Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0027627 (metastases)
 103,950 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatic metastasis is a major clinical problem in cancer treatment. We examined antitumor activity of alpha-galactosylceramide (KRN7000) on mice with spontaneous liver metastases of reticulum cell sarcoma M5076 tumor cells (spontaneous metastasis model). In this model, all mice that were s.c. challenged with one million tumor cells developed a solid s.c. mass by day 7 and died of hepatic metastases. In the current study, we administered 100 microg/kg of KRN7000 to the model mice on days 7, 11, and 15. This treatment suppressed the growth of established liver metastases and resulted in the prolongation of survival time. Fluorescence-activated cell sorter analysis of phenotypes of spleen cells, hepatic lymphocytes, and regional lymph node cells around the s.c. tumor revealed that CD3+NK1.1+ (NKT) cells increased in hepatic lymphocytes of the KRN7000-treated mice. Cytotoxic activity and IFN-gamma production of hepatic lymphocytes were augmented in comparison with those of spleen cells and regional LN cells. At the same time, interleukin (IL)-12 production of hepatic lymphocytes was markedly enhanced. Neutralization of IL-12 using a blocking monoclonal antibody diminished the prolonged survival time. These results showed that the in vivo antitumor effects of KRN7000 on spontaneous liver metastases were dependent on the endogenous IL-12 production, where NKT cells in the liver are suggested to be involved. Adjuvant immunotherapy using KRN7000 could be a promising modality for the prevention of postoperative liver metastases.
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PMID:Antitumor effect of alpha-galactosylceramide (KRN7000) on spontaneous hepatic metastases requires endogenous interleukin 12 in the liver. 1095 26

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is expressed by in vitro activated natural killer (NK) cells, but the relevance of this observation to the biological function of NK cells has been unclear. Herein, we have demonstrated the in vivo induction of mouse TRAIL expression on various tissue NK cells and correlated NK cell activation with TRAIL-mediated antimetastatic function in vivo. Expression of TRAIL was only constitutive on a subset of liver NK cells, and innate NK cell control of Renca carcinoma hepatic metastases in the liver was partially TRAIL dependent. Administration of therapeutic doses of interleukin (IL)-12, a powerful inducer of interferon (IFN)-gamma production by NK cells and NKT cells, upregulated TRAIL expression on liver, spleen, and lung NK cells, and IL-12 suppressed metastases in both liver and lung in a TRAIL-dependent fashion. By contrast, alpha-galactosylceramide (alpha-GalCer), a powerful inducer of NKT cell IFN-gamma and IL-4 secretion, suppressed both liver and lung metastases but only stimulated NK cell TRAIL-mediated function in the liver. TRAIL expression was not detected on NK cells from IFN-gamma-deficient mice and TRAIL-mediated antimetastatic effects of IL-12 and alpha-GalCer were strictly IFN-gamma dependent. These results indicated that TRAIL induction on NK cells plays a critical role in IFN-gamma-mediated antimetastatic effects of IL-12 and alpha-GalCer.
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PMID:Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) contributes to interferon gamma-dependent natural killer cell protection from tumor metastasis. 1125 33

The glycolipid alpha-galactosylceramide (alpha-GalCer), ligand of NKT cells, has been recently shown to induce antitumor immunity in mice through the induction of IL-12 production by dendritic cells. In the present study we compared alpha-GalCer and rIL-12 antitumor activities in the treatment of hepatic metastases of the C-26 murine colon carcinoma. We show that in immunocompetent mice the two molecules display similar efficacy, whereas in mice knockout (KO) for beta2-microglobulin (beta2m), IFN-gamma or IL-12p40, alpha-GalCer antitumor activity is severely impaired. Conversely,in all such KO mice, rIL-12 retains its efficacy. In this context, the IL-12 effect relies on NK cell function since it is abrogated by antibodies to NK1.1, expressed by both NK and NKT cells, but not in beta2m KO mice that lack NKT and CD8 T cells, but have a perfectly functional NK cell population. Furthermore, in IFN-gamma and IL-12p40 double KO mice, exogenous rIL-12 completely loses antitumor efficacy, suggesting the existence of an IFN-gamma-independent IL-12 effect that does require the presence of endogenous IL-12p40 chain.
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PMID:Different requirements for alpha-galactosylceramide and recombinant IL-12 antitumor activity in the treatment of C-26 colon carcinoma hepatic metastases. 1159 87

