Enhanced interleukin-2 diphtheria toxin conjugate-induced growth suppression in retinoic acid-treated hypoxic hepatocellular carcinoma cells

Cancer Lett. 2009 Feb 18;274(2):259-65. doi: 10.1016/j.canlet.2008.09.025. Epub 2008 Nov 4.

Abstract

Hypoxia induces survival signals in hepatocellular carcinoma (HCC). Hypoxia and retinoic acid (RA) may also induce interleukin-2 (IL-2) receptor expression, and thus we evaluated if RA and IL-2 receptor-targeted therapy are indicated in hypoxic HCCs. RA induced IL-2 receptor expression (R alpha, R beta, R gamma) in HCC cells, whereas hypoxia specifically induced IL-2 R gamma expression. IL-2 stimulated hypoxic HCC cell growth via p42/44 MAPK activation. Combination of denileukin diftitox and RA significantly suppressed hypoxic HCC cell growth compared to single agent-treated or normoxic cells. Therefore, denileukin diftitox and RA may be therapeutically implicated in infiltrative HCCs which are exposed to hypoxic environments.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blotting, Western
  • Carcinoma, Hepatocellular / enzymology
  • Carcinoma, Hepatocellular / pathology*
  • Cell Division / drug effects*
  • Cell Hypoxia
  • Cell Line, Tumor
  • Diphtheria Toxin / chemistry
  • Diphtheria Toxin / pharmacology*
  • Enzyme Activation
  • Humans
  • Interleukin-2 / chemistry
  • Interleukin-2 / pharmacology*
  • Liver Neoplasms / enzymology
  • Liver Neoplasms / pathology*
  • Mitogen-Activated Protein Kinases / metabolism
  • Tretinoin / pharmacology*

Substances

  • Diphtheria Toxin
  • Interleukin-2
  • Tretinoin
  • Mitogen-Activated Protein Kinases