# Novel Adenine–Hydrazone Hybrids Against Human Lung Adenocarcinoma (A549): Design, Synthesis, Cellular Mechanistic Investigation and Molecular Docking Studies

## TL;DR

Scientists designed new adenine-hydrazone compounds that show promise in fighting lung cancer by causing cell death through mitochondrial damage and oxidative stress.

## Contribution

The study introduces novel adenine–hydrazone hybrids with substituent-dependent anticancer activity and identifies their cellular mechanisms.

## Key findings

- Compounds with electron-withdrawing or donor–acceptor substituents showed highest cytotoxicity against A549 cells.
- Treatment induced oxidative stress, mitochondrial depolarization, and apoptosis in cancer cells.
- Molecular docking revealed strong binding to VEGFR2 and ALK5, suggesting dual inhibition as a mechanism.

## Abstract

Background/Objectives: Adenine derivatives are promising anticancer scaffolds, but their cellular mechanisms remain unclear. This study aimed to synthesize adenine–hydrazone hybrids and evaluate their cytotoxic effects in human lung adenocarcinoma (A549) cells. Methods: A series of adenine–hydrazone compounds (3a–r) was synthesized and tested for cytotoxicity in A549 and MRC-5 cells. Selected compounds were further analyzed for LDH release, oxidative stress markers, ROS production, mitochondrial membrane potential, cell-cycle distribution, apoptosis, and in silico docking against VEGFR2, ALK5, and EGFR. Results: Compounds with electron-withdrawing or donor–acceptor substituents showed the highest cytotoxicity, while halogenated and methoxy analogs were moderately active. Among the synthesized derivatives, 4F-substituted derivatives (3c) showed more activity than 2F- and 3F-substituted ones (3a and 3b). 4F- and 3Br-substituted derivatives (3f) showed more activity than only 4F-substituted ones (3c). 4-Nitro-substituted derivative (3i) showed more activity than 4F- (3c), 4Cl- (3d) and 4OMe- (3h) derivatives. Trimethoxy-substituted derivative (3l) showed more activity than di- and mono-substituted methoxy derivatives (3g, 3h, 3j and 3k). Among the salicyl aldehydederivatives (3m–r), 4-N(et)2-substituted derivative (3r) showed more activity than non-substituted (3m), 5Br-(3n), 5Cl-(3o), 5Me (3p) and 3OCH3 (3q) derivatives. Treatment induced oxidative stress, mitochondrial depolarization, Sub-G1 cell-cycle accumulation, and apoptosis. Docking studies indicated strong binding to VEGFR2 and ALK5, suggesting dual inhibition as a potential mechanism. Conclusions: Adenine–hydrazone derivatives exert substituent-dependent anticancer effects by inducing redox imbalance-associated mitochondrial dysfunction and regulated cell death. These results highlight their potential as lead structures for lung cancer therapy.