2011-01-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/646861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，可促進細胞增生、抗凋亡、血管新生、侵襲及轉移。近年來EGFR 抑制劑，小分子tyrosine kinaseinhibitor (TKI)對某些肺癌病人有明顯的療效，尤其是東亞之不抽煙女性肺腺癌病患。但使用數個月後就產生抗藥性。最近有研究發現EGFR kinase domain 突變與非小細胞肺癌對EGFR TKI 之敏感性有關。而第二個EGFR 突變（T790M）及C-Met 基因倍增是造成EGFR TKI 抗藥性的原因。有報導指出epithelium mesenchymal transition (EMT)與EGFR-TKI 抗藥性有關，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 可使EGFR TKI敏感性的細胞減少細胞凋亡，以si-RNA 抑制Slug 之表現可使EGFR TKI 抗藥性之細胞轉成敏感性。目前已知 Slug 在細胞分化、細胞抗凋亡、以及細胞轉移扮演重要角色。我們之前利用已cDNA 微陳列技術、體外侵襲力分析、實驗性癌轉移模式及肺癌病人組織，發現Slug 的確是一轉移促進基因。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 直接對AP-2a 基因之轉動子抑制，並抑制AP-2a 以及Bim 基因之表現。而AP-2a 以及Bim 有促進細胞凋亡及抑制癌轉移之作用。在此計畫，我們希望進一步以肺癌病患之檢體，驗證 Slug 及其下游基因AP-2a 和Bim 在EGFR TKI 藥物敏感性的角色，此基因表現與臨床使用EGFR TKI 效果之關連性，以及EGFR TKI 抗藥性對腫瘤轉移之影響。經此證實，由抗藥性細胞株所發現 Slug 具EGFR-TKI 抗藥性。進一步將利用此細胞株，以RNAi library 篩檢之方式及病人檢體，印證其他可能的EGFR-TKI 抗藥機制，最終期望能對原發性或次發性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, including Taiwan.Activation of EGFR stimulates cell proliferation, anti-apoptosis, angiogenesis, invasion andmetastasis. Several EGFR molecular tyrosine kinase inhibitors (TKIs), such as gefitinib anderlotinib, have been developed in recent years. The clinical response of non-small cell lungcancer (NSCLC) to EGFR TKI therapy was dramatic in some patients, especially in EastAsian people. Studies have identified mutations of the EGFR catalytic domain that predict theresponse to TKIs of NSCLC. In East Asia, around 30-40% of NSCLC patients has EGFRmutations and has good response to EGFR TKIs. Despite initial responses to these EGFRinhibitors, most patients ultimately have a relapse. A single secondary mutation, a substitutionof methionine for threonine at position 790 (T790M) and c-Met amplification were found tobe causes of primary and secondary resistant to EGFR TKI. Furthermore,epithelial-mesenchymal transition (EMT) was also reported to be associated with EGFR TKIsresistance. However, the mechanisms underlying EGFR TKIs resistance are not wellunderstood.We screened the EMT related genes in the paired gefitinib sensitive cell line (PC9) andresistant cell line (PC9-IR) and found Slug was overexpressed in the gefitinib resistant cells.Previously, we demonstrated that Slug, identified by a genome-wide cDNA microarrayscreening, was an invasion-promoting gene. Slug is a transcription suppressor. Increase ofcancer cell invasion by Slug was mediated through the suppression of E-cadherin andup-regulation of MMP-2. Slug regulates epithelial–mesenchymal transition (EMT). Slug mayalso play a role in EGFR TKI resistance. We performed cDNA microarray, Q-RT-PCR, EMSAand chromatin immunoprecipitation and disclosed that Slug suppressed activator protein-2a(AP-2a) and Bim transcription. AP-2a plays a pivotal role in regulating the expression ofseveral genes, involved in metastasis and apoptosis. AP-2a also determined thechemosensitivity of cancer cells. Bim is a pro-apoptosis molecule and is involved in EGFRTKI induced apoptosis.We collected lung cancer tissue from patients treated with EGFR TKI. The clinicalsample will be used to confirm the critical roles of Slug and its down-stream genes in theEGFR TKI resistance.After the proof of concept that siRNA of Slug can revert EGFR TKI resistance throughstudies of cell lines and lung cancer tissue, RNAi library will be used to screen the genesinvolved in EGFR TKI resistance. Through the study of mechanism of resistance to EGFRTKI, we hope to find the ways to overcome the EGFR TKI resistance and to treat patients ofNSCLC with primary or secondary resistance to EGFR TKI.肺癌上皮生長因子受體激脢抑制劑抗藥性lung cancerEGFR tyrosine kinase inhibitorsdrug resistance