Alternative Splicing of Amyloid Precursor-Like Protein 2 during the Epithelial-Mesenchymal Transition and Cancer Metastasis

 描述(申请人提供)：癌症转移是大多数癌症相关死亡的主要因素。了解促进癌症转移的调控和分子机制对于开发新的预防措施和治疗至关重要。上皮-间充质转化(EMT)是上皮细胞转化为成纤维细胞间充质细胞的基本生物学过程，具有迁移和侵袭其他组织的能力。越来越多的证据表明，癌细胞劫持EMT是为了转移。目前对EMT和肿瘤转移调控的研究大多集中在转录因子和信号转导事件上，然而，选择性的mRNA剪接正在成为调控EMT和转移转移的主要调控网络。该提案旨在表征机械驱动EMT的关键剪接事件以及控制这些事件的选择性剪接的剪接调控组件，以深入了解癌症转移的调控。APLP2是EMT过程中剪接差异最大的基因之一，它是淀粉样前体蛋白家族的成员，在许多组织中表达，参与细胞迁移、黏附、增殖和伤口愈合。然而，APLP2的具体功能，特别是其剪接异构体，目前尚不清楚。编码KPI结构域的APLP2外显子7在胚胎移植过程中被交替剪接，产生长异构体(APLP2-L)和短异构体(APLP2-S)。该项目的中心假设是APLP2的选择性剪接在EMT和乳腺癌转移中是必不可少的。这一假说将通过两个特定的目标来解决，这两个目标是探索APLP2的选择性剪接对APLP2的蛋白分解处理、EMT和癌症转移的机制贡献以及APLP2的选择性剪接的调节。目的1确定APLP2选择性剪接是否在子宫内膜癌和肿瘤转移中起重要作用，以及APLP2选择性剪接是否因果控制APLP2蛋白分解过程从α-分泌酶途径转换为？分泌酶途径。目的2将确定APLP2前mRNA中促进APLP2选择性剪接的反式作用剪接因子和顺式作用元件。总之，这些目标将描述选择性剪接在EMT和癌症转移中的关键作用，并通过靶向APLP2剪接途径为转移性乳腺癌的治疗提供一种令人兴奋的新治疗方法。

 DESCRIPTION (provided by applicant): Cancer metastasis is the major contributing factor to the majority of cancer-related deaths. Understanding the regulation and molecular mechanisms contributing to the promotion of cancer metastasis is paramount to developing new preventative measures and treatments. The epithelial-mesenchymal transition (EMT) is a fundamental biological process where epithelial cells transform into fibroblastic mesenchymal cells capable of migrating and invading other tissues. Increasing evidence suggests that cancer cells hijack EMT in order to become metastatic. Much of the current research into the regulation of EMT and cancer metastasis focuses on transcription factors and signaling events, however alternative mRNA splicing is emerging as a major regulatory network that governs EMT and metastatic transitions. This proposal seeks to characterize the key splicing events that mechanistically drive EMT as well as the splicing regulatory components that control alternative splicing of these events in order to gain insight into the regulation of cancer metastasis. One of the most differentially spliced genes during EMT is APLP2, a member of the amyloid precursor protein family, which is expressed in many tissues and is involved in cell migration, adhesion, proliferation, and wound healing. However, the specific function of APLP2, especially its splice isoforms, is unknown. Exon 7 of APLP2 encoding a Kunitz Protease Inhibitor (KPI) domain is alternatively spliced during EMT yielding a long isoform (APLP2-L) and short isoform (APLP2-S). The central hypothesis of this project is that alternative splicing of APLP2 is essential for EMT and breast cancer metastasis. This hypothesis will be addressed through two specific aims that explore the mechanistic contribution of alternative splicing of APLP2 to APLP2 proteolytic processing, EMT, and cancer metastasis as well as the regulation of APLP2 alternative splicing. Aim 1 seeks to determine if APLP2 alternative splicing is essential for EMT and cancer metastasis and whether APLP2 alternative splicing causally controls switching of APLP2 proteolytic processing from an α-secretase to a ß-secretase pathway. Aim 2 will determine the trans-acting splicing factors and cis-acting elements in APLP2 pre-mRNA that facilitate alternative splicing of APLP2. Together these aims will describe the critical role of alternative splicing in EMT and cancer metastasis as well as offering an exciting new therapeutic approach for the treatment of metastatic breast cancer by targeting the APLP2 splicing pathway.