基因转染内皮抑素与阿霉素协同作用对小鼠肝癌细胞的影响

Gene transfection of endostatin synergizes with doxorubicin to suppress human hepatocellular carcinoma： experiment with mice

目的探讨内皮抑素作为一种抑制血管生成的蛋白，能否与阿霉素协同作用治疗肝细胞癌（HCC）。方法构建内皮抑素表达质粒和在BALB／c裸鼠皮下建立HepG2人肝细胞肝癌动物模型，用阿霉素和生长抑素表达质粒基因转染治疗。结果构建的内皮抑素表达质粒在体内、外均可稳定表达。内皮抑素蛋白与阿霉素协同抑制肿瘤和血管内皮细胞的增殖。内皮抑素基因治疗及阿霉素均可抑制裸鼠皮下肿瘤的生长及新生血管的生成，并且呈现协同作用。内皮抑素基因转染下调了缺氧诱导因子（HIF-1α）和血管内皮生长因子（VEGF）的表达，而阿霉素仅能下调VEGF的表达。内皮抑素及阿霉素协同下调VEGF的表达。结论内皮抑素及阿霉素联合作用对抑制HCC治疗有确切效果，内皮抑素可提高阿霉素对肝癌细胞生长的抑制。

Objective To investigate whether endostatin, a potent antiangiogenic agent, synergizes with doxorobicin to suppress human hepatocellular carcinoma （HCC）. Methods An endostatin expression plasmid, Endo-cDNA3.1, was constructed and transfected into COS-1 cells. Human HCC cells of the line HepG2 and human umbilical vein endothelial cells of the line HUVEC were cultured and stimulated by the supematant of the COS-1 cells transfected with Endo-pcDNA3.1 and doxorobicin of different concentrations. MTT method was used to detect the proliferation of the cells. （ How many ） BALB/c mice were inoculated with HepG2 cells to establish HCC models, and then divided into 4 groups to undergo intratumoral injection of pcDNA3.1, End-pcDNA3.1, doxorobicin, or doxorobicin ＋ Endo-pcDNA3.1. Other mice were used as untreated control group. Two weeks later 5 mice from each group were killed with the tumors taken out. Immunostaining was used to calculate the microvessel density and Western blotting was sued to detect the expression of endostatin, hypoxia-inducible factor （HIF） and vascular endothelial growth factor （VEGF）. Results The proliferation of the HUVEC cells, but not that of the HepG2 cells, transfected with EndopcDNA3.1 ＋ doxorubicin was inhibited. Doxorubicin dose-dependently inhibited the proliferation of both HUVEC and HepG2 cells. Endostatin was strongly expressed in the cells treated with Endo-pcDNA3.1 the tumor size of the Endo-pcDNA3.1 and doxorubicin groups were （ 1545 ± 180） mm^3 and （953 ± 250） mm^3 respectively, both significantly lower than that of the untreated and pcDNA3.1 groups [ （2360 ± 330） mm^3 and （2235 ± 268） mm^3, respectively, all P 〈 0.01 ] , and the tumor size of the Endo-pcDNA3. 1 ＋ doxorubicin group was （426 ± 87） mm^3, significantly lower than any other groups （all P 〈0.01）. The number of microvessels of the Endo-pcDNA, doxorubicin, and doxorubicin ＋ Endo-pcDNA3.1 groups were all significantly less than those of the pcDNA3. 1 and untreated groups （ P 〈 0.05 or P 〈 0.01 ）. The expression of HIF-1 otwas downregnlated in the Endo-pcDNA3.1 and Endo-pcDNA3.1 ＋ doxorobicin groups, but not in the doxorubicin group. The VEGF expression was down-regulated in the Endo-pcDNA3. 1, doxorubicin, and Endo-pcDNA3.1 ＋ doxorubicin groups, especially in the latter. Conclusion Endostatin gene therapy synergizes with doxorubicin to suppress HCC.