• Oncology Letters
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• v.17 no.4
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• pp.3981-3989
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• 2019

Tamoxifen (TAM) is the most widely used treatment for estrogen receptor-positive breast cancer patients. Unfortunately, the majority of these patients exhibit TAM resistance following treatment. We previously reported that proliferation and migration were greater in TAM-resistant MCF-7 (TAMR-MCF-7) cells than in parental MCF-7 cells. Janus kinases (JAKs) are cytosolic tyrosine kinases that transduce signals from plasma membrane cytokines and growth factor receptors. JAK2 selectively phosphorylates signal transducer and activator of transcription (STAT)-3, and the JAK2-STAT3 signaling pathway is known as a crucial signaling pathway for the regulation of cancer progression and metastasis. In the present study, basal phosphorylation of STAT3 was revealed to be greater in TAMR-MCF-7 cells than in control MCF-7 cells. Ruxolitinib, a potent JAK2 inhibitor, was demonstrated to attenuate STAT3 phosphorylation and the proliferation of TAMR-MCF-7 cells. Ruxolitinib also suppressed the enhanced cell migration of TAMR-MCF-7 cells through the inhibition of epithelial mesenchymal transition. Vascular endothelial growth factor (VEGF), a representative target gene of the JAK2-STAT3 pathway, functions as a key regulator of invasion and angiogenesis. Ruxolitinib significantly inhibited VEGF mRNA expression and transcriptional activity. The present study also performed a chick embryo chorioallantoic membrane assay to assess tumor growth and angiogenesis in TAMR-MCF-7 cells. Ruxolitinib reduced tumor weight and the number of blood vessels produced by TAMR-MCF-7 cells in a concentration-dependent manner. These results indicated that JAK2 could be a new therapeutic target for TAM-resistant breast cancer.

• The Korean Journal of Pharmacology
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• v.32 no.1
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• pp.103-112
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• 1996

Roles of protein kinase C and protein tyrosine kinase in the activation of neutrophil respiratory burst, degranulation and elevation of cytosolic $Ca^{2+}$ in platelet-activating factor (PAF)-stimulated neutrophils were investigated. Superoxide and $H_2O_2$ production and myeloperoxidase and acid phosphatase release in PAF-stimulated neutrophils were inhibited by protein kinase C inhibitors, staurosporine and H-7 and protein tyrosine kinase inhibitors, genistein and tyrphostin. The PAF-induced elevation of $[Ca^{2+}]_i$ in neutrophils was inhibited by staurosporine, genistein and methyl-2,5-dihydroxycinnamate. Staurosporine inhibited both intracellular $Ca^{2+}$ release and $Mn^{2+}$ influx in PAF-stimulated neutrophils. Genistein and methyl-2,5-dihydroxycinnamate inhibited $Mn^{2+}$ influx induced by PAF, whereas their effects on intracellular $Ca^{2+}$ release were not detected. In neutrophils preactivated by PMA, the stimulatory effect of PAF on the elevation of $[Ca^{2+}]_i$ was reduced. Protein kinase C and protein tyrosine kinase may be involved in respiratory burst, lysosomal enzyme release and $Ca^{2+}$ mobilization in PAF-stimulated neutrophils. The elevation of $[Ca^{2+}]_i$ appears to be accomplished by intracullular $Ca^{2+}$ release and $Ca^{2+}$ influx which are differently regulated by protein kinases. Preactivation of protein kinase C appears to attenuate the stimulatory action of PAF on intracellular $Ca^{2+}$ mobilization.

• Journal of Ginseng Research
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• v.33 no.1
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• pp.26-32
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• 2009

Diabetic nephropathy is associated with the dysfunction of proximal tubule cells. Insulin-like growth factor 1(IGF-I) has also been considered to play an important role in the development of diabetic nephropathy. Ginsenosides have been used as a remedy for diabetes in Asian countries. Therefore, we examined the preventive effect of ginsenosides against high glucose-induced alteration of IGF-I secretion in the primary cultured proximal tubule cells. In present study, Ginseng saponin (GS) completely blocked high glucose-induced stimulation of IGF-I secretion in proximal tubule cells, whereas panaxatriol (PI) and panaxadiol (PD) partially suppressed. In addition, high glucose stimulated cAMP formation and protein kinase C(PKC) activity from cytosolic to membrane fraction. GS completely prevented high glucose-induced stimulation of cAMP and PKC activity while PT and PD partially did. Furthermore, high glucose-induced stimulation of IGF-I was blocked by the treatment of PKI (protein kinase A inhibitor) and bisindolylmaleimide I (protein kinase C inhibitor). In conclusion, GS prevented high glucose-induced dysfunction of proximal tubule cells.

