The effect of adenovirus expressing wild-type p53 on 5-fluorouracil chemosensitivity is related to p53 status in pancreatic cancer cell lines

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),PANC1^(p53mut),and rat pancreatic cancer cell lines AS^(p53wt) and DSL6A^(p53null) were used for in vitro studies.Following infection with different ratios of Ad- p53-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 vivo studies. 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 vitro and in vivo analyses 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.

整合素αV和β3反义基因抑制大鼠胰腺癌生长的实验研究

目的:探讨整合素αV和β3反义基因对大鼠胰腺癌生长及肿瘤血管生成和细胞凋亡的影响。方法:建立大鼠胰腺癌模型,应用电转染方法分别用整合素αV、β3及αVβ3反义基因治疗,观察治疗后抑瘤率并应用免疫组织化学技术检测肿瘤微血管密度变化,TUNEL法检测肿瘤细胞凋亡情况。结果:对照组、αV组、β3组及αVβ3组肿瘤质量分别为(1.17±0.79)g、(0.95±0.26)g、(1.013±0.42)g和(0.79±0.56)g,各组间差异有统计学意义(P<0.05);微血管密度分别为(18.33±1.39)、(13.80±1.06)、(15.96±1.24)和(12.16±1.23),各组间差异有统计学意义(P<0.05);肿瘤细胞凋亡指数分别为(12.30±1.393)、(22.17±1.23)、(20.37±1.07)和(24.10±0.99),各组间差异有统计学意义(P<0.01)。结论:整合素αV、β3反义基因对大鼠胰腺癌的血管生长具有明显的抑制作用,可促进肿瘤细胞的凋亡,进而影响肿瘤生长,联合应用整合素αVβ3对肿瘤的生长抑制作用更为显著。

反义K-ras基因对胰腺癌细胞增殖和凋亡的影响

目的 探讨反义Kras癌基因对胰腺癌细胞增殖和凋亡及Fas／FasL、Bcl-2、Bax表达的影响。方法 将重组逆转录病毒载体pLXSN转染包装细胞PT-67，获得重组逆转录病毒。在细胞和动物水平将该重组逆转录病毒分别感染PC3和BxPC3胰腺癌细胞，经G418筛选获得稳定细胞系，应用MTT、流式细胞仪和免疫组化法分别研究其增殖、凋亡及其相关基因表达情况。结果 成功制备含反义K-ras基因的重组逆转录病毒。感染含反义K-ras基因重组病毒后，胰腺癌PC3细胞和移植瘤（有K-ras基因第12密码子点突变GGT→GTT）增殖受到抑制，G0/1期细胞增加而S期细胞明显减少，细胞凋亡增加。免疫组化显示含反义Kras癌基因逆转录病毒感染后PC-3细胞Bax／Bcl-2比值升高，Fas表达上调。结论 反义K-ras基因可使胰腺癌细胞及移植瘤增殖受到抑制，并可通过上调Bax／Bcl-2比值和（或）促进Fas表达诱导细胞凋亡。