2011-08-012024-05-14https://scholars.lib.ntu.edu.tw/handle/123456789/657409摘要：肺癌是台灣以及世界各國最嚴重的癌症死亡原因。表皮生長素受體 (EGFR) 是ErbB 受體家族的一員。EGFR 受到活化，可促進抗凋亡、細胞增生、血管新生、侵襲及轉移。近年來EGFR 抑制劑，小分子tyrosine kinase inhibitor (TKI)對某些肺癌病人有明顯的療效。但使用數個月後就產生抗藥性。有報導指出epitheliummesenchymal transition (EMT)與抗凋亡有關，但是此現象的機制並不清楚。我們在EGFR-TKI 抗藥性細胞株篩檢EMT 調控因子，初步研究發現對EGFR TKI 抗藥性的細胞有較高Slug 之表現；轉殖Slug 可抑制Bim 之表現，使EGFR TKI敏感性的細胞產生抗藥性，而減少細胞凋亡；以si-RNA 抑制Slug 之表現可使EGFR TKI 抗藥性之細胞轉成敏感性。我們之前利用已 cDNA 微陳列技術，發現Slug 是一轉移促進基因。我們進一步利用Slug 基因轉植入低表現的細胞株，以cDNA microarray 研究Slug 所調控的基因。發現Slug 抑制AP-2a 以及Bim 基因之表現。而AP-2a 以及Bim 有促進細胞凋亡之作用。可知Slug 在細胞抗凋亡、細胞分化、以及細胞轉移扮演重要角色。微小核醣核酸(microRNA)是體內的非蛋白質製造(non-protein coding)之小核醣核酸，是重要之基因調節因子。最近之證據顯示，微小核醣核酸之異常表現與腫瘤形成、病患預後及化療反應間成相關性。微小核醣核酸可調控EMT，而EMT 之調控基因也可反過來調控微小核醣核酸表現。在此計畫，我們希望找出Slug 調控的微小核醣核酸，驗證Slug 及其調控的微小核醣核酸在EGFR TKI 藥物敏感性的角色，此微小核醣核酸表現與臨床使用EGFR TKI 效果之關連性。最終期望能對EGFR-TKI 抗藥性之病患的治療指出一條新的方向。<br> Abstract: Lung cancer is the leading cause of cancer mortality in most countries, includingTaiwan. The treatment of lung cancer is still disappointing. Activation of EGFRstimulates anti-apoptosis, cell proliferation, angiogenesis, invasion and metastasis.EGFR molecular tyrosine kinase inhibitors (TKIs) have been developed for treatmentof non-small cell lung cancer. Despite initial responses to these EGFR inhibitors,tumor ultimately developed resistance. Cancer cell that have undergone anepithelial-mesenchymal transition (EMT) have been found to show increasedresistance to apoptosis. However, the mechanism of EMT conferring EGFR TKIsresistance is not well understood. We screened the EMT related genes in the pairedgefitinib sensitive cell line (PC9) and resistant cell line (PC9/IR) and found only Slugwas overexpressed in the gefitinib resistant cells. Previously, we demonstrated thatSlug, identified by a genome-wide cDNA microarray screening, was aninvasion-promoting gene. Slug suppressed E-cadherin and up-regulate MMP-2. Slugwas shown to play roles in a broad spectrum of biological functions such as celldifferentiation, cell adhesion, cell movement, cell invasion, cell cycle regulation andapoptosis. We also performed cDNA microarray analysis and disclosed that Slugsuppressed Bim mRNA expression. Bim is a pro-apoptosis molecule and is involvedin EGFR TKI-induced apoptosis. Slug regulates EMT and metastasis, and plays arole in EGFR TKI resistance. Our works showed that 1) knockdown of Slug by siRNApromotes gefitinib-mediated cell apoptosis; 2) on the contrary, overexpression of Slugprotects gefitinib-mediated cell apoptosis; 3) Slug inhibits gefitinib-induced apoptosisthrough suppressing the expression of Bim.The microRNAs are a new class of small non-protein-coding RNAs that can act asendogenous RNA interference. Recent study showed that microRNAs can be keyregulators of EMT. EMT-related transcriptional factors-ZEB can suppress expressionof microRNAs. In this project, we will investigate the regulation of microRNAs by Slugand the role of Slug-regulated microRNAs involved in regulation of anti-apoptosis,EGFR TKI resistance and metastasis. And we will validate those microRNAs in drugresistance with clinical lung cancer specimens. Through the study of mechanism ofresistance to EGFR TKI, we hope to find the ways to overcome the EGFR TKIresistance. This will bring a new era to the treatment of lung cancer.Our specific aims:1. Identify the Slug regulated microRNAs and confirm that Slug regulates thepromoters of microRNAs.2. Explore Slug conferring EGFR TKI resistance through microRNAs.3. Characterize the putative genes suppressed by the Slug-regulated micro RNAs4. Investigate the clinical relevance of Slug-regulated microRNAs a in lung cancerpatients.肺癌SlugmicroRNAEGFR TKI 抗藥性Lung CancerSlugmicroRNAEGFR TKI resistance