Pz-1 is a cell-permeable, non-cytotoxic (up to 0.1 μM and 6 days; NIH/3T3 cells), and highly potent type II kinase inhibitor that potently inhibits RET and VEGFR2 tyrosine kinase activity (IC50 <1 nM; [ATP] = 190 μM) by targeting the kinases in their inactive DFG-out conformation, displaying significant affinity (Kd <50 nM) toward only TRKB, TRKC, GKA, FYN, SRC, TAK1, MUSK from a panel of 96 other kinases. Pz-1 inhibits cellular RET mutants (C634R, C634Y, V804L, V804M, M918T) and VEGFR2 phosphorylations, and selectively inhibits the growth of RET C634Y- than HRas G12V-transformed NIH/3T3 cultures (IC50 = 0.5 vs. 34.4 nM). Likewise, Pz-1 completely abrogated tumor formation from RET C634Y-transformed NIH/3T3 cells in mice in vivo (1 mg/kg/d, p.o.), while only up to 70% tumor suppression of HRas G12V-transformed cells was achieved with 10 mg/kg daily oral dosage.
Pz-1 is a cell-permeable, non-cytotoxic and highly potent type II kinase inhibitor that potently inhibits RET and VEGFR2 tyrosine kinase activity.
