【摘要】：近年研究表明,Hippo-YAP信號通路參與哺乳動物器官大小維持、干細胞全能性維持和腫瘤發(fā)生。YAP基因作為Hippo信號通路中的核心轉(zhuǎn)錄共激活因子,與人類腫瘤的發(fā)生關(guān)系密切。TEAD家族是YAP基因下游重要的核內(nèi)轉(zhuǎn)錄因子,它的轉(zhuǎn)錄活化水平直接影響YAP基因?qū)ζ湎掠伟谢虻恼{(diào)控及一系列功能行使。目前,YAP作為癌基因的相關(guān)研究僅限于體外,在體研究未見報道。在卵巢癌的發(fā)生發(fā)展過程中,TEAD家族作為YAP基因下游重要的核轉(zhuǎn)錄因子,是否參與了YAP誘導卵巢腫瘤發(fā)生的過程,TEAD家族中的幾個重要亞型是否也都參與其中,以及臨床上YAP與TEAD活性與卵巢癌患者預后的關(guān)系目前均未見研究報道。另一方面,YAP同樣參與了干細胞的干性維持與調(diào)控。YAP的高表達能夠維持誘導多能干細胞的未分化狀態(tài),YAP的表達水平隨著干細胞的終末分化而下降。這些研究均提示YAP也可能在癌干細胞的發(fā)生、維持與分化中發(fā)揮作用。而癌干細胞的存在可能是腫瘤耐藥、復發(fā)及轉(zhuǎn)移的主要原因。目前,YAP在卵巢癌干細胞中的作用研究也未見報道。因此,進一步深入了解YAP在卵巢癌干細胞中的作用對于揭示YAP在卵巢癌的發(fā)生發(fā)展及耐藥中的作用機制有重要意義。 本研究通過體外及體內(nèi)實驗驗證了YAP基因促進卵巢癌細胞增殖、腫瘤形成及轉(zhuǎn)移,并且與卵巢癌患者的臨床預后密切相關(guān)。首先,通過對正常卵巢上皮組織及卵巢腫瘤組織檢測證實YAP在卵巢癌中高表達。通過病例隨訪及生存分析我們證明YAP的高表達與卵巢癌患者臨床預后相關(guān)。接下來通過一系列體內(nèi)及體外實驗證明YAP促進卵巢癌細胞增殖及腫瘤形成,YAP促進卵巢癌細胞耐藥性以及遠處轉(zhuǎn)移。TEAD4作為YAP下游轉(zhuǎn)錄因子,其活性對于YAP發(fā)揮促癌作用非常重要。在本研究中我們首次發(fā)現(xiàn)YAP基因的表達水平與TEAD4的表達密切相關(guān),卵巢癌組織中YAP/TEAD的共表達水平能夠預測卵巢癌患者預后。 已有研究表明YAP信號通路與干細胞全能性關(guān)系密切,因此我們推測YAP-TEAD在調(diào)節(jié)癌干細胞的多能性和自我更新方面可能也起到關(guān)鍵作用。在本研究中我們首次通過體外干細胞分離培養(yǎng),獲得并鑒定了具有干細胞特性的卵巢癌干細胞,首次發(fā)現(xiàn)YAP及TEAD家族在卵巢癌干細胞中表達上調(diào),TEAD1、3、4三個亞型參與了YAP對癌干細胞干性維持調(diào)控,而TEAD2作用不明顯。在干細胞分化方面,我們發(fā)現(xiàn)YAP通過結(jié)合TEAD活化轉(zhuǎn)錄,下調(diào)Hippo通路下游靶基因CTGF的表達,上調(diào)干細胞干性維持相關(guān)基因C-FOS的表達而抑制分化以維持癌干細胞干性。在耐藥方面,YAP通過調(diào)控GSK3A基因而上調(diào)耐藥基因ABCB1的表達從而增強卵巢癌干細胞耐藥性。在卵巢癌干細胞中,GSK3A參與了YAP對耐藥基因的調(diào)控而GSK3B并未直接參與,ABCB1確實受到Wnt信號通路中GSK3A的調(diào)節(jié)。 綜上所述,本研究主要論證了YAP作為Hippo信號通路中重要的癌基因,通過結(jié)合核內(nèi)轉(zhuǎn)錄因子TEAD促進卵巢癌發(fā)生及遠處轉(zhuǎn)移,與卵巢癌患者預后密切相關(guān)。YAP調(diào)節(jié)卵巢癌干細胞的增殖和分化而增強癌干細胞耐藥性。這一機制可能是卵巢癌發(fā)生、遠處轉(zhuǎn)移及耐藥的根本原因。YAP有望作為臨床上卵巢癌化療的一個新的分子藥物靶點,為降低卵巢癌復發(fā)及遠處轉(zhuǎn)移,提高卵巢癌臨床治愈率提供新的思路。
[Abstract]:Recent studies have shown that the Hippo-YAP signaling pathway is involved in the maintenance of mammalian organ size, the maintenance of stem cell totipotency and tumorigenesis. As a core transcriptional co-activator in the Hippo signaling pathway, the YAP gene is closely related to the occurrence of human tumors. At present, the study of YAP as an oncogene is confined to in vitro and has not been reported in vivo. During the development of ovarian cancer, TEAD family, as an important downstream nuclear transcription factor of YAP gene, is involved in the development of ovarian cancer induced by YAP. On the other hand, YAP is also involved in the maintenance and regulation of stem cells. The high expression of YAP can maintain the undifferentiated state of induced pluripotent stem cells and the expression of YAP. These studies suggest that YAP may also play a role in the occurrence, maintenance and differentiation of cancer stem cells. The presence of cancer stem cells may be the main cause of tumor resistance, recurrence and metastasis. Understanding the role of YAP in ovarian cancer stem cells is important to reveal the mechanism of YAP in the development and drug resistance of ovarian cancer.
In this study, in vitro and in vivo experiments confirmed that YAP gene promotes ovarian cancer cell proliferation, tumor formation and metastasis, and is closely related to the clinical prognosis of ovarian cancer patients. First, through the detection of normal ovarian epithelial tissues and ovarian tumor tissues confirmed that high expression of YAP in ovarian cancer. It is concluded that the high expression of YAP is associated with the clinical prognosis of ovarian cancer patients. Next, a series of in vivo and in vitro experiments have proved that YAP promotes ovarian cancer cell proliferation and tumor formation, and YAP promotes ovarian cancer cell resistance and distant metastasis. We found for the first time that the expression level of YAP gene was closely related to the expression of TEAD4. The co-expression level of YAP/TEAD in ovarian cancer tissues could predict the prognosis of ovarian cancer patients.
We speculate that YAP-TEAD may also play a key role in regulating the pluripotency and self-renewal of cancer stem cells. Three subtypes of TEAD 1,3,4 are involved in the regulation of YAP on stem cell maintenance, while TEAD 2 is not. In stem cell differentiation, we found that YAP down-regulates the expression of CTGF downstream of the Hippo pathway and up-regulates stem cell maintenance by binding to TEAD activation transcription. In terms of drug resistance, YAP enhances the resistance of ovarian cancer stem cells by regulating the expression of the drug-resistant gene ABCB1 by regulating the GSK3A gene. In ovarian cancer stem cells, GSK3A participates in the regulation of YAP on drug-resistant genes, but GSK3B is not directly involved. ABCB1 is indeed subject to Wnt. Regulation of GSK3A in signaling pathways.
In conclusion, this study demonstrated that YAP, as an important oncogene in the Hippo signaling pathway, promotes the occurrence and distant metastasis of ovarian cancer by binding to the nuclear transcription factor TEAD, which is closely related to the prognosis of ovarian cancer patients. YAP regulates the proliferation and differentiation of ovarian cancer stem cells and enhances cancer stem cell resistance. YAP is expected to be a new molecular drug target for clinical chemotherapy of ovarian cancer, providing new ideas for reducing recurrence and distant metastasis of ovarian cancer and improving the clinical cure rate of ovarian cancer.
【學位授予單位】：浙江大學
【學位級別】：博士
【學位授予年份】：2014
【分類號】：R737.31

