MAGE-1 and MAGE-3 or -6 expression in neuroblastoma-related pediatric solid tumors

MAGE-1 and MAGE-3 or -6 are genes encoding melanoma-rejection antigens recognized by cytotoxic T lymphocytes in an HLA-AI restriction manner. MAGE-1 and MAGE-3 or -6 were expressed in 5/14 (36%) and 6/14 (43%) neuroblastoma (NB) cell lines, and in 20/41 (49%) and 24/41 (59%) clinical NB-related tumors, respectively. Additionally, they were also expressed in pediatric tumors of other types such as rhabdomyo-sarcoma and Wilms' tumor. MAGE-1 expression at a functional level in tumor cells was confirmed by the cytotoxicity assay using MAGE-1-specific tumor-infiltrating lymphocytes (TIL). In clinical NB-related tumors, MAGE-3 or -6 expression demonstrated an inverse correlation to clinical stage. Furthermore, although the sample number was small, the incidence of MAGE-1 and/or MAGE-3 or -6 expression was significantly correlated to the absence of metastasis and a more favorable clinical outcome (p < 0.05). These results may suggest that NB cells silent for the expression of MAGE genes escape from the host anti-tumor immune response and consequently retain a growth advantage. Finally, NB-related tumors could be reliable candidates for immunotherapy targeted towards MAGE gene products. © 1996 Wiley-Liss, Inc.     

Monoclonal antibodies against recombinant-MAGE-1 protein identify a cross-reacting 72-kDa antigen which is co-expressed with MAGE-1 protein in melanoma cells

The MAGE-1 gene codes for tumor-associated peptides recognized by cytolytic T lymphocytes in association with MHC-class-I molecules such as HLA-AI and HLA-Cw16. In the course of a study aiming at the immunohistochemical detection of the MAGE-1 gene product in tumor samples, 2 mouse monoclonal antibodies (MAbs) directed against a full-length recombinant MAGE-1 fusion protein were found to react strongly not only with the 46-kDa MAGE-1 protein, but also with a 72-kDa product in immunoblots of lysates obtained from several MAGE-1-mRNA-positive melanoma cell lines. Pre-incubation of the antibodies with the recombinant MAGE-1 fusion protein abolished their reactivity both with MAGE-1 protein and with the 72-kDa product, thus confirming the occurrence of antigenic determinant(s) shared by the 2 proteins. The 72-kDa protein is not an alternative product of MAGE-1, since it was still detected in lysates of a MAGE-1 loss variant derived from a MAGE-1-positive melanoma cell line. Moreover, the 72-kDa protein does not appear to be a product of the other members of the MAGE gene family known to be expressed in tumors (such as MAGE-2, -3, -4 and -12). Interestingly, expression of the 72-kDa protein was found to be correlated with that of MAGE-I protein. Thus, in 30 tumor cell lines analyzed by immunoblotting and RT-PCR, the 72-kDa protein was never detected in MAGE-1-mRNA-negative cell lines, while it was co-expressed with MAGE-1 protein in 12 out of 15 cell lines expressing MAGE-1. Furthermore, the 72-kDa protein was detected in lysates of human testis, the only normal tissue known to express MAGE-1. Finally, treatment of MAGE-1-mRNA-negative cell lines with 5-Aza-2′-deoxycytidine, a hypomethylating agent known to induce MAGE-1 expression, resulted in the expression of the 72-kDa protein. Taken collectively, these findings suggest that expression of the gene encoding the 72-kDa protein identified in this study through antigenic determinant(s) shared with MAGE-1 protein is regulated in a way similar to that of MAGE-1. © 1996 Wiley-Liss, Inc.     

Expression of mage genes in transitional-cell carcinomas of the urinary bladder

Human genes MAGE-1 and MAGE-3 code for distinct antigens, which are recognized on melanoma cells by autologous cytolytic T lymphocytes (CTL). These antigens may constitute useful targets for anti-cancer immunotherapy, since no expression of MAGE genes has been observed in normal tissues other than testis. Out of 57 samples of primary transitional-cell carcinomas of the bladder, 12 (21%) expressed MAGE-1 and 20 (35%) expressed MAGE-3. All but one of the tumors expressing MAGE-1 also expressed MAGE-3. Genes MAGE-2 and MAGE-4, which are closely related to MAGE-1 and MAGE-3, were expressed by 30% and 33% of the tumors respectively. MAGE expression was more frequent in advanced tumor stages: 61% of the invasive tumors (stage ± T2) were positive for expression of at least one of the four genes, whereas only 28% of the superficial tumors (stages Ta and Tl) expressed these genes. © 1995 Wiley-Liss, Inc.     

