Suppression of lipopolysaccharide-induced cytokine production of gingival fibroblasts by a soybean, Kunitz trypsin inhibitor

BACKGROUND

Human bikunin, a Kunitz-type trypsin inhibitor, inhibits inflammation by down-regulating the expression of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) in tumor cells and inflammatory cells.

OBJECTIVES

We analyzed the effect of a soybean-derived Kunitz trypsin inhibitor (KTI) on TNF-alpha production in human gingival fibroblasts stimulated by lipopolysaccharide (LPS), an inflammatory inducer.

MATERIAL AND METHODS

Mitogen-activated protein kinase (MAPK) activation and cytokine levels were monitored using western blot and a specific enzyme-linked immunosorbent assay (ELISA).

RESULTS

Here, we show (i) a soybean KTI abrogates LPS-induced up-regulation of TNF-alpha mRNA and protein expression in a dose-dependent manner in gingival fibroblasts, (ii) KTI also blocks the induction of TNF-alpha target molecules interleukin-1beta (IL-1beta) and IL-6 proteins, (iii) inhibition by KTI of TNF-alpha induction correlates with the suppressive capacity of extracellular signal-regulated kinase 1/2 (ERK1/2) and p38 signaling pathways, implicating repressed ERK1/2 and p38 signalings in the inhibition, and (iv) pretreatment of cells with KTI blocked LPS-induced nuclear factor kappaB (NFkappaB) activation.

CONCLUSION

Our results indicate that KTI inhibits LPS-induced up-regulation of cytokine expression possibly through suppression of ERK1/2 and p38 kinase-mediated NFkappaB activation. These findings may identify anti-inflammatory properties of KTI at the level of gingival fibroblasts and may be relevant to the use of KTI in modulating inflammation, including periodontal disease.

A soybean Kunitz trypsin inhibitor reduces tumor necrosis factor-alpha production in ultraviolet-exposed primary human keratinocytes

BACKGROUND

Cytokines are produced as a consequence of photo-damaged DNA and oxidative stress in ultraviolet (UV)-exposed keratinocytes. A soybean Kunitz trypsin inhibitor (KTI) down-regulates the expression of proinflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) in tumor cells and inflammatory cells.

AIM

The effect of KTI on TNF-alpha production in UV-exposed primary human keratinocytes was analyzed.

RESULTS

We show (i) UV induced up-regulation of TNF-alpha mRNA and protein expression in keratinocytes; (ii) cells treated with KTI before UV irradiation showed a significantly lower accumulation of TNF-alpha protein in a dose-dependent manner and a reduced UV-induced up-regulation of TNF-alpha mRNA expression; (iii) KTI inhibited the induction of TNF-alpha target molecules interleukin-1beta (IL-1beta) and IL-6 proteins; (iv) UV irradiation transiently activated c-Jun N-terminal kinase (JNK) and Akt signaling but only weakly activated extracellular signal-regulated kinase (ERK) and p38; (v) KTI specifically inhibited UV-induced activation of ERK, JNK, and p38, but not Akt; (vi) treatment of cells with SP600125, a pharmacological inhibitor of JNK, predominantly suppressed UV-induced up-regulation of TNF-alpha expression; and (vii) KTI did not enhance suppression of UV-induced JNK phosphorylation by SP600125.

CONCLUSIONS

KTI specifically inhibited UV-induced up-regulation of cytokine expression predominantly through suppression of JNK signaling pathway.