【相似文獻】

相關(guān)期刊論文 前10條

1 潘猛;竇駿;李雅婷;文萍;顧寧;;癌、干細胞和癌干細胞共同擁有的信號傳導通路[J];生物技術(shù)通訊;2007年05期

2 江世亮;;癌干細胞理論何以受到青睞[J];世界科學;2008年06期

3 張朵;朱海英;謝東甫;王新民;胡以平;;癌干細胞的研究現(xiàn)狀[J];福州總醫(yī)院學報;2008年01期

4 吳生華;俞繼衛(wèi);姜波健;;胃癌干細胞的研究現(xiàn)狀[J];腹部外科;2009年06期

5 陸旭偉;凡杰;;腎癌干細胞研究進展[J];現(xiàn)代腫瘤醫(yī)學;2010年01期

6 葉夏;黃正接;;胃癌干細胞研究進展[J];齊齊哈爾醫(yī)學院學報;2011年04期

7 李媛;曾世京;翟震;只向成;;癌干細胞的研究進展[J];中國醫(yī)學工程;2011年07期

8 ;研究揭示腦癌干細胞如何爭奪營養(yǎng)[J];生物學通報;2013年10期

9 ;《自然-神經(jīng)科學》:研究揭示腦癌干細胞如何爭奪營養(yǎng)[J];現(xiàn)代生物醫(yī)學進展;2013年34期

10 劉龔玫子;周，

本文編號：2188429