探討植物化學素Pterostilbene抑制乳癌幹細胞及其腫瘤微環境調節之研究

Dietary agents Pterostilbene suppresses the generation of breast cancer stem cells within tumor microenvironment and metastasis in breast cancer cells

麥家傑(Ka-Kit Mak)

指導教授 ： 葉淇臺

共同指導教授 ： 趙祖怡

臺北醫學大學/醫學院/臨床醫學研究所/碩士(2013年)

摘要

介紹：腫瘤相關巨噬細胞(Tumor-associated macrophages, TAMs)具有促進癌細胞轉移及提高腫瘤惡性程度的作用。Pterostilbene是存在於莓類的天然stilbene化合物，許多研究證實其具有抗癌功效。本研究探討乳癌幹細胞及及其TAMs腫瘤微環境對乳癌細胞之影響以及pterostilbene之調控機制。
方法和結果：我們使用流式細胞儀及Boyden chamber分析發現MCF-7及MDA-MB-231兩株細胞分別與M2 TAMs共培養後能增加CD44+/CD24− 癌幹細胞之比例以及提昇細胞移行及侵犯之能力。另外 CD44+/CD24− 癌幹細胞高度表現HIF-1α, β-catenin, TWIST 1及 NF-κB並且可以促進腫瘤球形細胞的生成。我們進一步證實pterostilbene能抑制M2 TAMs所誘導之癌幹細胞生成以及轉移能力並呈現劑量效應。在分子機制方面，pterostilbene能抑制NF-κB, TWIST 1及vimentin並提昇E-cadherin的表現。我們同時以基因靜默的方式抑制NF-κB的表現並證實pterostilbene透由提昇miR-448的表現進而降低NF-κB的表現。我們也在動物試驗發現pterostilbene能抑制與M2 TAMs共培養之MDA-MB-231細胞在活體產生腫瘤及轉移的功效。
結論：本研究證實pterostilbene能透由調控EMT訊息傳遞路徑，特別是針對NF-κB/miR-448而抑制M2 TAMs所誘導之癌幹細胞之生長及轉移的能力。因此，我們認為pterostilbene可以作為有潛力的乳癌臨床治療藥物。

關鍵字

乳癌幹細胞, 上皮-間質轉化作用, 腫瘤相關巨噬細胞, 植物化學素-紫檀

並列摘要

Scope: Tumor-associated macrophages (TAMs) have been shown to promote metastasis and malignancy. Pterostilbene, a natural stilbene isolated from blueberries, has been suggested for anti-cancer effects. Here, we explored the potential cancer stem cells (CSCs)/TAM modulating effects of pterostilbene in breast cancer.
Methods and results: Using flowcytometric and Boyden chamber assay we showed that MCF-7 and MDA-MB-231 breast cancer cells co-cultured with M2 TAMs demonstrated increased percentage of CD44+/CD24- CSC population and migratory/invasive abilities. RT-PCR results showed that CD44+/CD24- cells contained an increased level of HIF-1α, β-catenin, TWIST 1 and NF-κB expression and enhanced tumor sphere forming ability. We then demonstrated that pterostilbene treatment dose-dependently overcame M2 TAM-induced enrichment of CSCs and metastatic potential of breast cancer cells. Mechanistically, pterostilbene suppressed NF-κB, TWIST 1, vimentin and increased E-cadherin expression. Using siRNA technique, we demonstrated that pterostilbene-mediated NF-κB downregulation was correlated to an increased amount of microRNA-448. Finally, pterostilbene-mediated suppression in tumorigenesis and metastasis was validated by non-invasive bioluminescence in mice bearing M2 TAM co-cultured MDA-MB-231 tumor.
Conclusion: Pterostilbene effectively suppressed the generation of CSCs and metastatic potential under the influence of M2 TAMs via modulating EMT associated signaling pathways, specifically NF-κB/miR488 circuit.

並列關鍵字

Breast cancer stem cells, Epithelial-to-mesenchymal transition, Tumor-associated macrophages, Pterostilbene

參考文獻

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