Mice deficient for the STAT6 gene (STAT6(-/-) mice) have enhanced immunosurveillance against primary and metastatic tumors. Because STAT6 is a downstream effector of the IL-4R, and IL-13 binds to the type 2 IL-4R, IL-13 has been proposed as an inhibitor that blocks differentiation of tumor-specific CD8(+) T cells. Immunity in STAT6(-/-) mice is unusually effective in that 45-80% of STAT6(-/-) mice with established, spontaneous metastatic 4T1 mammary carcinoma, whose primary tumors are surgically excised, survive indefinitely, as compared with <10% of STAT(+/+) (BALB/c) mice. Surprisingly, STAT6(-/-) and BALB/c reciprocal bone marrow chimeras do not have increased immunosurveillance, demonstrating that immunity requires STAT6(-/-) hemopoietic and nonhemopoietic components. Likewise, CD1(-/-) mice that are NKT deficient and therefore IL-13 deficient also have heightened tumor immunity. However, STAT6(-/-) and CD1(-/-) reciprocal bone marrow chimeras do not have increased survival, suggesting that immunity in STAT6(-/-) and CD1(-/-) mice is via noncomplementing mechanisms. Metastatic disease is not reduced in BALB/c mice treated with an IL-13 inhibitor, indicating that IL-13 alone is insufficient for negative regulation of 4T1 immunity. Likewise, in vivo depletion of CD4(+)CD25(+) T cells in BALB/c mice does not increase survival, demonstrating that CD4(+)CD25(+) cells do not regulate immunity. Cytokine production and tumor challenges into STAT6(-/-)IFN-gamma(-/-) mice indicate that IFN-gamma is essential for immunity. Therefore, immunosurveillance in STAT6(-/-) mice facilitates survival against metastatic cancer via an IFN-gamma-dependent mechanism involving hemopoietic and nonhemopoietic derived cells, and is not exclusively dependent on counteracting IL-13 or CD4(+)CD25(+) T cells.
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PMID:Resistance to metastatic disease in STAT6-deficient mice requires hemopoietic and nonhemopoietic cells and is IFN-gamma dependent. 1242 60

The crafting of genetic and biochemical techniques to identify cancer antigens yielded the unexpected discovery that immune recognition of tumors regularly accompanies cancer development. The failure of the host to suppress tumor formation or attenuate disease progression may thus reflect the limited immunogenicity of nascent tumors. One critical determinant of host immunity is the mixture of cytokines produced in the tumor microenvironment. We have compared a large number of secreted and surface molecules for their relative abilities to augment tumor immunity following gene transfer into cancer cells. In multiple murine models, granulocyte-macrophage colony stimulating factor (GM-CSF) proved to be the most potent immunostimulatory product. Vaccination with irradiated tumor cells engineered to secrete GM-CSF involves enhanced tumor antigen presentation by recruited dendritic cells (DCs) and macrophages; the coordinated functions of CD4+ and CD8+ T cells, CD1d-restricted NKT cells and antibodies mediate protective immunity. The evaluation of this vaccination strategy in patients with advanced melanoma revealed the consistent induction of cellular and humoral antitumor responses capable of effectuating substantial necrosis of distant metastases. The formulation of simplified methods for manufacturing autologous, GM-CSF-secreting tumor cells has enabled more extensive clinical testing in diverse patient settings.
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PMID:GM-CSF-based cancer vaccines. 1244 88

IL-18 administration promotes innate immunity resulting in significant antitumor effects in multiple murine tumor models. Here, we examined the effector population mediating the innate immunity. Most NK cells and some NKT cells express IL-18Rs without prior stimulation (65% positive in NK cells, 18% positive in NKT cells), though few naive T cells do. In vivo depletion of NK cells, but not NKT cells, using AsGM1 antibody significantly reduces IL-18-induced cytotoxicity. However, NK-like activity of hepatic MNCs for the NK target YAC-1 was present in Valpha 14 NKT cell-deficient animals. Furthermore, administration of rIL-18 greatly reduced B16 pulmonary metastases in vivo in NKT cell-deficient animals. When sorted NK and NKT cells were exposed to IL-18 in vitro, NK cells showed more IFN-gamma production and cytolysis against YAC-1 than NKT cells in response to IL-18. These results are consistent with the notion that NK cells, but not NKT cells, are the major effectors in IL-18-induced innate immunity.
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PMID:Natural killer, but not natural killer T, cells play a necessary role in the promotion of an innate antitumor response induced by IL-18. 1247 67

The development of biochemical and genetic schemes to characterize cancer antigens led to the recognition that malignant melanoma frequently evokes a host response. While the generation of brisk T-cell infiltrates in early stage disease is correlated with prolonged survival, host reactions in most cases are insufficient to impede tumor progression. One variable that may limit the potency of the host response against nascent melanoma is the mixture of cytokines present in the tumor microenvironment. In a murine melanoma model, we identified granulocyte-macrophage colony stimulating factor (GM-CSF) as the most potent molecule for augmenting tumor immunity following gene transfer into melanoma cells. Vaccination with irradiated melanoma cells engineered to secrete GM-CSF enhances host responses through improved tumor antigen presentation by recruited dendritic cells and macrophages. Melanoma-specific CD4(+) and CD8(+) T-cells, CD1d-restricted NKT-cells, and antibodies mediate tumor rejection. Initial testing of this immunization strategy in patients with metastatic melanoma revealed the consistent induction of cellular and humoral antitumor responses that provoked the extensive necrosis of distant metastases without significant toxicity.
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PMID:GM-CSF-secreting melanoma vaccines. 1278 95