MAGE-11 protein is highly conserved in higher organisms and located predominantly in the nucleus

The MAGE-11 gene belongs to a family whose products were identified first in tumor tissue. The MAGE-11 gene product has not been characterized in detail. We have isolated MAGE-11 cDNA from HeLa cells and confirmed the presence of MAGE-11 protein and of at least 2 other MAGE proteins (MAGE-1 and MAGE-3) in this cell line. Monoclonal antibodies (MAbs), obtained by using a GST-MAGE-11 fusion protein, detect MAGE-11 protein in HeLa cells as a 48 kDa protein. In contrast to other known proteins of the MAGE family, MAGE-11 is found mainly in the nucleus. Immunoprecipitation out of whole-cell extracts from different species reveals that MAGE-11 protein is highly conserved among mammalian cells, suggesting a conserved and important function. Int. J. Cancer 75:762–766, 1998.© 1998 Wiley-Liss, Inc.     

Detection of MAGE-4 protein in sera of patients with head-and-neck squamous-cell carcinoma

The MAGE-4 gene, a member of the MAGE gene family, is expressed in various cancers, including head-and-neck squamous-cell carcinomas (HN-SCC), but is not expressed in any normal tissues except for the testis and placenta. The aim of this study was to determine whether serum MAGE-4 protein is a useful tumor marker for detection of HN-SCC. An enzyme-linked immunosorbent assay was used to measure serum level of MAGE-4 protein. The serum level of MAGE-4 in pre-operative HN-SCC patients was significantly higher than that in patients with non-malignant diseases (NMD) of the head and neck, volunteers undergoing cancer screening (VOL), or healthy donors (HD). When the cut-off level was determined at 1.15 ng/ml (mean plus 3 SD of HD), sera from 28 of 96 patients with HN-SCC (p < 0.0001 vs. the other groups), 7 of 82 patients with NMD, 2 of 92 with VOL, and 0 of 68 HD were positive for MAGE-4. Serum levels of MAGE-4 protein in all 7 HN-SCC patients whose sera were positive for MAGE-4 before operation decreased after operation, and, in one patient, a renewed rise in serum level was followed by recurrence. These results indicate that MAGE-4 protein is detectable in sera of a significant number of HN-SCC patients, and that serum MAGE-4 protein might be a useful tumor marker to monitor the recurrence of MAGE-4-positive HN-SCC. Int. J. Cancer, 70:287–290, 1997. © 1997 Wiley-Liss, Inc.     

Identification of HLA-A*0201-restricted CTL epitopes encoded by the tumor-specific MAGE-2 gene product

MAGE-2 is expressed in many tumors, including melanoma, laryngeal tumors, lung tumors and sarcomas, but not in healthy tissue, with the exception of testis. Thus, MAGE-2-derived peptides that bind to HLA class I molecules and elicit cytotoxic T lymphocyte (CTL) responses could be of significant therapeutic importance. In this study, we show that several MAGE-2-derived peptides bind with high affinity to HLA-A*0201. Three of them form complexes with HLA-A*0201 that are stable at 37°C and are immunogenic in HLA-A*0201K^b transgenic mice. Moreover, CTLs against 2 of them (M2 112-120, and M2 157-166) specifically recognize cells that express both the MAGE-2 protein and HLA-A*0201K^b. These 2 peptides are processed and presented in the context of HLA-A*0201. Therefore, these peptides are candidate components in peptide-based vaccines for the treatment and prevention of several types of MAGE-2-expressing cancers. Int. J. Cancer 73:125–130, 1997. © 1997 Wiley-Liss, Inc.     

E-cadherin expression in human epithelial ovarian cancer and normal ovary

The ovarian surface epithelium (OSE) is the origin of the majority of human ovarian cancers. These adenocarcinomas are characterized by initial local growth followed by spreading into the peritoneal cavity at later stages of tumor progression. The cell-adhesion molecule E-cadherin (E-cad) plays an important role in maintaining tissue integrity. Disappearance or impaired function of E-cad have often been associated with tumor formation and invasion in vivo and in vitro. The cell-specific expression of E-cad was investigated in normal human ovaries (n = 12), in benign (n = 5) and borderline (n = 4) ovarian epithelial tumors and in adenocarcinomas of different stages and histological grades (n = 18), by immunohistochemistry and immunoblotting. An ovarian cancer cell line (NIH-OVCAR3) was used as a reference. The epithelial origin of the cells was confirmed with cytokeratin (AE1/AE3) staining. In normal ovaries, the expression of E-cad was limited to inclusion cysts or deep clefts lined with OSE, whereas no staining of the OSE could be demonstrated at the surface of the ovary. In contrast, benign and borderline tumors uniformly expressed E-cad. This was observed in malignant tumors of all stages despite their degree of differentiation. E-cad was also present in metastasis from such tumors. The cell-specific expression of E-cad in inclusion cysts of normal ovaries and in epithelial layers of borderline tumors indicates a role for E-cad in the early events of the progression to a malignant phenotype. E-cad was not downregulated in later stages of ovarian cancer progression. Int. J. Cancer 74:275-280, 1997. © 1997 Wiley-Liss, Inc.     

