RESUMO
Neutrophils are expanded and abundant in cancer-bearing hosts. Under the influence of CXCR1 and CXCR2 chemokine receptor agonists and other chemotactic factors produced by tumors, neutrophils, and granulocytic myeloid-derived suppressor cells (MDSCs) from cancer patients extrude their neutrophil extracellular traps (NETs). In our hands, CXCR1 and CXCR2 agonists proved to be the major mediators of cancer-promoted NETosis. NETs wrap and coat tumor cells and shield them from cytotoxicity, as mediated by CD8+ T cells and natural killer (NK) cells, by obstructing contact between immune cells and the surrounding target cells. Tumor cells protected from cytotoxicity by NETs underlie successful cancer metastases in mice and the immunotherapeutic synergy of protein arginine deiminase 4 (PAD4) inhibitors, which curtail NETosis with immune checkpoint inhibitors. Intravital microscopy provides evidence of neutrophil NETs interfering cytolytic cytotoxic T lymphocytes (CTLs) and NK cell contacts with tumor cells.
Assuntos
Armadilhas Extracelulares/metabolismo , Neoplasias Experimentais/terapia , Receptores de Quimiocinas/agonistas , Receptores de Interleucina-8A/agonistas , Receptores de Interleucina-8B/agonistas , Animais , Linhagem Celular Tumoral , Citotoxicidade Imunológica/imunologia , Células HT29 , Humanos , Microscopia Intravital/métodos , Células Matadoras Naturais/imunologia , Ligantes , Camundongos , Neoplasias Experimentais/imunologia , Neoplasias Experimentais/metabolismo , Receptores de Quimiocinas/imunologia , Receptores de Quimiocinas/metabolismo , Receptores de Interleucina-8A/imunologia , Receptores de Interleucina-8A/metabolismo , Receptores de Interleucina-8B/imunologia , Receptores de Interleucina-8B/metabolismo , Linfócitos T Citotóxicos/imunologiaRESUMO
Surgically resectable synchronic and metachronic liver metastases of colon cancer have high risk of relapse in spite of standard-of-care neoadjuvant and adjuvant chemotherapy regimens. Dendritic cell vaccines loaded with autologous tumor lysates were tested for their potential to avoid or delay disease relapses (NCT01348256). Patients with surgically amenable liver metastasis of colon adenocarcinoma (n = 19) were included and underwent neoadjuvant chemotherapy, surgery and adjuvant chemotherapy. Fifteen patients with disease-free resection margins were randomized 1:1 to receive two courses of four daily doses of dendritic cell intradermal vaccinations versus observation. The trial had been originally designed to include 56 patients but was curtailed due to budgetary restrictions. Follow-up of the patients indicates a clear tendency to fewer and later relapses in the vaccine arm (median disease free survival -DFS-) 25.26 months, 95% CI 8.74-n.r) versus observation arm (median DFS 9.53 months, 95% CI 5.32-18.88).