Expression and prognostic relevance of MAGE-C1/CT7 and MAGE-C2/CT10 in osteolytic lesions of patients with multiple myeloma

Mutational signatures and their association with survival and gene expression in urological carcinomas

Different sources of mutagenesis cause consistently identifiable patterns of mutations and mutational signatures that mirror the various carcinogenetic processes. We used publicly available data from the Cancer Genome Atlas to evaluate the associations between the activity of the mutational signatures and various survival endpoints in six types of urological cancers after adjusting for established prognostic factors. The predictive power of the signatures was evaluated with dynamic area under curve models. In addition, links between mutational signature activities and differences in gene expression patterns were analysed. APOBEC-related signature SBS2 was associated with improved overall survival (OS) and disease-specific survival (DSS) in bladder carcinomas in the multivariate analysis, while clock-like signature SBS1 predicted shortened DSS and progression-free interval (PFI) in clear cell renal cell carcinomas (ccRCC). In papillary renal cell carcinomas (pRCC), SBS45 was a predictor of improved outcomes, and APOBEC-related SBS13 was a predictor of worse outcomes. Gene expression analyses revealed various enriched pathways between the low- and high-signature groups. Interestingly, in both the ccRCC and pRCC cohorts, the genes of several members of the melanoma antigen (MAGE) family were highly upregulated in the signatures, which predicted poor outcomes, and downregulated in signatures, which were associated with improved survival. To summarize, SBS signatures provide substantial prognostic value compared with just the traditional prognostic factors in certain cancer types. APOBEC-related SBS2 and SBS13 seem to provide robust prognostic information for particular urological cancers, maybe driven by the expression of specific groups of genes, including the MAGE gene family.

JW. Multivariant Transcriptome Analysis Identifies Modules and Hub Genes Associated with Poor Outcomes in Newly Diagnosed Multiple Myeloma Patients

The molecular mechanisms underlying chemoresistance in some newly diagnosed multiple myeloma (MM) patients receiving standard therapies (lenalidomide, bortezomib, and dexamethasone) are poorly understood. Identifying clinically relevant gene networks associated with death due to MM may uncover novel mechanisms, drug targets, and prognostic biomarkers to improve the treatment of the disease. This study used data from the MMRF CoMMpass RNA-seq dataset (N = 270) for weighted gene co-expression network analysis (WGCNA), which identified 21 modules of co-expressed genes. Genes differentially expressed in patients with poor outcomes were assessed using two independent sample t-tests (dead and alive MM patients). The clinical performance of biomarker candidates was evaluated using overall survival via a log-rank Kaplan-Meier and ROC test. Four distinct modules (M10, M13, M15, and M20) were significantly correlated with MM vital status and differentially expressed between the dead (poor outcomes) and the alive MM patients within two years. The biological functions of modules positively correlated with death (M10, M13, and M20) were G-protein coupled receptor protein, cell-cell adhesion, cell cycle regulation genes, and cellular membrane fusion genes. In contrast, a negatively correlated module to MM mortality (M15) was the regulation of B-cell activation and lymphocyte differentiation. MM biomarkers CTAG2, MAGEA6, CCND2, NEK2, and E2F2 were co-expressed in positively correlated modules to MM vital status, which was associated with MM's lower overall survival.

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.

Novel Immunotherapeutic Agents for the Treatment of Multiple Myeloma

Multiple myeloma (MM) is a B-cell malignancy characterized by the abnormal proliferation of clonal plasma cells in the bone marrow leading to end-organ manifestations. Despite the advancement in the therapy and care of patients with MM, relapse and resistance to standard therapy remain significant. The development of immunotherapy as a treatment modality for many types of cancers has led investigators to explore its use in MM in order to elicit myeloma-targeted immune responses, especially given that immune dysregulation is an underlying feature in the pathogenesis and progression of MM. In this concise review, we discuss the different advances in the immune-based therapy of MM, from immunomodulation, vaccines, to monoclonal antibodies, checkpoint inhibitors, adoptive T-cell therapies, and future promising therapies under investigation.

