3′‐(4‐(Benzyloxy)phenyl)‐1′‐phenyl‐5‐(heteroaryl/aryl)‐3,4‐dihydro‐1′H,2H‐[3,4′‐bipyrazole]‐2‐carboxamides as EGFR kinase inhibitors: Synthesis, anticancer evaluation, and molecular docking studies

Abstract

Pyrazoline‐linked carboxamide derivatives were designed, synthesized, and evaluated for potential epidermal growth factor receptor (EGFR) kinase inhibition, anticancer activity, and apoptotic and cardiomyopathy toxicity. Compounds 6m and 6n inhibit EGFR kinase at a concentration of 6.5 ± 2.91 and 3.65 ± 0.54 µM, respectively. Some of these compounds showed effects on proliferation, which were also then evaluated against four different human cancer cell lines, that is, MCF‐7 (breast cancer), A549 (non‐small‐cell lung tumor), HCT‐116 (colon cancer), and SiHa cells (cancerous tissues of the cervix uteri). The results showed that certain synthetic compounds showed significant inhibitor activity; compounds 6m and 6n were more cytotoxic than doxorubicin against A549 cancer cells, with IC₅₀ values of 10.3 ± 1.07 and 4.6 ± 0.57 µM, respectively. Additionally, compounds 6m and 6n induced apoptosis in A549 cancer cells, as evidenced by 4′,6‐diamidino‐2‐phenylindole (DAPI) staining and phase‐contrast microscopy. Potency to induce apoptosis by compound 6n was further confirmed by fluorescence‐activated cell sorting using Annexin V‐FITC and propidium iodide labeling. Compound 6n showed normal cardiomyocytes with no marked sign of pyknotic nuclei in cardiomyopathy and also normal histological appearance of the renal cortex when compared with that of control. Results of molecular docking studies suggested that compounds 6m and 6n can bind to the hinge region of the adenosine triphosphate‐binding site of EGFR kinase, like the standard drug erlotinib. Therefore, the present study suggests that compounds 6m and 6n have potent in vitro antitumor activities against the human non‐small‐cell lung tumor cell line A549, which can be further explored in other cancer cell lines and in animal studies.