AIM: There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU).Therefore the objective of this study was to determine the combined effects of adenovirus-med...AIM: There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU).Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status.METHODS: Human pancreatic cancer cell lines Capan-1^p53mut,Capan-2^p53wt, FAMPAC^p53mut, PANG1^p53mut, and rat pancreatic cancer cell lines AS^p53wt and DSL6A^p53null were used for in vitro studies. Following infection with different ratios of Adp53-particles (MOI) in combination with 5-FU, proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining). In addition, DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivostudies.Tumor size, apoptosis (TUNEL) and survival were determined.RESULTS: Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53. In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU. Both in vitroand in vivoanalyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU.CONCLUSION: Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function. These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.展开更多
目的:探讨外源性p53AIP1(p53-regulated apoptosis-inducing protein 1)基因抗肿瘤效应及其作用机制,以评估p53AIP1基因在肿瘤基因治疗中应用的可行性。方法:构建携带p53AIP1基因的重组复制缺陷型腺病毒Ad-p53AIP1,感染人肝癌细胞HepG2...目的:探讨外源性p53AIP1(p53-regulated apoptosis-inducing protein 1)基因抗肿瘤效应及其作用机制,以评估p53AIP1基因在肿瘤基因治疗中应用的可行性。方法:构建携带p53AIP1基因的重组复制缺陷型腺病毒Ad-p53AIP1,感染人肝癌细胞HepG2,应用MTT比色法、Western blotting、流式细胞术、罗丹明染色以及电镜等观察外源性p53AIP1基因表达对肿瘤细胞的作用及其相关机制。小鼠皮下接种感染Ad-p53AIP1的小鼠乳腺癌4T1细胞,观察Ad-p53AIP1对肿瘤细胞体内成瘤性的影响;建立4T1细胞皮下移植瘤小鼠模型,直接瘤内多点注射重组腺病毒,观察Ad-p53AIP1的抗肿瘤疗效。结果:感染Ad-p53AIP1的HepG2细胞能够高效表达P53AIP1蛋白。MTT检测显示Ad-p53AIP1对人肝癌细胞HepG2的生长抑制率达50%以上;流式细胞术分析证实p53AIP1使肿瘤细胞周期阻滞于G_2/M期;罗丹明染色、电镜观察以及凋亡相关蛋白PARP表达的检测均证实p53AIP1能诱导肿瘤细胞发生明显凋亡。感染Ad-p53AIP1的肿瘤细胞体内成瘤受到非常明显的抑制(P<0.01),Ad-p53AIP1瘤体注射对移植瘤生长也有明显的抑制作用(P<0.05)。Western blotting以及RT-PCR检测证实Ad-p53AIP1对p53 mRNA表达无影响,能下调mdm2基因的表达;p53AIP1能上调P53蛋白的表达、下调MDM2蛋白的表达水平,同时还影响P21等细胞周期相关蛋白和凋亡相关蛋白的表达。结论:p53AIP1有明显的体内外抗肿瘤作用,其作用机制与其反向调控P53蛋白、调控多种细胞周期和细胞凋亡相关蛋白、诱导细胞周期阻滞和细胞凋亡有关,该基因在肿瘤基因治疗中具有潜在的应用前景。展开更多
文摘AIM: There are conflicting data about p53 function on cellular sensitivity to the cytotoxic action of 5-fluorouracil (5-FU).Therefore the objective of this study was to determine the combined effects of adenovirus-mediated wild-type (wt) p53 gene transfer and 5-FU chemotherapy on pancreatic cancer cells with different p53 gene status.METHODS: Human pancreatic cancer cell lines Capan-1^p53mut,Capan-2^p53wt, FAMPAC^p53mut, PANG1^p53mut, and rat pancreatic cancer cell lines AS^p53wt and DSL6A^p53null were used for in vitro studies. Following infection with different ratios of Adp53-particles (MOI) in combination with 5-FU, proliferation of tumor cells and apoptosis were quantified by cell proliferation assay (WST-1) and FACS (PI-staining). In addition, DSL6A syngeneic pancreatic tumor cells were inoculated subcutaneously in to Lewis rats for in vivostudies.Tumor size, apoptosis (TUNEL) and survival were determined.RESULTS: Ad-p53 gene transfer combined with 5-FU significantly inhibited tumor cell proliferation and substantially enhanced apoptosis in all four cell lines with an alteration in the p53 gene compared to those two cell lines containing wt-p53. In vivo experiments showed the most effective tumor regression in animals treated with Ad-p53 plus 5-FU. Both in vitroand in vivoanalyses revealed that a sublethal dose of Ad-p53 augmented the apoptotic response induced by 5-FU.CONCLUSION: Our results suggest that Ad-p53 may synergistically enhance 5-FU-chemosensitivity most strikingly in pancreatic cancer cells lacking p53 function. These findings illustrate that the anticancer efficacy of this combination treatment is dependent on the p53 gene status of the target tumor cells.