Backbone modified TBA analogues endowed with antiproliferative activity

Area of Science:

• Biochemistry and Molecular Biology
• Medicinal Chemistry
• Cancer Research

Background:

• Thrombin binding aptamer (TBA) exhibits antiproliferative properties but is limited by concurrent anticoagulant activity.
• Developing TBA analogues requires overcoming the dual activity to enhance therapeutic potential.

Purpose of the Study:

• To investigate modified thrombin binding aptamer (TBA) analogues for enhanced antiproliferative activity and reduced anticoagulant effects.
• To explore the structural and functional properties of G-quadruplex forming oligonucleotides (ODNs) containing l-residues and inversion of polarity sites.

Main Methods:

• Synthesized five oligonucleotides (ODNs) based on the TBA sequence, incorporating l-residues and/or inversion of polarity sites.
• Characterized G-quadruplex structure formation using Nuclear Magnetic Resonance (NMR) and Circular Dichroism (CD) spectroscopy.
• Assessed anticoagulant activity via Prothrombin Time (PT) assay and antiproliferative effects using MTT assay against cancer cell lines. Evaluated stability in fetal bovine serum.

Main Results:

• Investigated ODNs successfully formed right- and left-handed G-quadruplex structures, confirmed by CD and NMR.
• All modified ODNs demonstrated a significant loss of anticoagulant activity compared to native TBA.
• The modified ODNs exhibited notable antiproliferative activity against two tested cancer cell lines, with variable in vitro stability.

Conclusions:

• Modified TBA analogues, featuring l-residues and inversion of polarity sites, effectively decouple antiproliferative and anticoagulant activities.
• The observed antiproliferative effects may stem from novel biological pathways or targets distinct from previously identified G-quadruplex aptamers.
• Guanine-based degradation products might also contribute to the observed antiproliferative activity of these TBA analogues.