14-3-3 inhibitor WS3 is a potent, allosteric inhibitor of 14-3-3 proteins, potently inhibits the NRF2-ARE signal with IC50 of 135 nM in A549 cells, selectively inhibits NRF2 activity in tumor cells.
WS3 directly binds to 14-3-3ζ in a 1 : 1 ratio, with ITC Kd value of 2.29 uM, also binds to 14-3-3τ and 14-3-3η with high affinities.
WS3 exhibits concentration and time dependent downregulation of the expression of NRF2 downstream targets HO-1 and GCLM at both mRNA and protein levels in A549 cells as well as other NSCLC cell lines.
WS3 also reduces the NRF2 protein level, does not affect NRF2 activity in normal HUVEC and BEAS-2B cells.
WS3-mediated NRF2 downregulation could be partially rescued by the proteasome inhibitor MG132.
WS3 binds allosterically to 14-3-3 and drives a conformational change, stabilizes 14-3-3 dimers both in vitro and in vivo.
WS3 enhances CUL1–β-TrCP E3 ligase-mediated NRF2 degradation via targeted intervention of 14-3-3ζ
WS3 promotes NRF2 ubiquitination and degradation through disrupting the interaction between 14-3-3 and pGSK3β
WS3 induces oxidative stress and ferroptosis and inhibits cell growth in a NRF2 dependent manner in A549 cells, significantly inhibits cell proliferation in A549 cells with IC50 of 110 nM, but not NRF2-KO cells.
WS3 (1 mg/kg) shows in vivo efficacy and sensitizes A549 cells to chemotherapeutics and ferroptosis.
WS3 also can induce proliferation of β cells with EC50 of 74 nM, modulates the activity of Erb3 binding protein-1 and the IκB kinase pathway.
WS3 can reversibly proliferates primary RPE cells isolated from fetal and adult human donors.
