2011-08-012024-05-13https://scholars.lib.ntu.edu.tw/handle/123456789/645461摘要：Gemcitabine（健擇；GCB）是一種具有廣泛活性，對抗各種實體腫瘤和淋巴系統惡性腫瘤，類似deoxycytidine的異構物，它會干擾核酸正常的代謝。GCB被細胞吸收並由deoxycytidine kinase轉換成活化的雙磷酸和三磷酸形式，干擾正常去氧核苷酸的合成及DNA鏈的延長。由於這二種強有力的作用而抑制DNA合成，導致細胞死亡。化學抗藥性會導致超過95%的轉移性泌尿上皮癌病人的治療失敗。近年來，對於cisplatin及paclitaxel之抗藥性了解較深入，但是對於GCB之抗藥性，則仍待努力。現有之報告指出，因細胞內運輸、代謝、細胞週期調控、增殖或細胞凋亡的改變，皆可能導致GCB之抗藥性。本計畫之的目，是研究GCB抗藥性的機制，並找出克服抗藥性的方法。我們已經從膀胱泌尿上皮癌細胞株(NTUB1)培養成功一株對GCB具抗藥性之子細胞株(NTUB1/G12)。初步研究結果顯示， NTUB1/G12的DNA修補速率比親代細胞NTUB1快。本研究計畫的優勢，在於我們有一個較準確的測量DNA損傷的方法。我們希望找出，較強的DNA修補活性(即較少之DNA傷害)在GCB抗藥性所扮演的角色為何？我們將用3H-labeled GCB研究我們將用siRNA之方法調降XXX之表現，觀察其與GCB抗藥性之關聯。此外，本研究將比較GCB合併cisplatin、paclitaxel、radiation、三氧化二砷，標靶藥物，或histone deacetylase抑制劑的毒殺效果為協同、加成、或拮抗作用。我們也將觀察合併治療時，何種投予方法較佳 (A􀃆B，B􀃆A或A+B同時)，以提供未來臨床試驗設計之參考。<br> Abstract: Gemcitabine (GCB) is a deoxycytidine-analog antimetabolite with broad activity against avariety of solid tumors and lymphoid malignancies. GCB is taken up by cells and converted bydeoxycytidine kinase to the active diphosphate and triphosphate forms, which depletedeoxynucleotide stores and interfere with DNA chain elongation. Both of these actions are mostlikely responsible for the potent inhibition of DNA synthesis, resulting in GCB-induced cell death.Chemoresistance causes treatment failure in over 95% of patients with metastatic urothelialcancer (UC). The chemoresistance mechanisms of cisplatin and paclitaxel have been wellunderstood. However, little is known about GCB chemoresistance. A variety of attempts haverecently been made in vitro to detect molecular markers of GCB resistance. Alterations involvedin drug uptake, cell cycle regulation, proliferation or apoptosis have been described in a variety ofcancers. Nucleotide transporters were also described as molecules related to the intracellulartransport of GCB from outside.The purpose of this research is to understand the GCB chemoresistance mechanism andfind out the way of overcoming resistance. We have successfully raised a subclone of bladderUC cell, NTUB1/G from parental NTUB1 cells, which provides a useful tool to study secondarychemoresistance. Our preliminary results indicated the GCB resistant cell, NTUB1/G had a DNArepair rate than the NTUB1 cells. The power of this investigation lies in that we have a moreaccurate way of measuring DNA damage.We will test whether cells with a stronger DNA adduct excision activity also have a strongerGCB resistance. The uptake of 3H-labeled GCB by NTUB1 and NTUB1/G12μM cells will becompared. Are there any small molecules that can alter GCB uptake in tumor cells? We will alsouse the siRNA strategy to down-regulate GCB activating enzymes to see if these enzymes areassociated with GCB resistance. We will also examine the combined effects of GCB plus avariety of anti-tumor agents, such as other chemotherapeutic agent (cisplatin, paclitaxel, arsenictrioxide, etc.), targeted agents, and histone deacetylase inhibitor. Drug-drug interaction will bequantified by the median-effect analysis to reveal potential synergistic, additive or antagonisticeffects in these combined treatments. All these studies will provide valuable rationale for thefuture design of clinical trials.健擇核酸修補泌尿上皮癌化學治療抗藥性機制gemcitabineDNA repairurothelial carcinomachemotherapyresistancemechanism