I.甲狀腺素受器作用蛋白質-6（TRIP6）及Rac2三磷酸鳥苷水解酶（Rac2 GTPase）在glioblastoma所扮演的角色 II.篩選新式化合物抑制大腸癌細胞DLD-1所衍生之類癌幹細胞之存活與增殖

I.The role of TRIP6 and Rac2 in glioblastoma II.Screening new compounds to inhibit the survival and proliferation of DLD-1-derived cancer stem cells

何幗瑛(HO Kuo-Ying)

指導教授 ： 賴韻如

國立臺灣師範大學/理學院/生命科學系/碩士(2020年)

https://doi.org/10.6345/NTNU202001645

摘要

I.
多型性神經膠質母細胞瘤（glioblastoma multiforme, GBM）是成人最常見且最具侵略性的原發性惡性腦腫瘤。它的侵略性和對傳統療法的抵抗性使其成為一種預後不良的高復發率惡性疾病。GBM中的膠質母細胞瘤幹細胞（glioblastoma stem cells, GSC）被認為與該病的抗性與復發有關。甲狀腺素受器作用蛋白質-6（Thyroid Hormone Receptor Interactor 6, TRIP6）是一種焦點附著分子（focal adhesion molecule），主要功能包括細胞運動、抗凋亡信號、轉錄控制和其他細胞反應。此外，我們還發現TRIP6是維持神經幹細胞的重要蛋白質。我們已知TRIP6在GBM細胞中高量表達，並且TRIP6的表現量高者其患者的預後愈差。然而在於腫瘤生成的過程中，TRIP6調控GBM的分子機制仍有進一步探討的空間。Rac三磷酸鳥苷水解酶（Rac GTPases）是Rho GTPases家族的成員。其主要功能是調節肌動蛋白（actin）細胞骨架的重組、細胞遷移、存活和凋亡。此外，我們亦發現Rac可調控神經膠質母細胞瘤類癌幹細胞的維持。前述所提到的兩個蛋白都與肌動蛋白及細胞的移動有關，因此TRIP6和Rac是否能交互調控維持腫瘤幹細胞的特性，以及TRIP6-Rac信號通路能否作為一種新的神經膠質瘤藥物靶點有待進一步研究。我們建立以干擾RNA將TRIP6表現量削弱後再額外表現Rac GTPase家族中Rac2的細胞株，檢測其衍生之類癌幹細胞增殖的能力發現，Rac2 應該作用於TRIP6下游，協助TRIP6調控神經膠質母細胞瘤類癌幹細胞的生長。

II.
大腸直腸癌亦簡稱為大腸癌，據2017年的報導，為世界上第三大被診斷出的惡性腫瘤，並為全球第四大的致死癌症。在台灣也是罹病人數最高的癌症，目前主要的治療方法為手術治療，再來是化學療法，但是大腸直腸癌在晚期的治癒率非常低，且經常在治療後復發與轉移。近年，許多癌症研究學者認為，癌症的預後不良與高機率的復發，是因為在腫瘤當中有一小群細胞具有幹細胞特性，稱為癌幹細胞。它們具有著自我更新、分裂與分化成癌細胞的能力，並認為這些細胞是造成癌症復發及癌細胞對藥物抗藥性的原因。為了篩選出有效抑制大腸癌細胞，尤其是大腸癌幹細胞增生的化學合成藥物，我們針對一系列吲哚合成化合物做大腸癌幹細胞的存活試驗。其中Gavin 05、Garvin14兩支藥物對大腸癌細胞DLD-1所衍生之類癌幹細胞中有抑制效果。為了進一步確認該藥物對於脊椎動物的毒性，我們利用了斑馬魚進行了毒性測試，結果發現隨著給藥時間越長，幼魚的心搏與控制組相比有明顯的下降，但其外表並無明顯畸形。

關鍵字

多型性神經膠質母細胞瘤 ； 甲狀腺素受體作用蛋白質-6 ； Rac2 ； 大腸直結腸癌 ； 癌症幹細胞 ； 藥篩

並列摘要

I.
Glioblastoma is the most common and aggressive malignant primary brain tumor in adults. Its invasiveness and resistance to traditional therapies make it a highly recurrent malignant disease with poor prognosis. Glioblastoma stem cells （GSC） in GBM are considered to be associated with the resistance and the recurrence of the disease. TRIP6 is a focal adhesion molecule which main functions include cell movement, anti-apoptotic signaling, transcriptional control, and other cellular responses. In addition, we also found that TRIP6 is an important protein in maintaining neural stem cells. TRIP6 is also highly expressed in GBM cells. Moreover, the prognosis of GBM patients are poorer with the higher TRIP6 expression levels. However, the molecular mechanism of TRIP6 in regulating GBM progression needs to be explored more. Rac GTPases is a member of Rho GTPases family. They regulate the rearrangement of actin cytoskeleton, cell migration, survival and apoptosis. Furthermore, we found that Rac GTPases positively regulate GSC maintenance. Therefore, whether TRIP6 and Rac coordinately maintain cancer stem cell properties, and whether TRIP6-Rac signaling pathway can serve as a new drug target for GBM need to be further studied . To investigate this possibility, we established TRIP6 shRNA expressing cell lines with overexpressing Rac2, and examined the proliferation ability of these cells-derived tumorspheres. We found that the Rac2 may act downstream of TRIP6 and mediate TRIP6-regulated proliferation of GBM tumorsphere.

II.
Colorectal cancer, also known as colon cancer, is the third largest diagnosed cancer and the fourth leading cause of cancer death in the world according to the report in 2017. In Taiwan, it is also the most common malignant disease. At present, the main treatment is surgery followed by chemotherapy. However, the cure rate of colorectal cancer in the late stage is very low, and the late stage disease often accompanies with relapse and metastasis after treatment. In recent years, many cancer researchers believe that the poor prognosis and high recurrence of cancer are due to a small group of cells with stem cell characteristics, called cancer stem cells. They have the ability of self-renewal, division and differentiation into cancer cells. These cells may be the cause of cancer recurrence and drug resistance. In order to screen the chemosynthetic drugs that can effectively inhibit the proliferation of colorectal cancer cells, especially the colorectal cancer stem cells, we performed the drug screening of indole compounds for inhibition of colorectal cancer cell, DLD-1. The results showed that Gavin 05 and 14 can inhibit DLD-1 cells and its derived tumorspheres. We further examine the toxicity effects of these two compounds by zebrafish. These two compounds caused mild decreation of heart beat rate but no clear abnormaty of appearance.

並列關鍵字

none

參考文獻

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