Figure 4.

Local 5-FC conversion in tumors leads to tumor regression in vivo. (a) PC3 tumor cells (4 × 10⁶) alone or mixtures of PC3 cells with AT-MSCs or with various ratio of therapeutic CDy-AT-MSCs were injected s.c. into flank of each nude mouse (n = 4 in each group). All cells were mixed with the same volume of Matrigel before inoculation. All animals were treated with daily dose of 500 mg/kg of 5-FC intraperitoneally (i.p.) starting on second day after tumor appearance in control group and up to the 27th day. Animals were inspected for tumors every 2 days. At day 40 the experiments were ended. (b) PC3 cells (3 × 10⁶) or mixtures of 3 × 10⁶ of PC3 tumor cells either with 40% of AT-MSCs or with 50% and 10% of therapeutic cells were injected into flank of each nude mouse (n = 4 in each group). All animals were treated with daily dose of 500 mg/kg of 5-FC i.p. as indicated by arrows. Animals were inspected by palpation for tumors every 2 days. At day 40 the experiments were ended and animals were inspected for tumors by biopsy. AT-MSCs, adipose tissue–derived mesenchymal stem cells; 5-FU, 5-fluorouracil.