Weber J, Salgaller M, Samid D, Johnson B, Herlyn M, Lassam N, Treisman J, Rosenberg S A
Surgery Branche, National Cancer Institute, Bethesda, Maryland.
Cancer Res. 1994 Apr 1;54(7):1766-71.
MAGE-1 is a gene that encodes an antigen on a melanoma cell line that is recognized by cytolytic T-cells. We have used a reverse transcription-polymerase chain reaction assay to analyze expression of the MAGE-1 gene by cell lines from different types of tumors, melanomas from different stages of disease progression, normal diploid cell lines, and melanocyte and nevus tissue from which malignant melanomas are derived. MAGE-1 is expressed by melanoma tissue from all stages of disease, but not melanocytes, nevus tissue, or any normal diploid cell line tested. A fraction of tumor lines derived from various epithelial and neuroectodermal malignancies expressed MAGE-1 but not peripheral blood cells from patients with melanoma. 5-Aza-2'-deoxycytidine (DAC), a demethylating agent, was capable of inducing MAGE-1 expression by a MAGE-1-negative melanoma cell line 888-mel as well as by a number of other melanoma cell lines. At an optimum concentration of 1 microM DAC, MAGE-1 expression was detectable by 24 h, plateaued by 72 h, but remained high for two weeks after removal of DAC from treated 888-mel cells, consistent with induction by demethylation. With the exception of tumor-infiltrating leukocytes, no normal diploid cell line could be induced with DAC to upregulate MAGE-1 expression. DAC-treated 888-mel cells were lysed by a MAGE-1-specific major histocompatibility complex restricted cytolytic T-cell clone, whereas control untreated cells were not, suggesting that production of the antigen encoded by the MAGE-1 gene was induced by DAC and that it was presented in association with major histocompatibility complex class I molecules at the cell surface for T-cell recognition.
MAGE-1是一种编码黑色素瘤细胞系上一种抗原的基因，该抗原可被细胞毒性T细胞识别。我们使用逆转录-聚合酶链反应分析方法，来分析不同类型肿瘤的细胞系、疾病进展不同阶段的黑色素瘤、正常二倍体细胞系以及恶性黑色素瘤所源自的黑素细胞和痣组织中MAGE-1基因的表达情况。MAGE-1在疾病各阶段的黑色素瘤组织中均有表达，但在所检测的黑素细胞、痣组织或任何正常二倍体细胞系中均不表达。源自各种上皮和神经外胚层恶性肿瘤的一部分肿瘤细胞系表达MAGE-1，但黑色素瘤患者的外周血细胞不表达。5-氮杂-2'-脱氧胞苷（DAC），一种去甲基化剂，能够诱导MAGE-1阴性的黑色素瘤细胞系888-mel以及其他一些黑色素瘤细胞系表达MAGE-1。在1 microM DAC的最佳浓度下，24小时即可检测到MAGE-1的表达，72小时达到平台期，但从处理后的888-mel细胞中去除DAC后，其表达在两周内仍保持高水平，这与去甲基化诱导一致。除肿瘤浸润白细胞外，没有正常二倍体细胞系能被DAC诱导上调MAGE-1表达。经DAC处理的888-mel细胞可被MAGE-1特异性的主要组织相容性复合体限制性细胞毒性T细胞克隆裂解，而未处理的对照细胞则不能，这表明MAGE-1基因编码的抗原的产生是由DAC诱导的，并且它与主要组织相容性复合体I类分子在细胞表面结合呈递以供T细胞识别。
