Genetic and epigenomic studies of testicular tumor

男性生殖细胞癌中microRNA的表观遗传失活 人员：Lee，Cheung，Chan，Rennert MicroRNAs(MiRNAs)是一类小的非编码RNA，已被证明在包括癌症在内的许多疾病中被解除调控。表观遗传学和miRNAs之间的一种相互交织的联系得到了最近发现的一种特殊的miRNAs亚群的支持，该亚群被称为“epi-miRNAs”，它可以直接和间接地调节表观遗传机制的活动。利用全基因组方法研究睾丸生殖细胞肿瘤细胞系的差异甲基化，我们在1号染色体上发现了一个新的高甲基化位点。基因组图谱显示，该高甲基化区域与MircroRNA候选基因miR-199a及其上游启动子区域重叠。在NTERA-2睾丸癌细胞中，亚硫酸氢盐测序和DNA甲基转移酶抑制剂5-aza处理证实了在平铺微阵列数据中的相同观察结果。 DNA甲基化的变化是癌症的一个标志，并且经常与癌症的进展有关。表观基因组图谱显示动力素3内含子-14有一个保守区，位于1q24.3；它的高甲基化与睾丸癌的进展和miR-199a的沉默有关。MiR-199a在睾丸癌细胞中的重新表达抑制了细胞的生长、癌细胞的迁移、侵袭和转移。MiR-199a-5p是由miR-199a衍生的两个成熟的miRNA物种之一，与癌症的进展有关。我们鉴定了一个胚胎性癌抗原，PODXL，作为miR-199a-5p的靶点。PODXL是一种抗黏附蛋白，在侵袭性睾丸癌中过度表达。PODXL基因的敲除抑制了肿瘤的侵袭。PODXL与miR-199a-5p表达呈负相关，提示PODXL是介导肿瘤侵袭转移的下游效应因子之一。 这份报告将DNA甲基化、miR-199a失调和PODXL表达联系起来，作为解释睾丸癌进展的机制。

Epigenetic inactivation of microRNA in male germ cell cancer Personnel: Lee, Cheung, Chan, Rennert MicroRNAs (miRNAs) are a class of small non-coding RNAs that have been shown to be deregulated in many diseases including cancer. An intertwined connection between epigenetics and miRNAs has been supported by the recent identification of a specific subgroup of miRNAs called "epi-miRNAs" that can directly and indirectly modulate the activity of the epigenetic machinery. Using a genome-wide approach for studying differential methylation in testicular germ cell tumor cell line, we previously identified a novel hypermethylated locus on chromosome 1. Genomic mapping revealed that the hypermethylated region overlapped with a mircroRNA candidate, miR-199a and its upstream promoter region. Bisulfite sequencing and treatment with DNA methyltransferase inhibitor 5-aza in the Ntera-2 testis cancer cells confirmed the same observation in the tiling microarray data. Changes in DNA methylation are a hallmark of cancer, and are frequently associated with cancer progression. Epigenomic profiling revealed a conserved region in intron-14 of dynamin 3, located at 1q24.3; its hypermethylation correlated with testicular cancer progression, and silencing of miR-199a. Re-expression of miR-199a in testicular cancer cells suppressed cell growth, cancer migration, invasion, and metastasis. miR-199a-5p, one of two mature miRNA species derived from miR-199a, is associated with cancer progression. We identified an embryonal carcinoma antigen, podocalyxin-like protein 1 (PODXL), as a target of miR-199a-5p. PODXL is an anti-adhesive protein overexpressed in aggressive testicular cancer. Knockdown of PODXL suppressed cancer invasion. The inverse relationship between PODXL and miR-199a-5p expression suggests that PODXL is one of the downstream effectors mediating cancer invasion and metastasis. This report links DNA methylation, miR-199a dysregulation, and PODXL expression as a mechanism to explain testicular cancer progression.