Towards novel anti-tumor strategies for hepatic cancer: ɛ-viniferin in combination with vincristine displays pharmacodynamic synergy at lower doses in HepG2 cells

OMICS. 2014 May;18(5):324-34. doi: 10.1089/omi.2013.0045. Epub 2013 Dec 17.

Abstract

Hepatocellular carcinoma is the fifth most common cancer and the third leading cause of cancer-related deaths worldwide. The efficacy of novel combination treatments are increasingly evaluated with use of integrative biology research and development (R&D) strategies and methodological triangulation. We investigated the anti-tumor effect of ɛ-viniferin alone, and the putative synergy of ɛ-viniferin with vincristine on the growth of HepG2 cells in vitro. Growth inhibition and apoptosis induction were determined by MTT assay and annexin V/propidium iodide (PI), respectively. Morphological changes and DNA fragmentation were investigated under electron microscopy and by agarose gel electrophoresis, respectively. The results collectively showed that treating cells with ɛ-viniferin and vincristine significantly inhibited cell viability at lower doses as compared to each agent applied alone. IC(50) values for ɛ-viniferin and vincristine were determined as 98.3 and 52.5 μM at 24 h, respectively. IC(50) value of ɛ-viniferin in combination with vincristine was 15.8+11.25 μM (mean/SD) at 24 h. The viability of cells treated with 17.9 μM vincristine alone for 24 h was 79.62%; it reduced to 26.53% when 25 μM ɛ-viniferin was added in combination with vincristine (p<0.05). We found that combination of drugs promoted the sensitivity of cells against to vincristine treatment. The effect of combined use was in support of a synergistic pharmacodynamic effect. Moreover, low doses of the combination regimen induced phosphatidyl re-localization, morphological changes, and DNA fragmentation, and therefore caused apoptotic death. This study thus suggests that low concentrations of ɛ-viniferin and vincristine can enhance the anti-tumor effects efficiently by inducing HepG2 cell apoptosis. Further studies in other model systems are warranted with a view to potential future applications in the clinic of such combination regimens and their putative mechanism of action in the observed synergy reported here.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Apoptosis
  • Benzofurans / pharmacology*
  • Carcinoma, Hepatocellular / drug therapy*
  • Cell Shape / drug effects
  • Cell Survival / drug effects
  • DNA Fragmentation
  • Dose-Response Relationship, Drug
  • Drug Screening Assays, Antitumor
  • Drug Synergism
  • Hep G2 Cells
  • Humans
  • Inhibitory Concentration 50
  • Liver Neoplasms / drug therapy*
  • Stilbenes / pharmacology*
  • Vincristine / pharmacology*

Substances

  • Antineoplastic Agents, Phytogenic
  • Benzofurans
  • Stilbenes
  • Vincristine
  • epsilon-viniferin