Hirasawa Yuichi, Arai Makoto, Imazeki Fumio, Tada Motohisa, Mikata Rintaro, Fukai Kenichi, Miyazaki Masaru, Ochiai Takenori, Saisho Hiromitsu, Yokosuka Osamu
Department of Medicine and Clinical Oncology, Graduate School of Medicine, Chiba University, Chiba, Japan.
Oncology. 2006;71(1-2):77-85. doi: 10.1159/000100475. Epub 2007 Mar 6.
BACKGROUND/AIMS: To determine the clinical significance of gene promoter methylation in hepatocellular carcinoma (HCC), we examined in clinical samples the methylation status of those promoters that showed elevated activity in hepatoma cell lines after 5-aza-2'-deoxycytidine treatment.
Regarding the genes with promoter hypermethylation in the cell lines, their expression levels and methylation status in HCC and non-HCC tissues were assessed by semiquantitive RT-PCR and methylation-specific PCR. To confirm the result, the expression levels and methylation status in 16 additional HCC and non-HCC tissues were assessed.
The promoter regions of caveolin 1 (CAV1), cysteine and glycine-rich protein 1 (CSRP1), Kruppel-like factor 6 (KLF6), myosin (light polypeptide 9) (MYL9), and transgelin (TAGLN) were highly methylated in the cell lines. CAV1 and CSRP1 were methylated in HCC more frequently than in non-HCC. KLF6, MYL9, and TAGLN were fully methylated in both HCC and non-HCC. Using additional clinical samples, downregulation of CAV1 and CSRP1 was observed in 38 and 56%, respectively, of the 16 HCC samples and aberrant methylation of CAV1 and CSRP1 was observed in 56% of HCC in both cases.
CAV1 and CSRP1 were inactivated in HCC by aberrant methylation and they may serve as important biomarkers of malignancy.
背景/目的：为了确定基因启动子甲基化在肝细胞癌（HCC）中的临床意义，我们检测了临床样本中那些在5-氮杂-2'-脱氧胞苷处理后肝癌细胞系中活性升高的启动子的甲基化状态。
对于细胞系中启动子高甲基化的基因，通过半定量逆转录-聚合酶链反应（RT-PCR）和甲基化特异性PCR评估其在HCC和非HCC组织中的表达水平和甲基化状态。为了证实结果，对另外16例HCC和非HCC组织的表达水平和甲基化状态进行了评估。
小窝蛋白1（CAV1）、富含半胱氨酸和甘氨酸的蛋白1（CSRP1）、Kruppel样因子6（KLF6）、肌球蛋白（轻链多肽9）（MYL9）和转胶蛋白（TAGLN）的启动子区域在细胞系中高度甲基化。CAV1和CSRP1在HCC中甲基化的频率高于非HCC。KLF6、MYL9和TAGLN在HCC和非HCC中均完全甲基化。使用另外的临床样本，在16例HCC样本中，分别有38%和56%观察到CAV1和CSRP1下调，在这两种情况下，56%的HCC中观察到CAV1和CSRP1的异常甲基化。
CAV1和CSRP1在HCC中因异常甲基化而失活，它们可能作为恶性肿瘤的重要生物标志物。
