利用細胞試驗及動物活體影像系統評估人類大腸直腸癌幹細胞之轉移潛力

Utilizing In vitro and In vivo System to Assess the Metastatic Potential of Cancer Stem-like Cells in Human Colorectal Cancer

林慧如(Huei-Ru Lin)

指導教授 ： 謝銘鈞

國立臺灣大學/工學院/醫學工程學研究所/碩士(2011年)

https://doi.org/10.6342/NTU.2011.10588

摘要

癌症轉移是造成癌症病患死亡的重要原因，在罹患大腸直腸癌的患者中很高比例會發生肝轉移的現象，嚴重影響大腸直腸癌患者的預後情形。近年來，許多研究致力於癌症幹細胞的理論，證據顯示腫瘤細胞中只有少數細胞有能力形成新的腫瘤病灶，並且主導腫瘤組織的生長，也有愈來愈多的研究結果指出癌症幹細胞不只與癌症的惡性程度有關，也極有可能在癌症轉移、復發的過程中扮演重要角色。目前，我們對這項假設的詳細機制所知不多，也缺乏完整建立的活體動物模型系統來進行這方面的探討。因此，設計實驗方法研究大腸直腸癌幹細胞在肝轉移過程中所扮演的角色有其必要性。
在本篇論文中，利用細胞試驗和動物試驗，並結合非侵入性的小動物活體影像系統來探討大腸直腸癌幹細胞的轉移潛力。首先，為了進行非侵入性光學影像的觀察，人類大腸直腸癌細胞株皆透過病毒的方式轉染冷光酵素基因。在體外細胞試驗的部份，主要研究細胞的侵襲力和移動能力，在體內動物實驗的部份，注射癌症細胞株和癌症幹細胞進入小鼠脾臟，透過門脈循環散播細胞，進一步結合非侵入性的活體影像系統觀察植入細胞在動物體內的生長及轉移情形。
結果顯示帶有癌症幹細胞表面抗原比例高的細胞株相較於抗原比例低的細胞株可能表現出較強的侵襲力和移動能力，在小鼠體內較易形成肝轉移病灶，但其表現程度與抗原表現程度並未完全一致，進一步利用癌症幹細胞表面抗原篩選出癌症幹細胞，細胞試驗結果發現這些細胞具有較強的侵襲和移動能力，在小鼠體內形成腫瘤的能力也比非癌症幹細胞強。由以上研究結果可知，此種結合體外試驗及動物模型並利用非侵入性活體影像系統的方法，應用於評估細胞轉移情形的研究是可行的，此外大腸直腸癌幹細胞確實表現出較強的轉移潛力。

關鍵字

肝轉移 ； 癌症幹細胞 ； 活體影像系統 ； 大腸直腸癌 ； 動物模型

並列摘要

Cancer metastasis is the primary cause of cancer-related death. Liver is the major site of metastasis for patient with colorectal cancer and it is also the major determinant of survival. In the last several years, cancer stem cells (CSCs) have been identified in several human malignancies, including colorectal cancer. Moreover, more and more studies evidence that CSCs may not only involve in malignant cancer initiation and progression, but also drive cancer metastasis and responsible for tumor recurrence, result in the poor prognostic. However, there is little known about the role of CSCs in metastasis of human cancer, also lacking a well established in vivo animal model system for present studies. Therefore, it is necessary to help elucidate the role of colorectal cancer stem cells in the liver metastatic spread.
In this study, in vitro cells experiments and in vivo animal models were established to observe colorectal cancer stem-like cells metastasis. In order to visualize by bioluminescence imaging system, cancer cells were all transfected with firefly luciferase gene. The metastatic potential of four colon cancer cell lines and CD133 sorted CSCs were assessed. The results showed that the CD133high cell lines were performed higher metastatic potential than CD133low cell lines, but not exact corresponded with CD133 expression levels. On the other hand, in vitro results indicated that the CD133+ cancer cells have great capacities of invasion and migration than CD133- cancer cells; in vivo experimental results showed that CD133+ cells expressed great tumor initiated ability in comparison with CD133- cells.
In conclusion, the in vitro and in vivo model in this study can give better way to help understand the role of CD133+ colorectal cancer stem-like cells in liver metastasis, and also apply to other type of cancer stem cells metastatic researches. Additionally, the CD133+ cancer cells may play a crucial role in colorectal cancer metastatic process.

並列關鍵字

colorectal cancer ； liver metastasis ； cancer stem cells ； bioluminescence imaging ； ultrasound ； animal model

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