To investigate the role of NO generated by macrophages on CDDP-induced apoptosis we chose human U373 and mouse GL261 glioma cell lines, which are defective in the expression of both constitutive (nNOS and eNOS) and iNOS enzymes (Figures S1A–C and S2A–C in Supplementary Material). Here, NOS2 is linked to central nervous system cancer.