https://scholars.lib.ntu.edu.tw/handle/123456789/188328
標題: | 皮質類固醇影響上皮細胞癌生長及化學藥物敏感性機轉之研究並探討與癌細胞反應模式相關之分子分類(2/3) | 其他標題: | Studies on the mechanisms of glucocorticoids on the growth and drug sensitivity of carcinomas, and exploring relevant molecular classification(2/3) | 作者: | 鄭安理 | 關鍵字: | 皮質類固醇;癌細胞;化學藥物感受性;Glucocorticoids;Glucocorticoid receptor;Carcinoma;Cell growth;Chemosensitivity;Drug resistance | 公開日期: | 2004 | 出版社: | 臺北市:國立臺灣大學醫學院內科 | 摘要: | 皮質類固醇除本身對於某些血液腫瘤 具細胞毒性之外,也常與抗癌化學藥物併 用以治療因化學藥物引起之噁心、嘔吐及 過敏反應等副作用。雖然類固醇己被証實 可以影響多種細胞之重要訊息傳遞徑路, 其中有些與癌細胞抗藥性有關。然而我們 對類固醇類藥物對於與一般癌細胞生長以 及化學藥物感受性可能產生之影響仍所知 極少。釐清這個問題對臨床腫瘤治療將會 有重要影響。 在我們先前的研究中,我們隨機選擇 了十四株癌細胞株有系統地進行研究以解 答這個問題。Dexamethasone (DEX )被 選為皮質類固醇代表藥物。我們已發現: DEX 確實對癌細胞株(十四株之中的七株) 的生長以及化學藥物感受性有影響。DEX 對癌細胞的影響呈現異質性而且似乎是彼 此互斥的。且此影響是皮質類固醇受體— 依賴性的。在我們今年的進一步研究中我 們發現 1. 為了尋找可能造成DEX 對癌細胞株的 生長以及化學藥物感受性異質性影響 的機轉或決定性因子(determinant factor),我們研究皮質類固醇受體共同 協調因子(steroid receptor co-regulator)在這些細胞的表現。我們 發現這些對DEX 有著不同反應的癌細 胞中皮質類固醇受體共同協調因子 (steroid receptor co-regulator)的表現 各有不同。而且其中有許多共同協調因 子之表現量本身亦受到皮質類固醇受 體所影響。 2. 利用即時定量RT-PCR 測定,以及利用 免疫組織化學染色檢驗一百多位病患 的(肺癌、乳癌、子宮頸癌)癌細胞檢體 我們發現在不同病人的癌細胞中的皮 質類固醇受體含量有高有低。我們推測 臨床上有一定比例之癌細胞含有高濃 度皮質類固醇受體,並可能對DEX 有 感受性。 3. 在我們先前的研究發現DEX 在SiHa 細胞所造成的化學藥物致敏感效應與 其對NF-kB 的調控有著高度相關。透 過轉殖含有dominant negative IkB 的 plasmid 進入SIHa cells 中以抑制 NFkB 活性,我們發現原先DEX 提高 SiHa 細胞對cisplatin 的化學藥物感受 性的現象消失。而在我們進一步的研究 發現在SiHa 細胞中皮質類固醇受體確 實會與NFkB 有直接作用(dirrect protein-protein interaction)。 4. 我們另外發現DEX 會直接作用於 MCF7 細胞的p21 promoter 上造成 p21 的向上調控,表現量增加進而造成 細胞週期G1 arrest, 抑制癌細胞的生 長。 Objectives: Glucocorticoids (GCs) are commonly co-administered with anti-cancer drugs such as cisplatin to prevent drug-induced allergic reaction, nausea, and vomiting. But little is known regarding the effects of GCs on the growth and chemosensitivity of common carcinomas cells. In our previous study, we have demonstrated that DEX had mutually exclusive effects on either growth or cisplatin sensitivity in 7 of the 14 cell lines. DEX inhibited cell growth of 4 (MCF-7, MCF-7/MXR1, MCF-7/TPT300, and HeLa), increased cisplatin cytotoxicity of one (SiHa), and decreased cisplatin cytotoxicity of 2 (H460 and Hep3B) cells lines. Although the effect of DEX on these carcinoma cells was unexpectedly diverse, it remained GC receptor (GCR) dependent. In this study, we further explore the mechanism and the determinant factor on the diverse effect of DEX effect on the cancer cells. Methods: Twenty one steroid receptor co-regulators were examined by RT-PCR in these 14 cancer cell lines. Chromosome immuno-precipitate with anti-GCR antibody and then PCR for the promoter area of these co-regulators was performed. Quantitative RT-PCR for GCR and immunohistochemico stain for GCR was performed in breast, lung and cervical cancer patient’s tumor specimens. Results: The expressions of the steroid receptor co-regulators of these cells are examined. Correlation with the difference between expression of the coregulators and DEX responsiveness were also examined. Furthermore, the expressions of some of the co-regulators were influenced by the GCR. In human cancer samples, we demonstrated that some of the breast, lung and uterine cervical cancer do express high level of GCR. In MCF7 cells, we found DEX induced p21 up-regulation and caused G1 phase arrest of MCF-7. Addition of excess amounts of a structure homologue of DEX, RU486, completely abolished the growth suppression effect of DEX, suggesting that DEX act via GCR-related signal transduction pathways. Furthers, DEX has no effect on the growth of MCF-7/GCR(-), an MCF-7 subclone contains vary low levels of GCR (<1x10 3 /cell). Compared with MCF-7, MCF-7/GCR(-) contains no detectable level of CBP300, HDAC1, and significantly lower levels of NCOR1, TIF2, GCN5L2, and ARA70. Transfection of GCR RNAi to MCF-7 cells also resulted in no detectable level of CBP300, HDAC1, and significantly lowers levels of NCOR1, TIF2, GCN5L2, and ARA70. Transfection of human GCR to MCF-7/GCR(-) restored the expression of GCR and all these co-regulators and sensitivity to DEX in MCF-7/GCR(-) cells. Chromosome IP with anti-GCR antibody and PCR study showed positive result with TIF-2, imply the possibility of direct regulation of TIF-2 expression by GCR. In SiHa cells, we demonstrated that the The cytotoxicity-enhancing effect of GC in SiHa cells correlated well with its effect on abrogating the cisplatin-induced activation of NF- κ B. Expression of a dominant-negative truncated IκBα gene in SiHa cells completely abolished the cytotoxicity-enhancing effect of DEX. Conclusions: GCs may affect growth or chemosensitivity of carcinoma cells containing high concentration of functional GCR. Although the effects are heterogeneous and currently unpredictable, our data underscore the importance of clarifying the impact on tumor control by the co-administed GCs to carcinoma patients receiving chemotherapy. It is mandatory to identify the molecular and cellular markers that help predict the diverse effect of GCs on carcinoma cells. |
URI: | http://ntur.lib.ntu.edu.tw//handle/246246/23631 | 其他識別: | 922314B002105 | Rights: | 國立臺灣大學醫學院內科 |
顯示於: | 醫學系 |
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