MAGE genes: Prognostic indicators in AL amyloidosis patients

A high frequency of MAGE-CT (cancer testis) antigens are expressed in Multiple Myeloma (MM) patients; however, in other plasma cell dyscrasias, their potential function remains unclear. We measured the expression of MAGE-CT genes (MAGE-C1/CT7, MAGE-A3, MAGE-C2/CT10) in 105 newly diagnosed amyloid light-chain (AL) amyloidosis patients between June 2013 and January 2018 at Peking University People's Hospital using real-time quantitative polymerase chain reaction. In the newly diagnosed AL patients, the positive expression rates of patients with MAGE-C1/CT7, MAGE-C2/CT10 and MAGE-A3 were 83.8% (88/105), 56.71% (38/67) and 22.0% (13/59) respectively. There was no significant correlation between organ propensity and MAGE-CT gene expression. Changes in the MAGE-C1/CT7 levels were consistent with a therapeutic effect. The expression levels of MAGE-C1/CT7, MAGE-C2/CT10 and MAGE-A3 provide potentially effective clinical indicators for auxiliary diagnoses and monitoring treatment efficacy in AL amyloidosis patients.

Expression and prognostic relevance of MAGE-A3 and MAGE-C2 in non-small cell lung cancer

Melanoma-associated antigen (MAGE)-A3 and MAGE-C2 are antigens encoded by cancer-germline genes, and have been recognized as potential prognostic biomarkers and attractive targets for immunotherapy in multiple types of cancer. The present study aimed to analyze the clinicopathological significance of MAGE-A3/C2 expression in non-small cell lung cancer (NSCLC). The association between MAGE-A3/C2 mRNA and protein expression, and the pathological characteristics and overall survival of patients with NSCLC was analyzed. In addition, the functional role of MAGE-A3 in human NSCLC cell line A549 was examined in vitro. MAGE-A3/C2 mRNA expression was identified in 73% (151/206) and 53% (109/206) of patients with NSCLC, respectively. MAGE-A3/C2 protein expression was identified in 58% (44/76) and 53% (40/76) of NSCLC cases, respectively. MAGE-A3 mRNA expression was observed to be associated with smoking history, disease stage and lymph node metastasis. However, no association was identified between MAGE-C2 mRNA expression and the clinicopathological characteristics of patients with NSCLC. MAGE-A3/C2-positive patients had a poorer survival rate compared with MAGE-A3/C2-negative patients. Multivariate analysis identified that MAGE-A3 expression may serve as an independent marker of poor prognosis in patients with NSCLC. Downregulation of MAGE-A3 mRNA expression in A549 cells resulted in lower migration and colony formation rates, and a higher amount of epithelial marker and lower amount of mesenchymal marker expression compared with the control group. These results indicate that MAGE-A3 serves a role in NSCLC cell metastasis through the induction of epithelial-mesenchymal transition. In conclusion, MAGE-A3 may serve as a diagnostic and prognostic biomarker for patients with NSCLC, due to its association with tumor progression and poor clinical outcome.

The cancer/testis antigen MAGEC2 promotes amoeboid invasion of tumor cells by enhancing STAT3 signaling

The biological function of MAGEC2, a cancer/testis antigen highly expressed in various cancers, remains largely unknown. Here we demonstrate that expression of MAGEC2 induces rounded morphology and amoeboid-like movement of tumor cells in vitro and promotes tumor metastasis in vivo. The pro-metastasis effect of MAGEC2 was mediated by signal transducer and activator of transcription 3 (STAT3) activation. Mechanistically, MAGEC2 interacts with STAT3 and inhibits the polyubiquitination and proteasomal degradation of STAT3 in the nucleus of tumor cells, resulting in accumulation of phosphorylated STAT3 and enhanced transcriptional activity. Notably, expression levels of MAGEC2 and phosphorylated STAT3 are positively correlated and both are associated with incidence of metastasis in human hepatocellular carcinoma. This study not only reveals a previously unappreciated role of MAGEC2 in promoting tumor metastasis, but also identifies a new molecular mechanism by which MAGEC2 sustains hyperactivation of STAT3 in the nucleus of tumor cells. Thus, MAGEC2 may represent a new antitumor metastasis target for treatment of cancer.

