RAB30内含子来源的box H/ACA snoRNA SNORA70E通过假尿嘧啶化修饰调控CXXC4促进卵巢癌发生、发展的机制解析

卵巢癌死亡率居妇科肿瘤首位。研究表明snoRNAs参与肿瘤发生发展。我们发现RAB30第1内含子来源的box H/ACA snoRNA SNORA70E在卵巢癌组织中高表达，CRISPR/Cas9敲除SNORA70E后抑制卵巢癌细胞增殖及侵袭，抑癌基因CXXC4表达增加，CXXC4下游基因发生相应变化，且假尿苷水平降低。此外，SNORA70E与CXXC4均与假尿嘧啶合酶DKC1相结合。结合RNA-seq测序，提示SNORA70E靶向假尿嘧啶化修饰CXXC4，影响其下游基因表达。本课题拟在前期工作基础上验证假说：RAB30内含子来源的SNORA70E通过与DKC1形成snoRNP复合物，靶向结合并假尿嘧啶化修饰CXXC4，调节其蛋白及下游基因表达，从而促进卵巢癌发生发展。本研究拟运用多种生物学技术和方法，从组织学、细胞学、动物模型多角度多层次全面验证此假说，深入探讨卵巢癌发生发展的分子机制。

Ovarian cancer is the leading cause of gynecologic cancer. Previous studies have shown that snoRNAs are abnormally expressed in a variety of tumors and participate in tumorigenesis and development. Our previous study found that the box H/ACA snoRNA SNORA70E, which was derived from the first intron of RAB30, was highly expressed in ovarian cancer tissues. The delpetion of SNORA70E by CRISPR/Cas9 inhibits ovarian cancer cell proliferation and invasion ability. In addition, the level of pseudouridine was decreased while CXXC4 expression level was increased after SNORA70E down-regulation. Besides, both SNORA70E and CXXC4 could combine with pseudo-uracil synthase DKC1. Combined with RNA-seq sequencing, it was suggested that SNORA70E targets pseudouracil-modified CXXC4 and affects its downstream gene expression. This topic is based on the preliminary work to verify the hypothesis: RAB30 intron-derived SNORA70E targets CXXC4 and regulats its pseudouridylation through the formation of snoRNP complex with DKC1, thereby regulates the expression of its protein and its downstream genes, promotes the tumorigenesis and development of ovarian cancer. This study intends to use a variety of biological techniques and methods to comprehensively verificate this hypothesis through the histology, cytology, and animal model, and study the molecular mechanism of tumorigenesis and progression of ovarian cancer in-depth.