Conjugates of podophyllotoxin and norcantharidin as dual inhibitors of topoisomeraseⅡ and protein phosphatase 2A

Eur J Med Chem. 2016 Nov 10:123:568-576. doi: 10.1016/j.ejmech.2016.07.031. Epub 2016 Jul 18.

Abstract

A series of novel conjugates of podophyllotoxin and norcantharidin was designed using association strategy, and synthesized by coupling 4'-demethylepipodophyllotoxin with N-amino acid norcantharimides, and their cytotoxicitiy was evaluated against four human tumor cell lines (A-549, HepG2, HeLa and HCT-8) and normal human diploid fibroblast line WI-38. These compounds exhibited potent cytotoxic effects on tumor cell lines, whereas it was less toxic to WI-38 cells than anticancer drug VP-16 or its parent compound norcantharidin. Furthermore, conjugates 7a, 7c, 7f, 7j, 7k and 7l displayed excellent PP2A inhibition activity with IC50 values of 0.49-9.52 μM. The most potent compound 7l also exhibited topoisomeraseⅡinhibition activity. In addition, compound 7l induced cell-cycle arrest in the G2/M phase in HepG2 by regulating levels of cyclinB1 and cdc2.

Keywords: Cantharidin; Cell-cycle arrest; PP2A; Podophyllotoxin; TOP-Ⅱ.

MeSH terms

  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology
  • Bridged Bicyclo Compounds, Heterocyclic / chemistry*
  • Bridged Bicyclo Compounds, Heterocyclic / pharmacology*
  • Cell Division / drug effects
  • Cell Line, Tumor
  • G2 Phase Cell Cycle Checkpoints / drug effects
  • Humans
  • Podophyllotoxin / chemistry*
  • Protein Phosphatase 2 / antagonists & inhibitors*
  • Structure-Activity Relationship
  • Topoisomerase II Inhibitors / chemistry*
  • Topoisomerase II Inhibitors / pharmacology*

Substances

  • Antineoplastic Agents
  • Bridged Bicyclo Compounds, Heterocyclic
  • Topoisomerase II Inhibitors
  • norcantharidin
  • Protein Phosphatase 2
  • Podophyllotoxin