Immunotherapy in Multiple Myeloma Using Cancer-Testis Antigens

Context:

Multiple myeloma (MM) is a B-cell malignancy characterized by monoclonal expansion of abnormal plasma cells in the bone marrow. It accounts for 10% of hematological malignancies. Although patients respond to a wide range of anticancer modalities, relapse occurs in a significant number of the cases. Immunotherapeutic approaches have been evolved to tackle this problem. Cancer-testis antigens CTAs as a group of tumor-associated antigens are appropriate targets for cancer immunotherapy as they have restricted expression pattern in normal tissues except for testis which is an immune-privileged site. Expression of these antigens has been assessed in different malignancies including MM.

Evidence Acquisition:

We performed a computerized search of the MEDLINE/PubMed databases with key words: multiple myeloma, cancer-testis antigen, and cancer stem cell and immunotherapy.

Results:

Several CTAs including NY-ESO-1, MAGE and GAGE family have been shown to be expressed in MM patients. Cellular and humoral immune responses against these antigens have been detected in MM patients.

Conclusions:

The frequent and high expression level of CTAs in MM patients shows that these antigens can be applied as cancer biomarkers as well as targets for immunotherapy in these patients.

Vaccination of multiple myeloma: Current strategies and future prospects

Tumor immunotherapy holds great promise in controlling multiple myeloma (MM) and may provide an alternative treatment modality to conventional chemotherapy for MM patients. For this reason, a major area of investigation is the development of cancer vaccines to generate myeloma-specific immunity. Several antigens that are able to induce specific T-cell responses are involved in different critical mechanisms for cell differentiation, inhibition of apoptosis, demethylation and proliferation. Strategies under development include infusion of vaccine-primed and ex vivo expanded/costimulated autologous T cells after high-dose melphalan, genetic engineering of autologous T cells with receptors for myeloma-specific epitopes, administration of dendritic cell/plasma cell fusions and administration expanded marrow-infiltrating lymphocytes. In addition, novel immunomodulatory drugs may synergize with immunotherapies. The task ahead is to evaluate these approaches in appropriate clinical settings, and to couple them with strategies to overcome mechanisms of immunoparesis as a means to induce more robust clinically significant immune responses.

Functional autoantibodies against SSX-2 and NY-ESO-1 in multiple myeloma patients after allogeneic stem cell transplantation

BACKGROUND

Multiple myeloma (MM) is the malignancy with the most frequent expression of the highly immunogenic cancer-testis antigens (CTA), and we have performed the first analysis of longitudinal expression, immunological properties, and fine specificity of CTA-specific antibody responses in MM.

METHODS

Frequency and characteristics of antibody responses against cancer-testis antigens MAGE-A3, NY-ESO-1, PRAME, and SSX-2 were analyzed using peripheral blood (N = 1094) and bone marrow (N = 200) plasma samples from 194 MM patients.

RESULTS

We found that antibody responses against CTA were surprisingly rare, only 2.6 and 3.1 % of patients evidenced NY-ESO-1- and SSX-2-specific antibodies, respectively. NY-ESO-1-specific responses were observed during disease progression, while anti-SSX-2 antibodies appeared after allogeneic stem cell transplantation and persisted during clinical remission. We found that NY-ESO-1- and SSX-2-specific antibodies were both capable of activating complement and increasing CTA uptake by antigen-presenting cells. SSX-2-specific antibodies were restricted to IgG3, NY-ESO-1 responses to IgG1 and IgG3. Remarkably, NY-ESO-1-positive sera recognized various non-contiguous regions, while SSX-2-specific responses were directed against a single 6mer epitope, SSX-2(85-90).

CONCLUSIONS

We conclude that primary autoantibodies against intracellular MM-specific tumor antigens SSX-2 and NY-ESO-1 are rare but functional. While their contribution to disease control still remains unclear, our data demonstrate their theoretic ability to affect cellular anti-tumor immunity by formation and uptake of mono- and polyvalent immune complexes.

