Synthesis of Quinazoline Derivatives and Mechanistic Approaches in Lung and Breast Cancers

The quinazoline/quinazolinone ring is known as a unique scaffold, and its derivatives possess a broad biological activity profile, including antibacterial, antifungal, anticonvulsant, anti-inflammatory, anti-HIV, and analgesic activity, primarily focusing on anticancer activity. In this study, the synthesis of 2-[[4-oxo-3-(substituted phenyl)-3,4-dihydro-(substituted quinazolin-2-yl)]thio]-N'-(aryl/heteroaryl methylene)acetohydrazide (4a-4x) derivatives and their potential anticancer activities were investigated on the lung cancer A549 cell line, the breast cancer MCF-7 cell line, and healthy fibroblast L929 cell line. Compounds 4c, 4i, 4m, and 4u were identified as the most cytotoxic and selective molecules on the A549 cell line (IC₅₀: 44.75-78.13 µM), while 4i, 4l, 4m, and 4u were identified as the most cytotoxic and selective molecules on the MCF-7 cell line (IC₅₀: 14.43-29.39 µM). The mechanisms of action of their anticancer activities were examined and studied. It was determined that these compounds induced strong apoptosis and significantly activated caspase-3 activation in both cell types and that they interrupted the cell cycle in the pre-G (sub G0) phase. Compounds 4m and 4u exhibited EGFR inhibition (IC₅₀: 4.80 µM, IC₅₀: 5.40 µM, respectively) at a level similar to the standard drug gefitinib (IC₅₀: 1.86 ± 0.43 µM). Based on the results of the biological activity assays, molecular docking, and molecular dynamics simulation studies, the 4-quinazolinone-acetyl hydrazone scaffold can be considered a promising structural framework with potential anticancer activity. More specifically, the findings of this study indicate that the acetyl moiety may function as an important pharmacophoric group, while the trisubstituted quinazolinone core may represent a favorable structural feature for caspase-3 activation. However, the same structural framework appears to be less favorable for EGFR inhibition, possibly due to steric constraints within the EGFR binding pockets.