Figure 3.

Reduction iNOS and arginase expression in murine and human MDSC treated with OSU-53. (A) MSC2 cells were treated with indicated doses of OSU-53 or DMSO (control) overnight and then stimulated with LPS. The levels of nitrite were measured in the supernatant using Griess reagent. (B) Fold change in NOS2 (iNOS) gene expression in MSC2 cells was treated with indicated doses of OSU-53 or DMSO. (C-D) iNOS and arginase gene expression in MDSC from EMT-6 tumor-bearing mice treated OSU-53 (5 µM) or DMSO. MDSC isolated from melanoma patients were treated overnight with DMSO or OSU-53 (5 µM). The expression of (E) inducible nitric oxide synthase and (F) arginase was determined using real time PCR. The bars show fold change in gene expression compared to DMSO (controls). Values represent mean ± SD. (p < 0.05).