Suppression of urokinase expression and invasion by a soybean Kunitz trypsin inhibitor are mediated through inhibition of Src-dependent signaling pathways

A soybean Kunitz trypsin inhibitor (KTI) interacts with cells as a negative modulator of the invasive cells. Using complementary pharmacological and genetic approaches, we provide novel findings regarding mechanisms by which KTI inhibits signaling pathways in ovarian cancer cells leading to invasion. Transforming growth factor-beta1 (TGF-beta1) directly activates Src kinase, which in turn activates ERK-phosphatidylinositol 3-kinase/Akt, the downstream targets of Src, for urokinase-type plasminogen activator (uPA) up-regulation in human ovarian cancer HRA cells. Preincubation of the HRA cells with KTI reduced the ability of TGF-beta1 to trigger the uPA expression at the gene level and at the protein level. To further elucidate the mechanism of the KTI-dependent suppressive effect of TGF-beta1-induced uPA expression and invasion, we investigated which signaling pathway transduced by KTI is responsible for this inhibitory effect. Here, we show that 1) KTI suppressed TGF-beta1-induced phosphorylation of Src, ERK1/2, and Akt by 40-60%; 2) KTI was insensitive to suppress the phosphorylation of ERK1/2 and Akt in the constitutively active (CA)-c-Src (Y529F) cells; 3) uPA expression was up-regulated in TGF-beta1-stimulated HRA cells and in unstimulated Y529F cells; 4) the addition of KTI reduced the TGF-beta1-induced increase of uPA gene and protein expression in the wild-type c-Src-transfected cells (in contrast, KTI could not inhibit uPA expression in the Y529F cells); and 5) CA-c-Src transfection resulted in a 2-fold increase in invasiveness, whereas KTI did not reduce invasion of the Y529F cells. Using additional complementary genetic approaches (CA-MEK1, CA-Akt, or kinase-dead-Akt), we conclude that KTI may suppress uPA expression and promotion of invasion possibly through one or more upstream targets of Src.

Suppressing effects of daily oral supplementation of beta-glucan extracted from Agaricus blazei Murill on spontaneous and peritoneal disseminated metastasis in mouse model

PURPOSE

The Basidiomycete fungus Agaricus blazei Murill has traditionally been used as a health food for the prevention of cancer.

METHODS

We examined whether beta-(1-6)-D: -glucan extracted from A. blazei is a potential anticancer agent in an in vitro and in vivo animal model.

RESULTS

Here we show that (1) beta-glucan had cytotoxic effect against human ovarian cancer HRA cells, but not against murine Lewis lung cancer 3LL cells, in vitro; (2) beta-glucan promotes p38 MAPK activity for suppressing HRA cell proliferation and amplifying the apoptosis cascade; (3) beta-glucan stimulates translocation of the proapoptotic protein, Bax, from the cytosol to mitochondria, cytochrome c release, and subsequent caspase-9 activation; (4) treatment with SB203580, a p38 MAPK-specific inhibitor, suppresses beta-glucan-induced effects, indicating that activation of p38 MAPK is involved in the suppression of cell proliferation and mitochondrial activation-mediated cell death pathway; (5) in mice, oral supplementation with beta-glucan reduces pulmonary metastasis of 3LL cells and peritoneal disseminated metastasis of HRA cells and inhibits the growth of these metastatic tumors in lung or peritoneal cavity, in part, by suppressing uPA expression; and (6) in an in vivo experimental metastasis assay, however, the oral supplementation with beta-glucan after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies.

CONCLUSION

Treatment with beta-glucan may be beneficial for cancer patients with or at risk for metastasis. The beta-glucan-dependent signaling pathways are critical for our understanding of anticancer events and development of cancer therapeutic agents.

Dietary supplementation of soybean kunitz trypsin inhibitor reduces lipopolysaccharide-induced lethality in mouse model

