2012-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/646859摘要：肺癌是台灣以及世界各國最嚴重的癌症死亡原因。表皮生長因子受體 (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 小分子抑制劑- tyrosine kinase inhibitor (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次發抗藥性的原因。有報導指出epithelium mesenchymal transition (EMT) 與EGFR-TKI 抗藥性有關，我們先前研究也發現EMT調控者-Slug的確可引起對EGFR TKI的抗藥性。近來研究發現不當蛋白質構型反應（unfolded protein response-UPR）會促進EMT。所以我們利用基因微陣列，以配對的EGFR TKI敏感性細胞（PC9, HC827）和抗藥性細胞（PC9/gef, HCC 827/gef）找尋表現量有差異的UPR蛋白質。發現stanniocalcin 2（STC2）在抗藥性細胞有較高的表現。而將STC2轉殖入PC9細胞，的確可造成對EGFR TKI的抗藥性，並抑制caspases以及Bim的表現。在使用EGFR TKI後產生次發性抗藥性病人的肺癌細胞內STC2表現量也比剛診斷的病患高。所以我們想研究STC2以及UPR相關蛋白質造成EGFR TKI抗藥性的機制。最近學者發現STC2可經由抑制細胞外Ca2+進入細胞內，而促進細胞的存活，所以我們也想研究STC2是否經由抑制Ca2+進入癌細胞達到EGFR TKI抗藥性。STC2在許多種癌有過度表現，造成癌症的轉移，以致病人預後較差。但是卻沒有STC2在肺癌的研究。所以我們也利用肺癌組織，研究STC2與肺癌臨床因子以及EGFR TKI抗藥性關係。經由對EGFR TKI抗藥性機制的研究，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, including Taiwan. The treatment of lung cancer is still disappointing. Activation of epidermal growth factor receptor (EGFR) stimulates cell proliferation, anti-apoptosis, angiogenesis, invasion and metastasis. Small molecular tyrosine kinase inhibitors (TKIs) have been developed to treat lung cancer. Studies have identified mutation of the EGFR catalytic domain that predicts the response to TKIs. Despite initial responses to EGFR inhibitors, most patients ultimately have a relapse. A single secondary mutation (T790M) and c-Met amplification were found to be causes of acquired resistance to EGFR TKI. Furthermore, cancer cell undergone an epithelial-mesenchymal transition (EMT) have been found to show increased resistance to apoptosis. Our previous report also showed that Slug, an EMT regulator, confers EGFR TKI resistance. However, the mechanism of EMT conferring EGFR TKIs resistance is not well understood.Endoplasmic reticulum (ER) stress, induced by various stimuli, evolves a group of signal transduction pathway, collectively termed unfolded protein response (UPR). UPR induces EMT. We screened the UPR related genes in the paired gefitinib sensitive cell lines (PC9, HCC827) and resistant cell linee (PC9/gef, HCC827/gef) and found that Stanniocalcin 2 (STC2) expression increased in resistant cells compared to sensitive cells. Overexpression of STC2 in PC9 cells protected cells from gefitinib induced-Bim expression, caspases activation and apoptosis. In clinical samples, STC2 expression was significantly higher in cancer cells with resistance to EGFR TKIs than in treatment-naïve cancer cells.STC2 is a component of UPR and acting as a prosurvival factor. STC2 can suppress the store-operated Ca2+ entry (SOCE) and protect cell from Ca2+ induced apoptosis. STC2 is overexpressed in various cancer types and is associated with poor prognosis. Overexpression of STC2 increases invasiveness and metastatic potential of cancer. However, the expression of STC2 in lung cancer and the role of STC2 in resistance mechanism of EGFR TKI-induced apoptosis have not been addressed before.In this study we will evaluate the effect of expression of STC2 in various EGFR TKI resistant conditions. And we will elucidate those roles of UPR, STC2 and SOCE in the mechanism of resistance to EGFR TKI. We will evaluate the prognostic role of the expression of UPR genes and STC2 in surgical samples of lung cancer patients. And we plan to validate the increased expression of STC2 in cancer cells of patients with acquired resistance to EGFR TKI. Through the study of mechanism of resistance to EGFR TKI, we hope to find the ways to overcome the EGFR TKI resistance. This will bring a new era to the treatment of lung cancer.肺癌表皮生長因子受體抑制劑抗藥性不當蛋白質構型反應lung cancerEGFR TKI resistanceunfolded protein response