不同剂量的X射线辐照对胰腺癌细胞Survivin表达的影响

Effect of exposure to varying doses of X-rays on the survivn expression in pancreatic cancer cells

目的观察不同剂量的X线辐照后胰腺癌细胞Survivin表达的变化。方法胰腺癌细胞室温下经不同剂量的X线辐照处理。实验分为A组：对照组，无照射；B组：2Gy照射；C组：半致死量4Gy照射；D组：致死量10Gy照射。RT—PCR法检测各组Survivinm RNA表达量；MTT法检测胰腺癌细胞增殖抑制率及流式细胞术检查细胞凋亡率。结果在X线辐照处理后1～2d，B组与c组的Survivin表达明显增加，且在4d达到高峰；D组的Survivin表达显著下降。X线照射后第6天，B组与C组的胰腺癌细胞的增殖未受抑制，而D组的增殖受到明显抑制。B组的凋亡率为3％，C组的凋亡率为5％，D组的凋亡率为53％，与B组、C组相比，差异有统计学意义（P〈0．01）。结论放疗后诱导的Sttrvivin表达上调可能是胰腺癌细胞对放疗不敏感的重要原因之一。

Objective To observe the changes in the survivin expression in pancreatic cancer （PC） cells after exposure to varying doses of X - rays. Methods Pancreatic cancer cells were irradiated with varying doses of X- rays. The experiments were assigned to group A （control group, no irradia- tion） ,group B （the dose of X- irradiation was 2 Gy） ,group C （the dose of X- irradiation was 4 Gy,sublethal dose） and group D （the dose of X - irradiation was 10 Gy, lethal dose）. The expression of survivin mRNA was detected quantitatively by RT- PCR assays,proliferation of cells was tested by using MTT assay and apoptosis was determined by flow cytometry. Results The expression level of survivin mRNA in pancreatic cancer cells was gradually increased after exposure to X - irradiation for 2 days in groups B and C,peaked at 4th day, but obviously decreased in group D. After exposure to X- irradiation for 6 days, the proliferation of pancreatic cancer cells was not obviously suppressed in groups B and C, but significantly increased in group D. The apoptosis rate in groups B,C and D was 3% ,5% and 53 96 respectively, with the difference being statistically significant between group D and groups B and C （ P 〈 0.01）. Conchlsion The up- regulation of the survivin expression induced by X - irradiation may be one of the important factors of radioresistance by pancreatic cancer cells.