Invasion suppressor cystatin E/M (CST6): high-level cell type-specific expression in normal brain and epigenetic silencing in gliomas.
Invasion suppressor cystatin E/M (CST6): high-level cell type-specific expression in normal brain and epigenetic silencing in gliomas.
复制标题
侵袭抑制因子胱抑素E/M（CST6）：在正常脑组织中呈高水平细胞类型特异性表达，在胶质瘤中发生表观遗传沉默 。
DOI：
10.1038/labinvest.2008.66
复制
发表时间：
2008-09
期刊：
影响因子：
--
通讯作者：
中科院分区：
文献类型：
--
作者：
DNA 高甲基化介导的基因沉默是癌症中异常细胞生长和侵袭的常见且早期的促成因素。恶性胶质瘤是成人中最常见的原发性脑肿瘤，也是儿童中第二常见的肿瘤。神经胶质瘤患者的发病率和死亡率很高，因为肿瘤对治疗有抵抗力，并且高度侵入周围的脑组织，导致完全手术切除是不可能的。侵袭性由分泌的蛋白酶（例如组织蛋白酶）与其内源性抑制剂（半胱氨酸蛋白酶抑制剂）之间的相互作用调节。在我们之前的研究中，我们发现胱抑素 E/M (CST6) 是神经胶质瘤表观遗传沉默的常见靶标。 Cystatin E/M 是组织蛋白酶 B 的有效抑制剂，组织蛋白酶 B 经常在神经胶质瘤中过度表达。在这里，我们研究了正常大脑中胱抑素 E/M 的表达，结果表明它分别在少突胶质细胞和星形胶质细胞中高表达和中度表达，但在神经元中不表达。与此一致的是，使用甲基化特异性 PCR、亚硫酸氢盐基因组测序和焦磷酸测序，所有正常样本中的 CST6 启动子均出现低甲基化。相比之下，使用组织微阵列，28 个原发性脑肿瘤中的 78% 表现出胱抑素 E/M 表达减少/缺失，并且这种表达减少与 CST6 启动子高甲基化相关。有趣的是，CST6 在神经干细胞 (NSC) 中表达，并在分化时被显着诱导，而神经胶质瘤起始细胞 (TIC) 系则通过启动子甲基化完全阻断 CST6 表达。对原发性小儿脑肿瘤来源细胞系的分析还显示，12 例病例中近 100% 存在 CST6 下调和甲基化。最后，神经胶质瘤系中胱抑素 E/M 的异位表达降低了细胞运动和侵袭。这些结果表明，CST6 的表观遗传沉默在成人和儿童脑肿瘤中很常见，并且发生在 TIC 中，而 TIC 被认为是引起肿瘤的原因。因此，CST6 甲基化可能代表一种新的预后标志物和在 TIC 中特异性改变的治疗靶点。
DNA hypermethylation mediated gene silencing is a frequent and early contributor to aberrant cell growth and invasion in cancer. Malignant gliomas are the most common primary brain tumors in adults and the second most common tumor in children. Morbidity and mortality are high in glioma patients because tumors are resistant to treatment and are highly invasive into surrounding brain tissue rendering complete surgical resection impossible. Invasiveness is regulated by the interplay between secreted proteases (e.g. cathepsins) and their endogenous inhibitors (cystatins). In our previous studies we identified cystatin E/M (CST6) as a frequent target of epigenetic silencing in glioma. Cystatin E/M is a potent inhibitor of cathepsin B, which is frequently over-expressed in glioma. Here we study the expression of cystatin E/M in normal brain and show that it is highly and moderately expressed in oligodendrocytes and astrocytes, respectively, but not in neurons. Consistent with this, the CST6 promoter is hypomethylated in all normal samples using methylation specific PCR, bisulfite genomic sequencing, and pyrosequencing. In contrast, 78% of 28 primary brain tumors demonstrated reduced/absent cystatin E/M expression using a tissue microarray and this reduced expression correlated with CST6 promoter hypermethylation. Interestingly, CST6 was expressed in neural stem cells (NSC) and markedly induced upon differentiation, while a glioma tumor initiating cell (TIC) line was completely blocked for CST6 expression by promoter methylation. Analysis of primary pediatric brain tumor-derived lines also showed CST6 downregulation and methylation in nearly 100% of 12 cases. Finally, ectopic expression of cystatin E/M in glioma lines reduced cell motility and invasion. These results demonstrate that epigenetic silencing of CST6 is frequent in adult and pediatric brain tumors and occurs in TICs, which are thought to give rise to the tumor. CST6 methylation may therefore represent a novel prognostic marker and therapeutic target specifically altered in TICs.
登录
查看更多内容
DOI：
10.1073/pnas.93.18.9821
发表时间：
1996-09-03
影响因子：
11.1
作者：
Herman, JG;Graff, JR;Baylin, SB
通讯作者：
Baylin, SB
影响因子：
3.5
作者：
Baylin, SB;Esteller, M;Herman, JG
通讯作者：
Herman, JG
影响因子：
82.9
作者：
Kononen, J;Bubendorf, L;Kallioniemi, OP
通讯作者：
Kallioniemi, OP
影响因子：
30.8
作者：
Cameron, EE;Bachman, KE;Baylin, SB
通讯作者：
Baylin, SB
影响因子：
11.2
作者：
Kim, Tae-You;Zhong, Sheng;Robertson, Keith D.
通讯作者：
Robertson, Keith D.