided by retrovirus domestication in the unstable genomes of mammals, for protecting male fertility in stress conditions, particularly that of humans, as compensation for the energy consumption of a large complex brain which also exploited retrotransposition. We found that the early and late evolutionary branches of human cancer are united by the immunity-proto-placental network, which evolved in the Cambrian and shares stress regulators with the finely-tuned sex determination system. We further propose that social stress and endocrine disruption caused by environmental pollution with organic materials, which alter sex determination in male foetuses and further spermatogenesis in adults, bias the development of PGCC-parthenogenetic cancer by default.

Biology of Cancer-Testis Antigens and Their Therapeutic Implications in Cancer

Tumour-specific antigens have been an area of interest in cancer therapy since their discovery in the middle of the 20th century. In the era of immune-based cancer therapeutics, redirecting our immune cells to target these tumour-specific antigens has become even more relevant. Cancer-testis antigens (CTAs) are a class of antigens with an expression specific to the testis and cancer cells. CTAs have also been demonstrated to be expressed in a wide variety of cancers. Due to their frequency and specificity of expression in a multitude of cancers, CTAs have been particularly attractive as cancer-specific therapeutic targets. There is now a rapid expansion of CTAs being identified and many studies have been conducted to correlate CTA expression with cancer and therapy-resistant phenotypes. Furthermore, there is an increasing number of clinical trials involving using some of these CTAs as molecular targets in pharmacological and immune-targeted therapeutics for various cancers. This review will summarise the current knowledge of the biology of known CTAs in tumorigenesis and the regulation of CTA genes. CTAs as molecular targets and the therapeutic implications of these CTA-targeted anticancer strategies will also be discussed.

Cancer-testis Antigen FATE1 Expression in Adrenocortical Tumors Is Associated with A Pervasive Autoimmune Response and Is A Marker of Malignancy in Adult, but Not Children, ACC

The SF-1 transcription factor target gene FATE1 encodes a cancer-testis antigen that has an important role in regulating apoptosis and response to chemotherapy in adrenocortical carcinoma (ACC) cells. Autoantibodies directed against FATE1 were previously detected in patients with hepatocellular carcinoma. In this study, we investigated the prevalence of circulating anti-FATE1 antibodies in pediatric and adult patients with adrenocortical tumors using three different methods (immunofluorescence, ELISA and Western blot). Our results show that a pervasive anti-FATE1 immune response is present in those patients. Furthermore, FATE1 expression is a robust prognostic indicator in adult patients with ACC and is associated with increased steroidogenic and decreased immune response gene expression. These data can open perspectives for novel strategies in ACC immunotherapy.

Sperm Protein Antigen 17 Expression Correlates With Lymph Node Metastasis and Worse Overall Survival in Patients With Breast Cancer

Purpose: The expression and role of sperm protein antigen 17 (SPA17), which has been confirmed to be immunogenic, in breast cancer remain unclear. We examined the expression of SPA17 in breast cancer and assessed its effect on patient prognosis and its function in breast cancer development.

Methods: SPA17 expression was evaluated by immunohistochemistry and Q-RT-PCR in 120 breast tissue samples. Correlation of SPA17 expression with the patients' clinicopathological parameters and overall survival was assessed. The function of SPA17 was also explored.

Results: By reviewing Gene Expression Omnibus datasets, we found that SPA17 expression in ductal breast carcinoma in situ (log2[fold change] = 1.14, p-value = 0.004) and invasive ductal breast cancer (log2[fold change] = 1.03, p-value = 0.016) tissues was 2.20 and 2.05 times higher, respectively, than that in normal breast tissues. Our result also showed that 27% (27/100) of breast cancer samples expressed SPA17 but none of the normal breast (0/20) samples did. Lymph node metastasis (p < 0.001) and molecular subtyping (p = 0.002) were independent factors associated with SPA17 expression. Most importantly, SPA17 expression resulted in poor prognosis. In addition, cell function assay validated that SPA17 increased the migration (p < 0.001) and invasion (p = 0.007) of breast cancer cells, but not affected the proliferation of breast cancer cells.

Conclusion: Our results demonstrated the vital role of SPA17 in the development and metastasis of breast cancer and that SPA17 may be a new therapeutic target in improving breast cancer prognosis.

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.

