Characterizing an alternatively spliced NTRK2 isoform in development and cancer

项目总结/摘要 发育信号传导与癌症发生、维持和转移之间的联系长期以来一直被忽视。 已知Wnt、Hedgehog和Notch途径的几个成员。仍然有可能是 发育调节的剪接事件可能与这些致癌途径具有相似的特征， 在解剖学上适当的、时间上受限制的环境中正常发育， 失调我们最近发现，激酶缺陷型NTRK 2神经营养因子受体剪接变体， TrkB.T1在神经胶质瘤中占主导地位，并放大几种致癌信号通路。我们的初步数据 表明TrkB.T1是胚胎发育期间跨多个器官表达的主要NTRK 2亚型， 在人类的各种癌症类型中高度表达，当过度表达时， 与PTEN缺失，导致广泛的癌症小鼠。这里提出的项目旨在描述 TrkB.T1在发育和癌症中的作用，使用新的抗体和新的小鼠模型来显示特异性 剪接变异体在出生后在表达它们的特定器官中过度表达时是致癌的 在发展过程中。通过干扰小鼠胚胎中细胞特异性TrkB.T1剪接变体的表达， 使用单细胞组合索引RNA测序分析来跟踪NTRK 2转录物在胚胎中的表达， 和出生后的发展，我的目标是（1）联系发展机制和剪接选择癌症，（2）联系 一种激酶缺陷蛋白，其信号传导增加，以及（3）试图辨别是否在特定的 发育状态会导致癌症通过进一步表征TrkB.T1发挥作用的机制， 这些项目有可能为多种癌症的诊断和治疗开辟新的途径 类型这里提出的实验建立在我以前在神经发育，神经营养生物学， 和癌症，并将有助于为我的长期职业目标奠定基础， 研究神经营养对肿瘤生物学的贡献和揭示 对肿瘤发生的发育影响。

Project Summary/Abstract The link between developmental signaling and cancer initiation, maintenance and metastasis has long been known for several members of the Wnt, Hedgehog, and Notch pathways. The possibility remains that a developmentally-regulated splicing event may share similar features with these oncogenic pathways, driving normal development in an anatomically appropriate, temporally restricted context, and causing cancer when dysregulated. We have recently shown that a kinase-deficient NTRK2 neurotrophin receptor splice variant, TrkB.T1, predominates in glioma and amplifies several oncogenic signaling pathways. Our preliminary data suggest that TrkB.T1 is the predominate NTRK2 isoform expressed across multiple organs during embryonic development, is highly expressed in various cancer types in humans, and when over-expressed in combination with PTEN loss, causes a wide range of cancers in mice. The project proposed here seeks to characterize the role TrkB.T1 in development and cancer using a novel antibody and a novel mouse model to show that specific splice variants are oncogenic when overexpressed, postnatally, in the specific organs that expressed them during development. By perturbing cell-specific TrkB.T1 splice variant expression in mice, embryonically, and using single cell combinatorial indexing RNA-sequencing analysis to follow NTRK2 transcripts across embryonic and postnatal development, I aim to (1) link developmental mechanisms and splicing choices to cancer, (2) link a kinase deficient protein with increases in signaling, and (3) seek to discern whether trapping cells in a particular developmental state can lead to cancer. By further characterizing the mechanism by which TrkB.T1 functions, these projects have the potential to open new avenues for diagnostic and therapeutic targets for multiple cancer types. The experiments proposed here build upon my previous work in neurodevelopment, neurotrophin biology, and cancer and will help set the stage for my long-term career goals which center around employing a developmentally guided approach to studying neurotrophic contributions to tumor biology and uncovering developmental influences on oncogenesis.