Cytotoxicity and mode of action of a naturally occurring naphthoquinone, 2-acetyl-7-methoxynaphtho[2,3-b]furan-4,9-quinone towards multi-factorial drug-resistant cancer cells

Phytomedicine. 2017 Sep 15:33:62-68. doi: 10.1016/j.phymed.2017.07.010. Epub 2017 Jul 31.

Abstract

Introduction: Malignacies are still a major public concern worldwide and despite the intensive search of new chemotherapeutic agents, treatment still remains a challenging issue. The present study was designed to evaluate the cytotoxicity of 2-acetyl-7-methoxynaphtho[2,3-b]furan-4,9-quinone (AMNQ) isolated from the bark of Milletia versicolor towards a panel of drug-sensitive and multidrug-resistant (MDR) cancer cell lines.

Methods: The resazurin reduction assay was used to evaluate the cytotoxicity of AMNQ against 9 drug-sensitive and multidrug-resistant (MDR) cancer cell lines. Cell cycle, mitochondrial membrane potential (MMP) and levels of reactive oxygen species were all analyzed by flow cytometry.

Results: Following resazurin assay, the naphthoquinone AMNQ displayed IC50 values ranging from 0.79 µM (against HepG2 hepatocarcinoma cells) to 3.26 µM (against MDA-MB231/BCRP breast cancer cells) on 9 tested cancer cell lines, whilst doxorubicin showed IC50 values ranging from 0.40 µM (against CCRF-CEM leukemia cells) to 91.37 µM (against CEM/ADR5000 leukemia cells). IC50 values below 1 µM were recorded with AMNQ towards CCRF-CEM cells (0.57 µM), U87MG.ΔEGFR gliobastoma multiforme cells (0.96 µM cells) and HepG2 cells (0.76 µM). Compared to its corresponding sensitive cell lines U87MG, sensitivity was observed in epidermal growth factor receptor-transfected U87MG.ΔEGFR cells to AMNQ. MMP was found to be the main mode of action of induction of apoptosis by AMNQ.

Conclusions: The results of this work demonstrate the cytotoxicity of AMNQ towards various types of cancer cell lines, including MDR phenotypes. AMNQ is a potential antiproliferative natural compound that deserves more investigations to develop novel cytotoxic drugs against sensitive and MDR cancers.

Keywords: 2-acetyl-7-methoxynaphtho[2,3-b]furan-4,9-quinone; Cancer; Cytotoxicity; Milletia versicolor; Multidrug-resistance; Naphthoquinone.

MeSH terms

  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Apoptosis / drug effects
  • Caspases / metabolism
  • Cell Cycle / drug effects
  • Cell Line, Tumor
  • Doxorubicin / pharmacology
  • Drug Resistance, Multiple / drug effects*
  • Drug Resistance, Neoplasm / drug effects*
  • Humans
  • Membrane Potential, Mitochondrial / drug effects
  • Naphthoquinones / pharmacology*
  • Plant Extracts / pharmacology
  • Reactive Oxygen Species / metabolism

Substances

  • 2-acetyl-7-methoxynaphtho(2,3-b)furan-4,9-quinone
  • Antineoplastic Agents, Phytogenic
  • Naphthoquinones
  • Plant Extracts
  • Reactive Oxygen Species
  • Doxorubicin
  • Caspases