Identification of XAGE-1 isoforms: predominant expression of XAGE-1b in testis and tumors.

XAGE-1 is a cancer/testis (CT) antigen and has been shown to be immunogenic in lung cancer patients. Among 4 alternative splicing variants, XAGE-1a, b, c and d, XAGE-1b mRNA was dominantly expressed in cancer. In this study, we generated a XAGE-1b mAb, USO9-13. The B cell epitope recognized by the USO9-13 mAb was in the C-terminal region of the XAGE-1b protein and is also recognized by sera from patients with lung adenocarcinoma. Using USO9-13 and an anti-Flag mAb, we examined the translation products of the 4 transcripts. The XAGE-1a and b transcripts translated to the XAGE-1b protein. The XAGE-1c transcript possibly translated to 9- and 17-aa polypeptides. The XAGE-1d transcript translated to a protein consisting of 69 amino acids. Immunofluorescence analysis using USO9-13 mAb showed that the XAGE-1b protein is located in the nuclei of cells. Immunohistochemically, nuclear staining was heterogeneously observed in 25/47 lung adenocarcinomas, 1/12 hepatocellular carcinomas and 1/11 gastric cancers, but not in adjacent normal tissues. These findings suggested that XAGE-1b is a promising target molecule for a cancer vaccine against lung cancer.

Identification of DR9-restricted XAGE antigen on lung adenocarcinoma recognized by autologous CD4 T-cells.

We previously demonstrated a dominant IgG response against XAGE-1b antigen in a lung cancer patient by serological analysis of antigens by recombinant expression cloning (SEREX) analysis using a cDNA library from the autologous OU-LU-6 tumor cell line. In this study, we investigated recognition of XAGE-1b on OU-LU-6 tumor by the patient CD4-expressing tumor-infiltrating lymphocytes (CD4 TIL). The response of CD4 TIL obtained from malignant pleural effusion was determined against autologous OU-LU-6 tumor cells and XAGE-1b mRNA-transfected PHA-stimulated CD4 T-cells (T-APC) from healthy individuals sharing HLA-DR with the patient by performing IFNgamma secretion and ELISPOT assays. The patient CD4 TIL recognized OU-LU-6 in an HLA-DR-restricted manner and XAGE-1b mRNA-transfected T-APC derived from DRB1 *0901-sharing healthy donor (HD)1 and HD2, but not DRB1 *1101-sharing HD3 or HD4. Epitope analysis using 17 18-mer peptides with 12 overlapping amino acids revealed that the CD4 TIL recognized XAGE-1b 33-49. The findings suggest that the patient CD4 T-cells recognized the XAGE-1b 33-49-related epitope on autologous OU-LU-6 tumor cells in a manner restricted by DR *0901.

In vitro stimulation of CD8 and CD4 T cells by dendritic cells loaded with a complex of cholesterol-bearing hydrophobized pullulan and NY-ESO-1 protein: Identification of a new HLA-DR15-binding CD4 T-cell epitope.

PURPOSE: NY-ESO-1 belongs to a class of cancer/testis antigens and has been shown to be immunogenic in cancer patients. We synthesized a complex of cholesterol-bearing hydrophobized pullulan and NY-ESO-1 protein (CHP/ESO) and investigated the in vitro stimulation of CD8 and CD4 T cells from peripheral blood mononuclear cells in healthy donors with autologous CHP/ESO-loaded dendritic cells as antigen-presenting cells. EXPERIMENTAL DESIGN: In vitro stimulation of CD8 or CD4 T cells was determined by IFNgamma ELISPOT assays against autologous EBV-B cells infected with vaccinia/NY-ESO-1 recombinant virus or wild-type vaccinia virus as targets and by ELISA measuring secreted IFNgamma. RESULTS: NY-ESO-1-specific CD8 and CD4 T cells were induced. In a donor expressing HLA-A2, CD8 T cells stimulated with CHP/ESO-loaded dendritic cells recognized naturally processed NY-ESO-1(157-165), an HLA-A2-binding CD8 T cell epitope. NY-ESO-1 CD4 T cells were Th1-type. We identified a new HLA-DR15-binding CD4 T cell epitope, NY-ESO-1(37-50). CONCLUSIONS: These findings indicate that CHP/ESO is a promising polyvalent cancer vaccine targeting NY-ESO-1.

XAGE-1 expression in non-small cell lung cancer and antibody response in patients.

