中藥抑制肺癌細胞侵入及移動能力之機制探討

癌細胞的轉移往往是惡性腫瘤的重要特徵之一，並且也是在臨床治療上最難以根治的。因此，在很多研究中，大都是以針對癌細胞的轉移過程，開發新藥或是利用天然藥物觀察是否會影響癌細胞的轉移。目前已有多種中藥已被確認具有抗發炎，抗過敏及抗癌的活性，且其中具有生物活性的有效成份，部分已被單離並經分析鑑定。中藥對癌症所引起的諸多症狀的治療能有所助益，已是眾所皆知的事實，而中藥的抗癌有效成份之作用機轉，常為有效地促使癌細胞凋亡及抑制癌細胞增生，但對其抑制侵襲及轉移作用和其詳細機制方面的研究還很少。因此，本研究選用一株具有高度轉移能力的人類肺癌細胞：A549，處理57種中藥來探討對於癌細胞侵入能力的影響。首先藉由modified Boyden chamber invasion assay，發現有26種中藥具有抑制A549侵入的能力，其中有骨碎補、葉下珠、夏枯草、卷柏、紫花地丁、欖仁樹的葉等6種中藥不具有細胞毒性，而當癌細胞轉移時常常會伴隨著細胞外基質的分解及細胞移動能力的改變，在gelatin zymography與casein zymography assay中也發現到它們可以抑制A549人類肺癌細胞的MMP-2及u-PA的表現。此外，還利用LLC-bearing C57BL/6 mice的動物模式，觀察到欖仁樹的葉及卷柏對於腫瘤生長曲線、最終腫瘤重量及腫瘤轉移至肺臟數目都有一個明顯的抑制情形，因此我們再利用RT-PCR及western blot發現處理欖仁樹的葉及卷柏後，會抑制蛋白酶及改變蛋白酶抑制劑的表現。最後我們推測，欖仁樹的葉及卷柏可能是透過抑制和癌細胞轉移相關的蛋白酶及影響蛋白酶抑制劑來達到抑制癌症轉移的能力。

The metastasis of cancer is a vital trait in malignance with extreme difficulties in early diagnosis and therapeutic management. Therefore, the development of new remedies or the utilization of natural medicines targeted at metastasis has been interested and studied extensively. At present many kinds of Chinese medicinal herbs have the anti- inflammation, anti-allergic and anti-cancer activeness. Part of active principles had to be isolated and identified. Recently, Chinese medicinal herbs have been reported to have various anti-carcinogenesis properties, including inducing cell apoptosis and suppressing cell proliferation. However, the in vitro effect and detailed mechanism of Chinese medicinal herbs on metastasis of cancer cells was still unclear. Hence, a highly metastatic human lung cancer cell line, A549, was chosen to be treated with fifty-seven Chinese medicinal herbs to investigate their potential for inhibiting cancer cell invasion. For a start, via modified Boyden chamber invasion assay, we found that twenty-six Chinese medicinal herbs can suppress A549 cell invasion. In this twenty-six Chinese medicinal herbs there are six Chinese medicinal herbs without toxicity, including Davallia mariesii Moore, Phyllanthus urinaria, Prunella vulgaris, Selaginella tamariscina, Viola yedoensis and Terminalia catappa. Based on that tumor metastasis are accompanied with proteolytic degradation of the extracellular matrix and changed cell motility. Both of MMP-2 and u-PA activity were also inhibited by above six Chinese medicinal herbs via gelatin zymography and casein zymography assay. In addition, LLC-bearing C57BL/6 mice were treated with TCE and STE which tumor weight monitoring throughout the experiment, finally tumor weight, and lung metastases of animals have decreased. We also found that TCE and STE can suppress the expression of proteinase and change proteinase inhibitor expression through RT-PCR and western blot. Finally, it was concluded that TCE and STE may inhibit tumor metastasis via suppressing tumor metastasis-related proteinase and affecting their inhibitor.