Zhang Guiyu, Hou Xinxin, Li Yue, Zhao Meng
Department of Gynecology, Qilu Hospital, Shandong University, 107 Wenhuaxi Road, Jinan 250012, P,R, China.
BMC Cancer. 2014 Jun 14;14:440. doi: 10.1186/1471-2407-14-440.
MicroRNAs (miRNAs) are frequently dysregulated in human cancers and can act as either potent oncogenes or tumor suppressor genes. In the present study, we intend to prove that the gene PTEN (phosphatase and tensin homolog deleted on chromosome ten) is a target gene of miR-205 and to investigate the suppressive effects on PTEN transcriptional activity by enhancing miR-205 expression in endometrial cancer Ishikawa cells.
Using Ishikawa cells as model systems, we up-regulated miR-205 expression by transient transfection with miR-205 mimics. A luciferase reporter assay, qRT-PCR and western blotting assays were used to verify whether PTEN is a direct target of miR-205. Meanwhile, the modulatory role of miR-205 in the AKT (protein kinase B) pathway was evaluated by determining the AKT phosphorylation. As a biological counterpart, we investigated cell apoptosis using flow cytometry.
Our data indicate that miR-205 down-regulates the expression of PTEN through direct interaction with the putative binding site in the 3'-untranslated region (3'-UTR) of PTEN. Moreover, we documented the functional interactions of miR-205 and PTEN, which have a downstream effect on the regulation of the AKT pathway, explaining, at least in part, the inhibitory effects on Ishikawa cell apoptosis of enhancing miR-205 expression.
For the first time, we demonstrate that the expression of PTEN is directly regulated by miR-205 in endometrial cancer cells and leads the inhibition of cellular apoptosis. This relationship could be targeted for new therapeutic strategies for endometrial cancer.
微小RNA（miRNA）在人类癌症中经常失调，可作为强效癌基因或肿瘤抑制基因发挥作用。在本研究中，我们旨在证明基因PTEN（第10号染色体缺失的磷酸酶和张力蛋白同源物）是miR - 205的靶基因，并通过增强子宫内膜癌Ishikawa细胞中miR - 205的表达来研究其对PTEN转录活性的抑制作用。
以Ishikawa细胞为模型系统，通过用miR - 205模拟物瞬时转染上调miR - 205表达。采用荧光素酶报告基因检测、qRT - PCR和蛋白质印迹分析来验证PTEN是否为miR - 205的直接靶标。同时，通过测定AKT磷酸化来评估miR - 205在AKT（蛋白激酶B）途径中的调节作用。作为生物学对照，我们使用流式细胞术研究细胞凋亡。
我们的数据表明，miR - 205通过与PTEN 3'非翻译区（3'-UTR）中的假定结合位点直接相互作用下调PTEN的表达。此外，我们记录了miR - 205与PTEN的功能相互作用，其对AKT途径的调节具有下游效应，至少部分解释了增强miR - 205表达对Ishikawa细胞凋亡的抑制作用。
我们首次证明在子宫内膜癌细胞中PTEN的表达受miR - 205直接调控，并导致细胞凋亡受到抑制。这种关系可作为子宫内膜癌新治疗策略的靶点。