Cancer-testis antigens in canine histiocytic sarcoma and other malignancies

Cancer-testis antigens (CTAs) are a category of self proteins aberrantly expressed in diverse malignancies, mostly solid tumours, due to epigenetic de-repression. Normally expressed only in fetal or gametogenic tissues, CTAs are tantalizing immunotherapy targets, since autoimmunity risks appear minimal. Few prevalent CTAs have been identified in human hematologic cancers, and just two in their veterinary counterparts. We sought to discover new CTAs in canine hematologic cancers such as histiocytic sarcoma (HS) and lymphoma to foster immunotherapy development. To accomplish this, the ligandome binding the dog leukocyte antigen (DLA)-88*508:01 class I allele overexpressed in an HS line was searched by mass spectrometry to identify possible CTA-derived peptides, which could serve as CD8+ T-cell epitopes. Twenty-two peptides mapped to 5 human CTAs and 12 additional proteins with CTA characteristics. Expression of five promising candidates was then evaluated in tumour and normal tissue by quantitative and end-point RT-PCR. The ortholog of an established CTA, IGF2BP3, had unexpectedly high expression in peripheral blood mononuclear cells (PBMCs). Four other testis-enhanced proteins were also assessed. AKR1E2, SPECC1 and TPX2 were expressed variably in HS and T-cell lymphoma biopsies, but also at high levels in critical tissues, including kidney, brain and marrow, diminishing their utility. A more tissue-restricted candidate, NT5C1B, was detected in T-cell lymphomas, but also at low levels in some normal dog tissues. These results illustrate the feasibility of discovering canine CTAs by a reverse approach, proceeding from identification of MHC class I-presented peptides to a comparative RNA expression survey of tumours and normal tissues.

Expression dynamics of Mage family genes during self-renewal and differentiation of mouse pluripotent stem and teratocarcinoma cells

The biological roles of cancer-testis antigens of the Melanoma antigen (Mage) family in mammalian development, stem cell differentiation and carcinogenesis are largely unknown. In order to understand the involvement of the Mage family genes in maintenance of normal and cancer stem cells, the expression patterns of Mage-a, Mage-b, Mage-d, Mage-e, Mage-h and Mage-l gene subfamilies were analyzed during the self-renewal and differentiation of mouse pluripotent stem and teratocarcinoma cells. Clustering analysis based on the gene expression profiles of undifferentiated and differentiating cell populations revealed strong correlations between Mage expression patterns and differentiation and malignant states. Gene co-expression analysis disclosed the potential contributions of Mage family members in self-renewal and differentiation of pluripotent stem and teratocarcinoma cells. Two gene clusters including Mage-a4 and Mage-a8, Mageb1, Mage-d1, Mage-d2, Mage-e1, Mage-l2 were identified as functional antagonists with opposing roles in the regulation of proliferation and differentiation of mouse pluripotent stem and teratocarcinoma cells. The identified aberrant expression patterns of Mage-a2, Mage-a6, Mage-b4, Mageb-16 and Mage-h1 in teratocarcinoma cells can be considered as specific teratocarcinoma biomarkers promoted the malignant phenotype. Our study first provides a model for the involvement of Mage family members in regulatory networks during the self-renewal and early differentiation of normal and cancerous stem cells for further research of the predicted functional modules and the development of new cancer treatment strategies.

Specific Features of Transcription Activity of Cancer-Testis Antigens in Patients with Metastatic and Non-Metastatic Breast Cancer

Cancer-testis antigens, effective markers of tissue malignant transformation, are characterized by heterogonous transcription depending on the pathological features of breast cancer. We performed screening of transcription profile of cancer-testis antigens specific for breast tumor tissues in female patients with and without regional metastasis. The relative expression of 16 genes (MAGEA1, MAGEA2, MAGEA3, MAGEA4, MAGEB1, MAGEB2, GAGE1, GAGE3, GAGE4, MAGEC1, BAGE, XAGE3, NY-ESO1, SSX2, SYCP1, and PRAME1) was analyzed by RT-qPCR method in biopsy specimens of the mammary gland tissues obtained during surgery from 25 patients. Differential transcription activity of cancer-testis antigens genes was observed in patients with metastatic (enhanced expression of MAGEA2, MAGEB1, and XAGE3 genes) and non-metastatic (enhanced expression of GAGE3 and PRAME1 genes) breast cancer.

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.

Cinacalcet inhibits neuroblastoma tumor growth and upregulates cancer-testis antigens

