title: Syntheses and characterization of non-bisphosphonate quinoline derivatives as new FPPS inhibitors.
abstract: BACKGROUND
  Farnesyl pyrophosphate synthase (FPPS) is a key regulatory enzyme in the biosynthesis of cholesterol and in the post-translational modification of signaling proteins. It has been reported that non-bisphosphonate FPPS inhibitors targeting its allosteric binding pocket are potentially important for the development of promising anti-cancer drugs.
  
  
  METHODS
  The following methods were used: organic syntheses of non-bisphosphonate quinoline derivatives, enzyme inhibition studies, fluorescence titration assays, synergistic effect studies of quinoline derivatives with zoledronate, ITC studies for the binding of FPPS with quinoline derivatives, NMR-based HAP binding assays, molecular modeling studies, fluorescence imaging assay and MTT assays.
  
  
  RESULTS
  We report our syntheses of a series of quinoline derivatives as new FPPS inhibitors possibly targeting the allosteric site of the enzyme. Compound 6b showed potent inhibition to FPPS without significant hydroxyapatite binding affinity. The compound showed synergistic inhibitory effect with active-site inhibitor zoledronate. ITC experiment confirmed the good binding effect of compound 6b to FPPS, and further indicated the binding ratio of 1:1. Molecular modeling studies showed that 6b could possibly bind to the allosteric binding pocket of the enzyme. The fluorescence microscopy indicated that these compounds could get into cancer cells.
  
  
  CONCLUSIONS
  Our results showed that quinoline derivative 6b could become a new lead compound for further optimization for cancer treatment.
  
  
  CONCLUSIONS
  The traditional FPPS active-site inhibitors bisphosphonates show poor membrane permeability to tumor cells, due to their strong polarity. The development of new non-bisphosphonate FPPS inhibitors with good cell membrane permeability is potentially important.
authors.forename: Jinggong
authors.initials: J
authors.lastname: Liu
authors.forename: Weilin
authors.initials: W
authors.lastname: Liu
authors.forename: Hu
authors.initials: H
authors.lastname: Ge
authors.forename: Jinbo
authors.initials: J
authors.lastname: Gao
authors.forename: Qingqing
authors.initials: Q
authors.lastname: He
authors.forename: Lijuan
authors.initials: L
authors.lastname: Su
authors.forename: Jun
authors.initials: J
authors.lastname: Xu
authors.forename: Lian-Quan
authors.initials: LQ
authors.lastname: Gu
authors.forename: Zhi-shu
authors.initials: ZS
authors.lastname: Huang
authors.forename: Ding
authors.initials: D
authors.lastname: Li
mesh_terms: D000595:Amino Acid Sequence; D004164:Diphosphonates / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000138:chemical synthesis* / Q000494:pharmacology / Q000627:therapeutic use; D051228:Geranyltranstransferase / Q000037:antagonists & inhibitors*; D007093:Imidazoles / Q000494:pharmacology; D008856:Microscopy, Fluorescence; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009369:Neoplasms / Q000188:drug therapy; D011804:Quinolines / Q000138:chemical synthesis* / Q000494:pharmacology / Q000627:therapeutic use; D000077211:Zoledronic Acid
chemical_list: D004164:Diphosphonates; D004791:Enzyme Inhibitors; D007093:Imidazoles; D011804:Quinolines; D000077211:Zoledronic Acid; D051228:Geranyltranstransferase
keywords: 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium bromide; Allosteric site; BPs; BSA; Bisphosphonate; Cancer; DL-dithiothreitol; DTT; FPPS; Farnesyl pyrophosphate synthase; HAP; MTT; Quinoline derivative; Tris; bisphosphonates; bovine serum albumin; farnesyl pyrophosphate synthase; hydroxyapatite; tris(hydroxymethyl)aminomethane