MAGEC2, an epithelial-mesenchymal transition inducer, is associated with breast cancer metastasis

MAGEC2 is a member of melanoma antigen (MAGE) family of cancer-testis antigens and associated with tumor relapse and metastasis. Here, we investigated the expression of MAGEC2 in patients with breast cancer and its clinical effects with underlying mechanisms. The expression levels of MAGEC2 were compared between 420 invasive ductal carcinoma (IDC) and 120 ductal carcinoma in situ of the breast. Correlations between MAGEC2 expression and clinico-pathologic factors or survival of patients with IDC were analyzed. In addition, MAGEC2 expression levels in tumor tissues dissected from the primary focus and matched tumor-invaded axillary lymph nodes were analyzed in 8 breast cancer patients. The functional effects of MAGEC2 overexpression were assessed in vitro using scratch assay and transwell chamber assay. MAGEC2 expression was increased in metastatic breast cancer in comparison to the non-metastatic. MAGEC2 expression was significantly associated with ER negative expression (P = 0.037), high tumor grade (P = 0.014) and stage (P = 0.002), high incidence of axillary lymph node metastasis (P = 0.013), and distant metastasis (P = 0.004). Patients with tumor with MAGEC2 positive expression have a worse prognosis and a shorter metastasis free interval. Multivariate analyses showed that MAGEC2 expression was an independent risk factor for patient overall survival and metastasis-free survival. Breast cancer cells that overexpressed MAGEC2 had stronger migratory and invasive potential than control-treated cells. Epithelial markers (E-cadherin and cytokeratin) were down-regulated in MAGEC2-overexpressing cells compared to controls, whereas mesenchymal markers (vimentin and fibronectin) were upregulated. Our results indicate that MAGEC2 has a role in breast cancer metastasis through inducing epithelial-mesenchymal transition. In addition, MAGEC2 is a novel independent poor prognostic factor in patients with IDC. Thus, targeting MAGEC2 may provide a novel therapeutic strategy for breast cancer treatment.

The clinical value of the quantitative detection of four cancer-testis antigen genes in multiple myeloma

BACKGROUND

Cancer-testis (CT) antigen genes might promote the progression of multiple myeloma (MM). CT antigens may act as diagnostic and prognostic markers in MM, but their expression levels and clinical implications in this disease are not fully understood. This study measured the expression levels of four CT antigen genes in Chinese patients with MM and explored their clinical implications.

METHODS

Real-time quantitative polymerase chain reaction (qPCR) was used to quantify the expression of MAGE-C1/CT7, MAGE-A3, MAGE-C2/CT10 and SSX-2 mRNA in 256 bone marrow samples from 144 MM patients.

RESULTS

In the newly diagnosed patients, the positive expression rates were 88.5% for MAGE-C1/CT7, 82.1% for MAGE-C2/CT10, 76.9% for MAGE-A3 and 25.6% for SSX-2. The expression levels and the number of co-expressed CT antigens correlated significantly with several clinical indicators, including the percentage of plasma cells infiltrating the bone marrow, abnormal chromosome karyotypes and the clinical course.

CONCLUSION

MAGE-C1/CT7, MAGE-A3, MAGE-C2/CT10 and SSX-2 expression levels provide potentially effective clinical indicators for the auxiliary diagnosis and monitoring of treatment efficacy in MM.

Gene expression profiling using nanostring digital RNA counting to identify potential target antigens for melanoma immunotherapy

PURPOSE

The success of immunotherapy for the treatment of metastatic cancer is contingent on the identification of appropriate target antigens. Potential targets must be expressed on tumors but show restricted expression on normal tissues. To maximize patient eligibility, ideal target antigens should be expressed on a high percentage of tumors within a histology and, potentially, in multiple different malignancies.

DESIGN

A Nanostring probeset was designed containing 97 genes, 72 of which are considered potential candidate genes for immunotherapy. Five established melanoma cell lines, 59 resected metastatic melanoma tumors, and 31 normal tissue samples were profiled and analyzed using Nanostring technology.

RESULTS

Of the 72 potential target genes, 33 were overexpressed in more than 20% of studied melanoma tumor samples. Twenty of those genes were identified as differentially expressed between normal tissues and tumor samples by ANOVA analysis. Analysis of normal tissue gene expression identified seven genes with limited normal tissue expression that warrant further consideration as potential immunotherapy target antigens: CSAG2, MAGEA3, MAGEC2, IL13RA2, PRAME, CSPG4, and SOX10. These genes were highly overexpressed on a large percentage of the studied tumor samples, with expression in a limited number of normal tissue samples at much lower levels.

CONCLUSION

The application of Nanostring RNA counting technology was used to directly quantitate the gene expression levels of multiple potential tumor antigens. Analysis of cell lines, 59 tumors, and normal tissues identified seven potential immunotherapy targets for the treatment of melanoma that could increase the number of patients potentially eligible for adoptive immunotherapy.

