Argonaute 2 drives miR-145-dependent gene expression program in breast cancer cells

miR-145 acts as a tumor suppressor miRNA in breast cancer cells expressing Argonaute-2 protein (AGO2), while in the absence of AGO2 miR-145 loses its inhibitory effect on migration. To identify mRNAs that are putatively targeted by miR-145 in breast cancer cells, we exogenously expressed miR-145 in MDA-MB-231 cells, in presence (mimic145) or absence (sirnaAGO2-mimic145) of AGO2 expression. mRNAs modulated by interference of AGO2 alone were also evaluated (sirnaAGO2). Experiment was performed in biological triplicate and includes: 1) MDA-MB-231 cells of control (cntrl), transfected with mimic and siRNA control oligonucleotides; 2) MDA-MB-231 cells overexpressing miR-145 (mimic145); 3) MDA-MB-231 cells interfered for AGO2 expression (sirnaAGO2); 4) MDA-MB-231 cells overexpressing miR-145 and interfered for AGO2 expression (sirnaAGO2+mimic145).

miR-145在表达Argonaute-2蛋白（AGO2）的乳腺癌细胞中作为抑癌微小RNA发挥功能，而在缺失AGO2的情况下，miR-145会丧失其对细胞迁移的抑制作用。为了鉴定乳腺癌细胞中miR-145潜在靶向的mRNA，我们在MDA-MB-231细胞中外源过表达miR-145，分别设置存在AGO2表达（mimic145）与缺失AGO2表达（sirnaAGO2-mimic145）两种条件。同时我们也评估了仅经AGO2干扰所调控的mRNA（sirnaAGO2组）。本实验采用三次生物学重复，包含以下四组样本：1）MDA-MB-231对照组细胞（cntrl），转染了模拟物对照与siRNA对照寡核苷酸；2）过表达miR-145的MDA-MB-231细胞（mimic145）；3）AGO2表达被干扰的MDA-MB-231细胞（sirnaAGO2）；4）同时过表达miR-145且干扰AGO2表达的MDA-MB-231细胞（sirnaAGO2+mimic145）。