Effects of IDO1 inhibition on the growth of multidrug resistant tumors.

<p><b>A</b>. 1 x 10⁵ human A549, A549/dx, HT29, HT29/dx cells were implanted subcutaneously in 6–8 weeks old female nude BALB/c mice, 1 x 10⁵ murine JC cells were implanted in immunocompetent BALB/c mice. Tumor growth was monitored daily by caliper measurement. Data are presented as means ± SD of 10 mice/group. * p < 0.02, ** p < 0.005, *** p < 0.001: A549/dx or HT29/dx cells versus A549 or HT29 cells, at the corresponding time points. <b>B</b>. Animals bearing A549/dx-, HT29/dx-, JC-tumors were randomized into two groups when tumors reached the volume of 100 mm³: “Control” group (treated with 100 μL of saline solution <i>per os</i>, 5 days/week for three weeks; CTRL); “Brassinin” group (treated with 400 mg/kg of the IDO1 inhibitor 5-Br-brassinin <i>per os</i>, 5 days/week for three weeks; BRA). Tumor growth was monitored daily by caliper measurement. Data are presented as means ± SD of 6 mice/group. ** p < 0.005: BRA-group versus CTRL-group, at the corresponding time points.