胰腺癌（Pancreatic ductal adenocarcinoma， PDAC）於美國癌症死亡排行高居第三名，其五年存活率也僅只有8%。轉型生長因子β（Transforming growth factor beta， TGF-β）是一具多功能之細胞激素，其功能視細胞種類而異，包括抑制腫瘤訊號傳遞，反之也可以促進胰臟癌進程中的細胞間質化，部分是藉由調控異位表現的VAV1。根據過去的研究也指出過度表達的VAV1與胰腺癌病人的低存活率有關聯。雖然核內VAV1表現量高的病人中的相較於細胞質中VAV1表現較高的病人來說明顯有較好的整體存活率，但是細胞核中VAV1的調控功能依舊未知。對於致癌基因VAV1未知的機制和其對於基因組上的分布與結合情況，以及在胰腺癌癌化過程中其訊息RNA表現量失調的現象仍然尚未清楚。因此我們假設VAV1在胰腺癌進程中可能具有調控轉錄的功能。藉由VAV1染色質免疫沉澱定序（chromatin immunoprecipitation sequencing, ChIP-Seq）的分析來探討PANC-1細胞株在給予或不給予轉型生長因子β後VAV1基因組佔據的情形。進一步為了瞭解在給予TGF-β後VAV1調控的區域與基因表現的關聯性，我們藉由RNA高通量定序分析（RNA sequencing，RNA-Seq）的方式比較PANC-04.03細胞株在給予VAV1小分子干擾RNA與陰性控制小分子干擾RNA後轉錄體的表現情形。結果顯示經由VAV1小分子干擾後有2104個基因表現量上升，而有1915個基因表現量下降。最後將這些經由RNA高通量定序分析篩選出的基因與染色質免疫沉澱定序的資料組比對找出於胰腺癌中調控轉型生長因子β下游的潛在基因進行後續的功能分析。總結來說，核內VAV1的表現情形可用來釐清VAV1在胰腺癌上皮細胞間質化過程中調控的機制。另一方面，源自於胰臟癌母細胞的外泌體（Exosome）包裹著高完整度的RNA被分泌到生物體液中，具有潛力作為早期胰臟癌診斷的依據，因此我純化來自於胰臟癌病人的胰液和血清中的外泌體中RNA進行RNA高通量定序分析找出特異性的生物標記。

Pancreatic ductal adenocarcinoma (PDAC) is the third leading cause of cancer-related death in the United States, and has a poor five-year overall survival rate of 8%. Transforming growth factor beta (TGF-β) is a multifunctional cytokine that operates context-dependently, either as a ligand for tumor suppressive signaling, or conversely as a trigger for mesenchymal differentiation of pancreatic cancer progression partly due to ectopic expression of VAV1. Previous research indicates that VAV1 over-expression is linked to poor survival in PDAC. Although the role of VAV1 in cell nucleus remains unclear, patients with nuclear VAV1 expression are associated with significantly better overall survival as compared to those with cytosolic VAV1. The underlying mechanisms of oncogenic VAV1 and its genome-wide occupancy, as well as the dysregulated messenger RNA expression in pancreatic carcinogenesis is not fully understood. Therefore, we hypothesized that VAV1 may have the potential to regulate transcription in PDAC progression. By conducting VAV1 chromatin immunoprecipitation sequencing (ChIP-Seq) analysis, we investigated the genome-wide binding patterns of VAV1 in PANC-1 cells with or without short-term TGF-β treatment. To correlate the effect of VAV1 binding and gene expression under TGF-β treatment, we compared the mRNA expression in PANC-04.03 cells that are transfected with VAV1 siRNA, as compared with control siRNA by RNA sequencing (RNA-Seq). Our result showed that 2104 upregulated and 1915 downregulated candidate genes were significantly altered in VAV1 siRNA transfected cells. Finally, a number of RNA-Seq candidates overlapped with the ChIP-Seq datasets with potential for TGF-β downstream effects in PDAC were selected for further functional investigation. In summary, nuclear VAV1 expression might functionally elucidate the mechanisms of VAV1 in mesenchymal differentiation of pancreatic cancer. On the other hand, since exosomes derived from the parental cells carry high integrity RNA and are released into bio-fluids in pancreatic carcinogenesis, RNA transcript packaging into exosome may be potential biomarkers in early pancreatic cancer diagnosis. Thus, I isolated the exosomes derived from both the pancreatic juice and the serum of pancreatic cancer patient followed by RNA-seq transcriptomic analysis to find out specific biomarker.

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