乳癌病患血漿載脂蛋白E之轉譯後修飾特徵的研究

The Study of Post-translational Modification Signature of Plasma Apolipoprotein E in Breast Cancer Patients

戴智君(Chih-Chun Tai)

指導教授 ： 林景堉

臺北醫學大學/醫學科技學院/醫學檢驗暨生物技術學系所/碩士(2014年)

摘要

目的：台灣女性癌症的死亡率中乳癌居癌症死因的第四位，若是乳癌於早期能被診斷出來時，其生存率可高達95%以上，因此開發早期診斷乳癌的生物標記是迫切需要的。在本研究中，我們研究在乳癌與正常受試者間的候選蛋白質生物標記與候選轉譯後修飾標記。
方法：在本研究中，我們使用一維凝膠電泳和奈米級液相層析串聯質譜儀從血漿樣品中篩選候選生物標記，血漿樣品來自24位乳癌患者和24位健康受試者。我們以年齡配對個別血漿樣品。
結果：在質譜分析中鑑定出載脂蛋白E在乳癌與正常控制組在轉譯後修飾比例相比有顯著差異，因此我們利用西方墨點法驗證質譜分析的結果，發現載脂蛋白E於乳癌與正常控制組的蛋白質表現量於Normal average = 104,381，在Breast Cancer average = 97,787相差0.93倍，學生t檢定為0.58，在統計上無顯著差異。再分別將24位乳癌與正常控制組依據年齡分別配對後進行質譜分析，發現了四個殘基具有轉譯後修飾差異，Glutamine-205有二甲基化 (Dimethylation)的修飾，Lysine-260有Aldohexosyl的修飾，Serine-281有n-Decanoate的修飾，及Threonine-307有NeuAc-Hex-HexNAc的修飾。Glutamine-205修飾有上升3.73倍的差異、Lysine-260修飾有上升2.09倍的差異、Serine-281修飾有上升1.68倍的差異和Threonine-307修飾有下降1.85倍的差異，利用ROC curve分析，四種新穎性轉譯後修飾的AUC分別為0.778、0.821、0.938與0.815，屬於可接受或是好的判別力。
結論：載脂蛋白E的蛋白質表現量差異，對乳癌檢測沒有判別力。此外，四個在載脂蛋白E的新穎性轉譯後修飾，對乳癌檢測屬於可接受或是好的判別力(0.7≦AUC≦0.8，可接受的判別力；0.8≦AUC≦0.9，好的判別力)。這些結果顯示，在載脂蛋白E發現的四個新穎性轉譯後修飾可能做為評估乳癌的標記。

關鍵字

乳癌 ； 載脂蛋白E

並列摘要

Objective: Taiwanese female breast cancer mortality ranking cause of cancer death in the fourth, when if breast cancer can be diagnosed at an early stage, the survival rate can be as high as 95%, so the development of biomarkers for early diagnosis of breast cancer are urgently needed. In the present study, we investigate the protein biomarker candidate and post-translational modification candidate in breast cancer and healthy volunteers plasma sample.
Methods: In the present study, we used one-dimensional gel electrophoresis and nano-LC-MS/MS to screen biomarker candidates in plasma samples obtained from 24 patients with breast cancer and 24 healthy volunteers. Our age-matched individual plasma samples.
Results: We identified in the nano-LC-MS/MS analysis modification of apolipoprotein E have a significant difference in breast cancer compared with the normal control group, Therefore, we use Western blot analysis to verify the results of nano-LC-MS/MS, Found that apolipoprotein E protein expression in breast cancer and normal control group in Normal average = 104,381, the Breast Cancer average = 97,787 difference 0.93 fold,Student’s t-test was 0.58, so there is no difference. Then were the 24 breast cancer and normal control group based on nano-LC-MS/MS were paired for age, found after four residues with translational modification differences, Glutamine-205 has Dimethylation modification, Lysine-260 has Aldohexosyl modification, Serine-281 modification with n-Decanoate, and Threonine-307 with NeuAc-Hex-HexNAc modification. Glutamine-205 modification have increased 3.73 fold difference, Lysine-260 modifications have increased by increased 2.09 fold difference, Serine-281 modification with increased 1.68 fold in the differences and Threonine-307 modifications have decreased 1.85 fold, The use of ROC curve analysis, the four novel translational modification of AUC and 0.815 respectively 0.778, 0.821, 0.938 belonging acceptable or good discriminative power. Conclusion: The difference in protein expression of apolipoprotein E in the detection of breast cancer is no discrimination power. In addition, four after the novelty of apolipoprotein E-translational modification, the detection of breast cancer are acceptable or good discriminating power (0.7 ≦ AUC ≦ 0.8, acceptable discriminant power; 0.8 ≦ AUC ≦ 0.9, good judgment force). These results show that after apolipoprotein E discovered four novel translational modification may be used as markers to assess breast cancer.

並列關鍵字

Breast cancer ； Apolipoprotein E

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