肿瘤的G-CSF基因治疗及肿瘤原位细胞生物学特性

Antitumor effect of intratumoral injection of liposomeencapsulated GCSF gene and in situ biological characteristics of the treated tumor cells

目的：研究瘤体内注射脂质体包裹的Ｇ－ＣＳＦ基因的抗肿瘤作用及其可能机制。方法：将脂质体包裹的Ｇ－ＣＳＦ基因直接注射至小鼠结肠癌瘤体内，观察Ｇ－ＣＳＦ基因治疗的抗肿瘤效果及肿瘤细胞性状的变化。结果：瘤体内注射脂质体包裹的Ｇ－ＣＳＦ基因后，可明显抑制结肠癌小鼠肿瘤的生长，显著延长存活期；配合大剂量化疗后效果更显著，有３０％的小鼠存活９０ｄ以上。从瘤体内分离的肿瘤细胞，经Ｇ４１８（６００μｇ／ｍｌ）抗性筛选后，产生抗Ｇ４１８的抗性克隆，并分泌人Ｇ－ＣＳＦ（ｈＧ－ＣＳＦ）；经Ｎｏｒｔｈｅｒｎ－ｂｌｏｔ鉴定显示，该肿瘤细胞可表达Ｇ－ＣＳＦｍＲＮＡ；肿瘤细胞表面表达ＩＣＡＭ－１分子、ＭＨＣⅠ类抗原（Ｈ－２Ｋｄ）均明显高于对照组。结论：瘤体内注射脂质体包裹的Ｇ－ＣＳＦ基因后，可在肿瘤原位将Ｇ－ＣＳＦ基因转染肿瘤细胞并有效表达，提高肿瘤细胞的免疫原性。

Objective: To investigate the antitumor effects of the in vivo GCSF gene therapy mediated by liposome and its mechanisms. Methods: Human GCSF gene was encapsulated into liposome and was directly injected into C26 colon adenocarcinoma tumor mass in mice. Results: After direct intratumoral injection of GCSF DNAliposome, the tumor growth was dramatically inhibited and the survival time was prolonged significantly. Tumor regression could be observed in about 30% of C26bearing mice.By the analysis of the antitumor mechanisms, we found that antiG418(600 μg/ml) clone could be selected from the tumor cells freshly separated from the treated C26 tumor mass,and secretion of GCSF in the supernatant could be detected. Northernblot also confirmed the expression of hGCSF by the tumor cells. Higher expressions of MHC class Ⅰ(H2Kd) molecule and ICAM1 on the tumor cells could be observed. Conclusion: The results demonstrate that liposome can effectively transfect GCSF gene into tumor cells in situ, and then increase the immunogenicity of the tumor cells which may contribute to the activation of the local antitumor immune responses.