郭彥彬臺灣大學：口腔生物科學研究所陳美齡Chen, Mei-LingMei-LingChen2007-11-262018-07-092007-11-262018-07-092005http://ntur.lib.ntu.edu.tw//handle/246246/51291根據衛生署民國九十三年的癌症登記報告指出，近年來，口腔癌的死亡率與發生率，已躍升為臺灣男性十大癌症第四位；儘管近年在診斷及治療之科技上已有不少進步，但口腔癌病人之五年存活率並未有顯著改變。因此，迫切需要研發更好的預防與治療方法來改善整體存活率及生活品質。 最近研究發現在口腔癌中有5-LOX過度表現的現象。先前已有研究發現5-LOX 與乳癌、攝護腺癌、胰臟癌與結腸直腸癌等腫瘤的癌化過程具有相關性。本研究在以人類口腔癌細胞株SAS探討5-LOX酶抑制劑esculetin對口腔癌細胞生長與增殖的影響，並進一步了解Esculetin誘導SAS cell apoptosis其可能的機制。我們發現，Esculetin (7.5ug/ml) 添加於 SAS 細胞中2天後，可以明顯抑制其細胞生長(p<0.05)，且具有劑量依賴性 (dose-dependent) 的毒殺效應 (IC50= 7.5ug/ml)。藉由流式細胞儀分析細胞細胞週期結果顯示，於細胞培養液中添加7.5Oral cancer is the fourth leading cause of cancer-related deaths in male population in Taiwan. Despite recent advances in radiotherapy and chemotherapy, the survival of patients with oral cancer has not improved significantly. Continued investigation of new chemotherapeutic agents is thus needed. Several studies have showed the importance of lipooxygenase (LOX) in the development of human cancer, including pancreatic, breast, prostate, and colon cancer. Recent study found 5-LOX overexpression in human oral cancer. In this study, we examined the effects of esculetin, a 5-LOX inhibitor, on cell proliferation, cell cycle and apoptosis of oral cancer cell line SAS. Esculetin significantly inhibited the proliferation of SAS oral cancer cell lines in a concentration-dependent manner. Esculetin treatment induced PARP cleavage and Caspase 3 activation. Unlike previous studies on other types of cancer cells, esculetin treatment did not change the expression of anti-apoptotic proteins Bcl-2、Bcl-x/l and Mcl-1 on SAS cells. Esculetin also did not cause cytochrome C release. However, esculetin treatment induced the expression of a death receptor, DR5. This result indicated that esculetin induced apoptosis in SAS cells via extrinsic pathway. Flow cytometric analysis showed that esculetin treatment induced cell cycle arrest in S phase. Esculetin treatment did not change the expression of p53、cyclin A、cyclin E、CDK1 and CDK2 in oral cancer cell line SAS. Whereas, it down-regulated the expression of p21、p27、cyclin B and cyclin D. These results indicated that the anticancer effects of esculetin on oral cancer cells may be related to the S phase arrest and induction of apoptosis.Chapter I 5 INTRODUCTION 5 Oral squamous cell carcinoma 5 Apoptosis 6 Molecular mechanisms of apoptosis 8 Death receptor 12 Cell cycle 13 Polyunsatured fatty acids and carcinogenesis 15 Lipoxygenase superfamily 16 5-lipoxygenase and carcinogenesis 19 Esculetin 21 Research objectives 23 Chapter II 24 MATERIALS AND METHODS 24 Cell and cell culture 24 Drug treatment 24 Cell viability (MTT) assay 24 Measurement of apoptosis by flow cytometry 25 Western blot analysis 26 Cytochrome c release 28 Caspase inhibition 28 Cell death detection ELISA 29 Chapter III 30 RESULTS 30 5-lipoxygenase inhibitors (esculetin and 6, 7-dihydroxy-4- methylcoumarin ) caused dose-dependent growth inhibition in oral cancer cell line SAS 30 Escultin induced cell cycle arrest and apoptosis in oral cancer cell line SAS 31 Esculetin did not change the levels of cytochrome c release and expression of Bcl-2 protein family 31 Esculetin treatment induces caspase-8 but not caspase-9 activation 32 Esculetin treatment induces DR5 expression but not Fas or the Other TRAIL Receptor 4 33 Effects of esculetin treatment on cell cycle regulatory proteins 33 Effect of esculetin treatment on survivin expression 34 Chapter IV 50 DISSCUSION 50 FUTURE RESEARCHES AND PERSPECTIVES 61 Chapter V 62 REFERENCES 621043970 bytesapplication/pdfen-US口腔癌化學預防治療藥物Oral CancerChemopreventionEsculetin[SDGs]SDG3otherhttp://ntur.lib.ntu.edu.tw/bitstream/246246/51291/1/ntu-94-R92450016-1.pdf