LncRNA MANCR介导LTF激活PI3K/AKT通路在甲状腺未分化癌中的促癌作用及机制研究

Anaplastic thyroid cancer (ATC) is one of the most lethal cancers and responds poorly to traditional treatments. So far, there have been very limited researches regarding the tumorigenesis of ATC. We have conducted whole transcriptome sequencing in ATC cancer tissues/ adjacent normal tissues and identified a specific lncRNA expression profile in ATC. Among these lncRNAs, MANCR was significantly upregulated in ATC, suggesting that it might be associated with tumorigenesis. Further studies suggested that LTF, a transcript factor, interacted with MANCR. Moreover, previous studies showed that LTF could regulate the PI3K/AKT pathway. Based on these facts, we hypothesized that MANCR could promote the development of ATC by inhibiting the transcript of inhibitory gene like PTEN and regulating PI3K/AKT pathway via LTF. In the current study, we aim: (1) to testify that MANCR could promote ATC using clinical samples and thyroid cancer cell lines; (2) to explore the mechanism through which MANCR/LTF complex regulates PI3K/AKT pathway on the transcriptional level, using RIP, ChIP-seq and so on. These above studies may reveal a new perspective in the mechanism of tumorigenesis in ATC and help to develop new treatment target for ATC patients.

甲状腺未分化癌（ATC）是预后最差的恶性肿瘤之一，缺乏有效治疗手段。目前对ATC癌变机制的研究非常有限。本研究前期通过ATC癌和癌旁组织的全转录组测序，发现ATC具有独特的lncRNA表达谱。其中MANCR在ATC中表达明显上调，提示有促癌作用。进一步研究发现转录因子LTF是MANCR的互作蛋白，其与PI3K/AKT通路相关。据此假设，MANCR可能通过下调LTF转录因子的活性，阻碍PTEN等抑制性基因的转录，进而激活PI3K/AKT通路，促进ATC的发生发展。本课题拟进行以下研究：1、从临床及细胞层面证实MANCR在ATC中的促癌作用；2、应用RIP、ChIP-seq等技术，研究MANCR与LTF结合后，在转录层面激活PI3K/AKT通路的具体分子机制。本研究从lncRNA的新视角揭示ATC的发生发展机制，为寻找潜在治疗靶点提供新思路。

甲状腺未分化癌（anaplastic thyroid cancer，ATC）是预后最差的恶性肿瘤之一，缺乏有效治疗手段。目前对ATC癌变机制的研究非常有限，非编码RNA在ATC发生发展中的作用尚不明了。本研究通过对ATC的肿瘤及癌旁组织的全转录组测序，发现ATC具有独特的长链非编码RNA（long non-coding RNA，lncRNA）表达谱，并筛选出182条有显著差异性表达的lncRNA。其中，我们选择在ATC中显著高表达的lncRNA MANCR（mitotically associated long non coding RNA）作为研究对象，进行了以下研究：（1）通过转录组数据、临床样本以及公共数据库验证，从临床层面证实了MANCR在ATC中的促癌作用；（2）构建MANCR高、低表达的ATC细胞株，进行细胞增殖、侵袭凋亡等功能学实验，从细胞层面证明MANCR通过增加肿瘤细胞增殖侵袭、减少细胞凋亡发挥促癌作用；（3）进一步分析转录组数据，鉴定出与MANCR共表达的451个基因，通过GO分析、GSEA分析及临床数据验证，发现涉及有丝分裂及细胞周期通路均显著上调，提示MANCR可能作用于细胞周期中的有丝分裂环节；（4）应用RNA pull-down、质谱分析等技术，提示MANCR特异性地与转录因子LTF结合，可能通过LTF介导了PI3K/AKT通路的激活，从而实现促进ATC的发生发展。本研究从临床、细胞两个层面证明MANCR在ATC中有促癌作用，并对其可能的促癌机制进行探讨。本研究有助于了解ATC的发病、进展机制，同时为寻找潜在的药物治疗靶点提供了新思路。