探討抗癌藥物抑制環氧化酶-2對CCR7的表現及調控癌細胞轉移相關基因的分子機制

Functional roles of COX-2 induced CCR7 and other metastasis-related genes in cancer progression and suppression by anti-cancer drugs

潘美仁(Mei-Ren Pan)

指導教授 ： 洪文俊

高雄醫學大學/醫學院/醫學研究所/博士(2008年)

https://doi.org/10.6832/KMU.2008.00083

摘要

本論文著重探討COX-2 參與調控腫瘤轉移和非類固醇抗發炎藥
物抑制轉移的分子機轉。
本論文共分二部份。第一部份，我們著重於COX-2增加淋巴性血管新生和癌細胞淋巴轉移的機制探討。我們則提出CCR7是COX-2的下游調控基因，在COX-2的作用下，會增加乳癌細胞往淋巴內皮細胞移動，進而提昇乳癌細胞淋巴結侵犯的能力。
我們也進一步的分析由植物Tubocapsium anomalum純化一種具生物活性的Withanolide Tubocapsanolide A (Tubo A)是否具有影響乳癌細胞CCR7表現和抑制乳癌細胞淋巴侵犯的效果。結果，我們發現Tubo A可藉由抑制IKK和MSK活性來降低乳癌細胞中NFκB對CCR7的調控作用。
第二部份，我們利用microarray 系統找到幾種與癌細胞轉移相關基因會受NSAIDs的調控。之前我們的研究已經發現NSAIDs可以藉由調控MMP-2的表現和活性來達到抑制細胞的侵犯。現在我們發現包括SPARC、TSP1、TSP3和TIMP-2都可以被NS398 (COX-2 inhibitor)誘導表現。首先我鎖定探討NS398對SPARC和TSP1的機制探討。因為兩者都已被報導在癌細胞中扮演的可能是抑癌蛋白的角色。藉由特異性抗體阻斷中和細胞中的功能後，我們發現會提高A549 cells本身的migration能力，故兩者在A549 cell的角色是一種腫瘤抑制蛋白。 進而，確認NSAIDs會藉由對它們的調控而抑制A549肺癌細胞的侵犯能力。並且進而發現NSAIDs 是透過不同方式機轉去促進細胞中TSP1和SPARC的表現。其中， NSAIDs可藉由調節promoter demethylation來提高細胞中SPARC的量，而 NSAIDs則是藉由改變TSP1轉錄活性和mRNA 穩定性來提昇TSP1在細胞中的量。
這篇論文我不僅提出COX-2可藉由調控腫瘤細胞CCR7表現以促進本身淋巴侵犯能力，我們也發現一些會受NSAIDs所調控的腫瘤轉移相關基因。更重要的是，我們更發現了一種新的抗癌藥物 Tubo A可以藉由減少乳癌細胞中CCR7的表現，以降低癌細胞往淋巴內皮細胞的轉移。

關鍵字

環氧化酶-2； 細胞激素； 淋巴轉移 ； 非類固醇抗發炎藥物

並列摘要

My thesis focuses on cyclooxygenase-2 (COX-2) - mediated tumor metastasis and anti-metastatic mechanism of non-steroidal anti-inflammatory drugs (NSAIDs).
It is divided into two major parts. In part I, I aimed to study the mechanism by which COX-2 enhances lymphangiogenesis and lymph node metastasis. I provided evidences that CCR7 is a downstream target for COX-2 to enhance the migration of breast cancer cells toward lymphatic endothelial cells (LECs) and to promote lymphatic invasion.
I also studied the effect of a bioactive withanolide Tubocapsanolide A (Tubo A) isolated from Tubocapsium anomalum on CCR7 expression and lymphatic invasion of breast cancer cells. I concluded that Tubo A inhibited CCR7 expression in breast cancers by down-regulating IKK and MSK1 signaling to repress NF-κB-mediated CCR7 gene expression.
In part Π, by using microarray system, I identified several metastasis–associated genes which are regulated by NSAIDs. In previous study, I found NSAIDs inhibited cancer cell invasion via negative regulation of the expression and activity of MMP-2. In the work, I found that several negative regulators of cell invasion including secreted protein acidic and rich in cycteine (SPARC), thrombospondin 1 (TSP1), thrombospondin 3 (TSP3) and tissue inhibitor of matrix metalloproteinase-2 (TIMP-2) were up-regulated by NS398. We focus on the study of TSP 1 and SPARC. Both of them belong to tumor suppressors in many cancer cell types. I used specific anti-body to block the activity of these two proteins, and found that the invasion ability was increased. I confirmed that they played critical roles in the inhibition of the A549 lung cancer cells by NSAIDs. I also found they were up-regulated by NSAIDs via different molecular mechanisms. I demonstrated NSAIDs increased SPARC exprsssion via regulation of promoter demethylation and induced TSP 1 expression via elevation of transcription and RNA stability.
In this study, I not only elucidates how COX-2 to enhance the lymphatic ability of tumor cell, but also identifies more novel genes regulated by NSAIDs. Moreover, I identifies another novel anti-cancer drug to decrease the migration of breast cancer cells toward LECs via inhibition of expression of CCR7.

並列關鍵字

COX-2 ； Cytokine ； Lymphatic invasion ； NSAIDs

參考文獻

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