Brucein D, a naturally occurring quassinoid, enhances the sensitivity of pancreatic ductal adenocarcinoma (PDAC) cells to gemcitabine (GEM) by promoting the ubiquitin-proteasome-dependent degradation of NRF2 and suppression of the NRF2 signaling pathway [104]. Here, NFE2L2 is linked to pancreatic ductal adenocarcinoma.