胰腺癌外泌体KLF5通过激活TMPRSS4促进侵袭转移的机制研究

Exosomes, which act as a signal transduction medium between cells, play an important role in the carcinogenesis and development of pancreatic cancer (PC). Our previous results showed that the expression of kruppel like factor 5（KLF5) was up-regulated in exosomes derived from PC patients with liver metastasis comparing with exosomes derived from PC patients without liver metastasis. KLF5-expressing PC-derived exosomes promoted the cell proliferation, migration and invasion in PC. TMPRSS4 (Transmembrane protease serine 4) was screened as a downstream target gene of KLF5 by bioinformatics analysis and qRT-PCR. However, the molecular mechanism of cell invasion and metastasis regulated by exosomes remains unclear. Therefore, we propose a hypothesis that KLF5-expressing PC-derived exosomes promotes the invasion and metastasis of PC by activating TMPRSS4. To test the above hypothesis, the project is intended to be carried out by means of the clinical pathology analysis, the functional experiments of exosomes acting cancer cells, in vitro imaging revealing cancer cell uptake of exosomes, the functional recovery tests, chromatin immunoprecipitation and bioinformatics, from the multiple layers of tissue, cells, and molecules to investigate the molecular mechanism of KLF5-expressing PC-derived exosomes in the mediation of invasion and metastasis by regulating TMPRSS4. This study will provide a new target for early detection and disease intervention of PC.

在细胞间担当信号传递介质的外泌体（exosomes）在胰腺癌发生发展中起重要调控作用。课题组预实验发现KLF5在胰腺癌伴有肝转移病人的外泌体中表达显著上调，外泌体KLF5可促进胰腺癌细胞的增殖、迁移与侵袭能力，生物信息学及qRT-PCR验证筛选出KLF5的下游靶基因TMPRSS4，然而外泌体KLF5调控胰腺癌迁移侵袭的具体机制尚不明确。因此，我们提出假说：胰腺癌外泌体KLF5通过激活TMPRSS4促进癌细胞的侵袭转移。为验证上述假说，本项目拟通过临床病理观察，外泌体作用癌细胞的功能实验，细胞摄取外泌体成像，功能回复实验，染色质免疫共沉淀技术及生物信息学等技术，从组织、细胞、分子等多层面探索外泌体KLF5调控TMPRSS4促进胰腺癌侵袭转移的分子机制，为胰腺癌诊治提供新的干预靶点。

胰腺癌（Pancreatic cancer, PC）是恶性程度极高的肿瘤之一，我们率先发现KLF5在胰腺癌伴有肝转移病人的外泌体中表达显著上调。进一步验证发现KLF5在PC组织中相对高表达，且KLF5表达水平与患者预后呈负相关，是胰腺癌患者不良预后的独立危险因素；KLF5在体内外增强PC细胞的增殖、侵袭和迁移能力；KLF5可经由外泌体在胰腺癌细胞间转移且发挥促癌作用；TMPRSS4是接受KLF5调控的下游靶基因，激活后的TMPRSS4促进PC细胞的增殖、侵袭和迁移；KLF5通过激活TMPRSS4表达进而促进上皮-间质转化。综上，胰腺癌细胞中的KLF5通过外泌体在细胞间转移并通过激活TMPRSS4促进上皮-间质的转化，促进胰腺癌的增殖、侵袭和转移，它为胰腺癌的靶向治疗提供新的干预靶点。