Figure 7: Combining IFN-γ and an IDO or AhR inhibitor disrupts murine TRC dormancy in vivo.

(a) C57BL/6 mice with 5 × 5 mm B16 melanoma were intratumorally treated with 10 μg IFN-γ once daily for 3 days (n=6 per group). Isolated primary tumour cells from a part of tumour tissue were analysed by western blot with anti-IDO1, p27 and β-actin antibody, respectively (left). Another part of tumour tissue was immunostained with anti-AhR (green), S100 (red) and DAPI (blue), and observed under confocal microscopy (right). Bar, 20 μm. (b,c) mice with 5 × 5 mm B16 melanoma were intratumorally treated with 10 μg IFN-γ, IFN-γ/1-MT (5 mg ml⁻¹, 3–4 ml per mouse per day) or IFN-γ/DMF (10 mg kg⁻¹) once daily for 3 days (n=6 per group). Isolated primary tumour cells were assayed for cell cycle analysis (b). The tumour cells were cultured in 3D soft fibrin gels. Four days later, the colony number was counted (c). The data represent mean±s.e.m. (analysis of Student’s t-test). (d) the same as b, but isolated primary tumour cells were used to analyse caspase 3, caspase 7 and their cleaved forms by western blot (n=6 per group). (e) tumour tissue from b were fixed in paraffin for immunocytochemical analysis with anti-p-STAT1 (red), anti-S100 (green) and DAPI (blue). Bar, 25 μm.