The calcium–sensing receptor is a G protein-coupled receptor that exerts cell-type specific functions in numerous tissues and some cancers. We have previously reported that this receptor exhibits tumor suppressor properties in neuroblastoma. We have now assessed cinacalcet, an allosteric activator of the CaSR approved for clinical use, as targeted therapy for this developmental tumor using neuroblastoma cell lines and patient-derived xenografts (PDX) with different MYCN and TP53 status. In vitro, acute exposure to cinacalcet induced endoplasmic reticulum stress coupled to apoptosis via ATF4-CHOP-TRB3 in CaSR-positive, MYCN-amplified cells. Both phenotypes were partially abrogated by phospholipase C inhibitor U73122. Prolonged in vitro treatment also promoted dose- and time-dependent apoptosis in CaSR-positive, MYCN-amplified cells and, irrespective of MYCN status, differentiation in surviving cells. Cinacalcet significantly inhibited tumor growth in MYCN-amplified xenografts and reduced that of MYCN-non amplified PDX. Morphology assessment showed fibrosis in MYCN-amplified xenografts exposed to the drug. Microarrays analyses revealed up-regulation of cancer-testis antigens (CTAs) in cinacalcet-treated MYCN-amplified tumors. These were predominantly CTAs encoded by genes mapping on chromosome X, which are the most immunogenic. Other modulated genes upon prolonged exposure to cinacalcet were involved in differentiation, cell cycle exit, microenvironment remodeling and calcium signaling pathways. CTAs were up-regulated in PDX and in vitro models as well. Moreover, progressive increase of CaSR expression upon cinacalcet treatment was seen both in vitro and in vivo. In summary, cinacalcet reduces neuroblastoma tumor growth and up-regulates CTAs. This effect represents a therapeutic opportunity and provides surrogate circulating markers of neuroblastoma response to this treatment.

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.

MAGE expression in head and neck squamous cell carcinoma primary tumors, lymph node metastases and respective recurrences-implications for immunotherapy

Melanoma associated antigens (MAGE) are potential targets for immunotherapy and have been associated with poor overall survival (OS) in head and neck squamous cell carcinoma (HNSCC). However, little is known about MAGE in lymph node metastases (LNM) and recurrent disease (RD) of HNSCC.To assess whether MAGE expression increases with metastasis or recurrence, a tissue microarray (TMA) of 552 primary tumors (PT), 219 LNM and 75 RD was evaluated by immunohistochemistry for MAGE antigens using three monoclonal antibodies to multiple MAGE family members. Mean expression intensity (MEI) was obtained from triplicates of each tumor specimen.The median MEI compared between PT, LNM and RD was significantly higher in LNM and RD. In paired samples, MEI was comparable in PT to respective LNM, but significantly different from RD. Up to 25% of patients were negative for pan-MAGE or MAGE-A3/A4 in PT, but positive in RD. The prognostic impact of MAGE expression was validated in the TMA cohort and also in TCGA data (mRNA). OS was significantly lower for patients expressing pan-MAGE or MAGE-A3/A4 in both independent cohorts.MAGE expression was confirmed as a prognostic marker in HNSCC and may be important for immunotherapeutic strategies as a shared antigen.

Decitabine treatment sensitizes tumor cells to T-cell-mediated cytotoxicity in patients with myelodysplastic syndromes

Decitabine treatment improves immunological recognition that increases expression of cancer-testis antigens (CTAs) against solid tumors. The mechanisms of decitabine enhancement of immunogenicity when used for patients with myelodysplastic syndromes (MDS) remain unclear. In the present study, we found relatively low baseline expression of MAGE-A1, MAGE-A3, and SP17 in MDS-derived cell lines. Decitabine treatment significantly improved MAGE-A1, MAGE-A3, and SP17 expression in these cell lines and in MDS patients. Decitabine-treated K562 and SKM-1 target cells with incrementally induced MAGE-A1, MAGE-A3, or SP17 levels up-regulated T lymphocyte function. Decitabine treatment improved CTA-specific cytotoxic T lymphocyte (CTL) recognition of MDS cells via the up-regulation of CTAs. This response was accompanied by enhanced T lymphocyte function and HLA class antigen expression, and increased ICAM-1. These findings suggested that decitabine may have a broad range of therapeutic applications when it is used in association with active adaptive immunity responses against up-regulated CTAs.

Expression and clinical significance of MAGE and NY-ESO-1 cancer-testis antigens in adenoid cystic carcinoma of the head and neck

BACKGROUND

Adenoid cystic carcinoma (ACC) of the head and neck is a rare but highly malignant tumor. Cancer-testis antigens (CTAs) represent an immunogenic family of cancer-specific proteins and thus represent an attractive target for immunotherapy.

METHODS

Eighty-four cases of ACC were identified, the CTAs pan-Melanoma antigen (pan-MAGE; M3H67) and New York esophageal squamous cell carcinoma (NY-ESO-1; E978) were detected immunohistochemically (IHC) and correlated with clinical data.

RESULTS

Expression of NY-ESO-1 was found in 48 of 84 patients (57.1%) and of pan-MAGE in 28 of 84 patients (31.2%). Median overall survival (OS) in NY-ESO-1 positive versus negative patients was 130.8 and 282.0 months (p = .223), respectively. OS in pan-MAGE positive versus negative patients was 105.3 and 190.5 months, respectively (p = .096). Patients expressing both NY-ESO-1 and pan-MAGE simultaneously had significantly reduced OS with a median of 90.5 months compared with 282.0 months in negative patients (p = .047).

