Investigation of Lung Cancer Cell Culture Supernatants Activated with Tlr Agonists Effect on Macrophage Polarization

Abstract

It is well known that inflammation is involved in the development of lung cancer. Macrophages in the tumor microenvironment are the anti-inflammatory M2 type and anti-tumor type M1. Inflammatory cytokines, such as IL-1β, IL-6, and IL-8, released from tumor-associated macrophages (TAM) in the tumor microenvironment, facilitate the development and metastasis of cancer cells. TAMs are found intensely in many tumors, and it is known that the higher the number of TAM is associated with the poor prognosis of the disease. For this reason, the control and regulation of TAMs in the tumor microenvironment is a key factor tumor prognosis. Various Toll-Like Receptor (TLR) agonists are used in clinical practice because they can direct the immune response against the tumor. Immune response against the tumor is stimulated by TLRs on antigen presenting cells and increasing tumor-specific T cell response. Tumor-releasing soluble factors are known to be efficient in converting macrophages to TAMs, but the effects of soluble factors released from small-cell lung cancer cells on macrophage polarization are unknown. Therefore, we have investigated the effects of the mediators released from small cell lung cancer cell line stimulated by TLR 3, TLR 5 and TLR 8 agonists on the macrophage polarization. Furthermore, we have detected the cytokines released from TLR stimulated lung cancer cell line.In our study, cell culture supernatants obtained from NCI-H82 small cell lung cancer cell lines stimulated by TLR agonist, polarize THP-1 monocytic cells into the M1 type macrophages. These macrophages were expressed CD68, CD11b, and CXCR7. We have detected an increase in the inflammatory cytokines, IL-1β, IL-6, TNFα, IL-12, and IFNγ. Furthermore, phagocytosis capacity of these cells was increased and accumulation of cells in G0/G1 phase in the cell cycle were detected. However, incubation of THP-1 cells with supernatants of NCI-H82 cell lines without TLR agonists end up with the polarization of M2 type macrophages. In conclusion incubation of TLR3, TLR5 and TLR8 agonists with small cell lung cancer cell line polarized THP-1 monocytic cell line to M1 type macrophages and TLR agonists may improve the effects of immunotherapeutic agents.