Rb94联合放疗对裸鼠肺腺癌皮下移植瘤的抑制作用

目的  观察人视网膜母细胞瘤基因（Rb94）对裸鼠肺腺癌皮下移植瘤的放射增敏作用及其机制。方法  将40只裸鼠分别皮下接种5×106个A549细胞，当肿瘤长至180mm3时随机分为8组，每组5只，即空白对照组、空白对照+射线组、脂质体组、脂质体+射线组、空载体组、空载体+射线组，每两组分别于肿瘤内注射PBS、脂质体、pIRES。另有转染Rb94基因组、转染Rb94基因+射线组，分别注射pIRES-Rb94。空白对照+射线组、脂质体+射线组、空载体+射线组、转染Rb94基因+射线组裸鼠瘤体内注射后加照一定剂量X线。观察肿瘤生长情况并计算抑瘤率，采用实时RT-PCR和Western bolt法检测瘤组织中Rb94基因的表达，Hoechst染色观察细胞凋亡情况，实时RT-PCR检测hTERT、Bcl-2mRNA的表达，免疫组织化学SP法检测细胞周期阻滞。结果  转染Rb94基因+射线组抑瘤率为95.84%，与转染Rb94基因组和空白对照+射线组相比，差异有统计学意义(P<0.01)。结论  Rb94基因对裸鼠皮下移植瘤具有明显的抑制作用,联合射线抑瘤效果更好，其作用机制可能与Rb94基因引起细胞凋亡、G2/M期周期阻滞以及下调hTERT、Bcl 2 mRNA的表达有关。

Inhibiting effects of combinative treatment of retinoblastoma 94 with radiotherapy in a mouse xenograft model

Objective  To investigate the effects and mechanisms of radiosensitising enhancement of Rb94 gene in nude mice xenograft model. Methods  5×106 cells suspension was subcutaneously injected into flanks of 40 nude mice. Then the inoculated mice were devided into 8 groups after tumors reached 180mm3: no treatment group and XRT alone goup treated with PBS, lipofectamine treatment group and lipofectamine with XRT group treated with lipofectamine, pIRES treatment group and pIRES with XRT group treated with pIRES empty vector, pIRES Rb94 treatment group and pIRES Rb94 with XRT group treated with pIRES-Rb94.  X-ray was given to XRT alone group, lipofectamine with XRT group, pIRES with XRT group and pIRES-Rb94 with XRT group. The tumor inhibiting rate was observed and the expression of Rb94 gene was detected by Real time RT-PCR and Western blot. The number of apoptosis cells was measured by Hoechst staining. Expressions of hTERT and Bcl-2mRNA were detected by Real time RT-PCR. Cell cycle blockage was measured by Immunohistology(IF). Results  The inhibited ratio of pIRES-Rb94 with XRT group tumor was 95.84%, and statistically significant differences in the inhibition ratios were found between the pIRES Rb94 with XRT group and the other groups (pIRES-Rb94 treatment group and XRT alone group). Conclusion  It is suggested that Rb94 has inhibitory effects for inoculated tumor in nude mice. The tumor inhibition rate of pIRES Rb94 with XRT group seems to be higher than those in other groups. The mechanisms of  radiosensitising enhancement of Rb94 gene may include cell apoptosis, G2/M phase blocking and down-regulation of hTERT and Bcl-2 mRNA expressions.