Quinazoline Ligands Induce Cancer Cell Death through Selective STAT3 Inhibition and G-Quadruplex Stabilization

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Cancer Research

Background:

• Signal transducer and activator of transcription 3 (STAT3) regulates key cancer hallmarks like proliferation and DNA damage response.
• G-quadruplex (G4) DNA structures are promising oncotherapy targets due to their role in replication stress and DNA damage in cancer cells.

Purpose of the Study:

• To design and synthesize novel quinazoline-based compounds targeting both G4 DNA structures and STAT3 protein.
• To evaluate the efficacy of these compounds in inhibiting cancer cell proliferation and inducing DNA damage.

Main Methods:

• In vitro assays, Nuclear Magnetic Resonance (NMR), and molecular dynamics simulations were used to characterize compound binding and G4 stabilization.
• Human cultured cells were treated to assess STAT3 inhibition, G4 structure formation, DNA replication, and apoptosis.
• Comparative sensitivity analysis between cancer and noncancerous cell lines was performed.

Main Results:

• The synthesized compounds bind to STAT3 and stabilize G4 DNA structures.
• Compounds inhibit STAT3 phosphorylation-dependent activation without affecting STAT1, and increase G4 structure formation in cells.
• Treated cancer cells exhibit slower DNA replication, activated DNA damage checkpoints, and increased apoptosis, with higher sensitivity compared to normal cells.

Conclusions:

• This study reports a novel class of quinazoline compounds with dual activity against G4 DNA and STAT3.
• These compounds represent a promising new approach in cancer therapy by targeting both cancer cell proliferation and DNA damage response pathways.