MicroRNA-218对宫颈癌干细胞的调控机制及其干预研究

Cancer stem cells are the key cells in cancer initiation, drug resistance, relapse, and metastasis. The expression character of microRNA in cancer stem cells may be related directly to stem characters in cells. In previous studies, we found the expression of microRNA-218 (miR-218) reduced significantly in cervical cancer stem cells compared with non-stem cervical cancer cells. Is the expression of miR-218 related to the maintainace of stem characters in cervical cancer stem cells? Based on previous study, this study will first verify the reduced expression of miR-218 in cervical cancer stem cells compared with non-stem cervical cancer cells. Then, by studying the expression difference of possible target genes of miR-218, we will look for the key target gene of miR-218 in cervical cancer stem cells and the mechanism. After transfecting with lentivirus vector to increase the expression of miR-218, the changes in stem characters in cervical cancer stem cells, and the changes in expression of target genes of miR-218 will be studied. On the other hand, we will silence target gene of miR-218 and watch the changes in stem characters in cervical cancer stem cells. The aim of the study is to find out the effect of miR-218 in cervical cancer stem cells and its mechanism, and explore the possibility of reversing stem characters in cervical cancer stem cells. The study will provide more scientific evidence for microRNA-218 to become potential therapeutic target in cervical cancer.

肿瘤干细胞是肿瘤发生、耐药、复发和转移中的关键细胞，其microRNA表达特征可能与"干性"表型直接相关。前期研究中，申请者发现宫颈癌干细胞microRNA-218 (miR-218)的表达较非干肿瘤细胞显著降低。miR-218的表达特征是否与宫颈癌干细胞"干性"表型的维持相关呢？本研究拟在前期工作的基础上，将宫颈癌干细胞与非干肿瘤细胞相比较，证实miR-218在宫颈癌干细胞中的表达特征，找出miR-218在宫颈癌干细胞内的靶基因并探索其作用机制。以慢病毒载体转染的方法，研究强制性增高miR-218表达对宫颈癌干细胞"干性"表型和靶基因表达的影响；及沉默miR-218的靶基因对宫颈癌干细胞表型的改变。本项目旨在揭示miR-218对宫颈癌干细胞"干性"表型的作用，阐明其调控机制，并探索逆转宫颈癌干细胞"干性"表型的可能性，为microRNA-218成为宫颈癌可能的治疗靶点提供科学依据。

宫颈癌是全球女性最常见的恶性肿瘤之一，其治疗失败的主要原因是肿瘤的复发与转移。microRNA与肿瘤的发生、发展密切相关。本课题通过悬浮培养筛选并鉴定了宫颈癌干性细胞群，发现miR-218在干性细胞群中的表达明显降低，且其低表达对细胞干性特征的维持起重要作用。在组织水平发现，miR-218在宫颈癌组织中的表达较癌旁组织下调，在转移组织中的表达低于未转移的宫颈癌组织，并且其表达量与宫颈癌的临床分期密切相关。在细胞水平，我们发现miR-218可以抑制宫颈癌细胞的EMT及侵袭迁移。应用生物信息学方法及双荧光素酶实验筛选并鉴定出miR-218的作用靶点DCUN1D1和SFMBT1，研究证实miR-218通过靶向抑制DCUN1D1和SFMBT1而抑制宫颈癌细胞的侵袭迁移，通过靶向抑制SFMBT1而发挥抑制宫颈癌细胞的EMT。HPV16E6是宫颈癌中已知的重要致癌基因。我们研究发现HPV16E6能够抑制miR-218的表达，且能促进宫颈癌细胞的EMT和迁移功能，而miR-218可以逆转HPV16E6对宫颈癌转移的促进作用，这说明miR-218在HPV16E6对宫颈癌转移的影响中发挥重要作用。在宫颈癌干性细胞中，我们进一步证实miR-218能够通过靶向抑制SFMBT1，从而抑制干性细胞的EMT和其他干性特征。综上所述，本课题揭示了miR-218通过靶向DCUN1D1和SFMBT1基因，抑制宫颈癌干细胞的干性特征、EMT和侵袭迁移的机制，为针对miR-218设计抗宫颈癌转移的策略提供了理论基础。