Silibinin是由奶薊子所萃取出的類黃酮(flavonoid)抗氧化物，早期用於治療肝臟的解毒，近來有研究指出silibinin 已被應用於抗癌的研究。在體外實驗中，為了要觀察silibinin 對於癌細胞轉移能力的影響。我們選取了一株具有高度轉移能力的人類肺癌細胞：A549，分別處理不同濃度的silibinin來探討此藥物對於癌細胞侵入能力的影響。癌細胞的轉移通常必須伴隨著一些生理變化，其中主要包括細胞外基質的瓦解，改變細胞與細胞基質間的貼附能力以及調控細胞的移動性等來影響細胞的侵入能力。首先，藉由modified Boyden chamber invasion assay，我們發現silibinin具有抑制A549侵入的能力，在gelatin zymography與casein zymography assay中也發現到silibinin可以抑制A549 MMP-2及u-PA的表現，此外，利用Boyden chamber assay 與 cell-matrix adhesion assay 發現A549在處理 silibinin之後，其細胞的移動能力與基質的貼附能力皆有明顯的下降。為了更進一步探求silibinin抑制癌細胞侵入的機轉，利用西方墨點法，我們發現到訊息傳遞途徑中的 Akt 、ERK1/2 、p38磷酸化與 NF-kB 的蛋白表現會因藥物的處理而受到抑制。然而這些蛋白的活化是否調控著A549 的侵入能力，藉由專一性抑制劑：LY294002、SB203580和U0126幫助我們釐清了PI-3K和p38路徑可以調控A549 MMP-2表現以及細胞移動和侵入的能力，而MEK路徑則是調控著細胞MMP-2和u-PA的表現以及侵入能力。
Silibinin is a flavonoid antioxidant extracted from milk thistle. It was used as a liver detoxicant previously. In recent studies, silibinin has shown its anti-carcinogenesis property. In order to observe the effect of silibinin to cancer cells metastasis in vitro. we chosed a high metastasis human lung cancer cell line : A549 cells treated with various concentration of silibinin to probe into the potential of inhibiting cancer cells invasion. Tumor metastasis are multifaceted processes that mainly involve proteolytic degradation of the extracellular matrix, changes cell-matrix adhesion, and regulate cell motility. In the first, we found that silibinin inhibited A549 cells invasion via modified Boyden chamber invasion assay and both of MMP-2 and its activator：uPA activity were also inhibited by silibinin via gelatin zymography and casein zymography assay. In the other side, silibinin also inhibited A549 cells motility and cell-matrix adhesion by Boyden chamber assay and cell-matrix adhesion assay. In the signal transduction pathway, we found Akt, ERK1/2 and p38 phosphorylation and NF-kB protein level were inhibited by silibinin via western blotting. In order to confirm the activation of above proteins whether regulate A549 invasion ability, we used specific inhibitors：LY294002, SB253080 and U0126 to clearified that PI-3K and p38 signaling regulate MMP-2 expression, cell motility and cell invasion of A549, and MEK signaling regulate MMP-2, u-PA expression and cell invasion.
