Pyridine-core scaffolds suppress A549 lung cancer cell progression: Evaluation of the antiproliferative activity, apoptosis, ROS generation, clonogenic suppression, and EGFR expression.

Targeting the epidermal growth factor receptor (EGFR) remains a proven strategy for the treatment of lung adenocarcinoma; however, acquired drug resistance and suboptimal long-term efficacy of the currently available EGFR inhibitors spurred the pursuit of new EGFR-targeted molecules. Hence, a series of pyridine-cored derivatives was rationally designed by strategically integrating pharmacophoric features of Gefitinib. Subsequently, the molecules were synthesised via promising synthetic approaches (Pd-catalyzed CN coupling, nucleophilic substitution reaction), and the characterized compounds (3-5 and 7a-h) were screened at the cellular level using the lung cancer cells (A549) via MTT assay. Consequently, the evaluated compounds were identified as promising leads at the cellular level. Specifically, molecule 5 exhibited potent antiproliferative activity against the A549 cells, with an IC50 value of 8.90 ± 1.6 μM, which was comparable to that of Gefitinib (IC50 = 9.22 ± 1.153 μM). Importantly, molecule 5 exhibited reduced cytotoxicity over the non-cancerous mouse fibroblast cells (L929). Moreover, mechanistic studies of molecule 5 demonstrated enhanced clonogenic survival, modulated intracellular ROS levels, substantially enhanced apoptotic cell populations, and modulation of EGFR protein expression as determined by ELISA. Notably, the combination of molecule 5 with gefitinib revealed the apparent IC50 value of 7.13 ± 0.53 μM under the specific experimental condition. On the other hand, molecular docking studies predicted the favourable binding modes with the EGFR binding sites, with predicted favourable binding affinities ranging from -7.4 to -10.3 kcal/mol. In addition, MD simulation and DFT calculations provide supportive insights into the predicted stability of the ligand-receptor complex and the electronic properties of the synthesised molecules. Collectively, molecule 5 represents as promising pyridine-based scaffold for further investigation as an anti-NSCLC lead, through additional structural modification, and further studies are required to establish its precise molecular mechanism.