ANTI-TUMOR EFFECT OF ANTI-ANGIOGENIC FACTOR GENES PRODUCED BY ELECTROPORATION

用化疗药物和高压电脉冲进行电化疗的抗肿瘤效果已有报道。本研究旨在明确抗肿瘤免疫参与电化疗中肿瘤结节消退的确切性质，并评价使用低电压电穿孔的效果。接受肿瘤内注射(I.T.)的小鼠结肠26肿瘤被根除。注射博莱霉素500μg，然后用50~150V/cm的电场治疗，完全缓解率为80~100%。小鼠拒绝接受再次挑战的结肠26细胞的接种，但不拒绝接种Meth A细胞。在Balb/c nu/nu裸鼠中，在与Balb/c裸鼠几乎完全治愈的相同治疗条件下，电化疗后肿瘤未见完全消退。我们的结果提示，T细胞依赖的、肿瘤特异性保护性免疫的产生可能参与了肿瘤…的过程抗血管生成因子是一种有效的内皮细胞生长抑制因子，已被证明能抑制体外血管生成和小鼠肿瘤生长。我们通过低电压电穿孔将抗血管生成基因(小鼠Angiostatin：pBLAST-Mangio和小鼠Endostatin：P-BLAST42-Mendo XV)转移到小鼠结肠26模型中，证明了其协同抗肿瘤作用。体内肿瘤生长动力学和小鼠生存研究强烈表明了协同抗肿瘤作用。RT-PCR证实各基因片段均通过低电压电穿孔在肿瘤内转移。肿瘤中微血管密度的降低也证实了两种基因协同抗肿瘤作用的有效性。1：1比例的血管抑素和内皮抑素基因对小鼠的生长有明显的抑制作用，并且两种基因转移的顺序(首先是内皮抑素基因，一周后是血管抑素基因)对肿瘤的生长有明显的抑制作用。这些数据表明，当两种基因联合应用时，通过低电压电穿孔在体内输送抗血管生成基因可能成为已建立的实体瘤的治疗策略。较少

The antitumor efficiency of electrochemotherapy using chemotherapeutic agents and high voltage electric pulse has been reported. This study was done to define the precise nature of the involvement of antitumor immunity in the regression of tumor nodules in electrochemotherapy, and to evaluate the effectiveness of using low voltage electroporation. Colon 26 tumors were eradicated in the mice given an intratumor (i.t.) injection of 500 μg bleomycin followed by treatment with electric fields ranging from 50 to 150V/cm, with complete response rates ranging from 80 to 100%. The mice rejected inoculations of re-challenged colon 26 cells, but not Meth A cells. In the Balb/c nu/nu nude mice, complete regression of the tumor was not seen after electrochemotherapy tinder the same therapeutic conditions that resulted in almost complete cure in the Balb/c mice. Our results suggest that the generation of T-cell-dependent, tumor-specific protective immunity might be involved in the process of tumor … More nodule regression in low-voltage electrochemotherapy.Anti-angiogenic factors are potent endothelial cell growth inhibitors that have been shown to inhibit angiogenesis in vitro and tumor growth in mice. We have demonstrated the synergistic anti-tumor effect of anti-angiogenic genes (mouse angiostatin : pBLAST-mAngio, and mouse endostatin : p-BLAST42-mEndo XV) delivered to tumors by low-voltage electroporation in mouse colon 26 models. A synergistic anti-tumor effect was strongly suggested by in vivo tumor growth kinetics, as well as in survival studies with the mice. RT-PCR confirmed the fragments of each gene were transferred by low-voltage electroporation in the tumor. Decreased microvessel density measurements in tumors also confirmed the efficacy of the synergistic antitumor effect of both genes. Significant growth inhibition was observed in mice treated with a 1:1-proportion of angiostatin and endostatin genes, and the order of the both genes transferred (first the endostatin-gene, followed one week later by the angiostatin-gene) had a profound inhibitory effect on tumor growth. These data suggest that in viva delivery of anti-angiogenic genes with low-voltage electroporation could be a possible therapeutic strategy for established solid tumors when both genes were applied in combination. Less