Investigating the preferential interaction between imatinib mesylate and VEGF G-quadruplex DNA as therapeutic strategies for cancer treatment: Biophysical and molecular modelling approaches.

G-Quadruplex DNA (GQ-DNA) is one of the most important non-canonical nucleic acid structures. GQ-DNA forming sequences are present in different crucial genomic regions and are abundant in promoter regions of several oncogenes. Therefore, GQ-DNA is an important target for anticancer drugs and hence binding interactions between GQ-DNA and small molecule ligands are of great importance. Since GQ-DNA is a highly polymorphic structure, it is important to identify ligand molecules which preferentially target a particular quadruplex sequence. In this present study, we have used a FDA approved drug called imatinib mesylate (ligand) which is a selective tyrosine kinase inhibitor, successfully used for the treatment of chronic myelogenous leukaemia, gastrointestinal stromal tumours. Different spectroscopic techniques as well as molecular docking investigations and molecular simulations have been used to explore the interaction between imatinib mesylate with VEGF GQ DNA structures along with duplex DNA, C-Myc, H-Telo GQ DNA. We found that imatinib mesylate shows preferential interaction towards VEGF GQ DNA compared to C-Myc, H-Telo GQ and duplex DNA. Imatinib mesylate seems to be an efficient ligand for VEGF GQ DNA, suggesting that it might be used to regulate the expression of genes in cancerous cells.