突变型K5重组蛋白抑制小鼠肝癌血管生成和肿瘤生长的作用

目的：体内实验观察人纤溶酶原K5缺失突变体Ⅰ（K5 mut1）对HepA小鼠肝癌血管生成和肿瘤生长的影响。 方法:大肠杆菌中表达，组氨酸结合柱亲和层析、纯化获得K5 mut1蛋白，SDS-PAGE和Western blotting方法鉴定其表达；建立皮下种植肝癌小鼠模型，腹腔注射不同剂量K5 mut1重组蛋白，检测抑瘤率及肝癌组织微血管密度（MVD）。结果： SDS-PAGE及Western blotting鉴定获得K5 mut1纯化蛋白；K5 mut1剂量依赖性地抑制小鼠肝癌（HepA）实体瘤生长，不同剂量K5 mut1治疗组肝癌组织MVD低于对照组，并随K5 mut1用药剂量增加而降低。 结论： K5 mut1具有抑制小鼠肝癌生长的作用，抑制肿瘤血管生成可能是K5 mut1抑制肿瘤生长的主要机制。结果提示K5 mut1具有治疗肝癌的潜在临床价值。

Plasminogen kringle 5 deletion mutant I inhibits the neovascularization and growth of the mouse hepatocarcinoma

AIM:To investigate the effects of plasminogen kringle 5(K5) deletion mutantⅠ(K5 mut1) on the neovascularization and growth of hepatocarcinoma in vivo. METHODS:K5 mut1 was expressed in E. coli BL-21(DE3) induced by IPTG and purified by Ni2+-His Bind Resin affinity chromatography. The purity and identity of K5 mut1 was examined by SDS-PAGE and Western blotting analysis. K5 mut1 activity was evaluated in vivo, HepA-grafed hepatocarcinoma mouse model was established by subcutaneously injection of mouse hepatoma cells(1×106) into the oxter of mice, and the mice were then divided into different groups and treated with PBS and K5 mut1 at different doses, respectively. The tumor suppressing rate and micro vascular density (MVD) in hepatoma tissues were assayed. RESULTS:The purity of recombinant K5 mut1 was over 90% according to the analysis of SDS-PAGE and Western blotting analysis. K5 mut1 significantly inhibited the growth of tumor in a HepA-grafed hepatocarcinoma mouse model and decreased microvessel density (MVD) in hepatoma tissues in a dose-dependent manner, compared with PBS control group. CONCLUSION:K5 mut1 exhibits anti-tumor effect in a HepA-grafted hepatocarcinoma mice model by the anti-angiogenic activity. These results support the conclusion that K5 mut1 may be a promising angiogenesis inhibitor and tumor suppressor with considerable therapeutic potential in liver cancer.