CONCLUSION

A significant fraction of patients with ACC show expression of the CTAs NY-ESO-1 and/or pan-MAGE with promising immunotherapeutic implications. © 2016 Wiley Periodicals, Inc. Head Neck 38: 1008-1016, 2016.

Predictive and prognostic effect of CD133 and cancer-testis antigens in stage Ib-IIIA non-small cell lung cancer

CD133 and cancer-testis antigens (CTAs) may be potential predicted markers of adjuvant chemotherapy or immune therapy, and they may be the independent prognostic factor of NSCLC. Nowadays, there is still no predictive biomarker identified for the use of adjuvant chemotherapy in non-small cell lung cancer (NSCLC) patients. To clarify the role of CD133 and CTAs as a predictive marker for adjuvant chemotherapy or prognostic factors of overall survival, we performed a retrospective study in 159 stage Ib-IIIA NSCLC patients receiving adjuvant chemotherapy or observe from April 2003 to March 2004 in our institute. Clinical data and gene anaylisis results were collected, while CD133 and three CTAs (MAGE-A4, NY-ESO-1, MAGE-A10) were determined according to their monoclonal antibodies such as CD133, 57B, D8.38 and 3GA11 by immunohistochemistry. All CTAs were more frequently expressed in squamous cell carcinoma (SCC) (50.0%, 26.9%, 34.6%) than in adenocarcinoma (16.2%, 16.2%, 16.2%). CD133 was more frequently found in patients with adenocarcinoma (P=0.044). Negative expression of CD133 was associated with a significantly longer overall survival compared to positive expression of CD133 (62.5 vs. 48.5 months, P=0.035). When combined with MAGEA4, NY-ESO-1or MAGE-A10, patients' OS showed significantly difference among different combination. (CD133-MAGEA4-/CD133-MAGEA4+/CD133+MAGEA4-/CD133+MAGEA4+: 65.6 months vs.51.5 months vs.32.2 months vs.19.8 months, P=0.000, CD133-NY-ESO-1-/ CD133+NY-ESO-1-/CD133-NY-ESO-1+/ CD133+NY-ESO-1+: 57.8 months vs. 55.7 months vs. 44.6 months vs. 28.5 months, P=0.000, CD133-MAGEA10-/CD133+ MAGEA10-/CD133-MAGEA10-/CD133+MAGEA10+: 66.2 months vs. 57.2 months vs. 48.8 months vs. 41.4 months, P=0.001). There is no difference between patients received adjuvant chemotherapy or not, but subgroup analysis showed that the patients with CD133+NY-ESO-1+ expression who received chemotherapy will survive longer than not receive adjuvant chemotherapy (received vs. not received, 52.1 vs. 27.1 months, P=0.020). In the subgroup with EGFR mutation/ALK translocation/Ros1 translocation/Ret fusion, the trend remained but without a statistically significant difference. Multivariate COX regression analysis showed that stage, CD133, CD133-MAGEA4- and CD133-NY-ESO-1- are independent prognostic factors. In conclusion, CTAs (MAGE-A4, NY-ESO-1, MAGE-A10) were more likely expressed in patients with squamous cell carcinoma and when CTAs combined with CD133, they can be better prognostic factors. Patients with CD133+NY-ESO-1+ expression may survive longer when treated with adjuvant chemotherapy, which indicates that the CD133 and CTAs might be a potential marker to guide adjuvant chemotherapy in this population.

Immunogenic tumor cell death induced by chemoradiotherapy in a clinical setting

Although it has been shown in murine models that chemoradiotherapy may induce immunogenic tumor cell death, which could trigger T-cell immunity upon the released of high-mobility group box 1 protein (HMGB1), whether this also occurs in clinical settings remains unclear. Here, we discuss tumor-antigen specific T-cell responses in esophageal cancer patients receiving chemoradiotherapy. Our findings indicate that chemoradiation induces tumor antigen-specific T-cell responses and that the release of HMGB1 is related to clinical outcome.

Expression of cancer-testis antigens MAGEA1, MAGEA3, ACRBP, PRAME, SSX2, and CTAG2 in myxoid and round cell liposarcoma

