一组在前列腺导管内癌（IDC-P）中高表达的box C/D snoRNA (snoRD9/snoRD116-8/snoRD20)在前列腺癌演进中的作用及机制探讨。

intraductal adenocarcinoma of the prostate (IDC-P) is a highly invasive prostate cancer entity with unique morphology. RNA-seq was performed and a panel of box C / D snoRNAs (represented by snoRD9) were screened for highly expressed in IDC-P. Overexpression of snoRD9 by recombinant adenoviral Ad-snoRD9 progressed prostate cancer cell proliferation, migration and invasiveness. In this project, we aimed to explore the role and possible molecular mechanisms of highly expressed of snoRD9 in IDC-P: (1) snoRD9 can bind to snRNA U6, guide 2'-O-me modification of U6 A53 site, promot host gene CHD8 pre-mRNA cleavage and maturation, and activate androgen pathway. (2) snoRD9 can bind to DGCR8 and be processed into sd-miR-653, which is similar in structure and function to miR-653, targeting inhibition of tumor suppressor gene PTEN and CHD1，activating of PI3K/AKT pathway and promoting the proliferation and migration of prostate cancer cells. (3) snoRD9 can bind to FMRP and assist Ras, PREX1, PAK to activate PI3K/AKT pathway and downstream molecules. (4)snoDR9 can guide 2'-O-me modification of the intron sequence of PTEN pre-mRNA, and inhibit the maturation of PTEN pre-mRNA, down regulate the expression of PTEN.

本课题前期对IDC-P和普通腺癌进行RNA-seq测序，筛选出以snoRD9为代表的一组IDC-P中高表达的box C/D snoRNAs。本课题拟探讨snoRD9促进前列腺癌演进的可能机制：（1）snoRD9结合小核RNA U6，指导U6 A53位点2'-O-me修饰，促进宿主基因CHD8 pre-mRNA剪切成熟，活化雄激素通路。（2）snoRD9结合DGCR8蛋白，剪切成结构和功能均类似miR-653的sd-miR-653，靶向抑制PTEN和CHD1，活化PI3K/AKT通路及下游靶分子，促进前列腺癌细胞增殖和迁移；（3）snoRD9结合或募集FMRP蛋白，辅助Ras、PREX1、PAK等分子活化PI3K/AKT通路及下游靶分子；（4）snoDR9促进PTEN pre-mRNA intron序列的2'-O-me修饰，抑制PTEN pre-mRNA的成熟，下调PTEN表达。

前列腺导管内癌（IDC-P）是一种具有独特形态学特征的高侵袭性前列腺癌。本课题前期对IDC-P和普通腺癌进行RNA-seq测序对比，筛选出以snoRD9为代表的一组IDC-P中高表达的box C/D snoRNAs。本课题通过一系列实验证实以下结论：（1）snoRD9在前列腺癌细胞株和组织中高表达；在伴有IDC-P的前列腺癌中表达水平更高，过表达snoRD9可促进前列腺癌细胞增殖、迁移和侵袭能力。（2）snoRD9表达水平与前列腺癌患者PSA水平、临床病理分期、Gleason评分及预后密切相关，是总体生存时间和无CRPC进展生存时间的不良预后指标。（3）snoRD9是具有指导U6 snRNA 2’-O-甲基化修饰的功能分子。snoRD9的 5’末端序列可衍生形成新的28nt piRNA（命名为pi-snoRD9）。pi-snoRD9的 3’末端碱基具有2’-O-甲基化修饰，可结合PIWIL2/4蛋白。（4）pi-snoRD9与PIWIL4结合形成pi-snoRD9/PIWIL4复合物，通过结合/募集组蛋白甲基转移酶复合物核心组分ASH2L，促进STAT1基因启动子组蛋白H3K4me3修饰，激活STAT1基因转录及下游分子PKCε转录，促进前列腺癌细胞增殖和迁移。