The regional administration of 5-fluorouracil (5-FU) has been the fundamental therapy against liver metastases for the improvement of patient prognosis; however, there have been few reports about the immunological effects of this agent. It is also unknown whether it affects the spleen, one of the major lymphoid organs. The objective of the present study was to determine the immunological effect of an intrasplenic injection of 5-FU against liver metastases. We investigated the effect of an intrasplenic injection of 5-FU on the formation of experimental liver metastasis resulting from an intraportal vein injection of colon 26 carcinoma cells in BALB/c mice and elucidated some of the underlying mechanisms involving the effects of this on cellular immunity. Liver metastases were significantly diminished by the splenic injection of 5-FU, particularly in comparison with the portal injection or systemic administration. This was followed by augmentation of the interleukin-12 (IL-12) level in the spleen and activation of hepatic mononuclear cells. In those cells, NK1.1+ (NKT) cells played a central role against metastases. A splenic injection of 5-FU is more effective on the involution of liver metastases than portal or systemic injection. This effect may be attributed to the augmentation of the IL-12 level in the spleen and of NKT cells in the liver rather than to the original effect of 5-FU, which is the so-called inhibition of DNA synthesis.
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PMID:Antitumor effect of a splenic injection of 5-fluorouracil on metastatic liver cancer in mice. 1456 73

Many tumor immunologists favor the hypothesis that optimal anti-tumor activity is mediated by type 1 CD4(+) and CD8(+) T cells, and that the production of type 2 CD4(+) T cells may be counterproductive for effective anti-tumor immunity. Since Stat6-deficient or "knockout" mice lack the signal transducer and activator of transcription-6 protein and are unable to transmit signals initiated by the type 2 cytokines, IL-4 and IL-13, they have been studied to confirm the T(h)1 vs T(h)2 paradigm. Using transplantable tumor cells that cause primary solid tumors and metastatic disease, as well as a spontaneous transgenic tumor model, multiple studies have demonstrated that Stat6(-/-) mice are able to reject or delay primary tumor growth, prevent recurrence of primary tumors, and/or reject established, spontaneous metastatic disease. Deletion of the Stat6 gene, therefore, provides significantly enhanced immunosurveillance. Comparable experiments with CD1-deficient mice, which lack NKT cells and hence are deficient for IL-13, give similar results and suggest that removal of NKT cells also enhances immunosurveillance. Because immunity is enhanced in the absence of Stat6 or CD1, it has been hypothesized that these deletions result in the removal of an inhibitor that blocks constitutive immunosurveillance. Several mechanisms have been tested as potential inhibitors, including CD4(+)CD25(+) T regulatory cells, IL-13, a T(h)2 shift, and myeloid suppressor cells. Although the first three mechanisms do not appear to be relevant, regression of myeloid suppressor cells in Stat6-deficient and CD1-deficient mice may be responsible for enhanced immunosurveillance. Although additional studies are clearly needed to clarify the mechanism(s) underlying improved anti-tumor immunity in Stat6(-/-) and CD1(-/-) mice, deletion of these genes results in a potent anti-tumor immunity and may be a basis for an immunotherapy strategy.
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PMID:Signal transducer and activator of transcription 6 (Stat6) and CD1: inhibitors of immunosurveillance against primary tumors and metastatic disease. 1459 99

While studying Ag-pulsed syngeneic dendritic cell (DC) immunization, we discovered that surprisingly, unpulsed DCs induced protection against tumor lung metastases resulting from i.v. injection of a syngeneic BALB/c colon carcinoma CT26 or a syngeneic C57BL/6 lung carcinoma LL/2. Splenocytes or immature splenic DCs did not protect. The protection was mediated by NK cells, in that it was abrogated by treatment with anti-asialo-GM1 but not anti-CD8, and was induced by CD1(-/-) DCs unable to stimulate NKT cells, but did not occur in beige mice lacking NK cells. Protection correlated with increased NK activity, and increased infiltration of NK but not CD8(+) cells in lungs of tumor-bearing mice. Protection depended on the presence of costimulatory molecules CD80, CD86, and CD40 on the DCs, but surprisingly did not require DCs that could make IL-12 or IL-15. Unexpectedly, protection sensitive to anti-asialo-GM1 and increased NK activity were still present 14 mo after DC injection. As NK cells lack memory, we found by depletion that CD4(+) not CD8(+) T cells were required for induction of the NK antitumor response. The role of DCs and CD4(+) T cells provides a novel mechanism for NK cell induction and innate immunity against cancer that may have potential in preventing clinical metastases.
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PMID:Dendritic cell-induced activation of adaptive and innate antitumor immunity. 1463 94


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