外源性PTEN增强放射线诱导胰腺癌ASPC-1细胞G2/M期阻滞

目的观察外源性PTEN在乏氧及放射前后对胰腺癌细胞系ASPC-1细胞周期及克隆形成的影响。方法将质粒pEAK8和pEAK8-PTEN分别转染ASPC-1细胞,获得ASPC-1-pEAK8细胞及ASPC-1-pEAK8-PTEN细胞,将ASPC-1、ASPC-1-pEAK8和ASPC-1-pEAK8-PTEN细胞各分成常氧组、乏氧组、照射组、乏氧照射组。乏氧组施加乏氧（1%O2）处理,乏氧时间为24 h,照射组接受4Gy单次照射,乏氧照射组在乏氧下进行照射。应用Western印迹杂交、流式细胞术、成克隆分析法检测外源性PTEN对ASPC-1细胞PTEN蛋白表达、细胞周期分布及细胞克隆形成能力的影响。结果ASPC-1-pEAK8-PTEN细胞较ASPC-1、ASPC-1-pEAK8细胞PTEN蛋白增加明显。常氧下,ASPC-1-pEAK8-PTEN细胞较ASPC-1、ASPC-1-pEAK8细胞G2/M期细胞增多,并且放射线进一步增强了G2/M期细胞阻滞。乏氧8h后,ASPC-1-pEAK8-PTEN细胞较ASPC-1、ASPC-1-pEAK8细胞凋亡比例显著提高。常氧及放射后,ASPC-1、ASPC-1-pEAK8、ASPC-1-pEAK8-PTEN细胞克隆形成率分别为33.33±8.38%、31.67±4.32%、24.00±3.90%和5.53±0.52%、5.33±0.74%、3.73±1.20%。乏氧及放射后,细胞克隆形成率分别为29.67±4.97%、29.50±3.39%、19.83±5.12%和12.08±0.78%、11.17±0.73%和7.38±0.58%。结果表明,ASPC-1-pEAK8-PTEN细胞较ASPC-1,ASPC-1-pEAK8细胞在照射及乏氧前后克隆形成率均明显降低。结论外源性PTEN可使胰腺癌ASPC-1细胞阻滞在G2/M期,增强乏氧诱导细胞凋亡,增强放射线诱导ASPC-1细胞G2/M期阻滞的能力,提高放射线对ASPC-1细胞在常氧及乏氧下的细胞杀伤。

EXOGENOUS PTEN ENHANCES RADIATION-INDUCED G2/M ARREST OF PANCREATIC CANCER CELL LINE ASPC-1

Objective To investigate the effect of phosphatase and tensin homologue deleted on chromosome ten(PTEN) on cell cycles and plating efficiency(PE) in human pancreatic cancer cell line ASPC-1 under hypoxia and/or radiation exposure.Methods After transfection with a eukaryotic expression plasmid(pEAK8) containing PTEN or not in vitro by lipofectin,the ASPC-1 cells were named ASPC-1-pEAK8-PTEN or ASPC-1-pEAK8.ASPC-1,ASPC-1-pEAK8 and ASPC-1-pEAK8-PTEN cells were assigned to the normal oxygen,hypoxia,radiation,an...