Synthesis And Antiproliferative Mechanism Of 5,7-dimethoxy-1,4-naphthoquinone Derivatives

Compared with normal cells,tumor cells have high levels of reactive oxygen species(ROS)and damaged antioxidant defense systems.Therefore,drugs that promote ROS can kill cancer cells by exacerbating the oxidative stress of cells.More importantly,having a strong antioxidant defense system,normal cells can resist the external ROS stress injury.Therefore,ROS-producing tumor drugs can reduce the side effects of drug therapy.Studies indicate that: 1,4-naphthoquinone compounds can increase the ROS levels of cells,killing the tumor cells.In this paper,a series of 5,7-dimethoxy-1,4-naphthoquinone derivatives were designed and synthesized by using lapachol as the lead compound,and their antiproliferative mechanism was studied.The main contents are as follows:1.Design of the target compounds: On the basis of the literature investigation,using 2-hydroxy-1,4-naphthoquinone as the core structure,we introduce the methoxy group into the aromatic ring to increase the electrophilicity of the quinonoid ring and reduce the redox potential.By changing the length of the side chains and the spatial structure,we aimed to increase the fat solubility of the compounds and study the effect of the length and volume of carbon chains on the antiproliferative activity.And we apply the same strategy to 2-methoxy-1,4-naphthoquinone and 2-chloro-1,4-naphthoquinone series.Finally,the target compounds were screened using the Lipinski rule and found to meet the requirements of this rule.2.Synthesis of the target compound: The synthetic route was designed according to the target compound,and the reaction conditions were optimized for the key steps: Friedel–Crafts acylation reaction and the synthesis of 2-chloro-1,4-naphthoquinone series,obtaining the optimal synthetic route.3.Study on the mechanism of antiproliferative activity of target compounds : The targeted compounds were evaluated for their in vitro antiproliferative activities against six tumor cell lines A549(human non-small cell lung cancer),Hela(human cervical cancer cells),Hep-G2(human liver cancer cells),NCI-H460(human large cell lung cancer cells),HL60(acute leukemia cells),K562(chronic myeloid leukemia cells)and two human normal cell lines WI-38(human embryo lung fibroblast cells)and HEK 293(human embryonic kidney cells)by MTT assay.Among them,compound 9e showed IC50 value of 3.80 ?M to HL60 cells.Compared to normal WI-38 cells,the selectivity index was 10.7,indicating that compound 9e had no effect on the normal cells while killing the cancer cells.We then found that compound 9e could induce apoptosis of HL-60 cells,block cell cycle in G2 /M phase,and induce the increase of ROS level.Addition of antioxidant NAC can inhibit apoptosis,cycle arrest and ROS production,indicating that ROS was involved in the process of killing cells.4.Structure-activity relationship analysis: With the elongation of the alkyl side chain,the antiproliferative activities of compounds 7a-7i showed a progressive increase in activity.Compounds 7j-7n which possessed a cyclohexane or substituted benzene displayed better antiproliferative activities.Compound 9e showed the most antiproliferative activity,indicating that C-2 position chlorine substitution was very beneficial for its antiproliferative activity.