Myxoid and round-cell liposarcoma is a frequently encountered liposarcoma subtype. The mainstay of treatment remains surgical excision with or without chemoradiation. However, treatment options are limited in the setting of metastatic disease. Cancer-testis antigens are immunogenic antigens with the expression largely restricted to testicular germ cells and various malignancies, making them attractive targets for cancer immunotherapy. Gene expression studies have reported the expression of various cancer-testis antigens in liposarcoma, with mRNA expression of CTAG1B, CTAG2, MAGEA9, and PRAME described specifically in myxoid and round-cell liposarcoma. Herein, we further explore the expression of the cancer-testis antigens MAGEA1, ACRBP, PRAME, and SSX2 in myxoid and round-cell liposarcoma by immunohistochemistry in addition to determining mRNA levels of CTAG2 (LAGE-1), PRAME, and MAGEA3 by quantitative real-time PCR. Samples in formalin-fixed paraffin-embedded blocks (n=37) and frozen tissue (n=8) were obtained for immunohistochemistry and quantitative real-time PCR, respectively. Full sections were stained with antibodies to MAGEA1, ACRBP, PRAME, and SSX2 and staining was assessed for intensity (1-2+) and percent tumor positivity. The gene expression levels of CTAG2, PRAME, and MAGEA3 were measured by quantitative real-time PCR. In total, 37/37 (100%) of the samples showed predominantly strong, homogenous immunoreactivity for PRAME. There was a variable, focal expression of MAGEA1 (11%) and SSX2 (16%) and no expression of ACRBP. Quantitative real-time PCR demonstrated PRAME and CTAG2 transcripts in all eight samples: six tumors with high mRNA levels; two tumors with low mRNA levels. The gene expression of MAGEA3 was not detected in the majority of cases. In conclusion, myxoid and round-cell liposarcomas consistently express PRAME by immunohistochemistry as well as CTAG2 and PRAME by qualitative real-time PCR. This supports the use of cancer-testis antigen-targeted immunotherapy in the treatment of this malignancy.

Sperm protein 17 is an oncofetal antigen: a lesson from a murine model

Sperm protein 17 (Sp17) was originally identified in the flagellum of spermatozoa and subsequently included in the subfamily of tumor-associated antigens known as cancer-testes antigens (CTA). Sp17 has been associated with the motility and migratory capacity in tumor cells, representing a link between gene expression patterns in germinal and tumor cells of different histological origins. Here we review the relevance of Sp17 expression in the mouse embryo and cancerous tissues, and present additional data demonstrating Sp17 complex expression pattern in this murine model. The expression of Sp17 in embryonic as well as adult neoplastic cells, but not normal tissues, suggests this protein should be considered an "oncofetal antigen." Further investigations are necessary to elucidate the mechanisms and functional significance of Sp17 aberrant expression in human adult cells and its implication in the pathobiology of cancer.

Development of a novel, quantitative protein microarray platform for the multiplexed serological analysis of autoantibodies to cancer-testis antigens

The cancer-testis antigens are a group of unrelated proteins aberrantly expressed in various cancers in adult somatic tissues. This aberrant expression can trigger spontaneous immune responses, a phenomenon exploited for the development of disease markers and therapeutic vaccines. However, expression levels often vary amongst patients presenting the same cancer type, and these antigens are therefore unlikely to be individually viable as diagnostic or prognostic markers. Nevertheless, patterns of antigen expression may provide correlates of specific cancer types and disease progression. Herein, we describe the development of a novel, readily customizable cancer-testis antigen microarray platform together with robust bioinformatics tools, with which to quantify anti-cancer testis antigen autoantibody profiles in patient sera. By exploiting the high affinity between autoantibodies and tumor antigens, we achieved linearity of response and an autoantibody quantitation limit in the pg/mL range-equating to a million-fold serum dilution. By using oriented attachment of folded, recombinant antigens and a polyethylene glycol microarray surface coating, we attained minimal non-specific antibody binding. Unlike other proteomics methods, which typically use lower affinity interactions between monoclonal antibodies and tumor antigens for detection, the high sensitivity and specificity realized using our autoantibody-based approach may facilitate the development of better cancer biomarkers, as well as potentially enabling pre-symptomatic diagnosis. We illustrated the usage of our platform by monitoring the response of a melanoma patient cohort to an experimental therapeutic NY-ESO-1-based cancer vaccine; inter alia, we found evidence of determinant spreading in individual patients, as well as differential CT antigen expression and epitope usage.

Simultaneous cytoplasmic and nuclear protein expression of melanoma antigen-A family and NY-ESO-1 cancer-testis antigens represents an independent marker for poor survival in head and neck cancer

The prognosis of head and neck squamous cell carcinoma (HNSCC) patients remains poor. The identification of high-risk subgroups is needed for the development of custom-tailored therapies. The expression of cancer-testis antigens (CTAs) has been linked to a worse prognosis in other cancer types; however, their prognostic value in HNSCC is unclear because only few patients have been examined and data on CTA protein expression are sparse. A tissue microarray consisting of tumor samples from 453 HNSCC patients was evaluated for the expression of CTA proteins using immunohistochemistry. Frequency of expression and the subcellular expression pattern (nuclear, cytoplasmic, or both) was recorded. Protein expression of melanoma antigen (MAGE)-A family CTA, MAGE-C family CTA and NY-ESO-1 was found in approximately 30, 7 and 4% of tumors, respectively. The subcellular expression pattern in particular had a marked impact on the patients' prognosis. Median overall survival (OS) of patients with (i) simultaneous cytoplasmic and nuclear expression compared to (ii) either cytoplasmic or nuclear expression and (iii) negative patients was 23.0 versus 109.0 versus 102.5 months, for pan-MAGE (p < 0.0001), 46.6 versus 50.0 versus 109.0 for MAGE-A3/A4 (p = 0.0074) and 13.3 versus 50.0 versus 100.2 months for NY-ESO-1 (p = 0.0019). By multivariate analysis, these factors were confirmed as independent markers for poor survival. HNSCC patients showing protein expression of MAGE-A family members or NY-ESO-1 represent a subgroup with an extraordinarily poor survival. The development of immunotherapeutic strategies targeting these CTA may, therefore, be a promising approach to improve the outcome of HNSCC patients.

