STK11/LKB1為serine/threonine 蛋白激酶，主要是腺嘌呤磷酸激酶活化蛋白激酶（AMPK）的上游活化激酶，對於細胞維持能量平衡的代謝反應是一個很重要的調控因子。雖然已經清楚知道在Peutz–Jeghers syndrome (PJS)以及一些癌症尤其在肺腺癌中是由於LKB1基因發生突變所造成，但在晚期惡性腫瘤中LKB1在低氧，低血糖與輻射的條件下其訊息傳遞如何控制新陳代謝過程和能源生產仍然了解甚少。因此，我們建立體外肺癌細胞模型來研究LKB1在人類肺腺癌中訊息傳遞所扮演的角色。結果我們發現當我們將LKB1大量表現在LKB1 null A549與H460這兩株肺癌細胞後，LKB1會抑制細胞的轉移，transformation與chemo-resistance。我們從comet assay發現人類肺癌細胞株經UV照射後，LKB1會阻止UV所誘發的DNA damage，另外從MTT assay我們也看到LKB1促使UV照射所引起的細胞凋亡。此外，為了了解體內LKB1的抗癌機制，我們利用Immunoprecipitation-HPLC- Mass Spectrometry (IP-LC-MS) 去找出在不同的cellular stress條件下與LKB1有interacting的新蛋白。結果我們發現LKB1在正常的條件下參與了Cystic Fibrosis Transmembrane Regulator (CFTR) 合成的路徑且在低氧、低血糖的環境下也參與了glycolysis與gluconeogenesis的路徑。從以上我們的實驗結果可以知道在肺癌細胞中LKB1參與了細胞的轉移，能量的代謝以及DNA的修復，而且蛋白質質體分析將提供更多的資訊進一步探討癌症生物能量學和不正常成長信號間的關係，使得肺癌患者具有更加有效且更多選擇性的治療。

STK11/LKB1, a serine/threonine protein kinase, is a key upstream kinase of adenine monophosphate-activated protein kinase (AMPK), a necessary kinase in the control of metabolism for maintaining energy homeostasis. Although it has become clear that LKB1 is mutated in a significant number of Peutz–Jeghers syndrome (PJS) and sporadic cancers, most frequently in adenocarcinoma of the lung, little is known about how the LKB1 signaling regulates the metabolic process and energy production underlying hypoxia and increased radiosensitivity of lung tumor. Here, we employed lung cancer cells as a model system to dissect the functional roles of LKB1 signaling in human lung adenocarcinoma. We found that LKB1 inhibits lung cancer cell migration, transformation and chemo-resistance in vitro after we restored LKB1 expression in LKB1 null A549 and H460 lung cancer cells. We also found that LKB1 prevents UV-induced DNA damage in human lung cancer cell lines by comet assay and activated UV-induced apopotsis by MTT assays. Furthermore, we designed a systems biology approach to provide a comprehensive protein-protein interaction analysis in order to elucidate the LKB1 tumor suppressor network in vivo. We employed Immunoprecipitation-HPLC- Mass Spectrometry (IP-LC-MS) to identify the novel proteins interacting with LKB1 under different cellular stress conditions. We have identified that LKB1 is involved in CFTR synthesis pathway underlying normoxia condition and participates in the glycolysis and gluconeogenesis pathways underlying hypoxia condition. Together, our findings indicated that LKB1 is involved in the regulation of cell migration, energy metabolism and DNA repair in lung cancer cells, and should provides insights to further exploit the concept of deranged cancer bioenergetics and aberrant growth signals to achieve more effective and selective strategies for lung cancer patients.

論文審定書 ------------------------------------------------------------------------------------------- i
中文摘要 -------------------------------------------------------------------------------------------- ii
英文摘要 -------------------------------------------------------------------------------------------- iii
Abbreviations ------------------------------------------------------------------------------------ 1
Introduction 2
Specific Aim 5
Materials and Methods 6
Results 12
Discussion 17
Figures and Tables 22
References 54

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