Design,Synthesis And Biological Activity Evaluation Of Novel Inhibitors To Overcome Kinase ALK Resistant Mutations

Lung cancer is one of cancer with the highest death rate in the world.Among them,NonSmall Cell Lung Cancer(NSCLC)accounts for up to 80%of all cases.Various studies have proved that ALK(Anaplastic Lymphoma Kinase)related fusion protein produced by chromosome rearrangement is a strong driving factor for the development of various cancers.EML4-ALK fusion protein has been validated to be an excellent target for the treatment of NSCLC.So far,FDA has approved five ALK kinase inhibitors for clinical use,but unfortunately,patients will eventually become resistant to these drugs due to the acquired of ALK point mutations such as L1196M and G1202R.Therefore,it is an urgent need to develop a new generation of ALK inhibitors to overcome the drug resistance.In this thesis,based on the reported structural featurese of ALK inhibitors,we designed molecules with pyrrolo[3,2-d]pyrimidine as the core skeleton through scaffold hopping and pharmacophore hybrid strategies.Two series of small molecule inhibitors with thiazoles and 1,2,3-triazoles substituted analines were synthesized in a total number of 120 compounds.Using antiproliferation assay against EML4-ALK mutant transformed Ba/F3 cells as a screening model,systematic structure-activity relationship(SAR)study was investigated.The key structural features for having bioactivities against ALK were realed,which included the substitution of o-isopropylsulfone aniline at 4-position of pyrrolo[3,2-d]pyrimidine,the substitution of meta-substituted thiazole or 1,2,3-triazole analines at 2-position of the core skeleton and introduction of dimethylamine,pyrrolidine or morpholine in the solvent exposed region.Among these analogs,Ⅳ-2 was identified as the best inhibitor with antiproliferative IC50s of 6.6 nM,46.5 nM and 43.2 nM against EML4-ALK,ML4-ALK-L1196M,EML4-ALKG1202R transformed Ba/F3 cells,respectively,which is better than the marketed drugs Crizotinib and Brigatinib.Further molecular docking study,revealed the binding mode of Ⅳ-2 with ALK and its mutansts,which will guide the optimization direction for next round of inhibitors design.In summary,with the aims to overcome drug resistant mutants of ML4-ALK-L1196M,EML4-ALK-G1202R,we have successfully identified the compound Ⅳ-2 with the capability to circumvent such drug resistant mutants through systematic SAR study.Ⅳ-2 will serve as a good starting point to develop a new generation of ALK-targeted therapeutics.