Immunological responses to a multi-peptide vaccine targeting cancer-testis antigens and VEGFRs in advanced pancreatic cancer patients

The prognosis of patients with advanced pancreatic cancer is extremely poor and there are only a few standard treatments. Here, we report the results of a Phase I clinical trial to investigate the safety, immunostimulatory effects, and antineoplastic activity of a multi-target vaccine composed of four distinct peptides derived from cancer-testis (CT) antigens and vascular endothelial growth factor receptors (VEGFRs). Nine patients with unresectable, advanced pancreatic cancer who were refractory to standard chemotherapy were enrolled. Each patient was vaccinated with HLA-A*2402-restricted peptides derived from the CT antigens kinesin family member 20A (KIF20A) and cell division cycle-associated 1 (CDCA1) as well as from VEGFR1 and VEGFR2 subcutaneously once a week, and disease progression was evaluated up to 6 mo later. Adverse events were assessed using the Common Terminology Criteria for Adverse Events v. 3.0. Immunological responses were monitored by ELISPOT assays and flow cytometry based on peptide-specific dextramers. The clinical outcomes that were measured were tumor response, progression-free survival (PFS) and overall survival (OS). In general, the multi-peptide vaccine was well-tolerated, and no grade 3 or 4 adverse events were observed upon vaccination. Peptide-specific T-cell responses were detected in all 9 patients, and clinical benefits were observed in four of them. Median PFS and OS were 90 and 207 d, respectively. The elicitation of multiple and robust peptide-specific T-cell responses as well as the status of host lymphocytes may be useful prognostic factors among patients with advanced pancreatic cancer treated with peptide-based anticancer vaccines.

Sperm protein 17, MAGE-C1 and NY-ESO-1 in hepatocellular carcinoma: expression frequency and their correlation with clinical parameters

This study is dedicated to investigate the expression patterns of sperm protein 17 (Sp17), melanoma-specific antigen (MAGE)-C1 and New York esophageal squamous cell carcinoma-1 (NY-ESO-1), to explore the correlation between these cancer-testis antigens and clinical parameters, and to evaluate their values in diagnosis and differentiation of hepatocellular carcinoma.

METHODS

Immunohistochemical staining was performed in 45 paraffin-embedded hepatocellular carcinoma specimens. 45 normal peripheral hepatic tissues collected from adjacent non-cancerous areas were used as controls.

RESULTS

Positive results of immunohistostaining were obtained in 16 (35.6%), 7 (15.6%) and 36 (80.0%) samples using MAGE-C1, NY-ESO-1 and Sp17 antibodies, respectively. The immunoreactivity of Sp17 was also found in 7 (14.0%) control samples. A statistical correlation between the frequency of Sp17 expression and tumor differentiation grade in hepatocellular carcinoma was confirmed.

CONCLUSIONS

Sp17 is highly expressed in hepatocellular carcinoma cells. The frequency of Sp17 expression is closely related to the pathologic differentiation in hepatocellular carcinoma.

The C-terminal common to group 3 POTES (CtG3P): a newly discovered nucleolar marker associated with malignant progression and metastasis

A gene family expressed in prostate, ovary, testis and placenta (POTEs) is newly defined and primate-specific. POTE genes have 13 paralogs, which are dispersed in 8 chromosomes and divided into three groups. The proteins encoded by these genes contain three domains: An N-terminal, ankyrin repeats and a C-terminus. Previous studies suggest that POTE proteins are localized in the inner aspect of cellular membrane and are considered as cancer-testis antigens, because they expressed widely in cancers, but in limited benign tissues. In this study, we will study the subcellular distribution of all POTE proteins and their associations with the progress and metastasis of malignancies. By performing Immunohistochemistry, Immunocytochemistry and immunofluorescence assay on tissue microarray slides containing tissues with different pathology and origins or on cell lines, we found that the epitopes of N- and C-terminals of all detected POTEs were widely expressed in benign and malignant tissues. Among these epitopes, C-terminal common to group 3 POTEs (CtG3P) was the only portion localized in nucleoli. The nucleolar IHC scores for CtG3P was lowest in benign tissues (4.47 ± 3.43), significantly higher in localized malignancies (5.32 ± 3.36, p = 3.63E-02), and highest in metastatic malignancies (7.90 ± 2.29, p = 8.13E-12). The CtG3P was better in differentiation of benign from malignant changes, and/or in differentiation of localized from metastatic cancers as compared with Ki-67 and AgNORs. In addition, transient transfection of siRNA against mRNA of group 3 POTEs influences the growth and survival of MCF-7 cells in vitro in a dose dependent manner.

