Tumor-produced versican V1 enhances hCAP18/LL-37 expression in macrophages through activation of TLR2 and vitamin D3 signaling to promote ovarian cancer progression in vitro

PLoS One. 2013;8(2):e56616. doi: 10.1371/journal.pone.0056616. Epub 2013 Feb 12.

Abstract

Tumor-associated macrophages have been shown to promote tumor growth. They may have an obligatory function in angiogenesis, invasion, and metastasis through release of inflammatory mediators. Their presence in ovarian cancer has been correlated with poor prognosis in these patients. The human cationic antimicrobial protein-18 (hCAP18)/LL-37 was originally identified as an effector molecule of the innate immune system. It is released by innate immune cells, such as macrophages, to combat microorganisms. Previous studies have characterized the hCAP18/LL-37 as a growth factor that has been shown to promote ovarian tumor progression. However, the role hCAP18/LL-37 has in macrophage-promoted ovarian tumor development and how its expression is controlled in this context remains poorly understood. Here, we demonstrate in co-culture experiments of macrophages and ovarian cancer cells a significant increase in the in vitro proliferation and invasiveness of the tumor cells is observed. These enhanced growth and invasion properties correlated with hCAP18/LL-37 induction. HCAP18/LL-37 expression was diminished by addition of two neutralizing antibodies, TLR2 or TLR6, as well as Cyp27B1 or VDR inhibitors. Furthermore, either the TLR2 or TLR6 antibody reduced vitamin D3 signaling and tumor cell progression in vitro. Addition of Cyp27B1 or VDR inhibitors abrogated TLR2/6 activation-induced expression of hCAP18/LL-37 in macrophages. Knockdown of tumor-produced versican V1 by RNAi in these tumor cells led to a decreased induction of hCAP18/LL-37 in macrophages. Versican V1 knockdown also inhibited TLR2 and vitamin D3 signaling, as well as growth and invasiveness of these tumor cells in the in vitro co-culture. In summary, we have found that versican V1 enhances hCAP18/LL-37 expression in macrophages through activation of TLR2 and subsequent vitamin D-dependent mechanisms which promote ovarian tumor progression in vitro.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • 25-Hydroxyvitamin D3 1-alpha-Hydroxylase / genetics
  • Antimicrobial Cationic Peptides
  • Cathelicidins / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation
  • Cholecalciferol / metabolism*
  • Disease Progression
  • Female
  • Gene Expression Regulation, Neoplastic*
  • Humans
  • Macrophages / metabolism*
  • Neoplasm Invasiveness
  • Ovarian Neoplasms / pathology*
  • Receptors, Calcitriol / genetics
  • Signal Transduction
  • Steroid Hydroxylases / genetics
  • Toll-Like Receptor 2 / metabolism*
  • Toll-Like Receptor 6 / metabolism
  • Tumor Microenvironment
  • Up-Regulation
  • Versicans / metabolism*
  • Vitamin D3 24-Hydroxylase

Substances

  • Antimicrobial Cationic Peptides
  • Cathelicidins
  • Receptors, Calcitriol
  • TLR2 protein, human
  • TLR6 protein, human
  • Toll-Like Receptor 2
  • Toll-Like Receptor 6
  • Versicans
  • Cholecalciferol
  • ropocamptide
  • Steroid Hydroxylases
  • Vitamin D3 24-Hydroxylase
  • 25-Hydroxyvitamin D3 1-alpha-Hydroxylase

Grant support

This work was supported by National Natural Science Foundation of China Grants (81272603); Research Program of the Committee of Science and Technology of Putuo District, Shanghai (PTKW09-B02). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.