NAMPT and colorectal carcinoma: To determine if MAPK signaling, including ERK1/2, JNK, and p38 kinases, regulates the visfatin effect on TYMS upregulation and subsequent capecitabine-induced death in human DLD-1 CRC cells, cells were pretreated with vehicle (DMSO) or inhibitors of ERK1/2 (PD98059, 25 μM), JNK (SP600125, 20 μM), and p38 (SB203580, 10 μM) for 30 min.