Department of Pediatric Hematology and Oncology Research, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan.
Division of Diagnostic Pathology, Keio University School of Medicine, Shinjuku-ku, Tokyo, Japan.
Pediatr Blood Cancer. 2023 Feb;70(2):e30058. doi: 10.1002/pbc.30058. Epub 2022 Oct 17.
Among pediatric renal tumors, rhabdoid tumor of the kidney (RTK) and clear cell sarcoma of the kidney (CCSK) are rare and associated with an unfavorable prognosis, while congenital mesoblastic nephroma (CMN) is associated with a good prognosis. Methylation of the Ras association domain-containing protein 1 isoform A (RASSF1A) promoter has been reported to correlate with a poor prognosis in patients with Wilms tumors, while its methylation status is unclear in other types of pediatric renal tumors.
DNA methylation of the RASSF1A promoter in several pediatric renal tumors was analyzed with pyrosequencing. In order to clarify the correlation between expression of RASSF1A and DNA methylation of its promoter, the RTK cell line was treated with 5-Aza-2'-deoxycytidine (5-Aza-dC). RASSF1A was overexpressed in the RTK cell line to evaluate its functional effects.
Quantitative methylation analysis demonstrated hypermethylation in the RASSF1A promoter region in RTK and CCSK, but not CMN. The 5-Aza-dC treatment induced demethylation of the RASSF1A promoter as well as increased RASSF1A mRNA expression. The transduction of RASSF1A has an effect on the suppression of viability and proliferation of RTK cells.
DNA methylation-mediated deficiency of RASSF1A might be involved in the development and aggressiveness of some pediatric renal tumors and correlated with a poor prognosis.
在儿科肾肿瘤中，肾横纹肌样瘤（RTK）和肾透明细胞肉瘤（CCSK）较为罕见，且预后不良，而先天性中胚层肾瘤（CMN）则具有良好的预后。Ras 相关结构域蛋白 1 异构体 A（RASSF1A）启动子的甲基化与 Wilms 瘤患者的不良预后相关，但其在其他类型儿科肾肿瘤中的甲基化状态尚不清楚。
采用焦磷酸测序法分析几种儿科肾肿瘤中 RASSF1A 启动子的 DNA 甲基化。为了阐明 RASSF1A 的表达与启动子甲基化之间的相关性，我们用 5-氮杂-2′-脱氧胞苷（5-Aza-dC）处理 RTK 细胞系。在 RTK 细胞系中过表达 RASSF1A，以评估其功能效应。
定量甲基化分析显示，RTK 和 CCSK 中 RASSF1A 启动子区域存在高度甲基化，但 CMN 中不存在。5-Aza-dC 处理诱导 RASSF1A 启动子去甲基化，同时增加 RASSF1A mRNA 的表达。转染 RASSF1A 对 RTK 细胞活力和增殖具有抑制作用。
RASSF1A 的 DNA 甲基化缺失可能参与了一些儿科肾肿瘤的发生和侵袭，并与不良预后相关。
