Design, novel one-pot green synthesis, and biological evaluation of pyrazolopyridine-congeners selectively targeting HER2+ breast cancer.

Breast cancer (BC) is among the most prevalent and most aggressive cancer types affecting females. Several targets were investigated to tackle this problem, among them HER2 receptors are one on the most studied targets. In this study we report the synthesis of 18 different pyrazolopyridine (3a-r) derivatives using a novel green one-pot method. The synthesized compounds were screened against NCI 60 human tumor cell panel at single concentration. The six top compounds (3c, 3d, 3f, 3l, 3m and 3o) were followed up by plotting their IC values and selectivity indices against different cancer types. Kinase profiling for the top two compounds (3f and 3o) was done against 20 different kinases and showed that they have selective inhibition of HER2 (with -88 and - 75 % inhibition) comparable to Tucatinib (-90 % inhibition). In addition, Annexin V PI/FITC apoptosis assay using BT474 cell lines on compounds 3l, 3o and 3f demonstrate the target specificity of our most potent compounds towards HER2 + ve harboring cells. In vivo antitumor activity of compound 3f on BC xenograft mouse model demonstrates that the recorded tumor size over the course of study was significantly reduced by 19.45 % when mice treated with 3f compared to 38.6 % reduction when treated with lapatinib. Finally molecular docking and molecular dynamics studies were used to investigate and understand the potential binding modes and interactions between the synthesized compounds and HER2 on the molecular level. In summary, this study presents the synthesis of this new promising scaffold as anti breast cancer medication using a novel green one-pot method.