The Mechanism Of Group-2 Innate Lymphoid Cells Promote Hepatocellular Carcinoma Progression Via CXCL2-Neutrophil Induced Immunosuppression

Obejective: Due to their inherent characteristic,the function of group-2 innate lymphoid cells(ILC2s)varies as tissue dependent.ILC2 s have been elucidated in various inflammatory processes however their role still remains unknown in hepatocellular carcinoma(HCC).Here,we assessed the role of an HCC-derived non-classical ILC2 population in promoting HCC progression.Materials and methods: We collected paired liver tumor,non-tumor tissues as well as some peripheral and portal vein blood from patients with HCC(n=150),normal liver tissues from patients with liver hemangioma(n=20).Human liver tissues were analyzed by flow cytometry,mass cytometry,immunofluorescence,immunoblotting,RNA expression array(from sorted hepatic ILC2s).Orthotopic HCC models were established by hydrodynamic injection(HDI)of oncogene plasmids together with transposase.Tumor burdened mice were given injections of isolated ILC2 s or PBS via caudal vein.To study the tissue-resident or circulating characteristics of ILC2,mice were given a single intravenous injection of PE conjugated CD45 antibody for 3 minutes.In-vivo bromodeoxyuridine(Brd U)assay was performed by given Brd U intra-peritoneally.Isolated murine ILC2 s were genetically modified by overexpressing or knockout of KLRG1 or CXCL2 gene.Results: We identified a new subset of HCC-derived ILC2 s that down regulated KLRG1 expression and lacked the cognate receptors(ST2,IL17 RB and TSLPR)of activating cytokine IL-33,IL-25 and TSLP.These hepatic ILC2 s lost KLRG1 and acquired an immature phenotype with high proliferative capacity.The enriched KLRG1 neg hepatic ILC2 s in HCC were tissue resident,and distinct from the circulating ILC2 s in peripheral and portal vein blood.These ILC2 s secrete high levels of CXCL2 and IL-13 after the KLRG1-mediated inhibitory signals are blocked,which recruit neutrophils to the tumor site and upregulate arginase1(Arg1)level that inhibit T cell proliferation and activity to foster tumor progression.The abundance of ILC2 s in HCC tissue was positively correlated with tumor recurrence and negatively with progress free survival(PFS)in the patients.Conclusion: We clarifies HCC-associated unconventional ILC2 s as emerging immune regulatory cells which could promote HCC development and indicates that targeting these ILC2 s may unlock new therapies to combat HCC.