結締組織生長因子誘導多功能性幹細胞基因並促進間質上皮轉化效應

Induction of pluripotent stem cell genes by connective tissue growth factor promotes mesenchymal-epithelial transition

許文豪(Wen-Hao Hsu)

指導教授 ： 張正琪

共同指導教授 ： 楊慕華(Muh-Hwa Yang)

國立臺灣大學/牙醫專業學院/口腔生物科學研究所/碩士(2012年)

https://doi.org/10.6342/NTU.2012.02815

摘要

結締組織生長因子(CTGF)是CCN(Cyr61/CTGF/Nov)家族中的一員，它目前已知參與在許多生物功能，如細胞分裂、細胞凋亡、細胞附著、細胞移動、細胞外基質製造與血管新生等，然而結締組織生長因子在不同的組織中扮演不同的角色，像是在肺癌細胞中扮演抑制腫瘤的角色但是在乳癌當中卻會造成腫瘤的惡化程度增加。上皮-間質轉化(EMT)在胚胎發育和癌細胞轉移是一個關鍵的機制，相反於上皮-間質轉化，在體細胞重製形成誘導多功能性幹細胞時間質-上皮轉化(MET)扮演重要的過程，而E-cadherin參與在間質-上皮轉化中相當重要。結締組織生長因子與間質-上皮轉化接抑制細胞移動，所以在本篇研究中，將要探討結締組織生長因子在頭頸癌細胞間質-上皮轉化與幹細胞特性的關聯性。實驗中利用質體外送入結締組織生長因子，使頭頸癌細胞大量表現結締組織生長因子蛋白，我們發現結締組織生長因子會造成頭頸癌細胞上皮-間質轉化並且表現幹細胞基因和幹細胞的標記。接著利用組蛋白免疫沉澱的實驗發現結締組織生長因子造成上皮-間質轉化並且表現幹細胞基因會透過兩條路徑，其一結締組織生長因子會改變在Oct4, Sox2, Nanog, E-cadherin 和N-cadherin的啟動序列(promoter region)上組蛋白甲基化和乙醯化的改變，其二結締組織生長因子會透過JUN去造成其下游反映。在異種器官移植發現結締組織生長因子會造成腫瘤的產生但是會抑制癌細胞侵入的現象，病人檢體的分析上也應證了體外實驗的結果。綜合以上實驗結果說明結締組織生長因子在頭頸癌細胞上皮-間質轉化與幹細胞特性的關聯，並且在治療頭頸癌的策略中提供了有效的訊息。

關鍵字

結締組織生長因子 ； 幹細胞基因 ； 間質上皮轉化

並列摘要

The epithelial-mesenchymal transition (EMT) is a key mechanism for both embryonic development and cancer metastasis. During somatic cells reprogramming, mesenchymal-epithelial transition (MET), a reverse process of EMT, is a crucial step toward pluripotency, and E-cadherin is critical for this process. Connective tissue growth factor (CTGF) is a member of the CCN family, which is capable of multi-functioning as an oncoprotein or a tumor suppressor among different types of cancers. CTGF exhibit diverse cellular functions in areas such as regulation of cell division, chemotaxis, apoptosis, adhesion, motility, and ion transport, and the regulatory cell motility of CTGF is inversely with EMT. Based on this conception, We investigate the role of CTGF induces mesenchymal-epithelial transition (MET) and promotes stem-like properties in head and neck squamous cell carcinoma (HNSCC). We founded that CTGF promotes MET and stem-like properties in HNSCC cells, we further demonstrated that CTGF promotes MET and activates the transcription of pluripotent stem cell genes Oct4, Sox2 and Nanog through two mechanisms: first, CTGF modifies histone codes on the pluripotent genes, including enrichment of H3K4me3, H3K4Ac, H3K9Ac and reduction of H3K27me3. Second, αvβ3enhance the promoter activity of JUN, which results in an increase of total JUN and phosphorylated JUN expression, leading to transactivation of the expression of the pluripotent stem cell genes. In CTGF transfectant, knockdown of pluripotent gene results in partially MET. Xenotransplantation and patient sample analysis confirm that CTGF induces pluripotent genes expression and MET, which promotes the growth of primary tumors but reduces their invasiveness. This finding will be valuable in elucidating the interplay between EMT/MET and stem cell properties during cancer progression and will provide useful information for developing novel classifications and therapeutic strategies against HNSCC.

並列關鍵字

CTGF ； pluripotent stem cell genes ； MET

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