RESUMO
PURPOSE: Anticancer-drug efficacy seems to involve the direct interaction with host immune cells. Although topoisomerase I (Top I) inhibitors have been suggested to block LPS-evoked inflammation, the interaction between these drugs and toll-like receptor 4 (TLR4) is unaddressed. METHODS: SN-38, the active metabolite of the Top I inhibitor irinotecan, and TLR4 interaction was assessed using the in vitro luciferase nuclear factor-κB reporter assay, neutrophil migration to murine air-pouch, in silico simulation, and the thermal shift assay (TSA). Topotecan was used as a positive anti-inflammatory control. RESULTS: Non-cytotoxic concentrations of SN-38 attenuated LPS (a TLR4 agonist)-driven cell activation without affecting peptidoglycan (a TLR2 agonist)-activating response. Similarly, topotecan also prevented LPS-induced inflammation. Conversely, increasing concentrations of LPS reversed the SN-38 inhibitory effect. In addition, SN-38 abrogated LPS-dependent neutrophil migration and reduced TNF-α, IL-6, and keratinocyte chemoattractant levels in the air-pouch model, but failed to inhibit zymosan (a TLR2 agonist)-induced cell migration. A two-step molecular docking analysis indicated two potential binding sites for the SN-38 in the MD-2/TLR4 complex, the hydrophobic MD-2 pocket (binding energy of - 8.1 kcal/mol) and the rim of the same molecule (- 6.9 kcal/mol). The topotecan also bound to the MD-2 pocket. In addition, not only the lactone forms, but also the carboxylate conformations of both Top I inhibitors interacted with the MD-2 molecule. Furthermore, the TSA suggested the interaction of SN-38 with MD-2. CONCLUSIONS: Therefore, SN-38 inhibits acute inflammation by blocking LPS-driven TLR4 signaling. This mechanism seems to be shared by other Top I inhibitors.
Assuntos
Inflamação/tratamento farmacológico , Irinotecano/uso terapêutico , Receptor 4 Toll-Like/genética , Inibidores da Topoisomerase I/uso terapêutico , Animais , Humanos , Irinotecano/farmacologia , Masculino , Camundongos , Inibidores da Topoisomerase I/farmacologiaRESUMO
Ifosfamide (IFO) is an antineoplastic drug that is commonly used to treat gynecological and breast cancers. Hemorrhagic cystitis (HC) is a common side effect associated with IFO injection, which courses with neutrophil accumulation and affects 6-50% of patients depending on dose intensity. Here, we investigated the role of neutrophils in this inflammatory process. Female Swiss mice (nâ¯=â¯8/group) were injected with saline, IFO (400â¯mg/kg, i.p.), fucoidan (a P- and L-selectins inhibitor, 100â¯mg/kg, i.v.) or IFOâ¯+â¯fucoidan (1-100â¯mg/kg) alone or combined with mesna (80â¯mg/kg i.p.). Another group of mice received anti-Ly6G antibody (500⯵g/mouse, once daily for 2â¯days) for neutrophil depletion before IFO injection. In another experimental setting, animals received granulocyte colony-stimulating factor (G-CSF, 400⯵g/kg), IFO (200â¯mg/kg), G-CSF (25-400⯵g/kg, for 5â¯days)â¯+â¯IFO (200â¯mg/kg, i.p.) or fucoidanâ¯+â¯G-CSFâ¯+â¯IFO. Bladder injury was evaluated 12â¯h after IFO injection. IFO 400â¯mg/kg significantly increased visceral hyperalgesia, bladder edema, hemorrhage, vascular permeability, MPO, IL-1ß and IL-6 tissue levels, and COX-2 immunostaining and expression versus the saline group (Pâ¯<â¯0.05). Conversely, fucoidan (100â¯mg/kg) significantly attenuated these parameters compared to IFO-injected mice (Pâ¯<â¯0.05). Additionally, fucoidan potentiated mesna protective effect when compared with IFOâ¯+â¯mesna group (Pâ¯<â¯0.05). Accordingly, neutrophil depletion with anti-Ly6G reduced inflammatory parameters and bladder injury compared to IFO (Pâ¯<â¯0.05). In contrast, G-CSF enhanced IFO (200â¯mg/kg)-induced HC, which was significantly attenuated by treatment with fucoidan (Pâ¯<â¯0.05). Therefore, neutrophils contribute to the pathogenesis of HC.