Functionally Active Toll‐Like Receptor 3 on Human Primary and Metastatic Cancer Cells

Abstract

Toll‐like receptor 3 (TLR3) is a member of Toll‐like receptors who recognize structurally conserved molecules derived from pathogens and trigger the immune response. To clarify if TLR3, is expressed in certain tumour cell lines and whether it is functional and what is the response of these cell lines to different concentrations of poly I:C treatment, we have screened SW480, SW620, FaDu and Detroit 562 cell lines using real‐time PCR, flow cytometry and ELISA. We have shown that all these cell lines express TLR3 on mRNA and protein level but it is only functional in Detroit 562 cell line since only in these cells poly I:C treatment triggered the IL‐6 secretion. In addition, poly I:C treatment inhibited cell growth and triggered up‐regulation of IL‐12p40, IL‐8 and Il‐1α in Detroit 562 cell line. By using annexin‐V apoptosis detection kit, we have found that poly I:C triggers apoptosis in Detroit 562 cell line. We have found here that based on the results of TLR3 functionality there is a huge difference between FaDu and Detroit 562 cell lines which are of the same origin (pharynx) but FaDu is primary and Detroit 562 metastatic carcinoma. Our study also shows that Detroit 562 cell line could be a good model for cancer therapy research and development as it is responsive to TLR3 agonists which consequently drives it to apoptosis.

Antitumor Activity from the Combined Application of Poly(I:C) and Chemotherapeutics in Human Metastatic Pharyngeal Cell Lines

“…We have previously shown that poly(I:C) induced apoptosis in Detroit 562 cells [15]. We have shown that all chemotherapeutics tested combined with poly(I:C) increased the apoptosis of Detroit 562 cells when compared with using chemotherapeutics alone.…”

“…The activation of TLR3, as well as of RIG-I, an MDA5, usually leads to type 1 IFN secretion. However, we and others have shown that poly(I:C) stimulation can also lead to IFN-γ secretion [15,16,17,18]. …”

Association between Toll-like receptor 7 Gln11Leu single-nucleotide polymorphism and basal cell carcinoma

“…TLRs have been found to be overexpressed in certain pre-malignant conditions and neoplasia (25)(26)(27)(28), responsible for increasing angiogenic and metastatic potential of tumors activating nitric oxide synthase 2 and cyclooxygenase 2, and upregulating vascular endothelial growth factor and transforming growth factor-β within the tumor microenvironment (29)(30)(31). By contrast, TLRs can cause tumor inhibition (32)(33)(34)(35) and TLR ligands can have an anticancer effect, as demonstrated by studies on TLR7/8 and TLR9 agonists (36)(37)(38). In particular, TLR7 and TLR8 have emerged as key targets in immunotherapy.…”

Dual Role of TLR3 in Inflammation and Cancer Cell Apoptosis

“…We have also observed TLR3 staining on lung squamous cell carcinoma and on a portion of HCC (our unpublished data). Furthermore, overexpression of TLR3 has been detected by flow c y t o m e t r y , b y w e s t e r n b l o t a n d / o r b y q P C R i n m e l a n o m a c e l l s [ 3 1 , 3 2 ] , e s o p h a g e a l squamous cell carcinoma [33], head and neck carcinoma cells [34] and multiple myeloma cells [35].…”