miR-520b 调控DKK-1基因对卵巢癌细胞上皮-间质转化的影响

miRNA-520b is one of newly discovered miRNAs. However,its mechanism remained elusive.We fristly reported that DKK-1 was overexpressed and promoted cell invasion in human ovarian carcinoma.Our previous study showed that DKK-1 overexpression could promote epithelial mesenchymal transition (EMT) in ovarian caricinoma. We also found that miRNA-520b was down-regulated twicely on DKK-1-overexpressed-microarray tissues of ovarian cancer.Computatinal approach for predicting miRNA targets showed that miRNA-520b might bind to 3′untranslated region (UTR) of 218-224 nucleotide of DKK-1 gene in which there are seven nucletide substitution in the core binding sites. Based on our results, our research will find whether miR-520b could directly bind to DKK-1 mRNA 3'UTR and its core binding sites.To predict whether miRNA-520b could inhibit EMT of ovarian cancer via targeting DKK-1 gene in vivio and vitro. To predict whether miRNA-520b could inhibit EMT of ovarian cancer through Wnt-Ca2+ signal pathway via targeting DKK-1 messenger RNA transcripts to inhibit DKK-1 protein, competed with Wnt protein, binding to Wnt signal receptor. Our research will contribute to clearify the mechanism of ovarian carcinoma and its clinical treatment.

miR-520b是新发现的microRNAs之一，其作用机制尚不清楚。我们首次报道DKK-1基因在人卵巢癌细胞（ovarian cancer, OCC）中高表达促进OCC侵袭。前期研究发现DKK-1基因过表达促进OCC上皮间质转化。miRNA-520b在DKK-1基因过表达的卵巢癌miRNA芯片组织中表达下降达2倍以上。生物信息学软件预DKK-1 mRNA-3'UTR218-224碱基位置存在miR -520b结合位点。结合前期基础本研究：①验证miR-520b通过"种子区"与DKK-1直接作用和关键结合位点；②在OCC与裸鼠模型中，明确miR-520b对DKK-1基因表达的调节作用及对上皮间质转化的影响；③深入研究miR-520b是否通过负性调控DKK-1基因，调控DKK-1蛋白与WNT蛋白竞争结合受体,调控WNT-Ca2+通路影响OCC上皮间质转化。为OCC发病机制及临床诊疗提供依据。

卵巢癌其临床生物学行为特点是起病隐匿、早期无明显症状及体征，临床诊断时多为晚期，总体生存率较低，预后较差.近年研究表明卵巢癌细胞上皮间质转化作用在卵巢癌细胞侵袭与转移过程中起着重要的作用。miR-520b及miR-335-5p是新发现的microRNAs之一，其在癌症中的作用机制尚不清楚。我们结合前期基础重要研究：①miR-520b及miR-335-5p通过“种子区”与DKK-1直接作用和关键结合位点；②miR-335-5p通过“种子区”与DKK-1的直接作用抑制DKK-1基因表达。③卵巢癌细胞中miR-335-5p通过 “种子区”与DKK-1的直接作用抑制DKK-1基因表达抑制卵巢癌细胞EMT转化。④DKK基因家族成员DKK2及DKK4在卵巢癌中的表达情况及DKK4基因具有促进卵巢癌侵袭的作用。为DKK4能否影响卵巢癌细胞EMT奠定理论基础.为探讨卵巢癌EMT转化机制奠定基础。