Figure 2.

Antitumor effects of combination IDO1 blockade-containing regimens. (A) Schematic of the treatment plan. B16F10 tumor cells (5×10⁴) were inoculated into the left flank of C57BL/6J mice on day 0, and the mice were treated with vehicle, l-1MTrp (orally, 5 g/kg feed) + CPA (150 mg/kg) or l-1MTrp+PTX (13.3 mg/kg) on days 7, 10, 13, and 16 postinoculation. ¹¹C-l-1MTrp PET/CT was performed on day 23. (B–D) Individual tumor growth curves of mice treated with vehicle, l-1MTrp+PTX, or l-1MTrp+CPA. (E) Tumor volume of mice on day 18 postinoculation. Data represent the mean±SEM, n=13 for vehicle group, n=8 for l-1MTrp+PTX group, and n=16 for l-1MTrp+CPA group. (F) H&E staining of tumor sections from treated mice on day 23 postinoculation. (G) Histochemical staining for the IDO1 protein in tumor sections from treated mice on day 23 postinoculation. Green indicates staining with an Alexa fluor 488-labeled anti-IDO1 antibody. (H–J) Quantification of the mRNA expression levels of several selected genes including interferon-gamma (IFN-γ), STAT1, and granzyme B in tumor tissues derived from the treated mice on day 23 postinoculaton. Data represent the mean±SEM, n=4. All comparisons were performed using an unpaired two-tailed Student’s t-test. CPA, cyclophosphamide; PTX, paclitaxel.