热休克蛋白70对X射线照射下wtp53蛋白的影响

目的 探讨反义热休克蛋白70（hsc70）在X射线照射下对野生型p53(wtp53）的影响。方法 利用脂质体方法将本室构建的反义hsc70真核表达重组质粒pXAhsc70转染wtp53的MCF-7乳腺癌细胞，PCR证实外源DNA存在。Western bolt检测hsc70蛋白下降程度。X射线照射转染细胞后，检测wtp53蛋白的表达情况及半衰期变化。结果 转染重组质粒的细胞中hsc70蛋白下降53%；不同剂量X射线照射下，反义hsc70的存在能够提高wtp53的表达；4Gy相同剂量照射后，转染反义hsc70重组质粒的细胞中wtp53的半衰期延长。结论 反义hsc70能够上调wtp53的表达、稳定X射线照射下的wtp53蛋白并延长其半衰期；推测hsc70可能参与了wtp53的稳定和降解过程。

Impact of antisense heat shock protein 70 on expression and stability of wild type p53 protein after X-ray irradiation

Objective To investigate the effect of antisense heat shock protein (hsc70) on expression and stability of wild type p53 protein (wtp53) after X ray irradiation. Methods An eukaryotic recombination plasmid expressing antisense hsc70 RNA was transfected into MCF 7 human breast cancer cell line (wild type p53 ) by lipofectamine. The existence of foreign DNA was confirmed by means of PCR while suppression of hsc70 protein was monitored by Western blot. The expression and half life change of wild type p53 protein was evaluated after the definitive irradiation was implemented.Results Stable transfected MCF 7 cell strain expressing antisense hsc70 RNA was obtained. The expression of wtp53 was increased as compared to that of the control cell line which recieved the same dose of X ray and the half life period of wild type p53 was longer than that of the control cell after 4?Gy. Conclusions HSC70 plays an important role in stabilizing the wild type p53 protein expression with its molecular chaperon function in tumor cells irradiated. It is deduced that hsc70 is able to raise the expression of wtp 53 and to stabilize the wtp53 protein as well as to prolong its half life. It is expected that hsc70 may participate in the stabilization and degradation of wtp53.