Profiling epigenetic inactivation of tumor suppressor genes in tumors and plasma from cutaneous melanoma patients
Profiling epigenetic inactivation of tumor suppressor genes in tumors and plasma from cutaneous melanoma patients
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DOI：
10.1038/sj.onc.1207505
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发表时间：
2004-05-13
期刊：
影响因子：
8
通讯作者：
Taback, B
中科院分区：
文献类型：
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作者：
Hoon, DSB;Spugnardi, M;Taback, B
在上皮源性肿瘤中，已经证实了肿瘤抑制基因（TSG）启动子区域的CpG岛异常甲基化。然而，甲基化亲。皮肤黑色素瘤中肿瘤相关基因启动子区的缺失还没有报道。在15个黑色素瘤细胞系和130个皮肤黑色素瘤肿瘤中，通过甲基化特异性聚合酶链反应（MSP）评估了7个已知或候选的TSGs，这些TSGs在癌中经常高度甲基化。在86例转移性肿瘤标本中，4种TSG经常高甲基化：维甲酸受体-β 2（RAR-β 2）（70%）、RAS相关结构域家族蛋白1A（RASSF 1A）（57%）、O-6-甲基鸟嘌呤DNA甲基转移酶（MGMT）（34%）和死亡相关蛋白激酶（DAPK）（19%）。与转移性黑色素瘤相比，原发性黑色素瘤（n = 20）中MGMT、RASSF 1A和DAPK的超甲基化显著降低。然而，在原发性和转移性黑色素瘤中，RAR-β 2的超甲基化均为70%。细胞系具有与转移性黑色素瘤相似的高甲基化特征。对这四个转移性肿瘤标志物的分析表明，97%的转移性肿瘤有大于或等于1个基因，59%的转移性肿瘤有大于或等于2个基因高甲基化。通过亚硫酸氢盐测序验证基因的甲基化。用5 ′-氮杂-2 ′-脱氧胞苷（5Aza-dC）处理后，在具有高甲基化基因的黑素瘤细胞系中可以重新表达mRNA转录物。对黑色素瘤患者血浆（术前血液; n = 31）的分析表明，29%的患者中至少有一种标志物的循环高甲基化MGMT、RAR-β 2和RASSF 1A DNA。我们的研究结果表明，TSG高甲基化的发生率在肿瘤进展过程中增加。TSG的甲基化可能在皮肤黑色素瘤的进展中起重要作用。
Aberrant methylation of CpG islands in promoter regions of tumor suppressor genes (TSG) has been demonstrated in epithelial origin tumors. However, the methylation pro. ling of tumor-related gene promoter regions in cutaneous melanoma tumors has not been reported. Seven known or candidate TSGs that are frequently hypermethylated in carcinomas were assessed by methylation-specific polymerase chain reaction (MSP) in 15 melanoma cell lines and 130 cutaneous melanoma tumors. Four TSGs were frequently hypermethylated in 86 metastatic tumor specimens: retinoic acid receptor-beta2 (RAR-beta2) (70%), RAS association domain family protein 1A (RASSF1A) (57%), and O-6-methylguanine DNA methylatransferase (MGMT) (34%), and death-associated protein kinase (DAPK) (19%). Hypermethylation of MGMT, RASSF1A, and DAPK was significantly lower in primary melanomas (n = 20) compared to metastatic melanomas. However, hypermethylation of RAR-beta2 was 70% in both primary and metastatic melanomas. Cell lines had hypermethylation profiles similar to those of metastatic melanomas. The analysis of these four markers of metastatic tumors demonstrated that 97% had greater than or equal to1 gene(s) and 59% had greater than or equal to2 genes hypermethylated. The methylation of genes was verified by bisulfite sequencing. The mRNA transcripts could be re-expressed in melanoma cell lines having hypermethylated genes following treatment with 5'-aza 2'-deoxycytidine (5Aza-dC). Analysis of melanoma patients' plasma (preoperative blood; n = 31) demonstrated circulating hypermethylated MGMT, RAR-beta2, and RASSF1A DNA for at least one of the markers in 29% of the patients. Our findings indicate that the incidence of TSG hypermethylation increases during tumor progression. Methylation of TSG may play a significant role in cutaneous melanoma progression.