TAK1, a member of the mitogen-activated kinase kinase kinase (MAPKKK) family, participates in proinflammatory cellular signaling pathways by activating JNK/p38 MAPKs and NF-B. To identify drugs that prevent inflammation, we screened inhibitors of TAK1 catalytic activity. We identified a natural resorcylic lactone of fungal origin, 5Z-7-oxozeaenol, as a highly potent inhibitor of TAK1. This compound did not effectively inhibit the catalytic activities of the MEKK1 or ASK1 MAPKKKs, suggesting that 5Z-7-oxozeaenol is a selective inhibitor of TAK1. In cell culture, 5Z-7-oxozeaenol blocked interleukin-1-induced activation of TAK1, JNK/ p38 MAPK, IB kinases, and NF-B, resulting in inhibition of cyclooxgenase-2 production. Furthermore, in vivo 5Z-7-oxozeaenol was able to inhibit picryl chlorideinduced ear swelling. Thus, 5Z-7-oxozeaenol blocks proinflammatory signaling by selectively inhibiting TAK1 MAPKKK.TAK1 is a member of the mitogen-activated protein kinase kinase kinase (MAPKKK) 1 family that phosphorylates and activates MKK3, MKK4, MKK6, and MKK7 MAPKKs, which in turn activate the c-Jun N-terminal kinase (JNK) and p38 MAPKs (1-3). We have recently demonstrated that TAK1 also activates IB kinases (IKKs), ultimately leading to activation of the transcription factor NF-B (4). TAK1 participates in proinflammatory cellular signaling pathways such as the interleukin-1 (IL-1) pathway by activating both JNK/p38 MAPKs and IKKs. Exposure of cells to IL-1 induces the interaction between endogenous TAK1 and TRAF6 (tumor necrosis factor (TNF) receptor-associated factor 6), a molecule essential for IL-1 activation of both JNK/p38 and NF-B. This interaction in turn leads to TAK1 activation. We have previously identified two TAK1-binding proteins, TAB1 and TAB2 (5, 6). When ectopically co-expressed, TAB1 augments the kinase activity of TAK1, indicating that TAB1 functions as an activator of TAK1 (5, 7). TAB2 functions as an adaptor linking TAK1 to TRAF6 by directly binding to both, thereby mediating TAK1 activation in the IL-1 signaling pathway (6,8).Several lines of evidence suggest that TAK1 is a key molecule in proinflammatory signaling pathways. Various proinflammatory cytokines and endotoxins activate the kinase activity of endogenous TAK1 (4, 9, 10). Overexpression of kinase-dead TAK1 inhibits IL-1-and TNF-induced activation of both JNK/p38 and NF-B (4, 10). The Drosophila homolog of TAK1 was recently identified as an essential molecule for host defense signaling in Drosophila (11). Furthermore, the TAK1 gene-silencing study using the small interfering RNA method defined that TAK1 is essential for both IL-1-and TNF-induced NF-B activation in mammalian cells (12). Therefore, it can be expected that inhibition of TAK1 activity may be effective in preventing inflammation and tissue destruction promoted by proinflammatory cytokines.In this study, we screened for compounds that can inhibit TAK1 kinase activity. This strategy resulted in the isolation of one natural compound 5Z-7-oxozeaenol, a resorcylic lactone of fungal ori...

Granulocyte colony-stimulating factor (G-CSF) is a member of the CSF family of hormone-like glycoproteins that regulate haematopoietic cell proliferation and differentiation, and G-CSF almost exclusively stimulates the colony formation of granulocytes from committed precursor cells in semi-solid agar culture. Recently, Nomura et al. have established a human squamous carcinoma cell line (designated CHU-2) from a human oral cavity tumour which produces large quantities of CSF constitutively, and the CSF produced by CHU-2 cells has been purified to homogeneity from the conditioned medium. We have now determined the partial amino-acid sequence of the purified G-CSF protein, and by using oligonucleotides as probes, have isolated several clones containing G-CSF complementary DNA from the cDNA library prepared with messenger RNA from CHU-2 cells. The complete nucleotide sequences of two of these cDNAs were determined and the expression of the cDNA in monkey COS cells gave rise to a protein showing authentic G-CSF activity. Furthermore, Southern hybridization analysis of DNA from normal leukocytes and CHU-2 cells suggests that the human genome contains only one gene for G-CSF and that some rearrangement has occurred within one of the alleles of the G-CSF gene in CHU-2 cells.

No abstract

For detection of hepatocellular carcinoma (HCC) in patients with liver cirrhosis, serum ␣-fetoprotein has been widely used, but its sensitivity has not been satisfactory, especially in small, well-differentiated HCC, and complementary serum marker has been clinically required. Glypican-3 (GPC3), a heparan sulfate proteoglycan anchored to the plasma membrane, is a good candidate marker of HCC because it is an oncofetal protein overexpressed in HCC at both the mRNA and protein levels. In this study, we demonstrated that its NH 2 -terminal portion [soluble GPC3 (sGPC3)] is cleaved between Arg 358 and Ser 359 of GPC3 and that sGPC3 can be specifically detected in the sera of patients with HCC. Serum levels of sGPC3 were 4.84 ؎ 8.91 ng/ml in HCC, significantly higher than the levels seen in liver cirrhosis (1.09 ؎ 0.74 ng/ml; P < 0.01) and healthy controls (0.65 ؎ 0.32 ng/ml; P < 0.001). In well-or moderately-differentiated HCC, sGPC3 was superior to ␣-fetoprotein in sensitivity, and a combination measurement of both markers improved overall sensitivity from 50% to 72%. These results indicate that sGPC3 is a novel serological marker essential for the early detection of HCC.

Human glypican 3 (GPC3) is preferentially expressed in the tumor tissues of liver cancer patients. In this study, we obtained a monoclonal antibody (mAb) against the COOHterminal part of GPC3, which induced antibody-dependent cellular cytotoxicity (ADCC). The mAb, designated GC33, exhibited marked tumor growth inhibition of s.c. transplanted Hep G2 and HuH-7 xenografts that expressed GPC3 but did not inhibit growth of the SK-HEP-1 that was negative for GPC3. GC33 was efficacious even in an orthotopic model; it markedly reduced the blood A-fetoprotein levels of mice intrahepatically transplanted with Hep G2 cells. Humanized GC33 (hGC33) was as efficacious as GC33 against the Hep G2 xenograft, but hGC33 lacking carbohydrate moieties caused neither ADCC nor tumor growth inhibition. Depletion of CD56 + cells from human peripheral blood mononuclear cells markedly abrogated the ADCC caused by hGC33. The results show that the antitumor activity of hGC33 is mainly attributable to ADCC, and in human, natural killer cellmediated ADCC is one possible mechanism of the antitumor effects by GC33. hGC33 will provide a novel treatment option for liver cancer patients with GPC3-positive tumors. [Cancer Res 2008;68(23):9832-8]