2011-05-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/657249摘要：小GTPase 功能異常在癌症發生扮演重要角色。本計畫第一個目的為釐清CXCR4 引發之Rho GTPase 傳導促成胰臟癌轉移的機制。第二個目的在於驗證由各子計畫所發現之可能分子來找出有用的生物標記及治療標的，開發對應的診斷試劑以供專利申請及臨床使用，以及篩選對應的抑制劑找尋新的抗癌藥物。實驗證據指出CXCR4 異常表現是胰臟癌轉移的重要因子，我們也證實CXCR4 表現與胰臟癌病患轉移及癒後不良有關。Guanine nucleotide exchange factors (GEFs)藉由促進GDP 與GTP 交換調控GTPases，而其功能不正常為GTPases 功能失調的主要機轉。VAV1是Rho GTPase 家族 (RhoA, Rac1 and Cdc42)的GEF，其表現在胰臟癌會增加。有趣的是，在T 細胞中CXCR4 能活化VAV1 及Rho GTPase 傳導，進而促進細胞骨架重構和細胞趨化反應，也能促進JNK 傳導及細胞增生。因此我們假設VAV1 的活化與Rho GTPase 傳導是CXCR4 造成胰臟癌轉移的機制。由實驗選出之可能分子必須經過臨床驗證，才能作為生物標記與新藥開發標的。我們已建立胃炎、胰臟癌、大腸癌之病患世代，並曾以此驗證相關的生物標記。我們將使用這些檢體與資料來驗證可能的生物標記與藥物標的。在生物標記方面，我們將與子計畫2 合作開發GTPase 路徑試劑供快速檢測病人腫瘤之GTPases 活性。至於藥物標的，將分析其抑制劑對腫瘤細胞株生長移動與侵犯能力的影響以評估其有用性。<br> Abstract: Mounting evidence supports a causal role for aberrant activity of small GTPasesin various malignancies. The first aim of this sub-project is to clarify the potentialrole of CXCR4-induced Rho GTPases signaling in pancreatic cancer (PC) metastasis,and to verify its clinical significance and usefulness as therapeutic targets. Thesecond aim is to validate the candidate molecules from every sub-project to identifyuseful diagnostic/prognostic biomarkers and therapeutic targets, develop acorresponding diagnostic kit (“GTPases pathways assay”) for patent application andclinical use, and screen corresponding pharmacologic inhibitors to discover novelanti-cancer therapies.Metastasis occurs early in pancreatic cancer (PC) with a dismal prognosis.Experimental evidences indicate aberrant CXCR4 expression as a critical mediatorof PC metastasis, and we have also confirmed an independent association betweentumor CXCR4 expression and metastasis/poor survival in PC patients. However, theunderlying mechanism remains unclear. Deregulated activity of guanine nucleotideexchange factors (GEFs), which turns on activities of small GTPases by facilitatingGDP to GTP exchange, is a common mechanism of abnormal GTPases function.Expression of VAV1, a GEF for Rho GTPase family (RhoA, Rac1 and Cdc42), isincreased in PC. Interestingly, CXCR4 signaling induces VAV1 activation in Tlymphocytes and downstream Rho GTPase-PAK1 signaling, which promotescytoskeleton remodeling and chemotaxis. VAV1-induced activation of Rho GTPasescan also induce JNK signaling and promote cell proliferation. Therefore, we aim toverify if VAV1 activation and subsequent Rho GTPases signaling is responsible forthe pro-metastasis effects of CXCR4 in PC and influences patient survival, and thusrepresents a potential therapeutic target.Candidate molecules identified in-vitro or in-vivo must be validated bylongitudinal clinical studies before they can be further used as biomarkers or targetsfor new drug discovery. We have established patient cohorts of gastric, pancreaticand colorectal carcinomas, and the tissue specimens and clinical outcome have beensuccessfully used to validate various biomarkers. These cohorts will be used tovalidate the candidate molecules identified in every sub-project to identify usefulbiomarkers and drug targets within GTPases signaling pathways. For the biomarkers,we will collaborate with sub-project 2 to develop a “GTPases pathways assay” toenable easy detection of abnormal GTPases pathway activities in patients’ tissuesand facilitates early diagnosis, prognosis prediction, or treatment selection in theclinical setting. For the identified novel drug target, we will explore the potential oftheir inhibitors as novel anti-tumor drugs by evaluating their effects on tumorproliferation, migration and invasion in various cancer cell lines.This sub-project covers biomarker/drug target discovery from GTPases pathways,their preclinical validation, development of a novel diagnostic kit (“GTPasespathways assay”), and in-vitro screening for potential anti-cancer therapies. Theproposed “GTPases pathways assay” should have a wide clinical application indiagnosis/risk stratification and treatment selection and thus a great potential forpatent application and technology transfer. Through collaboration with othersub-projects, this sub-project aims to facilitate personalized medicine for cancer byprofiling of key GTPase pathways in the clinical setting and subsequent tailor-madetreatments.CXCR4Rho GTPasesVAV1胰臟癌生物標記CXCR4Rho GTPasesVAV1pancreatic cancerbiomarker