MAGE-A1, MAGE-A3, and NY-ESO-1 can be upregulated on neuroblastoma cells to facilitate cytotoxic T lymphocyte-mediated tumor cell killing

Approximately half of patients with stage IV neuroblastoma are expected to relapse despite current therapy, and when this occurs, there is little likelihood of achieving a cure. Very few clinical trials have been conducted to determine whether cellular immune responses could be harnessed to fight this tumor, largely because potential tumor antigens for cytotoxic T lymphocytes (CTL) are limited. MAGE-A1, MAGE-A3, and NY-ESO-1 are cancer-testis (CT) antigens expressed on a number of malignant solid tumors, including neuroblastoma, but many tumor cell lines down-regulate the expression of CT antigens as well as major histocompatibility (MHC) antigens, precluding recognition by antigen-specific T cells. If expression of cancer antigens on neuroblastoma could be enhanced pharmacologically, CT antigen-specific immunotherapy could be considered for this tumor. We have demonstrated that the expression of MAGE-A1, MAGE-A3, and NY-ESO-1 can be upregulated on neuroblastoma cells following exposure to pharmacologic levels of the demethylating agent 5-aza-2'-deoxycytidine (decitabine, DAC). Expression of NY-ESO-1, MAGE-A1, or MAGE-A3 was induced in 10/10 neuroblastoma cell lines after 5 days of exposure to DAC. Culture of neuroblastoma cell lines with IFN-γ was also associated with an increased expression of either MHC Class I or II by cytofluorometry, as reported by other groups. MAGE-A1, MAGE-A3, and NY-ESO-1-specific CTL were cultured from volunteer donors by stimulating peripheral blood mononuclear cells with dendritic cells pulsed with overlapping peptide mixes derived from full-length proteins, and these CTL preferentially lysed HLA partially matched, DAC-treated neuroblastoma and glioblastoma cell lines. These studies show that demethylating chemotherapy can be combined with IFN-γ to increase the expression of CT antigens and MHC molecules on neuroblastoma cells, and pre-treatment with these agents makes tumor cell lines more susceptible to CTL-mediated killing. These data provide a basis to consider the use of demethylating chemotherapy in neuroblastoma patients, in conjunction with immune therapies that facilitate the expansion of CT antigen-specific CTL.

Treatment of ovarian cancer cell lines with 5-aza-2'-deoxycytidine upregulates the expression of cancer-testis antigens and class I major histocompatibility complex-encoded molecules

PURPOSE

To test the hypothesis that decrease in DNA methylation will increase the expression of cancer-testis antigens (CTA) and class I major histocompatibility complex (MHC)-encoded molecules by ovarian cancer cells, and thus increase the ability of these cells to be recognized by antigen-reactive CD8(+) T cells.

METHODS

Human ovarian cancer cell lines were cultured in the presence or absence of varying concentrations of the DNA demethylating agent 5-aza-2'-deoxycytidine (DAC) for 3-7 days. The expression levels of 12 CTA genes were measured using the polymerase chain reaction. The protein expression levels of class I MHC molecules and MAGE-A1 were measured by flow cytometry. T cell reactivity was determined using interferon-gamma ELISpot analysis.

RESULTS

DAC treatment of ovarian cancer cell lines increased the expression of 11 of 12 CTA genes tested including MAGE-A1, MAGE-A3, MAGE-A4, MAGE-A6, MAGE-A10, MAGE-A12, NY-ESO-1, TAG-1, TAG-2a, TAG-2b, and TAG-2c. In contrast, DAC treatment decreased the already low expression of the MAGE-A2 gene by ovarian cancer cells, a finding not previously observed in cancers of any histological type. DAC treatment increases the expression of class I MHC molecules by the cells. These effects were time-dependent over a 7-day interval, and were dose-dependent up to 1-3 microM for CTA and up to 10 microM for class I MHC molecules. Each cell line tested had a unique pattern of gene upregulation after exposure to DAC. The enhanced expression levels increased the recognition of 2 of 3 antigens recognized by antigen-reactive CD8(+) T cells.

CONCLUSIONS

These results demonstrate the potential utility of combining DAC therapy with vaccine therapy in an attempt to induce the expression of antigens targeted by the vaccine, but they also demonstrate that care must be taken to target inducible antigens.

