Promoter hypermethylation inactivate tumor suppressor FAM134B and is associated with poor prognosis in colorectal cancer
Promoter hypermethylation inactivate tumor suppressor FAM134B and is associated with poor prognosis in colorectal cancer
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DOI：
10.1002/gcc.22525
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发表时间：
2018-05-01
影响因子：
3.7
通讯作者：
Lam, Alfred King-yin
中科院分区：
文献类型：
--
作者：
Islam, Farhadul;Gopalan, Vinod;Lam, Alfred King-yin
本研究的目的是检查在一个大队列的结直肠腺癌患者的FAM 134 B启动子甲基化状态。分析了FAM 134 B基因启动子甲基化与其表达的相关性及临床意义。测序后的甲基化特异性高分辨率熔解曲线分析用于鉴定结直肠腺瘤（N = 32）、结直肠腺癌（N = 164）、匹配的相邻非肿瘤性结直肠粘膜（N = 83）和结肠癌细胞系（N = 4）中的FAM 134 B启动子甲基化。通过实时定量聚合酶链反应、免疫组织化学和Western印迹研究FAM 134 B表达。与腺瘤（28%; 9/32）和非肿瘤性粘膜（35%; 29/83）相比，腺癌（52%; 85/164）中FAM 134 B启动子甲基化更频繁。与非肿瘤细胞相比，癌细胞表现出更高的甲基化。FAM 134 B启动子甲基化与低FAM 134 B拷贝数和mRNA/蛋白表达呈负相关，而体外去甲基化恢复了结肠癌细胞中的FAM 134 B表达。FAM 134 B启动子甲基化与高组织学分级（P = .025）、神经周围浸润（P = .012）、淋巴管浸润（P = .021）、淋巴结转移（P = .0001）、远处转移（P =.0001）和晚期病理分期（P = .0001）相关。此外，FAM 134 B启动子甲基化与结直肠腺癌患者的癌症复发和低生存率相关。总之，FAM 134 B启动子甲基化在体内外调控FAM 134 B表达中起关键作用，这反过来有助于预测结直肠腺癌的生物学侵袭性。此外，FAM 134 B甲基化可能作为预测结直肠腺癌患者临床预后的标志物。
The present study aims to examine promoter methylation status of FAM134B in a large cohort of patients with colorectal adenocarcinomas. The clinical significances and correlations of FAM134B promoter methylation with its expression are also analysed. Methylation-specific high-resolution melt-curve analysis followed by sequencing was used to identify FAM134B promoter methylation in colorectal adenomas (N = 32), colorectal adenocarcinomas (N = 164), matched adjacent non-neoplastic colorectal mucosae (N = 83) and colon cancer cell lines (N = 4). FAM134B expression was studied by real-time quantitative polymerase chain reaction, immunohistochemistry, and Western blots. FAM134B promoter methylation was more frequent in adenocarcinomas (52%; 85/164) when compared to that of adenomas (28%; 9/32) and non-neoplastic mucosae (35%; 29/83). Cancer cells exhibited higher methylation when compared to non-neoplastic cells. FAM134B promoter methylation was inversely correlated with low FAM134B copy number and mRNA/protein expressions, whereas in-vitro demethylation has restored FAM134B expression in colon cancer cells. FAM134B promoter methylation was associated with high histological grade (P = .025), presence of peri-neural infiltration (P = .012), lymphovascular invasion (P = .021), lymph node metastasis (P = .0001), distant metastasis (P = .0001) and advanced pathological stages (P = .0001). In addition, FAM134B promoter methylation correlated with cancer recurrence and poor survival rates of patients with colorectal adenocarcinomas. To conclude, FAM134B promoter methylation plays a key role in regulating FAM134B expression in vitro and in vivo, which in turn contributes to the prediction of the biological aggressiveness of colorectal adenocarcinomas. Furthermore, FAM134B methylation might act as a marker in predicting clinical prognosis in patients with colorectal adenocarcinomas.