Discovery and preclinical evaluation of 7-benzyl-N-(substituted)-pyrrolo[3,2-d]pyrimidin-4-amines as single agents with microtubule targeting effects along with triple-acting angiokinase inhibition as antitumor agents

Bioorg Med Chem. 2017 Jan 15;25(2):545-556. doi: 10.1016/j.bmc.2016.11.026. Epub 2016 Nov 15.

Abstract

The utility of cytostatic antiangiogenic agents (AA) in cancer chemotherapy lies in their combination with cytotoxic chemotherapeutic agents. Clinical combinations of AA with microtubule targeting agents (MTAs) have been particularly successful. The discovery, synthesis and biological evaluations of a series of 7-benzyl-N-substituted-pyrrolo[3,2-d]pyrimidin-4-amines are reported. Novel compounds which inhibit proangiogenic receptor tyrosine kinases (RTKs) including vascular endothelial growth factor receptor-2 (VEGFR-2), platelet-derived growth factor receptor-β (PDGFR-β) and epidermal growth factor receptor (EGFR), along with microtubule targeting in single molecules are described. These compounds also inhibited blood vessel formation in the chicken chorioallantoic membrane (CAM) assay, and some potently inhibited tubulin assembly (with activity comparable to that of combretastatin A-4 (CA)). In addition, some of the analogs circumvent the most clinically relevant tumor resistance mechanisms (P-glycoprotein and β-III tubulin expression) to microtubule targeting agents (MTA). These MTAs bind at the colchicine site on tubulin. Two analogs displayed two to three digit nanomolar GI50 values across the entire NCI 60 tumor cell panel and one of these, compound 7, freely water soluble as its HCl salt, afforded excellent in vivo antitumor activity against an orthotopic triple negative 4T1 breast cancer model and was superior to doxorubicin.

Keywords: Antiangiogenic; Combination chemotherapy; Microtubule targeting agents; Multitargeted agents; Receptor tyrosine kinase inhibitors.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Angiogenesis Inhibitors / chemical synthesis
  • Angiogenesis Inhibitors / chemistry
  • Angiogenesis Inhibitors / pharmacology*
  • Antineoplastic Agents / chemical synthesis
  • Antineoplastic Agents / chemistry
  • Antineoplastic Agents / pharmacology*
  • Cell Line
  • Cell Proliferation / drug effects
  • Dose-Response Relationship, Drug
  • Drug Discovery*
  • Drug Screening Assays, Antitumor
  • Humans
  • Microtubules / drug effects*
  • Molecular Docking Simulation
  • Molecular Structure
  • Neovascularization, Pathologic / drug therapy*
  • Protein Kinase Inhibitors / chemical synthesis
  • Protein Kinase Inhibitors / chemistry
  • Protein Kinase Inhibitors / pharmacology*
  • Pyrimidines / chemical synthesis
  • Pyrimidines / chemistry
  • Pyrimidines / pharmacology*
  • Pyrroles / chemical synthesis
  • Pyrroles / chemistry
  • Pyrroles / pharmacology*
  • Receptor Protein-Tyrosine Kinases / antagonists & inhibitors*
  • Receptor Protein-Tyrosine Kinases / metabolism
  • Structure-Activity Relationship

Substances

  • 7-benzyl-N-pyrrolo(3,2-d)pyrimidin-4-amine
  • Angiogenesis Inhibitors
  • Antineoplastic Agents
  • Protein Kinase Inhibitors
  • Pyrimidines
  • Pyrroles
  • Receptor Protein-Tyrosine Kinases