目的：研究三氧化二砷(arsenic trioxide，As₂O₃)对腺样囊性癌(adenoid cystic carcinoma，ACC)中ACC-2细胞增殖、凋亡的影响，并从基因和蛋白水平分析其对ACC-2细胞中MDM2基因表达的影响， 从而探讨As₂O₃诱导ACC-2细胞凋亡的具体机制。

方法：体外培养ACC-2细胞，分为实验组和对照组，向培养至指数生长期的ACC-2细胞加入不同浓度(2、4、6、8μmol/L)的含As₂O₃的细胞培养液作为实验组，对照组给予等量的细胞培养液，加入As₂O₃后分别培养不同时间。倒置显微镜下密切观察各时间点不同浓度As₂O₃对ACC-2细胞的生长抑制作用和细胞凋亡的形态变化，应用荧光定量RT-PCR和免疫细胞化学技术检测MDM2基因(24、48h)和蛋白(24、48、72h)的表达变化。

结果：经As₂O₃处理后ACC-2细胞体积缩小变圆，核质固缩，悬浮凋亡细胞增多，存活细胞数量明显减少。RT-PCR及免疫细胞化学结果一致显示，ACC-2细胞随着药物浓度的增加及作用时间的延长，MDM2表达明显减少，与对照组比较，差异有统计学意义(P<0.05)，不同浓度不同时间各组两两比较差异有统计学意义(P<0.05)，MDM2蛋白表达量与浓度及时间呈显著负相关性(r<-0.7，P<0.05)，即呈浓度和时间依赖性。

结论：As₂O₃对ACC-2细胞具有生长抑制和诱导凋亡的作用，且As₂O₃能够下调腺样囊性癌ACC-2细胞中癌基因MDM2 mRNA及蛋白的表达，可能是其诱导腺样囊性癌ACC-2细胞凋亡的机制。

AIM:To investigate effects of arsenic trioxide(As₂O₃)on the proliferation and apoptosis of on adenoid cystic carcinoma-2(ACC-2)cells and detect the expression of MDM2 gene from gene and protein level and to explore detailed mechanism of As₂O₃ inducing ACC-2 cells apoptosis.

METHODS: ACC-2 cells were cultured in vitro and divided into the experiment group and control group. Different concentrations of As₂O₃(2, 4, 6, 8μmol/L)were applied to cells in logarithmic growth phase at different time as experiment group, the control group was given the same amount of cell culture fluid, after added As₂O₃, the cells were cultured at different times, respectively. The effect of different As₂O₃ concentrations at each point time on inhibition and metamorphoses of ACC-2 cells was observed under inverted phase contrast microscope. Expression changes of MDM2 mRNA(24, 48h)and protein(24, 48, 72h)were determined by reverse transcription polymerase chain reaction(RT-PCR)and immunohistochemistry test(IHCT)respectively.

RESULTS: Cells shrinkage, nuclear chromatin condensation, apoptotic cells increased and the number of viable cells significantly reduced after being cultured with different concentrations of As₂O₃. The results of RT-PCR and IHCT were showed consistent the expression of MDM2 in experiment group decreased gradually with the increase of As₂O₃ concentrations and extension of action time, which was significantly different to that in the control group(P<0.05). Campared with each other, it was statistically significant between the different concentration and time of two groups(P<0.05). MDM2 expression was negatively correlated with concentration and time(r<-0.7, P<0.05), that was, it presented in dose- and time-dependent manner.

CONCLUSION: As₂O₃ has the inhibitory and apoptosis-inducing effect on ACC-2 cells, and it can downregulate the expression of MDM2 mRNA and protein in ACC-2 cell line. This may be the mechanism of As₂O₃ induced ACC-2 cells apoptosis.

山东省自然科学基金资助项目(No.ZR2012HM062)