- 學位論文
卵巢亮細胞癌之早期上皮-間質可塑性調控
Regulation of early epithelial-mesenchymal plasticity (EMP) in ovarian clear cell carcinoma (OCCC)
摘要
卵巢癌於女性十大死因中位居第五名，且晚期病人之遠距離轉移被發現與其存活率極為相關。於上皮性卵巢癌中，卵巢亮細胞癌為一種於亞洲女性中好發率高的亞型，且被發現常因其對化療物之抗藥性相對較嚴重而有較不良的預後。上皮-間質可塑性為一已知廣泛影響癌細胞侵略性及轉移的過程。先前於卵巢癌亮細胞癌的研究指出：上皮性與間質性基因表現之細胞亞型與病人的疾病分期及預後具相關性。為研究卵巢亮細胞癌之上皮間-質可塑性，本篇研究中利用TAYA級RMG2兩種細胞株，藉由降低維持細胞上皮性的轉錄因子GRHL2的表現或過度表現幫助上皮-間質轉移的轉錄因子TWIST1來建立卵巢癌亮細胞在早期上皮-間質轉移的模型，其中降低GRHL2表現造成了部分上皮-間質轉移，而過度表現TWIST1則造成部分間質-上皮轉移。我們利用RNA定序進行基因差異表現量分析，並以雞胚尿囊絨毛膜模型觀察細胞的轉移特性。在基因轉錄部分，我們發現一由GRHL2, GRHL1, SOX9, HES1和OVOL1共同調控之迴路。而在細胞功能部分，GRHL2表現降低使得細胞增生能力沿著上皮-間質轉移的梯度輕微提升；TWIST1過度表現則使得細胞改變轉移時的特性，其中整體轉移能力並為提升，但肝器官趨性上升。本研究提供一個卵巢癌量細胞早期上皮-間質可塑性的細胞研究模型，並提出雞胚尿囊絨毛膜模型是為一適合研究卵巢亮細胞癌器官趨性之模型。此研究亦顯示在部分上皮-間質及部分間質-上皮轉移過程中，腫瘤細胞之生長及轉移趨性能在細胞形態產生變化前發生。
並列摘要
Ovarian cancer (OC) is the fifth cause of cancer death among women with advanced stage associated with distant metastasis being highly related to patient survival. Ovarian clear cell carcinoma (OCCC), one of the epithelial ovarian cancer (EOC) subtypes with high prevalence for Asian women, is known to have poorer prognosis due to its relative chemoresistance than other EOCs. Epithelial-mesenchymal plasticity (EMP) is a well-known developmental process that extensively influences aggressiveness and metastasis of cancer cells. In OCCC, the epithelial and mesenchymal gene expression subtypes have been suggested to correlate with advanced disease stages and poor patient prognosis. Here, we examined the early transition phase of EMP in OCCC by establishing epithelial-mesenchymal transition gradients in TAYA and RMG2 cell lines via downregulating an epithelial gatekeeper GRHL2 or overexpressing the EMT transcriptional driver TWIST1. Differential gene expression profiles by RNA-sequencing and changes in the metastatic pattern by using the in vivo chick chorioallantoic membrane (CAM) model were assessed. Transcriptionally, partial EMT and MET models were established by knocking down GRHL2 or overexpressing TWIST1, respectively. A transcriptional regulation feedback loop connected by GRHL2, GRHL1, SOX9, HES1 and OVOL1 was identified. Functionally, the partial EMT model via GRHL2 knockdown showed slightly increased cell proliferation along the EMT gradient both in vitro and in vivo. Overexpression of TWIST1, on the other hand, changed the metastatic organotropism to the liver but not the overall metastatic potential. The study provided a working model for the research of early EMP transition in OCCC and indicated that the CAM model can serve as an appropriate model to study organotropism of OCCC. Moreover, it was demonstrated that partial EMT or MET could cause perturbations in tumor growth and metastatic potential in organotropism prior to major morphological changes.