A potential role for epigenetic modulatory drugs in the enhancement of cancer/germ-line antigen vaccine efficacy

The discovery of epigenetic silencing as a key mechanism of tumor suppressor gene inactivation in human cancer has led to great interest in utilizing epigenetic modulatory drugs as cancer therapeutics. It is less appreciated that medically important tumor-associated antigens, particularly the Cancer Testis or Cancer/Germ-line family of antigens (CG antigens), which are being actively tested as cancer vaccine targets, are epigenetically activated in many human cancers. However, a major limitation to the therapeutic value of CG antigen-directed vaccines is the limited and heterogeneous expression of CG antigens in tumors. Recent work has begun to dissect the specific epigenetic mechanisms controlling differential expression of CG antigen genes in human cancers. From a clinical perspective, convincing data indicate that epigenetic modulatory agents, including DNA methyltransferase (DNMT) and histone deacetylase (HDAC) inhibitors, robustly promote the expression of CG antigens, as well as class I major histocompatibility complex (MHC I) and other immune costimulatory molecules, in tumors. Importantly, the effects of these agents on CG antigen gene expression often show marked specificity for tumor cells as compared to normal cells. Taken together, these data encourage clinical evaluation of combination therapies involving epigenetic modulatory drugs and CG antigen-directed tumor vaccines for the treatment of human malignancies.

Immunotherapy of myeloid leukaemia

The treatment of myeloid leukaemia has progressed in recent years with the advent of donor leukocyte infusions (DLI), haemopoietic stem cell transplants (HSCTs) and targeted therapies. However, relapse has a high associated morbidity rate and a method for removing diseased cells in first remission, when a minimal residual disease state is achieved and tumour load is low, has the potential to extend remission times and prevent relapse especially when used in combination with conventional treatments. Acute myeloid leukaemia (AML) and myelodysplastic syndrome (MDS) are heterogeneous diseases which lack one common molecular target while chronic myeloid leukaemia (CML) patients have experienced prolonged remissions through the use of targeted therapies which remove BCR-ABL(+) cells effectively in early chronic phase. However, escape mutants have arisen and this therapy has little effectivity in the late chronic phase. Here we review the immune therapies which are close to or in clinical trials for the myeloid leukaemias and describe their potential advantages and disadvantages.

Leukemia associated antigens: their dual role as biomarkers and immunotherapeutic targets for acute myeloid leukemia

Leukemia associated antigens (LAAs) are being increasingly identified by methods such as cytotoxic T-lymphocyte (CTL) cloning, serological analysis of recombinant cDNA expression libraries (SEREX) and mass spectrometry (MS). In additional, large scale screening techniques such as microarray, single nucleotide polymorphisms (SNPs), serial analysis of gene expression (SAGE) and 2-dimensional gel electrophoresis (2-DE) have expanded our understanding of the role that tumor antigens play in the biological processes which are perturbed in acute myeloid leukemia (AML). It has become increasingly apparent that these antigens play a dual role, not only as targets for immunotherapy, but also as biomarkers of disease state, stage, response to treatment and survival. We need biomarkers to enable the identification of the patients who are most likely to benefit from specific treatments (conventional and/or novel) and to help clinicians and scientists improve clinical end points and treatment design. Here we describe the LAAs identified in AML, to date, which have already been shown to play a dual role as biomarkers of AML disease.

Antitumor monoclonal antibodies enhance cross-presentation ofcCellular antigens and the generation of myeloma-specific killer T cells by dendritic cells

The mechanism of antitumor effect of monoclonal antibodies (mAbs) is not fully understood. Here we show that coating myeloma cells with anti-syndecan-1 antibody promotes cross-presentation of cellular antigens by dendritic cells (DCs) to autologous T cells from healthy donors. The tumor cells treated with anti-syndecan-1 or isotype-matched control antibody were fed to HLA-mismatched monocyte-derived immature DCs. Tumor cell-loaded mature DCs induced a strong CD8(+) T cell response that was specific for the cancer-testis (C-T) antigens expressed in the tumor. The CD8(+) T cells killed peptide-pulsed targets, as well as myeloma tumor cells. Importantly, mAbs-coated tumor-loaded DCs were consistently superior to DCs loaded with peptides or dying cells for eliciting tumor-specific killer T cells. This enhanced cross-presentation was not due to enhanced tumor cell uptake or to DC maturation. When mixtures of NY-Eso-1-positive and -negative myeloma cells were captured by DCs, the anti-syndecan-1 antibody had to be on the NY-Eso-1-positive cells to elicit NY-Eso-1-specific response. Cross-presentation was inhibited by pretreatment of DCs with Fc gamma receptor blocking antibodies. Targeting of mAb-coated tumors to DCs may contribute to the efficacy of tumor-reactive mAb and offers a new strategy for immunotherapy.