A new anticancer derivative of the natural alkaloid, theobromine, as an EGFR inhibitor and apoptosis inducer

Abstract

The epidermal growth factor receptor (EGFR) plays a key role in the pathogenesis of cancers of different types. It has been shown that EGFR and EGF-like peptides are often overexpressed in human carcinomas and that these proteins can cause cell transformation both in vivo and in vitro. In order to design a new apoptotic EGFR inhibitor, we used the essential pharmacophoric structural properties of EGFR inhibitors. We started with the natural alkaloid, theobromine, to get a new semisynthetic N-cyclohexyl acetamide derivative (T-1-NCA). T-1-NCA was extensively examined computationally for its potential against the EGFR protein. We initially performed deep density functional theory (DFT) computations to validate its 3D structure. The electrostatic potential, global reactive indices, and total density of states anticipating a high degree of reactivity were also indicated by the DFT analyses. Second, T-1-NCA's propensity to bind and inhibit the EGFR protein was investigated and verified using structure-based computational investigations such as molecular docking against EGFR^WT, molecular dynamics (MD) over 100 ns, MM-GPSA, and PLIP experiments. T-1-NCA's computational ADME and toxicity profiles were examined before the synthesis, and its safety and general drug-likeness were anticipated. As a consequence, T-1-NCA was semi-synthesized to examine the proposed design and the in silico findings. In comparison with erlotinib, T-1-NCA suppressed EGFR^WT in vitro with an IC₅₀ value of 24.25 nM. (5.87 nM). Furthermore, T-1-NCA suppressed the proliferation of A549 and HCT-116 malignant cell lines with IC₅₀ values of 40.20 and 34.05 µM, respectively, as compared to erlotinib, which had IC₅₀ values of 17.13 and 17.32 µM. Interestingly, T-1-NCA’s selectivity indices were 3.29 and 3.89 against the two cancer cell lines indicating its general safety. Finally, the apoptotic effects of T-1-NCA were confirmed by flow cytometry and RT-PCR through the significant increase of the levels BAX, Casp3, and Casp9 in addition to the significant decrease of Bcl-2 level.