Cytochrome c oxidase subunit Va在非小型細胞肺癌轉移所扮演之功能角色

Abstract

肺癌為世界前十大死因之ㄧ，在治療與預防上亦面臨重大挑戰，因此biomarker 之鑑識及肺癌早期診斷技術為重要研究範疇。蛋白質是基因表現過程的最終產物，因此 藥物治療和診斷方式也經常是以蛋白質產物為目標。所以蛋白質體將有利於新藥開發及 快速診斷，並將引領新的診斷及治療方式，因此在本計畫先導試驗中利用2D-PAGE 及 MASS spectrometry 分析六株非小型細胞肺癌細胞發現兩蛋白質(COX Va and gelatin-1)顯著表現於invasion 能力高之細胞株。在先前研究中以報導gelatin-1 與癌細 胞之轉移有相關性，而COX Va 並未被研究與癌症有關。因此我們將深入探討COX Va 於癌細胞轉移之相關性。COX Va 為cytochrome c oxidase subunit 之ㄧ，主要由細胞 核所轉譯出，能專一性與3,5-diiodothyronine 結合進而破壞allosteric ATP inhibition。 在cytochrome c oxidase 中allosteric ATP inhibition 主要藉由cAMP-indendent phosphorylation 及calcium-induce dephosphorylation 來調控呼吸作用。更在近期研 究中發現當COX Va 受質(palmitate and 3,5-diiodothyronine)高時會導致ROS 產生。ROS 會造成蛋白質、脂質及DNA 受損，更會活化MMP 之活性，而活化MMP 切除細胞外基 質為癌細胞之轉移之主要因素，因此我們認為COX Va 應参與癌細胞之轉移。所因在本 計畫中將利用in vitro 及in vivo 探討COX Va 與非小型細胞肺癌轉移之關係。本計畫執 行目標如下 1. 分析COX Va 對非小型細胞肺癌migration and invasion 之關係。(第一年) 2. 探討COX Va 影響migration and invasion 之機制。(第一年及第二年) 3. 利用動物實驗模式探討COX Va 與腫瘤轉移之關係。(第二年) 4. 病理學分析統計COX Va 與非小型細胞肺癌相關性。(第一年及第二年)

Lung cancer is the leading cause of cancer death and its prevention is a major worldwide challenge. Therefore, it is important to identify biomarkers and establish rapid screening method for the early detection of lung cancer. Proteomics is complementary to genomics because it focuses on the gene products, which are the active agents in cells. For this reason, proteomics directly contributes to drug development and diagnosis and it will be the novel diagnosis and therapy for lung cancer by proteomic mapping. In our preliminary study, we analyzed the seven non small cell lung cancer cell lines using 2D-electrophoresis and MASS spectrometry assay and found two proteins (cytochrome c oxidase subunit Va (COX Va) and gelatin-1) showing statistically significant expression in the highly invasive cells. Previous reports have shown that gelatin-1 is associated with cancer metastasis. However, COX Va has not reported. Therefore, we will focus on COX Va correlate with tumor migration and invasion. COX Va, one of cytochrome c oxidase subunit, encoded from nuclear which specific bind with 3,5-diiodothyronine and abolish the allosteric ATP inhibition. Allosteric ATP inhibition of cytochrome c oxidase switches on by cAMP-indendent phosphorylation and switches off by calcium-induce dephosphorylation which is the mechanism of respiratory control. A recent study shows that high substrate pressure (sigmoidal v/s kinetics), palmitate and 3,5-diiodothyronine (binding to subunit Va) increase also delta p, ROS production and slip but without dephosphorylation of COX. ROS will damage proteins, lipids, and DNA and may induce activated matrix metalloproteinases (MMPs). Cell migration is intimately linked to degradation of the extracellular matrix, and activated MMPs are a prerequisite for cancer cell invasion and metastasis. Therefore, we postulate that COX Va may involve tumor migration and invasion. We attempt to investigate the influence of COX Va on tumor migration and invasion using in vitro and in vivo model system. The specific aims of this study in next three years will be: 1) To investigate COX Va involved in tumor migration and invasion. 2) To study the mechanism of COX Va in tumor migration and invasion. 3) To study COX Va involved in migration and invasion by using mice as an animal model. 4) To correlate COX Va with the outcome of non-small cell lung cancer patients.