The MAGE cancer-testis antigens (CTA) are attractive candidates for immunotherapy. The aim of this study was to determine the frequency of expression, humoral immunity and prognostic significance of MAGE CTA in human epithelial ovarian cancer (EOC). mRNA or protein expression frequencies were determined for MAGE-A1, -A3, -A4, -A10 and -C1 (CT7) in tissue samples obtained from 400 patients with EOC. The presence of autologous antibodies against the MAGE antigens was determined from 285 serum samples. The relationships between MAGE expression, humoral immunity to MAGE antigens, and clinico-pathologic characteristics were studied. The individual frequencies of expression were as follows: A1: 15% (42/281), A3: 36% (131/390), A4: 47% (186/399), A10: 52% (204/395), C1: 16% (42/267). Strong concordant expression was noted with MAGE-A1:–A4, MAGE-A1:–C1 and MAGE-A4:–A10 (p<0.0005). Expression of MAGE-A1 or -A10 antigens resulted in poor progression free survival (PFS) (OR 1.44, CI 1.01–2.04, p = 0.044 and OR 1.3, CI 1.03–1.64, p = 0.03, respectively); whereas, MAGE-C1 expression was associated with improved PFS (OR 0.62, CI 0.42–0.92, p = 0.016). The improved PFS observed for MAGE-C1 expression, was diminished by co-expression of MAGE-A1 or -A10. Spontaneous humoral immunity to the MAGE antigens was present in 9% (27/285) of patients, and this predicted poor overall survival (log-rank test p = 0.0137). These findings indicate that MAGE-A1, MAGE-A4, MAGE-A3, and MAGE-A10 are priority attractive targets for polyvalent immunotherapy in ovarian cancer patients.

Epithelial ovarian cancer (EOC) is typically diagnosed at advanced stages, and is associated with a high relapse rate. Patients in remission are ideal candidates for immunotherapy aimed at cure or prolonging disease-free periods. However, immunosuppressive pathways in the tumor microenvironment are obstacles to durable anti-tumor immunity. In a metastatic syngeneic mouse model of EOC, immunosuppressive macrophages and myeloid-derived suppressor cells (MDSCs) accumulate in the local tumor environment. In addition, resident peritoneal macrophages from non-tumor-bearing mice were highly immunosuppressive, abrogating stimulated T cell proliferation in a cell contact-dependent manner. Immunization with microparticles containing TLR9 and NOD-2 ligands (MIS416) significantly prolonged survival in tumor-bearing mice. The strategy of MIS416 immunization followed by anti-CD11b administration further delayed tumor progression, thereby establishing the proof of principle that myeloid depletion can enhance vaccine efficacy. In patients with advanced EOC, ascites analysis showed substantial heterogeneity in the relative proportions of myeloid subsets and their immunosuppressive properties. Together, these findings point to immunosuppressive myeloid cells in the EOC microenvironment as targets to enhance vaccination. Further studies of myeloid cell accumulation and functional phenotypes in the EOC microenvironment may identify patients who are likely to benefit from vaccination combined with approaches that deplete tumor-associated myeloid cells.

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Objectives The differential metabolic phenotype observed between malignant and non-transformed cells may constitute a biochemical basis for therapeutic intervention. Increased glucose uptake is one of the major metabolic changes found in malignant tumors, a process that is mediated by glucose transporters such as Glut1. Cellular growth can be regulated by mTOR in response to the nutrient milieu. In this study, we sought to determine if endometrial carcinoma cells express Glut1 and mTOR, and if inhibition of these factors is cytotoxic to endometrial carcinoma cells in vitro. Methods Expression of Glut1, pAkt, and pmTOR was assessed in tissue microarrays constructed from 42 type I and 34 type II endometrial tumors by immunohistochemistry, and in a panel of endometrial carcinoma cell lines. Representative endometrial carcinoma cells with wild type or mutant endogenous PTEN were treated with the glucose analog 2-deoxyglucose (2-DG) and rapamycin, an mTOR inhibitor or cisplatin. Inhibition of cell growth and mechanism of cell death was determined. Results Glut1, pAkt, and pmTOR were expressed strongly in both types I and II endometrial carcinoma. 2-DG and rapamycin induced apoptotic cell death in type I endometrial carcinoma cells, and profound growth inhibition and cytostasis in type II endometrial carcinoma cells. Conclusions Glut1, pAkt, and pmTOR are overexpressed in endometrial carcinomas. Distinct alterations in the phosphatidylinositol 3′-kinase (PI3K) pathway upstream of mTOR, such as pAkt, may identify endometrial carcinoma patients who may benefit from adjuvant treatment with mTOR inhibitors and/or glucose analogs.

SEREX has proven to be a powerful method that takes advantage of the presence of spontaneous humoral immune response in some cancer patients. In this study, immunoscreening of normal testis and two ovarian cancer cell line cDNA expression libraries with sera from ovarian cancer patients led to the isolation of 75 independent antigens, designated KP-OVA-1 through KP-OVA-75. Of these, RT-PCR showed KP-OVA-52 to be expressed strongly in normal testis, in ovarian cancer cell lines (3/9) and in ovarian cancer tissues (1/17). The expression of KP-OVA-52 in cancer cells is also induced by the demethylating agent 5-aza-2′-deoxycytidine (ADC). To test immunogenicity, we used the Serum Antibody Detection Assay (SADA) to analyze anti-IgG antibodies against the 75 antigens that were initially isolated by SEREX. Four of the 75 antigens (KP-OVA-25, KP-OVA-35, KP-OVA-68 and KP-OVA-73) reacted exclusively with sera from cancer patients. However, KP-OVA-52 reacted with 1 of 20 ovarian cancer sera. These data suggest that the KP-OVA-52 can be considered a novel CT antigen that is regulated by DNA methylation.