单用自杀基因疗法或单用细胞因子基因疗法抗肿瘤效果不理想,本研究中我们观察了大肠杆菌胞嘧啶脱胺酶(CD)基因与白细胞介素2(IL-2)基因联合转移对荷瘤小鼠的治疗效果及其对抗肿瘤免疫的诱导作用。复制荷瘤小鼠模型后在荷瘤部位注射表达CD基因的重组腺病毒(AdCD)及表达小鼠IL-2基因的重组腺病毒(AdIL2),并连续10天、每天1次腹腔注射5氟胞嘧啶(5FC)对荷瘤小鼠进行治疗。结果表明,AdCD/5FC/AdIL2联合基因治疗能显著抑制荷瘤小鼠皮下肿瘤的生长,并明显延长其生存期(P<0.01)。联合基因治疗组小鼠肿瘤细胞发生明显的坏死,瘤内及瘤周有大量的炎性细胞浸润,瘤内CD4~ 和CD8~ T细胞明显增加,脾细胞NK和CIL杀伤活性明显高于单用AdCD/5FC、对照病毒AdLacZ/5FC或PBS组。实验结果表明,联合应用自杀基因与细胞因子基因治疗可更有效诱导机体的抗肿瘤免疫反应,从而更显著地抑制荷瘤小鼠肿瘤的生长。

Antitumor effect of combined transfer of suicide gene and cytokine gene was evaluated in the present study. Adenoviruses expressing E. coli. cytosine deaminase (AdCD) and adenoviruses expressing murine interleukin 2 (AdTL2) were used for the treatment of tumor-bearing mice. The mice were inoculated s. c. with FBL-3 leukemia cells and 3 days later received intratumoral injection of AdCD in the presence or absence of AdIL2 followed by intraperitoneal 5-fluorocytosine (5FC) administration. The results demonstrated that tumor-bearing mice treated with AdCD/5FC in combination with AdTL2 showed more .potent inhibition of tumor growth and survived much longer as compared with mice treated with AdCD/5FC, AdEL2, AdlacZ/5FC or PBS. It was illustrated that the tumor mass showed obvious necrosis and inflammatory cell infiltration, and more CD4 and CD8 T cells infiltrated into the tumor after combined therapy. The splenic NK and CTL activities increased significantly in mice after combined transfer of CD gene and EH gene. Our results demonstrated that combined transfer of suicide gene and IL-2 gene could inhibit the growth of established tumor in mice significantly and induce antitumor immunity of the host efficiently.

国家自然科学基金39600181资助