Cytogenetics of extramedullary manifestations in multiple myeloma

Extramedullary disease in patients with multiple myeloma is a rare event, occurring mostly in advanced disease or relapse. Outcome is poor and prognostic factors predicting the development of extramedullary disease have not been defined. We investigated cytogenetic alterations of myeloma cells in different extramedullary manifestations by adapting the fluorescence in situ hybridization (FISH) technique in combination with cytoplasmic immunoglobulin staining to study the cytogenetics of plasma cell tumours on paraffin embedded material. Thirty six patients were investigated: 19 with extramedullary disease, 11 with skeletal extramedullary disease and six with solitary extramedullary plasmacytoma. The first two groups showed the following results: del(17p13) 32% vs. 27%, del(13q14) 35% vs. 27%, MYC-overrepresentation 28% vs. 18% and t(4;14) 37% vs. 18%. We detected an overall higher incidence of del(17p13) in both groups compared to data from bone marrow samples of multiple myeloma reported to date (range 7-16%). The solitary extramedullary plasmacytomas presented overall less cytogenetic aberrations than the other groups. Most important, three patients with extramedullary disease and one with skeletal extramedullary disease presented different FISH findings in the extramedullary tumour compared to their bone marrow plasma cells. del(17p13), occurring additional in three of four cases, seems a strong marker for extramedullary progression of myeloma.

Heterogeneous expression of CT10, CT45 and GAGE7 antigens and their prognostic significance in human breast carcinoma

OBJECTIVE

The goal of this study was to detect the intertumoral heterogeneity of CT10, CT45 and GAGE7 expression and further to analyze their prognostic value.

METHODS

The intertumoral heterogeneity of three cancer/testis antigens was examined by immunohistochemistry using 120 samples from patients with infiltrating ductal breast carcinoma. The expression patterns were classified and correlated with the clinicopathologic variables and outcome of the patients.

RESULTS

CT10 showed punctate, focal and diffuse expression patterns according to the characteristic of its distribution. CT45 showed cytoplasmic, nuclear or combined cytoplasmic and nuclear expression patterns according to its subcellular location. GAGE7 exhibited nuclear, cytoplasmic and nucleolar expression patterns. Three cancer/testis antigens were also observed coordinately expressed in infiltrating ductal breast carcinoma. Patients with tumors with CT10 expression was significantly correlated with nodal metastases (P < 0.001) and advanced clinical stages (P = 0.001). Patients with tumors with cytoplasmic GAGE7 and with the expression of two or more cancer/testis antigens were significantly correlated with advanced clinical stages (P = 0.001 and P = 0.030). No significant difference was identified between the different expression patterns of CT45 and clinicopathologic variables. In addition, Kaplan-Meier analysis revealed that diffuse CT10 expression and coexpression of three cancer/testis antigens were related to the poor prognosis of patients with infiltrating ductal breast carcinoma.

CONCLUSIONS

Diffuse CT10 expression and the coexpression of three cancer/testis antigens can be used as a biomarker to distinguish patients with a poorer outcome of the breast carcinoma. Our finding may provide useful data for evaluating the prognosis of this disease and improving the effectiveness of therapeutic application based on the three cancer/testis antigens.

MAGE-C1/CT7 and MAGE-C2/CT10 are frequently expressed in multiple myeloma and can be explored in combined immunotherapy for this malignancy

The exact function of MAGE-C1/CT7 and MAGE-C2/CT10 is not yet understood in multiple myeloma (MM). However, the homologs MAGE-C1/CT7 and MAGE-C2/CT10 genes encode highly immunogeneic cancer/testis antigens (CTAs) and can be potential targets for T cell-based immunotherapy. MAGE-C1/CT7 and MAGE-C2/CT10 mRNA expression were investigated in MM patients, solitary plasmacytomas, monoclonal gammopathies of undetermined significance (MGUS) and bone marrow (BM) aspirates from healthy donors by RT-PCR. MAGE-C1/CT7 and MAGE-C1/CT10 were expressed in 67 and 59 % of the 46 MM analyzed patients. At least one of the genes was expressed in 76 % of MM cases. Solitary plasmacytoma also showed MAGE-C1/CT7 and MAGE-C2/CT10 expression. MAGE-C1/CT7 and MAGE-C2/CT10 were not expressed in normal BM samples, showing restricted expression of these CTA genes in MM, solitary plasmacytoma and MGUS. In the present study, we found high expression of the homologs MAGE-C1/CT7 and MAGE-C2/CT10 in monoclonal gammopathies and speculate whether these genes might represent a valuable therapeutic option for myeloma, in particular for combined immunotherapy.

