The role of mouse liver NK1.1 Ag+ T (NKT) cells in the antitumor effect of α-galactosylceramide (α-GalCer) has been unclear. We now show that, whereas α-GalCer increased the serum IFN-γ concentration and alanine aminotransferase activity in NK cell-depleted C57BL/6 (B6) mice and B6-beige/beige mice similarly to its effects in control B6 mice, its enhancement of the antitumor cytotoxicity of liver mononuclear cells (MNCs) was abrogated. Depletion of both NK and NKT cells in B6 mice reduced all these effects of α-GalCer. Injection of Abs to IFN-γ also inhibited the α-GalCer-induced increase in antitumor cytotoxicity of MNCs. α-GalCer induced the expression of Fas ligand on NKT cells in the liver of B6 mice. Whereas α-GalCer did not increase serum alanine aminotransferase activity in B6-lpr/lpr mice and B6-gld/gld mice, it increased the antitumor cytotoxicity of liver MNCs. The α-GalCer-induced increase in survival rate apparent in B6 mice injected intrasplenically with B16 tumor cells was abrogated in beige/beige mice, NK cell-depleted B6 mice, and B6 mice treated with Abs to IFN-γ. Depletion of CD8+ T cells did not affect the α-GalCer-induced antitumor cytotoxicity of liver MNCs but reduced the effect of α-GalCer on the survival of B6 mice. Thus, IFN-γ produced by α-GalCer-activated NKT cells increases both the innate antitumor cytotoxicity of NK cells and the adaptive antitumor response of CD8+ T cells, with consequent inhibition of tumor metastasis to the liver. Moreover, NKT cells mediate α-GalCer-induced hepatocyte injury through Fas-Fas ligand signaling.

Liver metastasis of primary tumors is clinically a major problem. We examined the antitumor activity of KRN7000, an α-galactosylceramide, in mice with liver metastasis of the B16 melanoma. KRN7000 significantly inhibited tumor growth in the liver, and its potency was similar to that of interleukin-12. The KRN7000 administration resulted in a high percentage of cured mice, which acquired tumor-specific immunity. To study what kinds of antitumor effector cells participated in killing tumor cells, we then performed immunohistological analysis of tumor-infiltrating cells, and found that KRN7000 induced marked invasion of NK1.1 + cells, CD8 + cells, and F4/80 + cells (macrophages) into B16 tumor nodules. In addition, it appeared that KRN7000-treated, liver-associated macrophages possessed strong lytic activity against tumor cells. These results suggest that NK cells, NK1.1 + T (NKT) cells, cytotoxic T lymphocytes, and macrophages play an important role in killing tumor cells in the liver, and that KRN7000 may be useful for the treatment of cancer liver metastasis.

The immediate-type allergic reaction is involved in many allergic diseases such as asthma, allergic rhinitis, and sinusitis. In this study, we investigated the effect of acteoside extracted from CISTANCHE TUBULOSA (Schrenk) R. Wight on the basophilic cell-mediated allergic reaction. The effect of acteoside on β-hexosaminidase release and intracellular [Ca (2+)] I level from rat basophilic leukemia (RBL-2H3) cells was determined. Also, ELISA was used to determine the level of histamine, tumor necrosis factor (TNF)- α, and interleukin (IL)-4 on human basophilic (KU812) cells. The effect of acteoside on basophilic cell viability was determined using the 3-[4,5-dimethylthiazolyl]-2,5-diphenyltetrazolium bromide (MTT) assay. These results indicated that 0.1-10.0 µg/mL acteoside inhibits the release of β-hexosaminidase and [Ca (2+)] I influx from IgE-mediated RBL-2H3 cells. Moreover, acteoside inhibited histamine release, TNF- α, and IL-4 production in a dose-dependent manner from calcium ionophore A23187 plus phorbol 12-myristate 13-acetate (PMA) or compound 48/80-stimulated KU812 cells. Our findings provide evidence that acteoside inhibits basophilic cell-derived immediate-type and delayed-type allergic reactions. This is the first report describing antiallergic activity of acteoside extracted from CISTANCHE TUBULOSA on basophilic cells.

We have previously reported that acteoside inhibits the release of β-hexosaminidase from immunoglobulin E (IgE)-sensitized and bovine serum albumin-stimulated rat basophilic leukemia cells as well as the intracellular calcium level, release of histamine from, and production of tumor necrosis factor-alpha and interleukin-4 in human basophilic (KU812) cells. However, the molecular mechanism underlying the anti-allergic effects of acteoside has not yet been elucidated. Here, we used microarray analysis to determine the global gene expression profile of KU812 cells treated with acteoside and calcium ionophore A23187 plus phorbol-12-myristate 13-acetate (A23187+PMA), and the results were validated by real-time polymerase chain reaction (PCR) and Western blotting. Microarray analysis results showed that of the 201 genes in the microarray, 149 genes were up-regulated, while 52 genes were down-regulated. The significantly down-regulated genes have functions as chemokine and IgE receptors, as well as for immune response. Results of the validation of the microarray results using real-time PCR showed a significant decrease in the expressions of Fc fragment of IgE, high affinity I, receptor for; alpha polypeptide (FCER1A) and nuclear factor of activated T cell, cytoplasmic, calcineurin-dependent 1 (NFATC1) genes. Furthermore, Western blotting showed a decrease in the phosphorylation of mitogen-activated protein kinase (MAPK) Jun N terminal kinase (JNK), revealing the role of JNK MAPK in acteoside-mediated allergy inhibition. We determined that the anti-allergy effects of acteoside were due to the down-regulation of the expressions of the chemokine ligand 1 (CCL1), CCL2, CCL3, CCL4, FCER1A and NFATC1 genes and the inhibition of the MAPK pathway through decreased JNK phosphorylation.

Bone marrow fibrosis and new bone formation were induced by Pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) injection in the rat. We investigated time course changes of megakaryocyte counts, circulating platelet counts, transforming growth factor-β1 (TGF-β1) levels in the bone marrow and those in platelet-poor plasma (PPP) when rats were injected with PEG-rHuMGDF at a dose of 0.1 mg/kg. Additionally, ultrastructural analysis of the circulating platelet and the bone marrow was performed by electron microscope. PEG-rHuMGDF injection daily for 5 days caused a megakaryocyte hyperplasia on days 5-7[after the commencement of the treatment], myelofibrosis on days 7-10, and new bone formation on days 8-15. TGF-β1 levels in the extracellular fluid of the marrow, megakaryocyte numbers, TGF-β1 levels in the PPP, and circulating platelet counts increased by PEG-rHuMGDF injection, and reached to the maximum level on days 7, 7, 8, and 10, respectively. Ultrastructural analysis showed that circulating platelets had no prominent morphological changes in the PEGrHuMGDF-treated rats on day 8, compared with vehicle-treated rats. Additionally, there were many platelets or fragments of megakaryocyte around mesenchymal cells, and those fragments deposited in the newly formed bone on day 10. These data suggested that myelofibrosis and new bone formation were induced by the increase of TGF-β1 levels derived from bone marrow megakaryocytes. (J Toxicol Pathol 2002; 15: 31-38)