Stabilization of G-quadruplex DNA and down-regulation of oncogene c-myc by quindoline derivatives

Area of Science:

• Medicinal Chemistry
• Molecular Biology
• Oncology

Background:

• G-quadruplex structures in oncogene promoter regions are key targets for anticancer drug design.
• The human c-myc gene, a critical oncogene, is transcriptionally regulated by G-quadruplexes.
• Stabilizing these structures offers a potential therapeutic strategy.

Purpose of the Study:

• To investigate the interaction of quindoline derivatives with c-myc G-quadruplexes.
• To evaluate the potential of these derivatives as anticancer agents by assessing their effect on c-myc expression.
• To elucidate the binding mode and selectivity of quindoline derivatives.

Main Methods:

• Synthesis and testing of quindoline derivatives.
• Cell-based assays using Hep G2 cell line to measure c-myc down-regulation.
• Experimental validation of G-quadruplex stabilization.
• Molecular modeling studies to determine binding interactions.

Main Results:

• Quindoline derivatives effectively induce/stabilize G-quadruplexes in the c-myc promoter.
• These derivatives lead to down-regulation of c-myc expression in Hep G2 cells.
• Derivatives with terminal amino groups show selective binding to specific G-quadruplex isomers.
• Molecular modeling indicates end-stacking at the 3'-position and highlights the role of charged side chains in selectivity and stabilization.

Conclusions:

• Quindoline derivatives represent a promising class of compounds for targeting c-myc G-quadruplexes.
• Their ability to stabilize G-quadruplexes offers a novel mechanism for anticancer therapy.
• The observed selectivity and stabilization mechanisms provide a basis for further drug optimization.