GDF15 and urinary bladder carcinoma: To explore whether CAPE increased GDF15, NDRG1, and maspin expressions in bladder carcinoma cells through the MAPK pathway, HT1376 cells were pretreated with MAPK inhibitors, ERK (PD0325901), p38 (SB202190), or JNK (SP600125) for 1 h before exposure to CAPE (30 μM).