中文摘要：

目的探讨5-氮杂脱氧胞苷（5-Aza—dC）与曲古抑菌素A（TSA）对膀胱癌细胞中抑癌基因ALDHla2启动子甲基化状态和基因表达及细胞凋亡的影响。方法使用5-Aza—dC、TSA处理RT-4、253J、5637、BIU-87和T24后，应用甲基化特异性PCR（MSP）法、逆转录PCR（RT—PCR）法、Western blot法分别检测这5株膀胱癌细胞经药物干预前后ALDHla2甲基化状态及基因表达情况，应用流式细胞学检测干预前后5株膀胱癌细胞株的凋亡情况。结果在5株膀胱癌细胞中，ALDHla2基因表现为高甲基化表达受到抑制，TSA不影响甲基化状态，5-Aza—dC可逆转高甲基化状态并恢复基因表达，联合给予5-Aza—dC和TSA的作用和单独给予5-Aza．dC相似；TSA和5-Aza—dC均可诱导膀胱癌细胞株凋亡，早期凋亡是膀胱癌细胞株死亡的主要方式，5-Aza—dC和TSA有协同作用，3个实验组与对照组比较，差异均有统计学意义（P〈0．05）。结论在5株膀胱癌细胞株中，ALDHla2基因启动子甲基化可能是导致其基因失活的主要原因；5-Aza．dC单独作用和5-Aza—dC及TSA联合应用效果相似，均能恢复基因重新表达进而诱导膀胱癌细胞株的早期凋亡。

英文摘要：

Objective To study the effect on promoter de-methylation, expression of ALDHla2 gene and cell apoptosis by treated with 5-Aza-dC and TSA in five human bladder cancer cell lines. Methods Human bladder cancer cell lines RT-4,253J, 5637, BIU-87 and T24 were cultured and treated with 5-Aza- dC and （or） TSA. The expression of the ALDHla2 gene was detected by RT-PCR and Western blot. The methylation status of gene promoter was determined by MSP, and the cell cycle profile was established by flow cytometry. Results ALDHla2 was silenced in five human bladder cancer cell lines. Re-expression of ALDHla2 was detected after treated with 5-Aza-dC alone or TSA in combination. ALDHla2 transcript was marked in each cell lines combined with 5-Aza-dC and TSA treatment which showed a synergistic effect on expression of ALDHla2 transcript. Early apoptotic was the main mode of apoptosis and death of human bladder cancer cell lines induced by 5-Aza-dC and TSA. The percentage of early apoptotic cells was 1.4% in control group and 2. 8% in TSA group, however, 20. 2% in 5-Aza-dC group and 33.8% in 5-Aza-dC ＋ TSA group, respectively. The groups of TSA, 5-Aza-dC and 5-Aza-dC ＋ TSA were significantly different from control group （ P 〈 0. 05 ）. Conclusions Aberrant methylation of ALDH1 a2 gene is the main cause for gene transcriptional inactivation. Re-expression of ALDH1 a2 gene and cell apoptosis are detected after either treatment with 5-Aza-dC alone or in combination with TSA.