Novel Acridone-Based EGFR Inhibitors: Design, Synthesis, and Integrated In Silico-In Vitro Evaluation

The epidermal growth factor receptor (EGFR) family is a key biomarker and therapeutic target for cancer therapy. Although acridone scaffolds have previously inhibited other tyrosine kinases, their specific targeting of EGFR has not been reported. This study provides novel acridone-N-aceto/benzohydrazide derivatives with anti-EGFR activity. Cytotoxicity screening revealed AE4, AE11, and AF11 as highly effective against the A-431 cell line, with IC₅₀ values 3.22 µM, 2.43 µM, and 4.06 µM, respectively, keeping Erb as a standard with an IC₅₀ of 1.62 µM. In vitro EGFR kinase assays confirmed their inhibition, with IC₅₀ values of 3.95 µM (AE4), 3.49 µM (AE11), and 4.45 µM (AF11), selectively reduced p-EGFR Tyr¹⁰⁶⁸ and ERK1/2 levels in a dose-dependent manner, while inducing G₀/G₁ cell-cycle arrest and apoptosis. SAR indicates isopropyl substitutions on the phenyl ring and 2-methoxy on the acridone ring are important for anti-proliferative activity. Notably, AE4 exhibited a high DNA-binding affinity (K_b = 7.41 × 10³M^{- 1}), suggesting that its efficacy might be due to DNA intercalation. In contrast, AE11 and AF11 demonstrated significant cytotoxicity, implying the involvement of the RAS/ERK downregulating pathway. Molecular docking indicated favorable EGFR active site interactions. In silico studies predicted oral bioavailability and low toxicity, supported by kinetic solubility and plasma stability assays, highlighting their potential as selective p-EGFR Tyr¹⁰⁶⁸ inhibitors for further development.