Synthesis of novel coumarin nucleus-based DPA drug-like molecular entity: In vitro DNA/Cu(II) binding, DNA cleavage and pro-oxidant mechanism for anticancer action

• Published in: PloS one Vol. 12; no. 8; p. e0181783
• Main Authors: Khan, Saman, Malla, Ali Mohammed, Zafar, Atif, Naseem, Imrana
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 01-08-2017; Public Library of Science (PLoS)
• Subjects: Acute toxicity; Amines - chemistry; Angiogenesis; Animals; Anticancer properties; Antineoplastic agents; Antineoplastic Agents - chemistry; Apoptosis; Binding, Competitive; Biochemistry; Biology and Life Sciences; Breast cancer; Cancer; Cancer therapies; Care and treatment; Cell death; Cell Line, Tumor; Cell Nucleus - metabolism; Chelating agents; Chelating Agents - chemistry; Chelation; Chemical synthesis; Chemotherapy; Chromatin; Circular Dichroism; Cisplatin; Cleavage; Coordination Complexes - chemistry; Copper; Copper - chemistry; Coumarin; Coumarins - chemistry; Cytotoxicity; Deoxyribonucleic acid; DNA; DNA - chemistry; DNA Damage; Dosage and administration; Drug resistance; Drug therapy; Drugs; Electrochemistry; Growth factors; Guanine; Health aspects; Humans; In vitro methods and tests; Leukemia; Life sciences; Ligands; Magnetic Resonance Spectroscopy; Medicine and Health Sciences; Mice; Molecular Docking Simulation; Neoplasms - drug therapy; NMR; Nuclear magnetic resonance; Oxidants - chemistry; Oxidizing agents; Oxygen; Oxygen - chemistry; Pharmacology; Physical Sciences; Potassium Iodide - chemistry; Prostate cancer; Reactive oxygen species; Reactive Oxygen Species - chemistry; Redox properties; Spectrometry, Mass, Electrospray Ionization; Spectrophotometry, Infrared; Spectroscopy, Fourier Transform Infrared; Studies; Targeted cancer therapy; Toxicity
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0181783

Despite substantial research on cancer therapeutics, systemic toxicity and drug-resistance limits the clinical application of many drugs like cisplatin. Therefore, new chemotherapeutic strategies against different malignancies are needed. Targeted cancer therapy is a new paradigm for cancer therapeutics which targets pathways or chemical entities specific to cancer cells than normal ones. Unlike normal cells, cancer cells contain elevated copper which plays an integral role in angiogenesis. Copper is an important metal ion associated with chromatin DNA, particularly with guanine. Thus, targeting copper via copper-specific chelators in cancer cells can serve as an effective anticancer strategy. New pharmacophore di(2-picolyl)amine (DPA)-3(bromoacetyl) coumarin (ligand-L) was synthesized and characterized by IR, ESI-MS, 1H- and 13C-NMR. Binding ability of ligand-L to DNA/Cu(II) was evaluated using a plethora of biophysical techniques which revealed ligand-L-DNA and ligand-L-Cu(II) interaction. Competitive displacement assay and docking confirmed non-intercalative binding mode of ligand-L with ctDNA. Cyclic voltammetry confirmed ligand-L causes quasi reversible Cu(II)/Cu(I) conversion. Further, acute toxicity studies revealed no toxic effects of ligand-L on mice. To evaluate the chemotherapeutic potential and anticancer mechanism of ligand-L, DNA damage via pBR322 cleavage assay and reactive oxygen species (ROS) generation were studied. Results demonstrate that ligand-L causes DNA cleavage involving ROS generation in the presence of Cu(II). In conclusion, ligand-L causes redox cycling of Cu(II) to generate ROS which leads to oxidative DNA damage and pro-oxidant cancer cell death. These findings will establish ligand-L as a lead molecule to synthesize new molecules with better copper chelating and pro-oxidant properties against different malignancies.