Design and Synthesis of Novel mTOR Inhibitors as Anticancer Agents

Abstract

The present research work was started with the detailed literature review on cancer. It was observed that lung cancer is one of the dangerous cancer among all the other type of cancer. Many genes get mutated in lung cancer but the involvement of EGFR, KRAS, PTEN and PIK3CA are more common. Unavailability of drugs or resistance to the available drugs is the major problem in the treatment of lung cancer. In the present research, mTOR was selected as an alternative target for the treatment of lung cancer which involves the PI3K/AKT/mTOR pathway. For the identification of the core scaffold, pharmacophore modelling was carried out with the aid of GASP module of Sybyl X which gave four feature pharmacophore which consisted of two hydrophobic features, one acceptor atom and one acceptor site of the receptor protein. Further, this model was validated by ROC curve and GH score analysis followed by the virtual screening through the NCI and ZINC databases. Obtained virtual hits further passed through the rigorous screening of molecular docking, in-silico ADMET study which gave Tetrahydroquinoline (THQ) as a core scaffold. Simultaneously for the identification of the substituents required for the mTOR inhibition 3D-QSAR (CoMFA and CoMSIA) study and knowledge-based drug designing approach was adopted. Based upon the computational methodology and knowledge-based drug designing 31 THQ derivatives were designed. For the synthesis of these desired THQ derivatives, Fmoc protection and deprotection chemistry were utilized for the selective nitration at the 6th position of the THQ which gave N-substituted 6-nitrotetrahydorquinoline. Further reduction was carried out with the aid of zinc/ammonium chloride resulted in the N-substituted 6-aminotetrahydorquinoline. Final desired compounds were synthesized by the derivatization of the amino group presented at the 6th position of N-substituted THQ derivatives. All these synthesized compounds were characterized by 1H, 13C NMR, Mass analysis, and FTIR while the purity was checked with the HPLC. All these compounds were screened for the antiproliferative activity against the panel of cancerous cell line along with cellular mTOR enzyme assay where 6 compounds were found to be potent which further taken for the specialized in-vitro biological evaluation viz. colony forming assay, flow cytometric analysis, gene expression study and western blot analysis. Based upon all these study compounds HB-UC-1 (145d) and HB-UC-5 (145h) were found to best against the lung cancer and mTOR. These two compounds were further taken for in-vivo biological evaluation. Initially, the effect of compounds HB-UC-1 (145d) and HB-UC-5 (145h) on the lifespan of cancer bearing animals were evaluated up to 30 days where these compounds gave a promising outcome. Further, these compounds were taken for the testing in the bezo[a]pyrene induced lung these study compounds HB-UC-1 (145d) and HB-UC-5 (145h) were found to best against the lung cancer and mTOR. These two compounds were further taken for in-vivo biological evaluation. Initially, the effect of compounds HB-UC-1 (145d) and HB-UC-5 (145h) on the lifespan of cancer bearing animals were evaluated up to 30 days where these compounds gave a promising outcome. Further, these compounds were taken for the testing in the bezo[a]pyrene induced lung cancer animal model where the effectiveness of this compounds was reflected through the biochemical parameters and histopathological evaluation of the lung tissue.