PP121 is a dual inhibitor of tyrosine and phosphoinositide kinases [1].
PP121 is found to inhibit both tyrosine kinases and PI3-Ks but not serine-threonine kinases. It potently inhibits p110α, p110β, p110γ, p110δ, DNA-PK and mTOR with IC50 values of 52nM, 1.4μM, 1.1μM, 150nM, 60nM and 10nM, respectively. For the tyrosine kinases, PP121 shows inhibition with IC50 values of 21nM, 4nM, 10nM,55nM, 550nM, 220nM and <1nM for Ab1, Hck, Src, VEGFR2, EGFR, EphB4 and PDGFR, respectively [1].
In cells, PP121 can reverse v-Src mediated cellular transformation and restore actin stress fiber staining. PP121 also potently inhibits the mutant Ret kinase with IC50 value less than 1nM in thyroid tumors34. Furthermore, PP121 is found to evade drug resistance through redundantly targeting Bcr-Abl mediated cell survival and PI3-K/mTOR mediated cell proliferation [1].
References:
[1] Apsel B, Blair J A, Gonzalez B, et al. Targeted polypharmacology: discovery of dual inhibitors of tyrosine and phosphoinositide kinases. Nature chemical biology, 2008, 4(11): 691-699.