Design,Synthesis And Mechanism Of Action Of 2-Nitroimidazoles As Anticancer Drugs

Cancer is a disease that seriously threatens human life and health safety,and is still in the stage of rapid development.The situation of cancer prevention and control is very serious.With the development of cancer,some anti-cancer drugs in clinical use have become increasingly defective in terms of poor selectivity and high toxicity,so the need to develop novel anti-cancer drugs with low toxicity and high efficiency has become increasingly urgent.In this work,two novel 2-nitroimidazole small molecules with dual DNA and spent oxygen targeting effects,were designed,screened and synthesized,and their mechanisms of action were investigated using electrochemical methods,molecular docking and spectroscopic methods.We first designed a series of candidate compounds combining 2-nitroimidazole structure with depleted oxygen activation and 1,8-naphthalimide structure with DNA embedding effect.We then simulated the interaction of the candidate compounds with DNA and DNA-Topo II complexes by molecular docking to screen two small molecules,D-2 and D-5,with high affinity for DNA and DNA-Topo II complexes.Then a simple and efficient synthetic route was designed and two small molecules were successfully synthesized.The redox mechanism was investigated by cyclic voltammetry（CV）and differential pulse voltammetry（DPV）,and it was found that the reduction process of both compounds was diffusion-controlled,and the oxidation mechanism of both compounds was the oxidation of the methylene linked to the naphthalimide to the carbonyl group by a two-step two-electron oxidation process,and the reduction mechanism of both compounds was the reduction of the nitro group of 2-nitroimidazole to hydroxylamine by a two-step two-electron reduction process.Then a three-dimensional model of the complexes of both compounds with DNA and DNA-Topo II was established by molecular docking,and it was found that both compounds could not only be embedded in DNA base pairs,but also interact with the amino acid residues of Topo II by hydrogen bonding.The interaction of two small molecules with DNA was studied by differential pulse voltammetry（DPV）using a DNA electrochemical biosensor and found that two species of small molecules can be embedded in DNA base pairs and cause oxidative damage to DNA.By using differential pulse voltammetry（DPV）to detect the interaction of the two small molecules with DNA in solution,the results were found to be in general agreement with the DNA electrochemical sensor.Using UV-Vis absorption spectroscopy and fluorescence spectroscopy,it was found that D-2 and D-5 bound to DNA by intercalation,with binding constants of 8.95×10~5 M^-1and 6.56×10~5 M^-1,respectively,both of which are spontaneous processes.The IC₅₀ of the two small molecules were found to be 11.18 mg m L^-1 and 32.03 mg m L^-1 for human umbilical vein endothelial cells（HUVEC）,9.41 mg m L^-1 and 47.88 mg m L^-1 for human non-small cell lung cancer cell line（A549）under normoxic conditions,and 1.84 mg m L^-1 and 2.86 mg m L^-1 for human non-small cell lung cancer cell line（A549）under depleted oxygen conditions,respectively.lung cancer cell line（A549）under hypoxic conditions were 1.84 mg m L^-1 and 2.86 mg m L^-1,respectively.The two small molecules have low cytotoxicity to normal cells and normoxic conditions and are selective for hypoxic cells,which are valuable for further clinical studies and have potential become anticancer drug.