• Journal of Life Science
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• v.32 no.9
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• pp.678-689
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• 2022

HK shiitake mushroom mycelium (HKSMM), containing 14% β-glucan, is a health functional food ingredient approved individually for liver health by the Ministry of Food and Drug Safety. The immune-enhancing efficacy of a 50% aqueous ethanol extract of HKSMM (designated HKSMM50) was studied in Jurkat cells activated with concanavalin A (ConA). Active hexose correlated compound (AHCC) was used as a positive control. ConA-activated Jurkat cells were treated with HKSMM50 (0, 25, 50, 100 ㎍ g/ml) or AHCC (100 ㎍ g/ml), and cultured for 3 and 6 hours. The nuclear factor of activated T cells (NFAT) protein content in the cytosol and the nucleus was measured by Western blotting. Interleukin-2 (IL-2), interferon-gamma (IFN-γ), and cyclooxygenase-2 (COX-2) were determined using enzyme-linked immunosorbent assay (ELISA) kits. HKSMM50 lowered NFAT content in the cytosol, but elevated NFAT content in the nucleus. The IL-2 and IFN-γ productions were elevated. Meanwhile, both COX-2 activity and apoptosis were suppressed. The efficacy of the AHCC treatment showed similar to those of HKSMM50 treatments. These results indicate that the HKSMM50 exhibited immune-enhancing effects in ConA-treated Jurkat cells by activation of NFAT protein, and suggest that HKSMM could be used as a health functional food ingredient to improve immune functions in humans.

• Journal of Microbiology and Biotechnology
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• v.28 no.1
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• pp.122-135
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• 2018

Listeriolysin O (LLO), one of the most immunogenic proteins of Listeria monocytogenes and its main virulence factor, mediates bacterial escape from the phagosome of the infected cell. Thus, its expression in a nonpathogenic bacterial host may enable effective delivery of heterologous antigens to the host cell cytosol and lead to their processing predominantly through the cytosolic MHC class I presentation pathway. The aim of this project was to characterize the delivery of a model antigen, chicken egg ovalbumin (OVA), to the cytosol of dendritic cells by recombinant Bacillus subtilis vegetative cells expressing LLO. Our work indicated that LLO produced by non-sporulating vegetative bacteria was able to support OVA epitope presentation by MHC I molecules on the surface of antigen presenting cells and consequently influence OVA-specific cytotoxic T cell activation. Additionally, it was proven that the genetic context of the epitope sequence is of great importance, as only the native full-sequence OVA fused to the N-terminal fragment of LLO was sufficient for effective epitope delivery and activation of $CD8^+$ lymphocytes. These results demonstrate the necessity for further verification of the fusion antigen potency of enhancing the MHC I presentation, and they prove that LLO-producing B. subtilis may represent a novel and attractive candidate for a vaccine vector.

• Biotechnology and Bioprocess Engineering:BBE
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• v.10 no.5
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• pp.451-461
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• 2005

The effect of carbon dioxide on yeast growth was investigated during the cultivation of pH 5.0 and pH 6.8. by replacing the nitrogen part with carbon dioxide under aerobic conditions. The values of the specific growth rate under pH 5.0 and pH 6.8 conditions became 64.0% and 46.9%, respectively, compared to those before the change in gas composition. This suggests that the effect of carton dioxide was greater pronounced in pH 6.8 than in pH 5.0. The genome-wide transcriptional response to elevated carbon dioxide was examined using a DNA microarray. As for upregulated genes, it was noteworthy that 3 genes were induced upon entry into a stationary phase and 6 genes were involved in stress response. Of 53 downregulated genes, 22 genes were involved in the ribosomal biogenesis and assembly and 5 genes were involved in the lipid metabolism. These facts suggest that carbon dioxide could bring the cell conditions partially to a stationary phase. The ALD6 gene encoding for cytosolic acetaldehyde dehydrogenase was downregulated, which would lead to a lack of cell components for the growth. The downregulation of ALD6 was greater in pH 6.8 than in pH 5.0. consistent with physiological response. This suggests that it might be the most effective factor for growth inhibition.

