中文摘要：

目的研究和厚朴酚对人鼻咽癌CNE-1和CNE-2细胞生长和放射敏感性的影响。方法采用四甲基偶氮唑盐比色法（MTT法）检测CNE-1和CNE-2细胞生长；流式细胞术检测细胞周期变化；磷脂酰丝氨酸外翻分析法检测细胞凋亡；Westernblot法测定相关蛋白表达水平；采用细胞克隆形成法观察和厚朴酚对细胞放射敏感性的影响。结果和厚朴酚明显抑制CNE-1和CNE·2细胞生长，且存在着明显剂量和时间依赖性，半数抑制浓度（IC50）在CNE．1和CNE-2细胞分别为2．84和2．68μmol／L（24h），2．50和2．20μmol／L（48h）。2．5μmol／L和厚朴酚处理24h后，CNE-1细胞的早期凋亡、晚期凋亡和坏死细胞分别达到24．53％、23．05％和7．13％，与未经处理的对照组之间差异均有统计学意义（t=-41．17、-8．18、-6．08，P〈0．05）。4和3μmol／L的和厚朴酚分别使CNE-1细胞和CNE-2细胞中促凋亡蛋白Bax和凋亡效应蛋白Caspase3的表达水平出现2．31倍和1．89倍（t=-15．92、-17．15，P〈0．05）及4．43倍和1．85倍（t=-29．39、-13．47，P〈0．05）的增加，同时抗凋亡蛋白Bcl-2蛋白的表达降低45．05％和36．50％（t=26．94、66．14，P〈0．05）。和厚朴酚24h预处理可以明显提高CNE-1和CNE-2细胞对x射线的放射敏感性，SER分别为1．41和1．88。3GyX射线照射明显增加两种细胞的G，／M期细胞数量（t=-14．96、-19．26，P〈0．05），和厚朴酚降低了辐射导致的G2／M期细胞阻滞（t=7．65、4．98，P〈0．05），同时CyelinB1蛋白表达明显增加（t=-33．07、-73．49，P〈0．05）。结论和厚朴酚诱导入鼻咽癌CNE-1和CNE-2细胞凋亡和细胞坏死而导致细胞生长的抑制。干预X射线诱导G2／M期细胞阻滞可能是和厚朴酚预处理提高两种鼻咽癌细胞放射敏感性的重要作用机制。

英文摘要：

Objective To explore the influence of honokiol on growth, cell cycle and radiosensitivity in nasopharyngeal carcinoma cells, CNE-1 and CNE-2. Methods MTT assay and clonogenic assay were used to detect cell growth and survival respectively. Flow cytometry was employed to analyze cell cycle progression. Annexin V-FITC kit was used to detect eell apoptosis. Western blot assay was applied to examine protein expression. Results Honokiol signficantly inhibited proliferation of CNE-1 and CNE-2 cells in a dose and time dependent manner, the ICso value was 2.84 and 2.68 μmol/L（24 h） and 2.50 and 2.20 μmol/L （48 h） , respectively. After being treated with 2.5 μmol/L honokiol for 24 h, the ratios of early apoptosis, late apoptosis and necrosis were 24. 53% , 23.05% and 7.13% in CNE-1 cells compared with the control group（t = - 41. 17, - 8. 18, - 6. 08, P 〈 0.05）. The expression levels of pro-apoptotic proteins Caspase-3 and Bax were significantly increased to 2.31 and 1.89 times （t = -15.92, - 17.15, P 〈 0.05）, 4.43 and 1.85 times（t = -29.39, - 13.47, P 〈 0.05）. Simultaneously the expression level of anti-apoptotie protein Bcl-2 was reduced by 2. 22 and 2.74 times（ t = 26.94, 66.14, P 〈 0. 05） as compared with controls after being treated with 4 and 3 ixmol/L honokiol. Additionally, honokiol at lower doses signicantly enhanced the senstivity of CNE-1 and CNE-2 cells to X-ray irradiation. The SER was 1.41 and 1.88 in CNE-1 and CNE-2 cells. 3 Gy irradiation of X-rays increased the proportion at GJM state in both cell lines （ t = - 14. 96, - 19.26, P 〈 0. 05 ）. Honokiol reduced the G2/M cell cycle arrest induced by irradiation significantly （ t = 7.65, 4. 98, P 〈 0. 05 ）. Simultaneously, cyclin B1 protein expression obviously elevated （ t = - 33.07, - 73.49, P 〈 0. 05 ）. Conclusions Honokiol is a potent inhibitor of nasopharyngeal carcinoma cell growth by inducing cell apoptosis and necrosis and works as a radiosensitizer by disrupting GJM cell cycle checkpoint.