PURPOSE: XAGE-1 was originally identified by the search for PAGE/GAGE-related genes using expressed sequence tag database and was shown to exhibit characteristics of cancer/testis-like antigens. Four transcript variants XAGE-1a, XAGE-1b, XAGE-1c, and XAGE-1d have been identified thus far. We recently identified XAGE-1b as a dominant antigen recognized by sera from lung adenocarcinoma patients. We here investigated the mRNA expression of four XAGE-1 variants and XAGE-1 protein expression in non-small cell lung cancer (NSCLC). Humoral immune response to XAGE-1b was also evaluated in patients. EXPERIMENTAL DESIGN: Forty-nine NSCLC specimens were analyzed for the expression of four XAGE-1 transcript variants by conventional 30-cycle and real-time reverse transcription-PCR and XAGE-1 protein expression by immunohistochemistry. Sera from 74 patients were analyzed for XAGE-1b antibody production by ELISA and Western blot. RESULTS: XAGE-1b and XAGE-1d mRNA were detected in 15 and 6 of 49 lung cancer specimens, respectively. No XAGE-1a or XAGE-1c mRNA expression was observed. XAGE-1b mRNA expression was observed in 14 of 31 (45%) adenocarcinoma and 1 of 18 (6%) lung cancer with other histologic types. Immunohistochemical analysis using a XAGE-1 monoclonal antibody showed that 14 of 15 XAGE-1b mRNA-positive and 3 of 34 XAGE-1b mRNA-negative specimens expressed XAGE-1 protein. Seropositivity was observed in 5 of 56 patients with adenocarcinoma, whereas none of 18 patients with other histologic types produced XAGE-1b antibody. CONCLUSION: XAGE-1b is highly and strongly expressed in lung adenocarcinoma and immunogenic in patients, suggesting that XAGE-1b is a promising antigen for immunotherapy against lung adenocarcinoma.

Immunoscreening of a cDNA library from a lung cancer cell line using autologous patient serum: Identification of XAGE-1b as a dominant antigen and its immunogenicity in lung adenocarcinoma.

By serologic identification of antigens by recombinant expression cloning (SEREX) analysis using an autologous lung adenocarcinoma cell line, OU-LU-6, as a cDNA library source, we demonstrated that XAGE-1 was the dominant antigen recognized by serum from a patient. By immunoscreening, we obtained 38 positive cDNA clones consisting of 16 genes designated as OY-LC-1 to -OY-LC-16. OY-LC-1, represented by 18 clones, was identical to XAGE-1. OY-LC-2 to -16, represented by either a single or 2 clones, were identical to known genes shown to be ubiquitously expressed in various normal tissues. RT-PCR analysis showed that of 4 XAGE-1 transcripts-XAGE-1a, b, c and d-XAGE-1b was expressed in OU-LU-6 dominantly. Furthermore, XAGE-1b mRNA was expressed in 4 of 10 lung cancer tissues, whereas no expression was observed in normal tissues. Of 4 XAGE-1b mRNA positive cancer tissues, 3 were adenocarcinoma and one was poorly differentiated squamous cell carcinoma. Of 32 sera from lung cancer patients, 8 sera were reactive with the XAGE-1b product. Those 8 sera were from patients with adenocarcinoma. These findings indicated strong immunogenicity of XAGE-1b in lung adenocarcinoma and suggested its potential use as a target for vaccine-based immunotherapies.

A-kinase anchoring protein 3 messenger RNA expression in ovarian cancer and its implication on prognosis.

A-kinase anchoring protein 3 (AKAP3) is a sperm protein and its expression appears to be restricted to the testis in normal adult tissues. We investigated AKAP3 mRNA expression in 20 normal ovaries and 54 ovarian cancers of different histological types, grades and stages by reverse transcription-polymerase chain reaction (RT-PCR). The PCR products were analyzed by conventional agarose gel electrophoresis and capillary electrophoresis on a microtip device to determine the expression semiquantitatively. Little or no expression was observed in the 20 normal ovarian specimens. High AKAP3 mRNA expression was observed in 15 ovarian cancer specimens (28 %). The expression was correlated with the histological grade and clinical stage. AKAP3 mRNA was observed at a significantly higher frequency in poorly differentiated (p = 0.009) and advanced stage (III and IV, p = 0.014) tumors. No correlation was found between AKAP3 mRNA expression and other variables. In Cox multivariate analysis, AKAP3 mRNA expression was found to be a significant predictor of both overall and progression-free survival in patients with poorly differentiated tumors.

Repression of bleomycin-induced pneumopathy by TNF.

Idiopathic pulmonary fibrosis is a chronic inflammatory lung disease with interstitial fibrosis. As a potent proinflammatory cytokine, TNF has been suggested to play critical roles in the pathogenesis of the human disease and its animal model, bleomycin-induced pneumopathy. However, studies using TNF-deficient mice have demonstrated that TNF also has an anti-inflammatory function. To determine the role of TNF in pulmonary inflammation induced by bleomycin, we injected bleomycin intratracheally into TNF-deficient mice. In this study, we demonstrated persistent and intense inflammation in TNF-deficient mice due to reduced apoptosis of inflammatory cells. We also showed that in TNF-deficient mice, challenge via airways with murine, but not human rTNF, efficiently eliminated inflammatory cells from the bronchoalveolar space by apoptosis, and thus promoted tissue repair of damaged lungs. Contrary to previous reports that showed that TNF was a central mediator of pulmonary inflammation, we have demonstrated that TNF is essential for repressing pulmonary inflammation in bleomycin-induced pneumopathy.