Digitoxin synergizes with sorafenib to inhibit hepatocelluar carcinoma cell growth without inhibiting cell migration

Mol Med Rep. 2017 Feb;15(2):941-947. doi: 10.3892/mmr.2016.6096. Epub 2016 Dec 30.

Abstract

Sorafenib is a chemotherapeutic agent approved for the treatment of hepatocellular carcinoma (HCC) in China. Digitoxin is a cardiotonic drug, which has been demonstrated to exhibit anticancer effects in a number of cancers, but not in HCC. The aim of the present study was to evaluate the combinational effect of sorafenib and digitoxin on the treatment of HCC and to investigate the relevant molecular mechanisms of action that underlie these effects. The proliferation, cell death and migration of HCC cell lines, HepG2 and BEL‑7402, were examined using MTT, acridine orange/ethidium bromide staining and scratch wound healing assays, respectively. In addition, alterations in the expression of phosphorylated-extracellular signal-regulated kinase (ERK), hypoxia‑inducible factor 1‑α (HIF‑1α), hypoxia‑inducible factor 2‑α (HIF‑2α) and vascular endothelial growth factor (VEGF) were measured prior to and following drug application using western blot analysis. Digitoxin and sorafenib synergistically inhibited cell viability, but did not inhibit migration, which was potentially mediated by suppression of ERK and hypoxia signaling. In downstream signaling pathways, the activity of ERK was synergistically suppressed by combinatorial treatment of HepG2 and BEL‑7402 cells with sorafenib and digitoxin. In addition, the expression of HIF‑1α, HIF‑2α and VEGF was synergistically downregulated by combinational treatment.

MeSH terms

  • Antineoplastic Agents / pharmacology*
  • Basic Helix-Loop-Helix Transcription Factors / metabolism
  • Carcinoma, Hepatocellular / drug therapy*
  • Carcinoma, Hepatocellular / metabolism
  • Carcinoma, Hepatocellular / pathology
  • Cardiotonic Agents / pharmacology*
  • Cell Line, Tumor
  • Cell Movement / drug effects*
  • Cell Proliferation / drug effects
  • Digitoxin / pharmacology*
  • Drug Synergism
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Hep G2 Cells
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Liver / drug effects
  • Liver / metabolism
  • Liver / pathology
  • Liver Neoplasms / drug therapy*
  • Liver Neoplasms / metabolism
  • Liver Neoplasms / pathology
  • Niacinamide / analogs & derivatives*
  • Niacinamide / pharmacology
  • Phenylurea Compounds / pharmacology*
  • Sorafenib
  • Vascular Endothelial Growth Factor A / metabolism

Substances

  • Antineoplastic Agents
  • Basic Helix-Loop-Helix Transcription Factors
  • Cardiotonic Agents
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • Phenylurea Compounds
  • Vascular Endothelial Growth Factor A
  • endothelial PAS domain-containing protein 1
  • Niacinamide
  • Sorafenib
  • Digitoxin
  • Extracellular Signal-Regulated MAP Kinases