運用奈米點陣列調控乳癌細胞的上皮-間葉轉換現象

Abstract

在細胞生長的過程中，細胞本身具有感知外在的化學或物理信號並整合與傳遞這些外在環境訊息的能力，進而改變其細胞形態及生長。例如：貼附、遷移、凋亡。上皮-間葉轉化( Epithelial-mesenchymal transition；EMT)是上皮細胞失去細胞極性而轉換為間葉形態的過程，在癌症惡化的過程中扮演關鍵的角色。 本研究主要探討透過不同尺度之奈米結構表面調控乳癌細胞之上皮間-葉轉換現象,將MCF-7 乳癌細胞株養在由陽極氧化鋁製程(AAO)在TaN表面的矽晶圓製備而成之10 nm 至200 nm奈米點陣列上，培養0、3、7天，藉由外在物理環境的影響，,探討細胞形態以及細胞骨架的改變對應乳癌上皮-間葉細胞轉換的基因表現的相關性，證明奈米點陣列可以調控乳癌細胞MCF-7之上皮-間葉轉換現象。 上皮-間葉轉化( Epithelial-mesenchymal transition；EMT)在早期研究是發現在胚胎發展的期間進行，當細胞開始具有分化能力時，上皮-間葉的轉化特性會隨之增加，細胞接合會發生改變，E-cadherin(cadherin；黏附接合的組成蛋白質分子)表現量會下降，失去上皮組織組織標記蛋白（epithelial marker），此時細胞具有上皮-間葉轉化能力，細胞極性特性消失、重新定向以及分化，而這些現象在癌細胞上也會發生,特點在於拆散細胞與細胞之間的接觸，重組細胞骨架和細胞變形。上皮-間葉轉化在腫瘤的發展中擔任侵略與轉移的角色，當癌症要開始轉移時，細胞經由上皮-間葉轉化，細胞之間的接觸消失使細胞具有爬行能力，癌症的轉移是造成癌症死亡率升高的主因。 本研究結果顯示培養在100 nm以及200 nm尺度奈米點陣列之MCF-7細胞株，培養7天後，使用掃描式電子顯微鏡觀察其細胞形態，從原本緊密排列的上皮形態變為消失細胞與細胞間接觸無固定方向之間葉細胞形態。進一步針對EMT標記進行聚合酶連鎖反應分析，結果與掃描式電子顯微鏡觀之圖片相符。 因此在此篇研究可利用特定的奈米尺度之奈米點陣列去調控乳癌細胞株MCF-7之EMT表現量，未來可應用在癌症轉移之藥物篩選平台，對於人類癌症治療藥物提供了一個新方向。

The interaction of cells with nanoscale topography has been proven to be an important signaling modality in controlling cancer cell function. Nanofabricated topography within the extracellular matrix present surrounding cells with mechanotransduction cues that influence migration, invasion, metastasis and apotosis. However, the manner of communication between cancer epithelial-mesenchymal transition (EMT) and nanotopography remains unclear. The epithelial-mesenchymal transition (EMT) is a process by which epithelial cells lose their cell polarity and cell-cell adhesion. EMT has also been shown to occur in wound healing, in organ fibrosis and in the initiation of metastasis for cancer progression. Initiation of cancer metastasis requires invasion, which is enabled by EMT. Carcinoma cells in primary tumor lose cell-cell adhesion mediated by E-cadherin repression and breakthrough the basement membrane with increased invasive properties, and enter the bloodstream through intravasation. In our study, we fabricated nanodot arrays with various sizes, ranging from a flat surface to 10 nm, 50 nm, 100 nm, and 200 nm arrays. Breast cancer cell line was seeded onto the different scale nanodot arrays culture for seven days. We found that cell morphology obviously changed from epithelial like to mesenchymal like on 200 nm. nanodot arrays could upregulate EMT markers and the downregulate the epithelial cell marker on 100 nm and 200 nm also. Our nanodot arrays have a great potential to research the relationship between EMT and breast cancer.