中草藥抑制乳癌細胞侵入能力及誘導細胞凋亡之機制探討

癌細胞的轉移和抗細胞凋亡都是惡性腫瘤的重要特徵，並且也是在臨床治療上最難以根治及治療複雜度提昇的主要原因。因此，如何治療癌症病人、開發新藥或是利用天然藥物觀察是否會抑制癌細胞轉移是一個迫切的問題。長期以來，中草藥被應用於傳統醫學及民俗療法中的各種治療，並且已有多種中草藥被確認其具有抗氧化、抗發炎、抗過敏及抗癌的活性，但是到目前為止，對於中草藥抑制癌細胞轉移、誘導癌細胞凋亡以及其中之詳細機轉的都還不是很清楚。在本篇論文中，我們利用補骨脂、欖仁樹的葉、魚腥草與半枝蓮之酒精(50%)萃取物觀察其抑制多種乳癌細胞(MDA-MB-231、JC 與Hs 578T)生長及抗轉移的功效，證實補骨脂萃取物(Psorlaea corylifolia L.extracts; PCE)隨著濃度的增加，可抑制乳癌細胞(MDA-MB-231 與JC細胞)的活細胞數並增加死亡的細胞數目，以DAPI stain 與DNA 斷裂分析方法，發現補骨脂萃取物會導致chromatin condensation 與DNA斷裂並進一步促使癌細胞走向凋謝死亡。在動物實驗中，我們利用BALB/c 老鼠於皮下種植JC 老鼠乳癌細胞，並餵食補骨脂萃取物發現其會抑制腫瘤在活體的生長。欖仁樹的葉萃取物(Terminalia catappaL extracts; TCE)也可透過chromatin condensation 使JC 細胞走向凋亡。在抗細胞轉移方面，魚腥草萃取物(Houttuynia cordata extracts;HCE)與半支連萃取物(Scutellaria barbata extracts; SBE)可顯著抑制具有高度轉移能力之人類乳癌細胞(Hs 578T)的侵入及移動能力，利用gelatin-及casein-zymography 分析方法，探討細胞外基質降解相關基因，如matrix metalloproteinase-2 (MMP-2)、urokinase-type plasminogen2activator (u-PA)、tissue inhibitor matrix metalloproteinase -2 (TIMP-2)與plasminogen activator inhibitor-1 (PAI-1)的蛋白表現，結果發現魚腥草萃取物與半枝蓮萃取物對 u-PA 的分泌量有明顯的抑制，並呈現濃度的效應關係，此外只有魚腥草萃取物也可明顯抑制細胞TIMP-2，但對於PAI-1 之蛋白表現則是沒有影響，深入探討其作用機轉，結果顯示半枝蓮萃取物可顯著抑制 p-ERK1/2 。綜合以上結果，推測補骨脂萃取物與欖仁樹的葉萃取物可以誘導癌細胞的凋亡；魚腥草萃取物與半枝蓮萃取物可透過抑制腫瘤細胞株 u-PA 分泌的作用進而抑制癌瘤細胞遷移和侵犯作用的能力，推論可應用於輔助癌症的治療，以提昇抗癌藥物療效。

Both the metastasis and anti-apoptosis of cancer are a vital trait inmalignance with extreme difficulties in early diagnosis and therapeuticmanagement. So far, the most important thing for finding new cancerdrug is urgent. Chinese medicinal herbs have been used for therapeuticpurposes in traditional and folk medicine for a long time. A recent reportshowed that many kinds of Chinese medicinal herbs have the antioxidant,anti- inflammation, anti-allergic and anti-tumor activeness. However, theeffects and detailed mechanisms of Chinese medicinal herbs on cancercell metastasis and inducing cell apoptosis were still unclear. In this study,anti-tumor and anti-metastasis agents were investigated using 50%alcohol extracts of Psorlaea corylifolia L., Terminalia catappa L.,Houttuynia cordata, and Scutellaria barbata on various breast cancercells (MDA-MB-231, Hs 578T, JC). We demonstrated that Psorlaeacorylifolia L. extracts (PCE) induced cell death, chromatin condensation,and DNA fragmentation on MDA-MB-231 and JC cells. Furthermore,PCE were evidenced by its inhibition on the growth of JC cells in vivo.Terminalia catappa L extracts (TCE) also exerted an anti-tumor effectthrough an increase of dead cells and chromatin condensation on JC cells.For anti-metastasis, in the absence of cytotoxicity, Houttuynia cordataextracts (HCE) and Scutellaria barbata extracts (Pereira,Strasberg-Rieber et al.) exerted a dose-dependent inhibitory effect on theinvasion, and motility of highly metastatic human breast cancer cells (Hs4578T). We examined the effects of HCE and SBE on factors of cancermetastasis. We treated tumor cells with various concentrations of HCEand SBE, for set periods, and then subjected cells to gelatin zymography,casein zymography, and Western blot to investigate the expression ofmatrix metalloproteinase-2 (MMP-2), urokinase-type plasminogenactivator (u-PA), tissue inhibitor matrix metalloproteinase -2 (TIMP-2),and plasminogen activator inhibitor-1 (PAI-1). Following treatment withthese compounds was found to decrease the expression of u-PA in aconcentration-dependent manner and only HCE could reduce theexpression of TIMP-2. Further, a treatment of SBE also resulted in aninhibition on the activation of p-ERK1/2. Together, these results suggestthat PCE and TCE could induce cell apoptosis; HCE and SBE may act todecrease the in vitro invasiveness of cancer cells and therefore, reduce theinvasion and metastasis of tumor cells. This study suggests a possible rolefor these extracts in cancer therapy.