A conjugated mTOR/MEK bifunctional inhibitor as potential polypharmacological anticancer agent: the prototype compound discovery

mTOR/MEK bifunctional inhibitors have the potential to surmount the drug resistance aroused from cross talk between PI3K/Akt/mTOR (PAM) and Ras/MEK/ERK pathways. Herein, we report the discovery of a conjugated dual-targeted molecule, compound 13, as the prototype mTOR/MEK bifunctional inhibitor. It exhibited moderately high inhibitory activity against mTOR and MEK1 with IC(50) values of 0.19 μM and 0.98 μM, respectively. In particular, it displayed attractive antiproliferative activity against both A549 (GI(50) = 4.66 μM) and HCT116 (GI(50) = 5.47 μM) cell lines. To our knowledge, it has been the first example of a conjugated mTOR/MEK bifunctional inhibitor. In addition, from this proof-of-principle study, it has become evident that the single-agent dual inhibition of mTOR and MEK can be fulfilled via covalently attaching mTOR kinase inhibitor to an allosteric MEK inhibitor.