Augmentation of therapeutic responses in melanoma by inhibition of IRAK-1,-4

Cancer Res. 2012 Dec 1;72(23):6209-16. doi: 10.1158/0008-5472.CAN-12-0337. Epub 2012 Oct 4.

Abstract

Toll-like receptors (TLR) are expressed by a variety of cancers, including melanoma, but their functional contributions in cancer cells are uncertain. To approach this question, we evaluated the effects of stimulating or inhibiting the TLR/IL-1 receptor-associated kinases IRAK-1 and IRAK-4 in melanoma cells where their functions are largely unexplored. TLRs and TLR-related proteins were variably expressed in melanoma cell lines, with 42% expressing activated phospho-IRAK-1 constitutively and 85% expressing high levels of phospho-IRAK-4 in the absence of TLR stimulation. Immunohistochemical evaluation of melanoma tumor biopsies (n = 242) revealed two distinct patient populations, one that expressed p-IRAK-4 levels similar to normal skin (55%) and one with significantly higher levels than normal skin (45%). Levels of p-IRAK-4 levels did not correlate with clinical stage, gender, or age, but attenuated IRAK-1,-4 signaling with pharmacologic inhibitors or siRNA-enhanced cell death in vitro in combination with vinblastine. Moreover, in a xenograft mouse model of melanoma, the combined pharmacologic treatment delayed tumor growth and prolonged survival compared with subjects receiving single agent therapy. We propose p-IRAK-4 as a novel inflammation and prosurvival marker in melanoma with the potential to serve as a therapeutic target to enhance chemotherapeutic responses.

Publication types

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

MeSH terms

  • Animals
  • Antineoplastic Combined Chemotherapy Protocols / pharmacology*
  • Apoptosis / drug effects
  • Cell Growth Processes / drug effects
  • Cell Line, Tumor
  • Cytokines / biosynthesis
  • Disease Models, Animal
  • Enzyme Activation
  • Female
  • Gene Expression Profiling
  • Humans
  • Interleukin-1 Receptor-Associated Kinases / antagonists & inhibitors*
  • Interleukin-1 Receptor-Associated Kinases / metabolism
  • Male
  • Melanoma / drug therapy*
  • Melanoma / enzymology*
  • Melanoma / pathology
  • Mice
  • Mice, Inbred NOD
  • Phosphorylation
  • Protein Kinase Inhibitors / pharmacology*
  • Signal Transduction
  • Toll-Like Receptors / biosynthesis
  • Toll-Like Receptors / metabolism
  • Xenograft Model Antitumor Assays

Substances

  • Cytokines
  • Protein Kinase Inhibitors
  • Toll-Like Receptors
  • IRAK1 protein, human
  • IRAK4 protein, human
  • Interleukin-1 Receptor-Associated Kinases