S100A9 interaction with TLR4 promotes tumor growth

PLoS One. 2012;7(3):e34207. doi: 10.1371/journal.pone.0034207. Epub 2012 Mar 28.


By breeding TRAMP mice with S100A9 knock-out (S100A9(-/-)) animals and scoring the appearance of palpable tumors we observed a delayed tumor growth in animals devoid of S100A9 expression. CD11b(+) S100A9 expressing cells were not observed in normal prostate tissue from control C57BL/6 mice but were readily detected in TRAMP prostate tumors. Also, S100A9 expression was observed in association with CD68(+) macrophages in biopsies from human prostate tumors. Delayed growth of TRAMP tumors was also observed in mice lacking the S100A9 ligand TLR4. In the EL-4 lymphoma model tumor growth inhibition was observed in S100A9(-/-) and TLR4(-/-), but not in RAGE(-/-) animals lacking an alternative S100A9 receptor. When expression of immune-regulating genes was analyzed using RT-PCR the only common change observed in mice lacking S100A9 and TLR4 was a down-regulation of TGFβ expression in splenic CD11b(+) cells. Lastly, treatment of mice with a small molecule (ABR-215050) that inhibits S100A9 binding to TLR4 inhibited EL4 tumor growth. Thus, S100A9 and TLR4 appear to be involved in promoting tumor growth in two different tumor models and pharmacological inhibition of S100A9-TLR4 interactions is a novel and promising target for anti-tumor therapies.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiogenesis Inhibitors / pharmacology
  • Animals
  • Antigens, CD / metabolism
  • Antigens, Differentiation, Myelomonocytic / metabolism
  • CD11b Antigen / metabolism
  • Calgranulin B / genetics
  • Calgranulin B / metabolism*
  • Cell Proliferation / drug effects
  • Down-Regulation
  • Humans
  • Lymphoma / metabolism*
  • Lymphoma / pathology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Mitogen-Activated Protein Kinases / deficiency
  • Mitogen-Activated Protein Kinases / genetics
  • Mitogen-Activated Protein Kinases / metabolism
  • Prostatic Neoplasms / metabolism*
  • Prostatic Neoplasms / pathology
  • Protein Binding / drug effects
  • Quinolines / pharmacology
  • Quinolones
  • Spleen / metabolism
  • Toll-Like Receptor 4 / deficiency
  • Toll-Like Receptor 4 / genetics
  • Toll-Like Receptor 4 / metabolism*
  • Transforming Growth Factor beta / blood


  • Angiogenesis Inhibitors
  • Antigens, CD
  • Antigens, Differentiation, Myelomonocytic
  • CD11b Antigen
  • CD68 antigen, human
  • Calgranulin B
  • Quinolines
  • Quinolones
  • Tlr4 protein, mouse
  • Toll-Like Receptor 4
  • Transforming Growth Factor beta
  • tasquinimod
  • Mok protein, mouse
  • Mitogen-Activated Protein Kinases