title: Expression of TLR9 in tumor-infiltrating mononuclear cells enhances angiogenesis and is associated with a worse survival in lung cancer.
abstract: Toll-like receptors (TLRs) play a crucial role in the innate and adaptive immune responses against microbial infection, tissue injury and cancer. Ligands of TLR9 have been developed as therapy in non-small-cell lung carcinoma (NSCLC). However, phase III clinical trials in metastatic NSCLC were negative. Our objective was to determine whether TLR9 affects tumor growth. We generated a mouse model of lung adenocarcinoma (ADC) mutated for K-ras (K-ras(LA1) ), with and without TLR9 inactivation (K-ras(LA1) TLR9(-/-) and K-ras(LA1) TLR9(+/+) , respectively). TLR9 was functionally expressed only in mononuclear cells of K-ras(LA1) TLR9(+/+) mice. These mice had significantly worse survival and a higher tumor burden than K-ras(LA1) TLR9(-/-) mice. Lung tumors were analyzed for 24 cytokines/growth factors using Bio-Plex multiplex bead-based assays. Factor VIII was assessed by immunochemistry. Tumors from K-ras(LA1) TLR9(+/+) mice were characterized by an angiogenic phenotype with higher concentrations of vascular endothelial growth factor (VEGF) and higher microvessel density than from K-ras(LA1) TLR9(-/-) mice. LKR13 cells, an ADC cell line derived from K-ras(LA1) mice, were subcutaneously injected into TLR9(-/-) and TLR9(+/+) mice. Syngeneic tumors regressed in TLR9(-/-) but not in TLR9(+/+) mice. Peripheral blood mononuclear cells from TLR9(-/-) mice released less VEGF than those from TLR9(+/+) mice. In 61 patients with early-stage NSCLC, TLR9 was expressed in mononuclear cells that infiltrated tumors, as assessed by immunochemistry, and contributed to worse survival. Our results suggest that TLR9 expression in mononuclear cells was associated with an angiogenic phenotype and promoted lung cancer progression. These findings may aid clinical development of TLR9 ligands to treat cancers.
authors.affiliation: Service de Pneumologie, AP-HP, Hôpital Tenon, Paris, France; Equipe de Recherche 2, GRC UPMC-04, Université Paris 6 Pierre et Marie Curie, Service de Pneumologie, Hôpital Tenon, Paris, France.
authors.forename: Laure
authors.initials: L
authors.lastname: Belmont
authors.forename: Nathalie
authors.initials: N
authors.lastname: Rabbe
authors.forename: Martine
authors.initials: M
authors.lastname: Antoine
authors.forename: Dominique
authors.initials: D
authors.lastname: Cathelin
authors.forename: Christophe
authors.initials: C
authors.lastname: Guignabert
authors.forename: Jonathan
authors.initials: J
authors.lastname: Kurie
authors.forename: Jacques
authors.initials: J
authors.lastname: Cadranel
authors.forename: Marie
authors.initials: M
authors.lastname: Wislez
mesh_terms: D000230:Adenocarcinoma / Q000098:blood supply / Q000235:genetics / Q000401:mortality / Q000473:pathology; D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D002289:Carcinoma, Non-Small-Cell Lung / Q000098:blood supply / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D002294:Carcinoma, Squamous Cell / Q000098:blood supply / Q000235:genetics / Q000401:mortality / Q000473:pathology; D049109:Cell Proliferation; D016207:Cytokines / Q000378:metabolism; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007124:Immunoenzyme Techniques; D007249:Inflammation / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D007963:Leukocytes, Mononuclear / Q000276:immunology / Q000378:metabolism / Q000473:pathology*; D008168:Lung / Q000378:metabolism / Q000473:pathology; D008175:Lung Neoplasms / Q000098:blood supply / Q000235:genetics / Q000401:mortality* / Q000473:pathology; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D009367:Neoplasm Staging; D009389:Neovascularization, Pathologic; D011379:Prognosis; D016283:Proto-Oncogene Proteins p21(ras) / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015996:Survival Rate; D051217:Toll-Like Receptor 9 / Q000502:physiology*; D047368:Tumor Burden; D042461:Vascular Endothelial Growth Factor A
chemical_list: D016207:Cytokines; D012333:RNA, Messenger; D051217:Toll-Like Receptor 9; D042461:Vascular Endothelial Growth Factor A; C495971:Hras protein, mouse; D016283:Proto-Oncogene Proteins p21(ras)
keywords: TLR9 activation; angiogenesis; non-small-cell lung cancer; prognosis