Division of Gastrointestinal Surgery, Department of General Surgery, First Affiliated Hospital, Nanjing Medical University, 300 Guangzhou, Nanjing 210029, Jiangsu Province, China.
World J Gastroenterol. 2011 Jun 28;17(24):2958-64. doi: 10.3748/wjg.v17.i24.2958.
To evaluate bacterial cytosine deaminase (bCD) mutant D314A and 5-fluorocytosine (5-FC) for treatment of colon cancer in a mouse model.
Recombinant lentivirus vectors that contained wild-type bCD gene (bCDwt), and bCD mutant D314A gene (bCD-D314A) with green fluorescence protein gene were constructed and used to infect human colon carcinoma LoVo cells, to generate stable transfected cells, LoVo/null, LoVo/bCDwt or LoVo/bCD-D314A. These were injected subcutaneously into Balb/c nude mice to establish xenograft models. Two weeks post-LoVo cell inoculation, PBS or 5-FC (500 mg/kg) was administered by intraperitoneal (i.p.) injection once daily for 14 d. On the day after LoVo cell injection, mice were monitored daily for tumor volume and survival.
Sequence analyses confirmed the construction of recombinant lentiviral plasmids that contained bCDwt or bCD-D314A. The lentiviral vector had high efficacy for gene delivery, and RT-PCR showed that bCDwt or bCD-D314A gene was transferred to LoVo cells. Among these treatment groups, gene delivery or 5-FC administration alone had no effect on tumor growth. However, bCDwt/5-FC or bCD-D314A/5-FC treatment inhibited tumor growth and prolonged survival of mice significantly (P < 0.05). Importantly, the tumor volume in the bCD-D314A/5-FC-treated group was lower than that in the bCDwt/5-FC group (P < 0.05), and bCD-D314A plus 5-FC significantly prolonged survival of mice in comparison with bCDwt plus 5-FC (P < 0.05).
The bCD mutant D314A enhanced significantly antitumor activity in human colon cancer xenograft models, which provides a promising approach for human colon carcinoma therapy.
评估细菌胞嘧啶脱氨酶（bCD）突变体 D314A 和 5-氟胞嘧啶（5-FC）在小鼠结肠癌模型中的治疗作用。
构建含有野生型 bCD 基因（bCDwt）和 bCD 突变体 D314A 基因（bCD-D314A）与绿色荧光蛋白基因的重组慢病毒载体，并用于感染人结肠癌细胞 LoVo，以生成稳定转染的细胞，LoVo/null、LoVo/bCDwt 或 LoVo/bCD-D314A。将这些细胞皮下注射到 Balb/c 裸鼠中建立异种移植模型。LoVo 细胞接种后 2 周，通过腹腔（i.p.）注射 PBS 或 5-FC（500mg/kg），每天一次，共 14d。在 LoVo 细胞注射的第二天，每天监测肿瘤体积和存活情况。
序列分析证实构建了含有 bCDwt 或 bCD-D314A 的重组慢病毒质粒。该慢病毒载体对基因传递具有高效性，RT-PCR 显示 bCDwt 或 bCD-D314A 基因转移到 LoVo 细胞。在这些治疗组中，基因传递或 5-FC 给药本身对肿瘤生长没有影响。然而，bCDwt/5-FC 或 bCD-D314A/5-FC 治疗显著抑制肿瘤生长并延长小鼠存活时间（P<0.05）。重要的是，bCD-D314A/5-FC 治疗组的肿瘤体积低于 bCDwt/5-FC 组（P<0.05），bCD-D314A 加 5-FC 与 bCDwt 加 5-FC 相比显著延长了小鼠的存活时间（P<0.05）。
bCD 突变体 D314A 显著增强了人结肠癌异种移植模型中的抗肿瘤活性，为人类结肠癌治疗提供了一种有前途的方法。
