Article Figures & Data
Figures
- Figure 1.
Tumor targeting of S. typhimurium A1 and A1-R in vitro. A, RFP-labeled HT-29 human colon cancer cells were grown in 24-well tissue culture plates. S. typhimurium-GFP, grown to late-log phase, were diluted in cell culture medium (1 × 106), added to the tumor cells, and placed in an incubator at 37°C. After 60 minutes, the cells were rinsed. Adherent bacteria were released and then quantitated by plating for CFU on LB agar medium. The number of A1-R bacteria attached to tumor cells was ∼6 times higher than the parental A1 bacteria. B and C, to measure invasion of bacteria, the cancer cells were first rinsed five times with PBS, and then the cells were cultured in medium containing gentamicin sulfate (20 μg/mL) to kill external but not internal bacteria. After incubation with gentamicin for 12 hours, the cancer cells were washed once with PBS, and the viable GFP-expressing intracellular bacteria were observed by fluorescence microscopy. A1-R (C) bacteria invaded and grew in tumor cells to a greater extent than the parental A1 (B). Bar, 58 μm.
- Figure 2.
Growth of S. typhimurium A1-R in MARY-X human breast cancer tissue after tail vein injection. NCR nude mice, 6 to 8 weeks, were s.c. implanted in the midright side with human breast cancer tissue. Bacteria were injected directly into the tail vein (107 CFU/100 μL PBS). The tumors were excised, and samples were observed under fluorescence microscopy. For histology, the tumor tissue was fixed with 10% buffered formalin and processed for paraffin section and HE staining by standard methods. A and B, bacteria growing in tumor tissue on day 2 after infection. Bar, 150 μm in (A and B). C, surface image of bacterial distribution in intact tumor tissue on day 5 after infection. Bar, 180 μm. D, bacterial distribution in transverse section of tumor showing inner surface on day 5 after infection. Bar, 180 μm. E, bacteria growth in the viable MARY-X tumor tissue. Bar, 25 μm. F, bacteria destroyed tumor tissue (day 4 after infection). Bar, 50 μm. G, bacteria growth within the vascular regions of tumors (day 4 after infection). Blue dots, arrows, S. typhimurium A1-R. Bar, 100 μm.
- Figure 3.
Efficacy of A1-R on MARY-X human breast cancer growing s.c. in nude mice. A and B, efficacy of A1-R on tumor growth. Six-week-old female nu/nu mice were s.c. implanted on the flank of the nude mice with 2 mm3 MARY-X human breast cancer tissue. The bacteria were grown overnight on LB medium and then diluted 1:10 in LB medium. Bacteria were harvested in late-log phase, washed with PBS, and then diluted in PBS (107 CFU/100 μL PBS). C, efficacy of A1-R on survival of nude mice with MARY-X tumor. Tumor growth was monitored by whole-body imaging. Mice were sacrificed when the tumor mass reached 2 cm3. Survival time was compared with the untreated mice. The survival of treated animals was prolonged, and the 40% cured mice survived as long as non–tumor-bearing mice. n = 10 mice for each group.
- Figure 4.
Efficacy of S. typhimurium A1-R on MARY-X human breast cancer growing orthotopically in nude mice. A and B, efficacy of A1-R on orthotopic MARY-X breast cancer. Nude mice, 6 to 8 weeks, were orthotopically implanted in the right second mammary gland fat pad with 2 mm3 MARY-X human breast cancer tissue. A1-R bacteria were injected directly into the tail vein (107 CFU/100 μL PBS). Tumor size was measured at indicated time points after infection. n = 10 animals.
Volume 66, Issue 15
