Plasmatic membrane toll-like receptor expressions in human astrocytomas

PLoS One. 2018 Jun 18;13(6):e0199211. doi: 10.1371/journal.pone.0199211. eCollection 2018.

Abstract

Toll-like receptors (TLRs) are the first to identify disturbances in the immune system, recognizing pathogens such as bacteria, fungi, and viruses. Since the inflammation process plays an important role in several diseases, TLRs have been considered potential therapeutic targets, including treatment for cancer. However, TLRs' role in cancer remains ambiguous. This study aims to analyze the expression levels of plasmatic cell membrane TLRs (TLR1, TLR2, TLR4, TLR5, and TLR6) in human astrocytomas the most prevalent tumors of CNS different grades (II-IV). We demonstrated that TLR expressions were higher in astrocytoma samples compared to non-neoplastic brain tissue. The gene and protein expressions were observed in GBM cell lines U87MG and A172, proving their presence in the tumor cells. Associated expressions between the known heterodimers TLR1-TLR2 were found in all astrocytoma grades. In GBMs, the mesenchymal subtype showed higher levels of TLR expressions in relation to classical and proneural subtypes. A strong association of TLRs with the activation of cell cycle process and signaling through canonical, inflammasome and ripoptosome pathways was observed by in silico analysis, further highlighting TLRs as interesting targets for cancer treatment.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Astrocytoma / metabolism*
  • Brain / metabolism
  • Brain Neoplasms / metabolism*
  • Cell Line, Tumor
  • Cell Membrane / metabolism*
  • Fluorescent Antibody Technique
  • Humans
  • Real-Time Polymerase Chain Reaction
  • Toll-Like Receptor 1 / metabolism
  • Toll-Like Receptor 2 / metabolism
  • Toll-Like Receptor 4 / metabolism
  • Toll-Like Receptor 5 / metabolism
  • Toll-Like Receptor 6 / metabolism
  • Toll-Like Receptors / metabolism*

Substances

  • TLR2 protein, human
  • TLR4 protein, human
  • TLR5 protein, human
  • TLR6 protein, human
  • Toll-Like Receptor 1
  • Toll-Like Receptor 2
  • Toll-Like Receptor 4
  • Toll-Like Receptor 5
  • Toll-Like Receptor 6
  • Toll-Like Receptors

Grants and funding

This work was supported by São Paulo Research Foundation (FAPESP, http://www.fapesp.br/), grants 2013/06315-3 (SKNM), 2013/02162-8 (SKNM), 2014/50137-5 (SKNM), and 2016/14695-9 (IFM); Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (http://www.capes.gov.br/) grant number NUFFIC 062/15 (SKNM); Conselho Nacional de Desenvolvimento Científico e Tecnológico (http://cnpq.br/) grant number 305730/2015-0; Fundação Faculdade de Medicina.