Toll-like receptor (TLR) 7and 8 were considered to recognize single-strand RNA (ssRNA) from viruses. Although these receptors also respond to synthetic small chemical ligands, such as CL075 and R848, it remains to be determined whether these receptors sense natural small molecules or not. In the structure of human TLR8 (huTLR8) with ssRNA, there are two ligand-binding sites: one binds a uridine and the other binds an oligoribonucleotide (ORN). This finding demonstrates that huTLR8 recognizes degradation products of ssRNA, suggesting the presence of natural small ligands. We here show that TLR7 works as the sensor for guanosine (G)/2'-deoxyguanosine (dG) in the presence of ORN where ORN strengthens TLR7 interaction with G/dG. In addition, modified nucleosides such as 7-methylguanosine, 8-hydroxyguanosine (8-OHG) and 8-hydroxydeoxyguanosine (8-OHdG) activated TLR7 with ORNs. Importantly, 8-OHdG-a well-known oxidative DNA damage marker with unknown function-induced strong cytokine production comparable to G and dG both in mouse and human immune cells. Although 8-OHdG bound TLR7/ORN with lower affinity than dG did in isothermal titration calorimetry, administered 8-OHdG was metabolically more stable than dG in the serum, indicating that 8-OHdG acts on TLR7 as an endogenous ligand in vivo To address a role of G analogs in the disease state, we also examined macrophages from Unc93b1 (D34A/D34A) mice, which suffer from TLR7-dependent systemic inflammation, and found that Unc93b1 (D34A/D34A) macrophages showed significantly enhanced response to G alone or 8-OHdG with ORN. In conclusion, our results provide evidence that G, dG, 8-OHG and 8-OHdG are novel endogenous ligands for TLR7.
BackgroundThere is an unmet need to identify markers that predict the response to nivolumab in patients with non-small-cell lung cancer (NSCLC). The neutrophil-to-lymphocyte ratio (NLR) was recently recognized as an indicator of a poor prognosis in patients with various cancers. In the present study, we quantified the predictive impact of NLR in patients with NSCLC treated with nivolumab.MethodsWe retrospectively analyzed 101 patients with advanced NSCLC treated with nivolumab at Kansai Medical University Hospital from December 2015 to December 2016. Patients were administered nivolumab at a dose of 3 mg/kg every 2 weeks. The predictive value of NLR for disease progression before treatment and 2 and 4 weeks after nivolumab treatment was assessed.ResultsThe median progression-free survival (PFS) of patients with an NLR of < 3 before treatment was 3.4 months, whereas that of patients with an NLR of ≥ 3 was 2.9 months (p = 0.484). The median PFS of patients with an NLR of < 3 at 2 weeks after treatment was 5.3 months, whereas that of patients with an NLR of ≥ 3 was 2.1 months (p = 0.00528). The median PFS of patients with an NLR of < 3 at 4 weeks after treatment was 5.3 months, whereas that of patients with an NLR of ≥ 3 was 2.0 months (p = 0.00515).ConclusionThe NLR at 2 and 4 weeks after treatment might be a useful marker for the prediction of the treatment response or disease progression in patients with advanced NSCLC receiving nivolumab.
BackgroundImmune checkpoint inhibitors have dramatically changed lung cancer treatment, demonstrating an overall survival benefit. There are limited data about re-challenge in patients with non-small cell lung cancer. We attempted to address this question for re-challenge of immune checkpoint inhibitor in patients with advanced non-small cell lung cancer.MethodsWe retrospectively analyzed 11 patients with advanced non-small cell lung cancer treated with nivolumab and re-challenged with nivolumab/pemblorizumab at Kansai Medical University Hospital from December 2015 to December 2017.ResultsThree patients achieved PR and two patients were in SD. These patients were apt to be good responders to the initial treatment, to develop immune-related adverse events and to be immediately started on re-challenge with immune checkpoint inhibitor. The median PFS was 2.7 (range, 0.5–16.1) months. Five patients (45%) had mild to moderate immune-related adverse events.ConclusionOur study shows the effectiveness of re-challenge of immune checkpoint inhibitors in a subset of non-small cell lung cancer patients. Re-challenge might become one of treatment option for advanced non-small cell lung cancer.
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