title: Synthesis of new steroidal imidazo [1,2-a] pyridines: DNA binding studies, cleavage activity and in vitro cytotoxicity.
abstract: A one-pot strategy for the catalytic synthesis of series of new 5α-cholestan-6-spiro-5'-phenylamino-2H-imidazo [1',2'-a] pyridines (4-14) has been investigated. The synthesized products were obtained in good yields (85-90%) and the protocol uses Multi-component Reaction (MCR) involving steroidal ketones, 2-aminopyridines, isocyanides and propylphosphonic anhydride (®T3P) as a catalyst. After characterization by spectral and analytical data, the interaction studies of compounds (4-6) with DNA were studied by UV-vis, fluorescence spectroscopy, gel electrophoresis and molecular docking. The compounds bind to DNA preferentially through electrostatic and hydrophobic interactions with Kb; 2.35×10(4), 3.71×10(4) and 3.24×10(4) M(-1), respectively, indicating the higher binding affinity of compound 5 towards DNA. Gel electrophoresis showed the concentration dependent cleavage activity of compounds 4-6 with DNA. Molecular docking studies suggested that compounds bind through minor groove to DNA. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay depicted promising anti-proliferative activity of compound 4-9 against different given cancer cells. In Western blotting, the expressions of relevant apoptotic markers depicted an apoptosis by steroidal imidazopyridines in A549 cells. Annexin V-FITC/PI staining data indicated that compounds could effectively induce apoptosis in A549 cells in a dose-dependent manner. FACS analysis shows that the compound 6 bring about cell cycle arrest at 2.62 μM concentration.
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202 002, India. Electronic address: ayazchem09@gmail.com.
authors.forename: Ayaz Mahmood
authors.initials: AM
authors.lastname: Dar
authors.affiliation: Department of Chemistry, Aligarh Muslim University, Aligarh 202 002, India.
authors.lastname: Shamsuzzaman
authors.affiliation: Department of Biochemistry, Jawaharlal Nehru Medical College, Aligarh Muslim University, Aligarh 202 002, India.
authors.forename: Manzoor Ahmad
authors.initials: MA
authors.lastname: Gatoo
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D001665:Binding Sites; D002417:Cattle; D059447:Cell Cycle Checkpoints / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D004247:DNA / Q000737:chemistry*; D053837:DNA Cleavage / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004354:Drug Screening Assays, Antitumor; D006801:Humans; D062105:Molecular Docking Simulation; D015394:Molecular Structure; D011725:Pyridines / Q000138:chemical synthesis* / Q000737:chemistry / Q000494:pharmacology*; D013256:Steroids / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured
chemical_list: D000970:Antineoplastic Agents; D011725:Pyridines; D013256:Steroids; D004247:DNA; C427203:calf thymus DNA; C001439:imidazo(1,2-a)pyridine
keywords: Cell cycle; DNA binding; Imidazopyridines; MTT assay; Western blotting