Novel strategies for immunotherapy in multiple myeloma: previous experience and future directions

Multiple myeloma (MM) is a life-threatening haematological malignancy for which standard therapy is inadequate. Autologous stem cell transplantation is a relatively effective treatment, but residual malignant sites may cause relapse. Allogeneic transplantation may result in durable responses due to antitumour immunity mediated by donor lymphocytes. However, morbidity and mortality related to graft-versus-host disease remain a challenge. Recent advances in understanding the interaction between the immune system of the patient and the malignant cells are influencing the design of clinically more efficient study protocols for MM. Cellular immunotherapy using specific antigen-presenting cells (APCs), to overcome aspects of immune incompetence in MM patients, has received great attention, and numerous clinical trials have evaluated the potential for dendritic cell (DC) vaccines as a novel immunotherapeutic approach. This paper will summarize the data investigating aspects of immunity concerning MM, immunotherapy for patients with MM, and strategies, on the way, to target the plasma cell more selectively. We also include the MM antigens and their specific antibodies that are of potential use for MM humoral immunotherapy, because they have demonstrated the most promising preclinical results.

Immunogenic targets for specific immunotherapy in multiple myeloma

Multiple myeloma remains an incurable disease although the prognosis has been improved by novel therapeutics and agents recently. Relapse occurs in the majority of patients and becomes fatal finally. Immunotherapy might be a powerful intervention to maintain a long-lasting control of minimal residual disease or to even eradicate disseminated tumor cells. Several tumor-associated antigens have been identified in patients with multiple myeloma. These antigens are expressed in a tumor-specific or tumor-restricted pattern, are able to elicit immune response, and thus could serve as targets for immunotherapy. This review discusses immunogenic antigens with therapeutic potential for multiple myeloma.

Cancer/Testis Antigen MAGE-C1/CT7: new target for multiple myeloma therapy

Cancer/Testis Antigens (CTAs) are a promising class of tumor antigens that have a limited expression in somatic tissues (testis, ovary, fetal, and placental cells). Aberrant expression of CTAs in cancer cells may lead to abnormal chromosome segregation and aneuploidy. CTAs are regulated by epigenetic mechanisms (DNA methylation and acetylation of histones) and are attractive targets for immunotherapy in cancer because the gonads are immune privileged organs and anti-CTA immune response can be tumor-specific. Multiple myeloma (MM) is an incurable hematological malignancy, and several CTAs have been detected in many MM cell lines and patients. Among CTAs expressed in MM we must highlight the MAGE-C1/CT7 located on the X chromosome and expressed specificity in the malignant plasma cells. MAGE-C1/CT7 seems to be related to disease progression and functional studies suggests that this CTA might play a role in cell cycle and mainly in survival of malignant plasma cells, protecting myeloma cells against spontaneous as well as drug-induced apoptosis.

Soluble factors secreted by glioblastoma cell lines facilitate recruitment, survival, and expansion of regulatory T cells: implications for immunotherapy

In patients with glioma, the tumor microenvironment can significantly impact pro-inflammatory immune cell functions. However, the mechanisms by which this occurs are poorly defined. Because immunosuppressive regulatory T cells (Treg) are over represented in the tumor microenvironment compared with peripheral blood, we hypothesized that the tumor may have an effect on Treg survival, migration, expansion, and/or induction of a regulatory phenotype from non-Treg conventional CD4+ T cells. We defined the impact of soluble factors produced by tumor cells on Treg from healthy patients in vitro to determine mechanisms by which gliomas influence T cell populations. We found that tumor-derived soluble factors allowed for preferential proliferation and increased chemotaxis of Treg, compared with conventional T cells, indicating that these mechanisms may contribute to the increased Treg in the tumor microenvironment. Conventional T cells also exhibited a significantly increased expression of pro-apoptotic transcripts in the presence of tumor-derived factors, indicating that survival of Treg in the tumor site is driven by exposure to soluble factors produced by the tumor. Together, these data suggest that tumor burden may induce increased Treg infiltration, proliferation, and survival, negating productive anti-tumor immune responses in patients treated with immunotherapies. Collectively, our data indicate that several mechanisms of Treg recruitment and retention in the tumor microenvironment exist and may need to be addressed to improve the specificity of immunotherapies seeking to eliminate Treg in patients with glioma.

