BCSCs是乳腺癌复发耐药根源。可变剪接（AS）是基因功能调节和多样化关键方式。LncRNA是调控基因表达重要分子，是否参与AS介导BCSCs干性？调控机制如何？待阐明。申请者发现：BCSCs中Linc00887、剪接体PKM2和剪接因子hnRNPA1高表达；沉默Linc00887降低BCSCs干性和PKM2表达，Linc00887与PKM pre-mRNA和hnRNPA1有结合位点。提示Linc00887募集hnRNPA1特异结合PKM pre-mRNA调控PKM2表达介导BCSCs干性。本项目旨在明确Linc00887与PKM pre-mRNA关键结合位点，阐释hnRNPA1介导PKM2变体表达作用，确认Linc00887募集hnRNPA1特异结合PKM pre-mRNA调控AS方式，阐明Linc00887调控AS介导BCSCs干性机制。为研究BCSCs干性维持新机制与新靶点提供依据。

Breast cancer stem cells (BCSCs) are responsible for the recurrence and chemoresistance of breast cancer. Alternative splicing (AS) is a key approach to regulate gene function and make gene diversity. LncRNAs play essential roles in regulating gene expression. Whether LncRNAs participate in AS-mediated stemness of BCSCs? What is the regulation mechanism? These remain to be clarified. We found that Linc00887, splice variant PKM2 and splicing factor hnRNPA1 were highly expressed in BCSCs, and silencing Linc00887 reduced the stemness of BCSCs and the expression of PKM2. And we also found that Linc00887 had binding sites with PKM pre-mRNA and hnRNPA1, respectively. It is suggested that Linc00887 specifically binds to PKM pre-mRNA to recruit hnRNPA1 to up-regulate PKM2 expression to mediate the stemness of BCSCs. This project aims to confirm the key binding sites between Linc00887 and PKM pre-mRNA, to elucidate that hnRNPA1 can promote the expression of PKM2 variants, to confirm that Linc00887 specifically binds to PKM pre-mRNA and recruits hnRNPA1 to regulate AS, and to further clarify the mechanism of Linc00887 regulating AS-mediated BCSCs. This study will provide a new idea and a new target for deep researching the mechanism of maintaining the BCSCs characteristics.