krn-7000 and Colitis

Cancer progression involves carcinogenesis, an increase in tumour size, and metastasis. Here, we investigated the effect of overexpressed CXC chemokine ligand 14 (CXCL14) on these processes by using CXCL14/BRAK (CXCL14) transgenic (Tg) mice. The rate of AOM/DSS-induced colorectal carcinogenesis in these mice was significantly lower compared with that for isogenic wild type C57BL/6 (Wt) mice. When tumour cells were injected into these mice, the size of the tumours that developed and the number of metastatic nodules in the lungs of the animals were always significantly lower in the Tg mice than in the Wt ones. Injection of anti-asialo-GM1 antibodies to the mice before and after injection of tumour cells attenuated the suppressing effects of CXCL14 on the tumor growth and metastasis, suggesting that NK cell activity played an important role during CXCL14-mediated suppression of tumour growth and metastasis. The importance of NK cells on the metastasis was also supported when CXCL14 was expressed in B16 melanoma cells. Further, the survival rates after tumour cell injection were significantly increased for the Tg mice. As these Tg mice showed no obvious abnormality, we propose that CXCL14 to be a promising molecular target for cancer suppression/prevention.

Topics: Animals; Antigens, Ly; Autoantibodies; Cell Transformation, Neoplastic; Chemokines, CXC; Chronic Disease; Colitis; Disease Models, Animal; Female; G(M1) Ganglioside; Galactosylceramides; Killer Cells, Natural; Lung Neoplasms; Lymphocyte Depletion; Melanoma, Experimental; Mice; Mice, Transgenic; Neoplasms; NK Cell Lectin-Like Receptor Subfamily B; Tumor Burden

The active form of vitamin D, 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] is synthesized by the 1α-hydroxylase, which is encoded by the Cyp27B1 gene. Using transgenic mice that have replaced the Cyp27B1 gene with the bacterial lacZ reporter gene (β-galactosidase), the inflammatory conditions that induce Cyp27B1 in the immune system were probed. A variety of stimuli including lipopolysaccharide, anti-CD3 or PMA/ionomycin were used to stimulate splenocytes and bone marrow derived macrophage in vitro. Only anti-CD3 stimulation resulted in a low induction of β-galactosidase activity in the spleen, indicating that T cells might be a source of Cyp27B1. In vivo, challenge with lipopolysaccharide, α-galactosylceramide, and Listeria monocytogenes failed to induce β-galactosidase activity outside of the kidneys. During more prolonged and severe inflammation there was staining in both the lungs and the gastrointestinal tract for β-galactosidase. Furthermore, wild-type reconstitution of the hematopoietic cell population in Cyp27B1 KO mice protected the mice from experimental colitis. T cell production of Cyp27B1 activity was shown to be from the CD8+ but not the CD4+ T cell population. CD8+ T cells expressed the reporter gene only after 48 h of stimulation. The data is consistent with a model where CD8+ T cells are activated to produce Cyp27B1 and 1,25(OH)2D3 that serves to turn off the local immune response.

Topics: 25-Hydroxyvitamin D3 1-alpha-Hydroxylase; Animals; beta-Galactosidase; Bone Marrow Cells; CD8-Positive T-Lymphocytes; Colitis; Galactosylceramides; Genes, Reporter; Intestinal Mucosa; Intestines; Ionomycin; Lipopolysaccharides; Listeria monocytogenes; Macrophages; Mice; Mice, Inbred C57BL; Mice, Knockout; Mice, Transgenic; Promoter Regions, Genetic; Spleen

Invariant natural killer T (iNKT) cells are considered innate-like lymphocytes, and regulate the immunity against inflammation and tumorigenesis. However, the impact of iNKT cells in inflammation-associated tumorigenesis remains unclear. In this study, we examined the physiological role of iNKT cells in a mouse colitis-associated colorectal cancer model. C57BL/6 (B6) and Jα18 NKT cell-deficient KO (KO) mice were used. Colitis-associated colorectal cancer was induced by azoxymethane (AOM) and dextran sodium sulfate (DSS). The resulting inflammation and tumours were examined. The surface markers of mononuclear cells from the liver and the colon were assessed by FACS. The levels of IL-13 from the colon were measured by ELISA. α-galactosylceramide (GC), or its close analog OCH, was administered intraperitoneally on the first day of each cycle of DSS-administration. In the AOM/DSS model, hepatic iNKT cells were significantly decreased. In KO mice there were significantly greater numbers of colon tumours and more severe inflammation than in B6 mice. FACS analysis revealed that the population of NK1.1 (+) T cells (non-invariant NKT cells) in the colon was increased when compared to B6 mice. The secretion of IL-13 was increased in the colon of KO mice after AOM/DSS. The number of colon tumours was significantly decreased in the GC-treated group compared to the control group. GC-treatment significantly inhibited IL-13 secretion from the colonic mononuclear cells and the number of colonic NK1.1 (+) T cells was significantly decreased. These results suggest that iNKT cells may play a critical role in the prevention of tumour progression and inflammation in the AOM/DSS model.

Topics: Animals; Colitis; Colorectal Neoplasms; Disease Models, Animal; Flow Cytometry; Galactosylceramides; Male; Mice; Mice, Inbred C57BL; Mice, Knockout; Natural Killer T-Cells; Specific Pathogen-Free Organisms

Primary sclerosing cholangitis is often complicated by ulcerative colitis. Recently, we reported on Th1-dominant cholangitis associated with experimental colitis, and natural killer T (NKT) cells might play an important role in this model. The aim of this study was to clarify the immunopathogenic role of NKT cells in this model using alpha-galactosylceramide. CD-1 mice were administered 2.0% dextran sulfate sodium for 29 days and injection of alpha-galactosylceramide was performed every 5 days, then inflammation was assessed. Mononuclear cells from the liver were analyzed with respect to cytokine production and the surface marker. alpha-Galactosylceramide improved survival rate, weight gain, and inflammation score. Also, interferon-gamma release from MNC, CD4/CD8 ratio, NKT cell population, and NK cell population were decreased by this treatment. These findings indicate that repeated stimulation of NKT cells modifies the Th1/Th2 balance to reduce Th1 dominance, and this may be a mechanism by which alpha-galactosylceramide has a therapeutic effect.

Topics: Animals; Cholangitis, Sclerosing; Colitis; Dextran Sulfate; Disease Models, Animal; Drug Administration Schedule; Galactosylceramides; Killer Cells, Natural; Male; Mice; Mice, Inbred ICR; Th1 Cells; Th2 Cells