探究具5-fluorouracil抗性之喉癌及口腔癌細胞株的核苷酸剪切修補能力

5-fluorouracil (5-FU)用在治療癌症上已經有好幾十年的歷史，最常用在治療直腸癌、大腸癌、乳癌、膀胱癌、肝癌、頭頸癌…等。隨著抗藥性的發生，增加了5-FU在治療上的限制。本論文主要是想探討具5-FU抗性之喉癌(H-F5, H-F10)及口腔癌(Ca-F1)細胞株與其原細胞株(HEp-2, Ca9-22)之DNA修補能力的差異。先將細胞株長時間培養在不同的5-FU的藥物濃度中以建立5-FU抗藥性細胞株，其IC50 (50% growth inhibitory concentration)分別為HEp-2：19.1 μM，H-F10：48.9 μM，Ca9-22：8.1 μM，Ca-F1：10.2 μM。接著進行核苷酸剪切修補(nucleotide excision repair，NER)、同源重組修補(homologous recombination repair，HRR)、末端接合(non-homologous end-joining，NHEJ)修補能力分析。結果發現H-F10的核苷酸剪切修補能力比HEp-2細胞高出40%；Ca-F1的核苷酸剪切修補能力比Ca9-22細胞高出3.2倍。以西方墨點法分析核苷酸剪切修補基因的蛋白質表現後發現，在H-F10抗藥株細胞可以看到RPA、DDB1有增加的現象；在Ca-F1抗藥性細胞株XPA、ERCC1、DDB1有增加的現象。另外，抗藥性細胞株與parental細胞的同源重組、末端接合修復能力並沒有明顯的差異。由以上的結果可以發現，具5-FU抗藥性細胞株的核苷酸剪切修補能力也許會有改變的現象。

關鍵字

核苷酸剪切修補能力

並列摘要

5-fluorouracil (5-FU) has been used for decades to treat various types of malignancies, including colon, breast, bladder, head and neck, and liver cancers. However, its efficacy is frequently reduced by acquisition of drug resistance in cancer cells. This study focuses on examining the hypothesis that DNA repair activity may be altered when the tumor cells acquire drug resistance. First, the 5-FU-resistant laryngeal (H-F5 and H-F10) and oral (Ca-F1, Ca-F2.5) cancer cell lines were established by long-term growing the HEp-2 and Ca9-22 cells, respectively, in various concentrations of 5-FU. The IC50 (50% growth inhibitory concentration) of these cells were HEp-2: 19.1 μM, H-F5: 22.1 μM, H-F10: 48.9 μM, Ca9-22: 8.1 μM, Ca-F1: 10.2 μM, Ca-F2.5: 9.9 μM. Next, nucleotide excision repair (NER), homologous recombination repair (HRR), and non-homologous end-joining (NHEJ) repair analyses were performed. The results showed that the NER activities of H-F10 and Ca-F1 were 1.4-fold and 3.2-fold higher than those of HEp-2 and Ca9-22, respectively. No apparent change of NER activity was found between H-F5 and HEp-2. For HRR and NHEJ repair, all cell lines exhibited similar activities between drug-resistant and parental cells, except for Ca-F1 whose NHEJ repair activity was lower than Ca9-22. By western blot analyses, we found that RPA and DDB1 had increased in H-F10, and XPA, ERCC1, and DDB1 had increased in Ca-F1 cells.This results suggested that cells acquired 5-FU resistance might also alter NER activites.

並列關鍵字

5-fluorouracil ； nucleotide excision repair (NER)

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