Synthesis and evaluation of antiproliferative microtubule-destabilising combretastatin A-4 piperazine conjugates

Org Biomol Chem. 2019 Jun 26;17(25):6184-6200. doi: 10.1039/c9ob00558g.

Abstract

Microtubules are a validated clinical target for the treatment of many cancers. We describe the design, synthesis, biochemical evaluation, and molecular modelling studies of a series of analogues of the microtubule-destabilising agent, combretastatin A-4 (CA-4). Our series of 33 novel compounds contain the CA-4 core structure with modifications to the stilbene linking group, and are predominantly piperazine derivatives. Synthesis was achieved in a two-step process by firstly obtaining the acrylic acid via a Perkin reaction using microwave enhanced synthesis, followed by coupling using either DCC or Mukaiyama's reagent. All target compounds were screened for antiproliferative activity in MCF-7 breast cancer cells. Hydroxyl derivative (E)-3-(4-hydroxy-3-methoxyphenyl)-1-(4-phenylpiperazin-1-yl)-2-(3,4,5-trimethoxyphenyl) propenone (4m) displayed potent antiproliferative activity (IC50 = 190 nM). Two amino-containing derivatives, (E)-3-(3-amino-4-methoxyphenyl)-1-(4-phenylpiperazin-1-yl)-2-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (4q) and (E)-3-(3-amino-4-methoxyphenyl)-1-(4-(p-tolyl)piperazin-1-yl)-2-(3,4,5-trimethoxyphenyl)prop-2-en-1-one (4x), were the most potent with IC50 values of 130 nM and 83 nM respectively. Representative compounds were shown to depolymerise tubulin, induce G2/M arrest and apoptosis in MCF-7 cells but not peripheral blood mononuclear cells, and induce cleavage of the DNA repair enzyme poly ADP ribose polymerase (PARP) in MCF-7 cells. Modelling studies predict that the compounds bind to tubulin within the colchicine-binding site. These compounds are a valuable addition to the library of CA-4 analogues and 4m, 4q and 4x will be developed further as novel, water-soluble molecules targeting microtubules.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / metabolism
  • Antineoplastic Agents / pharmacology*
  • Apoptosis / drug effects
  • Binding Sites
  • Drug Screening Assays, Antitumor
  • G2 Phase Cell Cycle Checkpoints / drug effects
  • Humans
  • MCF-7 Cells
  • Molecular Docking Simulation
  • Piperazines / chemical synthesis
  • Piperazines / metabolism
  • Piperazines / pharmacology*
  • Poly(ADP-ribose) Polymerases / metabolism
  • Protein Binding
  • Stilbenes / chemical synthesis
  • Stilbenes / metabolism
  • Stilbenes / pharmacology*
  • Tubulin / chemistry
  • Tubulin / metabolism
  • Tubulin Modulators / chemical synthesis
  • Tubulin Modulators / metabolism
  • Tubulin Modulators / pharmacology*

Substances

  • Antineoplastic Agents
  • Piperazines
  • Stilbenes
  • Tubulin
  • Tubulin Modulators
  • Poly(ADP-ribose) Polymerases
  • fosbretabulin