Exploring Carboxamide Derivatives as Promising Anticancer Agents: Design, In Vitro Evaluation, and Mechanistic Insights

Carboxamide derivatives are a promising class of compounds in anticancer drug discovery, owing to their ability to interact with multiple oncogenic targets and their favorable pharmacological profiles. In this study, we report the design, synthesis, and biological evaluation of a series of <i>N</i>-substituted 1<i>H</i>-indole-2-carboxamides as potential anticancer agents. The synthesized compounds were assessed for antiproliferative activity using the MTT assay against MCF-7 (breast cancer), K-562 (leukemia), and HCT-116 (colon cancer) cell lines, with normal human dermal fibroblasts included as a non-cancerous control. Several compounds demonstrated notable cytotoxicity and selectivity. Compounds 12, 14, and 4 exhibited potent activity against K-562 cells, with IC₅₀ values of 0.33 µM, 0.61 µM, and 0.61 µM, respectively. Compound 10 showed the most significant activity against HCT-116 cells (IC₅₀ = 1.01 µM) with a high selectivity index (SI = 99.4). Moderate cytotoxicity was observed against MCF-7 cells. To elucidate the mechanism of action, molecular docking and induced-fit docking studies were conducted against key cancer-related targets, including topoisomerase-DNA (PDB ID: 5ZRF), PI3Kα (4L23), and EGFR (3W32), revealing favorable binding interactions. Additionally, principal component analysis of molecular descriptors indicated that the compounds possess promising drug-like and lead-like properties, particularly compound 10. Overall, this study highlights N-substituted indole-2-carboxamides as promising scaffolds for further optimization. The integration of synthetic chemistry, biological assays, and computational modeling provides a robust foundation for the continued development of these compounds as potential anticancer agents.