Activation of Toll-like receptors signaling in non-small cell lung cancer cell line induced by tumor-associated macrophages

Xing Ke; Meng Wu; Jianfang Lou; Shuping Zhang; Peijun Huang; Ruihong Sun; Lei Huang; Erfu Xie; Fang Wang; Bing Gu

doi:10.3978/j.issn.1000-9604.2015.03.07

Activation of Toll-like receptors signaling in non-small cell lung cancer cell line induced by tumor-associated macrophages

Chin J Cancer Res. 2015 Apr;27(2):181-9. doi: 10.3978/j.issn.1000-9604.2015.03.07.

Authors

Xing Ke¹, Meng Wu¹, Jianfang Lou¹, Shuping Zhang¹, Peijun Huang¹, Ruihong Sun¹, Lei Huang¹, Erfu Xie¹, Fang Wang¹, Bing Gu¹

Affiliation

¹ 1 Department of Laboratory Medicine, the First Affiliated Hospital of Nanjing Medical University, Nanjing 210029, China ; 2 National Key Clinical Department of Laboratory Medicine, Nanjing 210029, China.

PMID: 25937780
PMCID: PMC4409966
DOI: 10.3978/j.issn.1000-9604.2015.03.07

Abstract

Background: Inflammation is often linked with the progress and poor outcome of lung cancer. The understanding of the relationship between tumor-associated macrophages (TAMs) and lung cancer cells involves in the underlying mechanism of inflammatory cytokine production. Toll-like receptors (TLRs) are engaged in promoting the production of pro-inflammatory cytokines and play an important role in tumor immunology.

Methods: To investigate the mechanisms by which TAMs influence the production of pro-inflammatory cytokines in lung cancer cells, we established an in vitro coculture system using TAMs and human non-small cell lung cancer (NSCLC) cell line SPC-A1. Levels of interleukin (IL)-1β, IL-6 and IL-8 in SPC-A1 were evaluated by RT-PCR and cytometric bead array assay after being cocultured with TAMs. Expression changes of TLRs and TLRs signaling pathway proteins in SPC-A1 were further confirmed by RT-PCR and western blot. The level changes of IL-1β, IL-6 and IL-8 in SPC-A1 were also detected after the stimulation of TLRs agonists.

Results: We found that the phenotype markers of TAMs were highly expressed after stimulating human monocyte cell line THP-1 by phorbol-12-myristate-13-acetate (PMA). Higher mRNA and supernate secretion levels of IL-1β, IL-6 and IL-8 were detected in SPC-A1 after being cocultured with TAMs. We also found that TLR1, TLR6 and TLR7 were up-regulated in SPC-A1 in the coculture system with TAMs. Meanwhile, TLRs signaling pathway proteins were also significantly activated. Moreover, pre-treatment with agonist ligands for TLR1, TLR6 and TLR7 could dramatically promote inductions of IL-1β, IL-6 and IL-8.

Conclusions: These findings demonstrated that TAMs may enhance IL-1β, IL-6 and IL-8 expressions via TLRs signaling pathway. We conclude that TAMs contribute to maintain the inflammation microenvironment and ultimately promote the development and progression of lung cancer.

Keywords: Toll-like receptors (TLRs); Tumor-associated macrophages (TAMs); non-small cell lung cancer (NSCLC); pro-inflammatory cytokines.