Antitumor activity of mutant bacterial cytosine deaminase gene for colon cancer

Figure 1 Sequencing results of recombinant plasmid pLJM1-bCDwt and pLJM1-bCD-D314A. The codon 985 of bCDwt, A, was mutated to C in bCD-D314A, which was the mutant D314A of bCD.

Figure 2 LoVo cell with fluorescence after transfection with lentiviral vector containing bCDwt-GFP gene (× 100). A: Green fluorescence field; B: Visible light field.

Figure 3 Identification of bCD gene in LoVo cells transfected with different lentiviral vectors. M: Marker; 1: Positive control (pcDNA3.1/bCDwt); 2: LoVo/bCDwt; 3: LoVo bCD-D314A; 4: LoVo/null; 5: Negative control (LoVo).

Figure 4 Growth of LoVo, LoVo/null, LoVo/bCDwt, and LoVo/bCD-D314A xenografts treated with PBS or 5-fluorocytosine. Treatment was started on 14 d after tumor cell inoculation. PBS or 5-fluorocytosine (5-FC) (500 mg/kg) was injected intraperitoneal once a day for 14 d. Data points represent the mean tumor volume of each group of animals. bCD: Bacterial cytosine deaminase; bCDwt: Wild-type bCD; bCD-D314A: bCD mutant D314A; LoVo/null: LoVo cell transfected with pLJM1-GFP; LoVo/bCDwt: LoVo cell transfected with pLJM1-bCDwt-GFP; LoVo/bCD-D314A: LoVo cell transfected with pLJM1-bCD-D314A-GFP.

Figure 5 Efficacy of wild-type bCD gene or bCD mutant D314A gene suicide gene therapy in human colon carcinoma xenografts. LoVo human colon carcinoma cells with different gene transfection (5 × 10⁶ cells/mouse) were injected into the right flank of athymic nude mice (10 mice/group). Two weeks after tumor cell injection, PBS or 5-fluorocytosine (5-FC) (500 mg/kg) was injected intraperitoneal once a day for 14 d. On the day after LoVo cell injection, mice were monitored daily for survival. bCD: Bacterial cytosine deaminase; bCDwt: wild-type bCD; bCD-D314A: bCD mutant D314A; LoVo/null: LoVo cell transfected with pLJM1-GFP; LoVo/bCDwt: LoVo cell transfected with pLJM1-bCDwt-GFP; LoVo/bCD-D314A: LoVo cell transfected with pLJM1-bCD-D314A-GFP.