Objective To study the apoptosis induction and its mechanisms of combinative effect of HDACls and cisplatin in oral squamous cell carcinoma (OSCC) cell lines. Methods (1 ) A pilot study was first used to observe the dose response of SAHA or cisplatin by MTS when used separately. (2) A subtoxic dose of SAHA and cisplatin was used alone or combination to compare their ability of apoptosis induction by flow cytometry and TUNEL System. (3) The analysis of expression of cytochrome C was performed by western blotting when drug used alone or combination. Results Both Tca8113 and KB cells were sensitive to SAHA or cisplatin alone. The apoptosis rate inducted by SAHA (2μmol/L) was 0. 9％ and 3.9％ in Tca8113 and KB cell lines, and the rate was 17.4％ and 12.6％ inducted by cisplatin(4μg/ml). However, the apoptosis rate achieved 34. 6％ and 40.4％ in the combinative treatment group. Compared with either SAHA or cisplatin treated alone, the percentages of TUNEL positive cells in the combinative treatment were significant higher in both Tca8113 and KB cell lines (P ＜0. 05). The increased drug sensitivity observed with co - treatment of the cells with SAHA was mediated by releasing of cytochrome C to cytosol. Conclusion Concurrent treatment with HDACls enhances tumor cell sensitivity to subtoxic dose of cisplatin through cytochrome C apoptosis pathway.%目的 研究组蛋白去乙酰化酶抑制剂(histone deacetylase inhibitors,HDACIs)与顺铂联合应用对口腔鳞癌细胞的凋亡诱导作用及相关分子机制.方法 (1)采用MTS法首先检测不同浓度的SAHA(suberoylanilide hydroxamic acid)和顺铂单独作用于口腔鳞癌细胞后,对其生长增生的影响,获得口腔鳞癌细胞对两种药物单独使用的剂量反应.(2)结合前面所得结果,采用流式细胞术及TUNEL分别检测低剂量SAHA(2μmol/L)及顺铂(4μg/ml)单独和联合用药后,对口腔鳞癌细胞的凋亡诱导情况.(3)采用western blotting 的方法观察单独及联合用药情况下Tca8113及κB两株口腔鳞癌细胞线粒体和胞质内细胞色素C(cytochrome C)的表达变化.结果 随单独用药剂量的增加,两株口腔鳞癌细胞都对SAHA及顺铂呈现出较好的敏感性.低剂量SAHA用药组Tca8113及κB的凋亡率分别为0.9%和3.9%,低剂量顺铂组Tca8113及κB的凋亡率分别为17.4%和12.6%,而在联合用药组凋亡率可以达到34.6%和40.4%;较低剂量SAHA及顺铂的单独用药组,联合用药组TUNEL染色阳性的细胞明显增多,差异具有显著统计学意义(P<0.05).联合应用低剂量的SAHA及顺铂,可以诱导cytochrome C从线粒体中释放到胞质.结论与单独使用两种药物相比较,低剂量的SAHA与顺铂的联合用药方式能诱导口腔鳞癌细胞通过线粒体相关通路发生凋亡.
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