PTGS2 and colitis: Instead, this molecule’s protective function was attributed to its inhibition of cyclooxygenase-2 (COX-2) signaling, a key inflammatory mediator in active macrophages upregulated during E. faecalis-associated colitis.130 Consistent with these studies, Wang et al.131 later showed that OG1RF-polarized macrophages induced heritable mutations in a normal colonic epithelial cell line (YAMC), and that allografts of these cells developed into poorly differentiated tumors in immunodeficient mice.