Cancer-testis antigen expression and its epigenetic modulation in acute myeloid leukemia

Cancer-testis antigens (CTA) represent attractive targets for tumor immunotherapy. However, a broad picture of CTA expression in acute myeloid leukemia (AML) is missing. CTA expression was analyzed in normal bone marrow (BM) as well as in AML cell lines before and after treatment with demethylating agents and/or histone acetylase inhibitors. Presence of selected CTA with a strictly tumor-restricted expression was then determined in samples of patients with AML before and after demethylating therapy. Screening AML cell lines for the expression of 20 CTA, we identified six genes (MAGE-A3, PRAME, ROPN1, SCP-1, SLLP1, and SPO11) with an AML-restricted expression. Analyzing the expression of these CTA in blast-containing samples from AML patients (N = 64), we found all samples to be negative for MAGE-A3 and SPO11 while a minority of patients expressed ROPN1 (1.6%), SCP-1 (3.1%), or SLLP1 (9.4%). The only CTA expressed in substantial proportion of patients (53.1%) was PRAME. Following demethylating treatment with 5'-aza-2'-deoxycytidine, we observed an increased or de novo expression of CTA, in particular of SSX-2, in AML cell lines. In AML patients, we detected increased expression of PRAME and induction of SSX-2 after demethylating therapy with 5-azacytidine. With the exception of PRAME, CTA are mostly absent from AML blasts. However, demethylating treatment induces strong expression of CTA, particularly of SSX-2, in vitro and in vivo. Therefore, we propose that CTA-specific immunotherapy for AML should preferentially target PRAME and/or should be combined with the application of demethylating agents opening the perspective for alternative targets like CTA SSX-2.

Cancer testis antigens in newly diagnosed and relapse multiple myeloma: prognostic markers and potential targets for immunotherapy

BACKGROUND

In multiple myeloma, expression of cancer testis antigens may provide prognostic markers and potential targets for immunotherapy. Expression at relapse has not yet been evaluated for a large panel of cancer testis antigens which can be classified by varying expression in normal tissue: restricted to testis, expressed in testis and brain and not restricted but selectively expressed in testis.

DESIGN AND METHODS

Evaluation of cancer testis antigen expression was made in newly diagnosed multiple myeloma cases (HOVON-65/GMMG-HD4 trial; n = 320) and in relapse cases (APEX, SUMMIT, CREST trials; n = 264). Presence of expression using Affymetrix GeneChips was determined for 123 cancer testis antigens. Of these 87 had a frequency of more than 5% in the newly diagnosed and relapsed patients, and were evaluated in detail.

RESULTS

Tissue restriction was known for 58 out of 87 cancer testis antigens. A significantly lower frequency of presence calls in the relapsed compared to newly diagnosed cases was found for 3 out of 13 testis restricted genes, 2 out of 7 testis/brain restricted genes, and 17 out of 38 testis selective genes. MAGEC1, MAGEB2 and SSX1 were the most frequent testis-restricted cancer testis antigens in both data sets. Multivariate analysis demonstrated that presence of MAGEA6 and CDCA1 were clearly associated with shorter progression free survival, and presence of MAGEA9 with shorter overall survival in the set of newly diagnosed cases. In the set of relapse cases, presence of CTAG2 was associated with shorter progression free survival and presence of SSX1 with shorter overall survival.

CONCLUSIONS

Relapsed multiple myeloma reveals extensive cancer testis antigen expression. Cancer testis antigens are confirmed as useful prognostic markers in newly diagnosed multiple myeloma patients and in relapsed multiple myeloma patients. The HOVON-65/GMMG-HD4 trial is registered under Dutch trial register n. NTR-213. CREST, SUMMIT and APEX trials were registered under ns. M34100-024, M34100-025 and NCT00049478/NCT00048230, respectively.