Adaptive immunity suppresses formation and progression of diethylnitrosamine-induced liver cancer.
ABSTRACT BACKGROUND: Hepatocellular carcinoma (HCC) is a typical inflammation-associated cancer, but may also provoke antitumour immune responses whose significance and underlying mechanisms are incompletely understood. OBJECTIVE: To characterise immune responses in the diethylnitrosamine (DEN)-liver cancer mouse model. DESIGN: Tumour development and immune cell functions upon DEN treatment were compared between C57BL/6 wild-type (WT), chemokine scavenging receptor D6-deficient, B cell- (Igh6), CD4 T cell- (MHC-II) and T-/B cell-deficient (Rag1) mice. Relevance for human HCC was tested by comparing gene array results from 139 HCC tissues. RESULTS: The induction of premalignant lesions after 24 weeks and of HCC-like tumours after 42 weeks by DEN in mice was accompanied by significant leucocyte infiltration in the liver and upregulation of distinct intrahepatic chemokines (CCL2, CCL5, CXCL9). Macrophages and CD8 (cytotoxic) T cells were most prominently enriched in tumour-bearing livers, similar to samples from human HCC. Myeloid-derived suppressor cells (MDSC) increased in extrahepatic compartments of DEN-treated mice (bone marrow, spleen). The contribution of immune cell subsets for DEN-induced hepatocarcinogenesis was functionally dissected. In D6(-/-) mice, which lack the chemokine scavenging receptor D6, hepatic macrophage infiltration was significantly increased, but tumour formation and progression did not differ from that of WT mice. In contrast, progression of hepatic tumours (numbers, diameters, tumour load) was strikingly enhanced in T-/B cell-deficient Rag1(-/-) mice upon DEN treatment. When mice deficient for B cells (Igh6(-/-), μMT) or major histocompatibility complex II were used, the data indicated that T cells prevent initial tumour formation, while B cells critically limit growth of established tumours. Accordingly, in tumour-bearing mice antibody production against liver-related model antigen was enhanced, indicating tumour-associated B cell activation. In agreement, T and B cell pathways were differentially regulated in gene array analyses from 139 human HCC tissues and significantly associated with patients' survival. CONCLUSIONS: Distinct axes of the adaptive immune system, which are also prognostic in human HCC, actively suppress DEN-induced hepatocarcinogenesis by controlling tumour formation and progression.
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ABSTRACT: Hepatocellular carcinoma (HCC) is a devastating consequence of chronic inflammatory liver diseases. The goal of this study was to investigate whether Toll-like receptor 4 (TLR4) activity contributes to HCC initiation and progression in mice. A mouse model of diethylnitrosamine (DEN)-induced HCC was generated with wild-type and TLR4 mutant mice, and the development and progression of HCC and senescent responses were assessed using morphologic, immunological, and biochemical criteria. We found that genetic or pharmacologic blocking of TLR4 increased susceptibility to DEN-induced HCC carcinogenesis and progression, which was indicated by increases in number of tumor nodules, tumor volume, and animal death. The enhanced HCC was associated with a broad-spectrum reduction of immune response to DEN liver injury, as indicated by decreases in the liver-infiltrating F4/80+ macrophages, the apoptosis signal-regulating kinase 1/p38 mitogen-activated protein kinase/NF-κB and IRF3 signaling activities, and the expression of inflammatory cytokines. Suppressed immune networks resulted in a halt of cellular senescence induction in TLR4 mutant liver tissue, which promoted proliferation and suppressed programmed cell death. Moreover, TLR4 mutation resulted in a suppressed capacity of DNA repair due to a decrease in TLR4-medicated expression of DNA repair proteins Ku70/80 in liver tissue and cells. Isotopic expression of Ku70 in TLR4 mutant mice restored senescence and interrupted the positive feedback loop of DNA damage and oxidative stress, which reversed TLR4 mutation–deteriorated HCC carcinogenesis and progression. Conclusion: TLR4 plays an integrated defense role against HCC carcinogenesis by enhancing the expression and function of DNA repair protein Ku70. Our studies provide novel insight into TLR4 activity in the regulation of HCC tumorigenesis, which may be useful for the prevention of HCC development. (HEPATOLOGY 2013)Hepatology 05/2013; 57(5). · 11.19 Impact Factor
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ABSTRACT: The development of robust non-viral vectors could facilitate clinical gene therapy applications and may overcome some of the immune complications of viral vectors. Nevertheless, most non-viral gene deliver approaches typically yield only transient and/or low gene expression. To address these caveats, we have explored piggyBac transposons to correct hemophilia B by liver-directed factor IX (FIX) gene therapy in hemophilic mice. To achieve this, we combined the use of: (i) a hyperactive codon-optimized piggyBac transposase, (ii) a computationally enhanced liver-specific promoter, (iii) a hyper-functional codon-optimized FIX transgene (FIX R338L Padua) and (iv) a modification of the transposon terminal repeats. This combination strategy resulted in a robust 400-fold improvement in vector performance in hepatocytes yielding stable supra-physiological human FIX activity (>1 year). Liver-specific expression resulted in the induction of FIX-specific immune tolerance. Remarkably, only very low transposon/transposase doses were required to cure the bleeding diathesis. Similarly, PB transposons could be used to express supra-physiologic factor VIII levels using low transposon/transposase doses. PB transposition did not induce tumors in a sensitive hepatocellular carcinoma-prone mouse model. These results underscore the potency and relative safety of the latest generation PB transposons, which constitutes a versatile platform for stable and robust secretion of therapeutic proteins.Molecular Therapy (2014); doi:10.1038/mt.2014.131.Molecular Therapy 07/2014; · 6.43 Impact Factor
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ABSTRACT: Sustained hepatic inflammation promotes progression of liver diseases, including hepatitis and nonalcoholic steatohepatitis. Liver inflammation is regulated by chemokines, which regulate the migration and activities of hepatocytes, Kupffer cells, hepatic stellate cells, endothelial cells, and circulating immune cells. However, the effects of the different chemokines and their receptors vary during pathogenesis of different liver diseases. During development of chronic viral hepatitis, CCL5 and CXCL10 regulate the cytopathic versus antiviral immune responses of T cells and natural killer cells. During development of nonalcoholic steatohepatitis, CCL2 and its receptor are up-regulated in the liver, where they promote inflammation, fibrosis, and steatosis, as well as in adipose tissue. CCL2 signaling thereby links hepatic and systemic inflammation related to metabolic disorders and insulin resistance. Several chemokine signaling pathways also promote hepatic fibrosis. Recent studies have shown that other chemokines and immune cells have anti-inflammatory and antifibrotic activities. Chemokines and their receptors can also contribute to the pathogenesis of hepatocellular carcinoma, promoting proliferation of cancer cells, the inflammatory microenvironment of the tumor, evasion of the immune response, and angiogenesis. We review the roles of different chemokines in the pathogenesis of liver diseases and their potential use as biomarkers or therapeutic targets.Gastroenterology 07/2014; · 13.93 Impact Factor