We examined the modifying effects of a Kunitz trypsin inhibitor (KTI) and a Bowman-Birk trypsin inhibitor (BBI), purified from soybean, as intraperitoneal (i.p.) injection and dietary supplements on bacterial lipopolysaccharide (LPS)-induced lethality in mice. We initially examined the suppressing effects of i.p. injection of KTI (50 mg/kg) and BBI (50 mg/kg) on LPS-induced lethality after i.p. injection of LPS. Furthermore, groups of female C57BL/6 were fed a basal diet (control group) or the basal diet supplemented with KTI (50 g/kg) or BBI (50 g/kg). Here, we show that i.p. and daily oral administration of KTI, but not BBI, caused a significant reduction of the LPS-induced lethality; that LPS significantly induced plasma TNF-alpha, IL-1beta, and IL-6 levels in mice after LPS challenge; that concomitant administration of KTI, but not BBI, inhibits the LPS-induced plasma levels of these cytokines; and that KTI, but not BBI, suppressed LPS-induced upregulation of cytokine expression through suppression of phosphorylation of three mitogen-activated protein (MAP) kinase pathways, ERK1/2, JNK, and p38, in peritoneal macrophages. These data allow us to speculate that i.p. injection and dietary supplementation of a soybean KTI may play a role as a potent anti-inflammatory agent by inhibiting activation of MAP kinases, leading to the suppression of cytokine expression.

Suppressing effects of dietary supplementation of soybean trypsin inhibitor on spontaneous, experimental and peritoneal disseminated metastasis in mouse model

The modifying effects of a Kunitz trypsin inhibitor (KTI) and a Bowman-Birk trypsin inhibitor (BBI), purified from soybean trypsin inhibitor, as dietary supplements on experimental and spontaneous pulmonary metastasis of murine Lewis lung carcinoma 3LL cells as well as peritoneal disseminated metastasis model in human ovarian cancer HRA cells were investigated in i.v., s.c. and i.p. injection models in mice. Seven groups of female C57BL/6 or nude mice were fed a basal diet (control group) or the basal diet supplemented with KTI or BBI (5, 15, or 50 g/kg). Here we show that, in an in vivo spontaneous metastasis assay, the diet supplementation with KTI (15 and 50 g/kg), but not with BBI, for 28 days immediately after s.c. tumor cell inoculation significantly inhibited the formation of lung metastasis in C57BL/6 mice in a dose-dependent manner. The inhibition of lung metastasis was not due to direct antitumor effects of KTI. In an in vivo experimental metastasis assay, the diet supplementation with KTI or BBI for 21 days after i.v. tumor cell inoculation did not reduce the number of lung tumor colonies. In addition, KTI (15 or 50 g/kg) treatment in a peritoneal disseminated metastasis model of HRA cells resulted in a 40% reduction in total tumor burden when compared with control animals. Immunoblot analysis revealed that KTI specifically reduced expression of uPA protein as well as phosphorylation of MAP kinase and PI3 kinase proteins in the cells stimulated with agonists (G-CSF for 3LL cells or TGF-beta1 for HRA cells). These results suggest that dietary supplementation of KTI more efficiently regulates the mechanism involved in the entry into vascular circulation of tumor cells (intravasation) than in extravasation during the metastatic process. KTI treatment may also be beneficial for ovarian cancer patients with or at risk for peritoneal disseminated metastasis; it greatly reduces tumor burden in part by inhibiting phosphorylation of MAP kinase and PI3 kinase, leading to suppression of uPA expression.

Quantification of glycated hemoglobin by electrospray ionization mass spectrometry

Glycated hemoglobin, considered to be the best index for the treatment of diabetes mellitus, was measured by electrospray ionization mass spectrometry (ESI/MS) according to the method proposed by Morris et al. at the 44th ASMS Conference on Mass Spectrometry and Allied Topics, 1996. They compared the values obtained by MS and affinity chromatography. Here, the values obtained by ESI/MS were compared with those obtained by high-performance liquid chromatography and by latex agglutination immunoassay. Whole blood samples were diluted 500 fold with 0.2% formic acid-50% acetonitrile solution and 5 microliters of the diluted solution was injected with the ESI/MS system (TSQ 7000) via a sample loop. The within-run and between-run relative standard deviations of the ratio of glycated and non-glycated beta-chain were less than 5%. The correlation coefficients between ESI/MS and conventional methods were higher than 0.96. However, considerable discrepancies were observed among methods. ESI/MS will allow reproducible measurements of glycated hemoglobin and will be useful in the quality control of HbA1c measurement by other principles and also in routine clinical laboratory tests.