FUDR对鼻咽癌CNE-1细胞系的放射增敏作用

Radiosensitization by Fluorodeoxyuridine in Human Nasopharyngeal Carcinoma Cell Line CNE-1

目的研究氟尿嘧啶脱氧核苷(FUDR)对鼻咽癌细胞系CNE-1的细胞毒性作用及联合放疗的放射增敏作用,同时和5-氟尿嘧啶(5-Fu)作比较。方法应用CCK-8法分析FUDR及5-Fu对鼻咽癌细胞的毒性作用,绘制药物的浓度抑制率曲线。通过成克隆分析法研究低浓度的FUDR及5-Fu(浓度均<50%半数致死浓度ID50的1/5)联合照射对鼻咽癌细胞系CNE-1的体外放射增敏作用。流式细胞仪分析加药后各时间段的细胞周期变化。Western blot分析5-Fu和FUDR处理后细胞p53蛋白表达变化。结果从浓度抑制率曲线得出FUDR和5-Fu的ID50分别为0.078和0.509 mg/mL;成克隆分析法得出FUDR的放射增敏比和放疗2 Gy时的增敏比分别为1.504和1.677;5-FU的放射增敏比和放疗2 Gy时的增敏比分别为1.159和1.287;加入FUDR或5-Fu后各时间段S期细胞较对照组均增多,加药12 h后各时间段的差异均有统计学意义(P<0.05),但两药比较无统计学差异。Western blot结果显示,应用FUDR和5-FU处理后CNE-1细胞系p53蛋白表达增加,FUDR组增加更明显。结论低浓度的FUDR和5-Fu分别联合放疗均能增加鼻咽癌细胞系CNE-1的放射敏感性,且FUDR的增敏作用强于5-Fu;FUDR和5-Fu作用于鼻咽癌CNE-1细胞系均增加p53蛋白表达,FUDR作用更明显。FUDR和5-Fu作用于CNE-1细胞系后未见细胞周期重新分布于放射敏感时相,且二者对细胞周期的影响无明显差异。

Objective To study the cytotoxicity of FUDR on nasopharyngeal carcinoma cell fine CNE-1 and evaluate the radiosensitivity of noncytotoxic FUDR,and compare the effieaey with 5-fluorouracil （5-Fu）. Methods The concentration suppression rate curve was estab- lished by using cell counting kit 8, and IDs0 of FUDR and 5-Fu was calculated ; then the radiosensitization of low concentration of FUDR and 5-Fu （〈1/5 ID50） on nasopharyngeal carcinoma line CNE-1 associated with radiotherapy was determined by clonogenic assay. Cell cycle of different groups was determined by flow cytometry. The expression of p53 was measured by Western blot analysis in 5-Fu and FUDR treated cells. Results The ID50 of FUDR and 5-Fu were 0.078 mg/mL and 0.509 mg/mL respectively from concentration suppression rate curve. Cell survival experiments showed the sensitivity enhancement ratio （SER） and SER2 of FUDR were 1.504 and 1.677,which were 1.159 and 1.287 of 5-Fu.The proportion of cells in S phase increased after 6,12,18,24 hours exposure to both FUDR and 5-Fu. The expression of p53 was significantly increased after FUDR and 5-Fu treatment, especially in FUDR treated cells. Conclusion Noncytotoxie concentration FUDR has better radiosensitization effect on human nasopharyngeal carcinoma cell line CNE-1 than 5-Fu. The results of Western blot demon- strated that the expression of IO53 were increased in 5-Fu and FUDR treated CNE-1 cells,especially in FUDR group. The mdiosensitization is not related to the distribution of cell cycle and there was no statistical significance of the cell cycle distribution between FUDR and 5-Fu treated groups.