中文摘要：

目的探索奥沙利铂对不同p53状态肝癌细胞的DNA损伤修复基因（GADD45β）诱导差异及可能调控机制。方法转染p53全序列建立Hep3B如”。体外合成GADD451]近端启动子序列群（-618至-314），构建荧光素表达质粒，转染肝癌细胞株HepG2、Hep3B和Hep3B＋p53。以实时荧光定量PCR比较奥沙利铂对GADD4β表达诱导及其近端启动子活性影响差异；比较对DNA合成和细胞克隆形成能力抑制差异；通过Caspase-3的表达变化测定凋亡的发生和发展。结果奥沙利铂对Hep3B中GADD45β诱导并不明显。转染p53全基因序列后，Hep3B＋p53对奥沙利铂的敏感性明显增加，并呈现出剂量-效应的正相关关系。荧光素分析提示奥沙利铂作用Hep3B＋p53后的启动子NF-κB（-618／＋6）和E2F-1（-470／＋6）活性较Hep3B明显增强约1．5倍和0．8倍。奥沙利铂能够更加明显地抑制Hep3B邯”的DNA合成能力和细胞克隆形成能力，100μmol／L奥沙利铂作用后Hep3B＋p53 DNA合成率为30．41％，对细胞克隆形成能力的抑制率则达到75．60％，与Hep3B相比差异显著。奥沙利铂作用后Hep3B＋p54的Caspase-3能够迅速地启动凋亡的发生和发展。结论p53对铂类化疗药物对肝癌细胞的GADD45β诱导具有重要作用，增强转录调节因子的表达水平是其可能的作用机制。

英文摘要：

Objective To identify the role of p53 in the induction of growth arrest DNA damage-inducible gene 4513 （GADD45β） in HCC cells by Oxaliplatin. Methods A Hep3B＋p53 clone was es- tablished by transfection of the full-length p53 sequence to Hep3B. Following oxaliplatin administration, quantitative real-time PCR was employed to validate the expression changes of GADDI5β. pGL3 basic luciferase plasmids including promoter fragments were synthesized in vitro and transfected into cells. The effects on promoter activity, cell growth and the cleavage of Caspase-3 were {urther focused on. Results Hep3B＋pSa expressed p53 protein stably. The transfection of p53 enhanced the induction of GADD45β in Hep3B by Oxaliplatin. The promoter activity of fragments constructed NF-κB and E2F-1 binding sites was induced about 1.5 and 0.8 folds by transfection of p53. The colony formation and DNA syntheses were inhibited apparently in Hep3B＋p53 with p53 by Oxaliplatin （30.41% and 75.60% by 100 μmol/L Oxaliplatin, respectively）. Moreover, p53 transfection triggered cleavage of Caspase3 more rapidly. Conclusion p53 played a role in the induction of GADD45β in Hep3B by Oxaliplatin.