Alteration of the p53 Tumor Suppressor Gene Occurs Independently of K-ras Activation and More Frequently in Serous Adenocarcinomas than in Other Common Epithelial Tumors of the Human Ovary

To clarify the role of the p53 tumor suppressor gene in the development of human ovarian epithelial tumors and to study the association of p53 alterations with K-ras activation, a series of 70 common epithelial ovarian tumors from Japanese patients was studied. These included 31 serous adenocarcinomas, 12 mucinous adenocarcinomas, 5 mutinous tumors of borderline malignancy, 13 endometrioid adenocarcinomas, and 9 clear cell carcinomas. Allelic loss, recognized at the polymorphic site in codon 72 of the p53 gene, was detected in 14 of 36 (39%) informative cases by restriction fragment length polymorphism analysis and by single-strand conformation polymorphism (SSCP) analysis of polymerase chain reaction(PCR)-amplified DNA fragments. Mutations in the highly conserved regions of the p53 gene were detected by SSCP analysis of PCR-amplifled fragments. Mutations were found in 22 of 70 (31%) ovarian tumors, including 1 of 5 mucinous tumors of borderline malignancy. Mutations were subsequently characterized by direct sequencing. Single missense base substitutions were detected in 13 ovarian carcinomas and in one case of mucinous tumor of borderline malignancy. Short (1-8 bp) deletions and insertions were found in 8 cases. Mutations in the p53 gene occurred more frequently in serous adenocarcinomas (14/31, 45%) than in all nonserous types of malignant epithelial tumors combined (7/34, 21%;P=0.032). Point mutations in K-ras were identified by dot blot hybridization analysis of PCR-amplified fragments with mutation-specific oligonucleotides and by direct sequencing. The overall frequency of K-ras mutations was 19/70 (27%).K-ras mutations were found in 12 of 17 (71%) mucinous tumors (8/12 mucinous carcinomas [67%] and 4/5 mucinous tumors of borderline malignancy [80%]), and occurred more frequently than in serous carcinomas (4/31, 13%;P=0.00009) or in all nonmucinous types of ovarian epithelial tumors combined (7/53, 13%; p=0.00002). These data suggest that different combinations of oncogenes and/or tumor suppressor genes may be involved in the genesis and development of histologically distinct categories of common epithelial tumors of the human ovary.     

黑色素瘤抗原基因MAGE-1、MAGE-3和抑癌基因p53在肺癌中表达的研究

目的:分析肺癌组织MAGE-1和MAGE-3基因以及p53基因表达及其相互关系。方法:取肺癌组织标本30例,另取癌周组织作为对照。采用逆转录聚合酶链反应(RT-PCR)方法,检测MAGE-1和MAGE-3基因以及p53基因的表达。结果:MAGE-1,MAGE-3在肺癌中有较高表达,MAGE-3的表达高于MAGE-1的表达。p53在肺癌中表达较低,在正常组织中表达较高;MAGE-1在肺腺癌中表达较鳞癌高,MAGE-3在肺鳞癌中表达较高;MAGE-1,MAGE-3的表达可能与肿瘤分化程度无关;p53在小细胞肺癌中的表达有待进一步研究;p53与MAGE在体内表达成负相关。结论:MAGE-1、MAGE-3和p53在肺癌组织与正常组织中有不同的表达,MAGE-1、MAGE-3的表达与病理类型有关,与肿瘤分化无关。     

Clinical implications of mRNA expression of KAI1 in ovarian cancer with or without metastasis

Background. KAI1 is a potential metastasis suppressor gene for prostate cancer. Decreased expression of KAI1 mRNA has been shown to be associated with the formation of metastasis and the progression of prostate, lung, breast, pancreatic, and bladder cancer. It has also been reported, however, that KAI1 expression is unchanged in metastatic and nonmetastatic esophageal and gastric cancer. We performed the present study to investigate the function of KAI1 in the progression and/or metastasis of ovarian cancer. Methods. We investigated the mRNA expression levels of the KAI1 gene, using quantitative polymerase chain reaction (PCR), in 29 ovarian tumors (1 adenoma, 2 low- malignant potential tumors, 9 adenocarcinomas without metastasis, and 17 adenocarcinomas with metastasis), seven ovarian cancer cell lines, and two normal ovaries. Using a thermal cycler, we found that the KAI1 gene was amplified in parallel with an internal control gene, β-Actin. The relative expression ratio (KAI1/β-Actin) as measured by densitometry was used to evaluate gene expression. Immunohistochemical localization of the KAI1 protein in ovarian cancer tissues was confirmed by the avidin-biotin peroxidase complex (ABC) method. Results. The mRNA expression levels of KAI1 were consistent in normal ovary, ovarian tumor samples, and ovarian cancer cell lines. No statistically significant difference in the KAI1 mRNA expression level was found in ovarian cancer samples with or without metastasis. Immunohistochemistry revealed that the KAI1 protein was expressed in the cell membranes of ovarian cancer cells. Conclusions. Our results suggest that reductions in KAI1 mRNA expression are not involved in either the progression or metastasis of ovarian carcinomas. Received: April 22, 1999 / Accepted: July 26, 1999