In silico high throughput screening and in vitro validation of a novel Raf/Mek dual inhibitor against colorectal carcinoma

Activation of the Raf/Mek pathway is critical in colorectal cancers (CRC). Several activating mutations have been reported in CRC, where activation of B-Raf by valine to glutamate at position 600 plays a critical role. This study aims to address CRCs with the use of dual inhibitors for B-Raf V600E and Mek kinases by using a multifaceted approach. Computational modeling and high throughput virtual screening of large libraries for the target kinases were studied. Caco-2 and HT-29 cells were used to study the effect of the compound on cell proliferation, and flow cytometry was used to analyze target inhibition in these cells by the compound. Atomistic molecular dynamics simulations of the compound predicated C4, a lead candidate to effectively bind B-RAF V600E and Mek proteins. C4 had similar binding stability and improved amino acid residue interactions with these targets compared to known inhibitors viz., GDC0879 (B-RAF V600E ) and GDC0973(Mek) kinase. The compound effectively inhibited Caco-2 and HT-29 cell proliferation with GI 50 values of 201.3 nM and 332.0 nM, respectively. In both CRC cells tested, C4 inhibited the percentage positive B-Raf V600E and phospho Mek 1/2 (S221) populations. C4 has been identified as a novel dual Raf/Mek inhibitor against colorectal carcinoma.