• Journal of Microbiology and Biotechnology
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• v.24 no.2
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• pp.160-167
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• 2014

Oligopeptidase B (OpdB) is a serine peptidase widespread among bacteria and protozoa that has emerged as a virulence factor despite its function has not yet been precisely established. By using an OpdB-overexpressing Escherichia coli strain, we found that the overexpressed peptidase makes the bacterial cells specifically less susceptible to several proline-rich antimicrobial peptides known to penetrate into the bacterial cytosol, and that its level of activity directly correlates with the degree of resistance. We established that E. coli OpdB can efficiently hydrolyze in vitro cationic antimicrobial peptides up to 30 residues in length, even though they contained several prolines, shortening them to inactive fragments. Two consecutive basic residues are a preferred cleavage site for the peptidase. In the case of a single basic residue, there is no cleavage if proline residues are present in the $P_1$ and $P_2$ positions. These results also indicate that cytosolic peptidases may cause resistance to antimicrobial peptides that have an intracellular mechanism of action, such as the proline-rich peptides, and may contribute to define the substrate specificity of the E. coli OpdB.

• Journal of Microbiology and Biotechnology
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• v.30 no.6
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• pp.822-829
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• 2020

Nutraceutical treatments can reduce inflammation and prevent the development of inflammatory diseases. In this study, the anti-inflammatory effects of Smilax guianensis Vitman extract (SGE) were examined. SGE suppressed lipopolysaccharide (LPS)-mediated nitrite production in RAW 264.7 cells. SGE also prevented the LPS-induced expression of inducible nitric oxide synthase (iNOS) but not cyclooxygenase (COX)-2. Western blot analysis showed that SGE attenuated LPS-induced phosphorylation of IκB kinase (IKK), inhibitor of kappa B (IκB), and p65. Additionally, SGE inhibited LPS-induced IκB degradation in RAW 264.7 cells. Western blot analysis of the cytosolic and nuclear fractions, as well as immunofluorescence assay results, revealed that SGE suppressed LPS-induced p65 nuclear translocation in RAW 264.7 cells. Moreover, SGE reduced LPS-induced interleukin (IL)-1β, IL-6, and tumor necrosis factor-α (TNF-α) mRNA expression and IL-1β and IL-6 protein expression in RAW 264.7 cells. Collectively, these results indicate that SGE suppresses the NF-κB signaling pathway and thereby inhibits the production of NO, IL-1β, and IL-6.

• The Journal of Korean Obstetrics and Gynecology
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• v.21 no.2
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• pp.166-183
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• 2008

Purpose: This study was performed to determine anti-imflammatory effects of Haedoksamultang. Methods: In this study, I examined the effects of Haedoksamultang on the production of nitric oxide(NO), tumor necrosis factor-${\alpha}$(TNF-${\alpha}$), and interlukin-1${\beta}$(IL-1${\beta}$) as well as the expression of inducible NO synthase(iNOS), cyclooxygenase-2(COX-2), TNF-${\alpha}$, and IL-1${\beta}$ in RAW 264.7 cells. Haedoksamultang inhibited LPS-stimulated NO production. Western blotting and RT-PCR analysis showed that Haedoksamultang suppressed LPS-induced iNOS and COX-2 protein and mRNA expression in RAW 264.7 cells. Haedoksamultang also suppressed the expression and production of LPS-stimulated TNF-${\alpha}$ and IL-1${\beta}$ in RAW 264.7 cells. Haedoksamultang inhibited NF-${\kappa}B$ activation in LPS-treated RAW 264.7 cells. Moreover, this compound blocked $I{\kappa}B-{\alpha}$ phosphorylation and nuclear translocation of the cytosolic NF-${\kappa}B$ p65 subunit, which highly correlated with the production and expression of inflammatory mediators. Results: Haedoksamultang suppresses that inflammation-associated gene expression by blocking NF-${\kappa}B$ activation. Conclusion: These results suggest that Haedoksamultang may be beneficial for treating inflammatory disease.

• Archives of Pharmacal Research
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• v.25 no.5
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• pp.561-571
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• 2002

The action mechanisms of several chemopreventive agents derived from herbal medicine and edible plants have become attractive issues in cancer research. Tea is the most widely consumed beverage worldwide. Recently, the cancer chemopreventive actions of tea have been intensively investigated. It have been demonstrated that the active principles of tea were attributed to their tea polyphenols. Recently, tremendous progress has been made in elucidating the molecular mechanisms of cancer chemoprevention by tea and tea polyphenols. The suppression of various tumor biomarkers including growth factor receptor tyrosine kinases, cytokine receptor kinases, P13K, phosphatases, ras, raf, MAPK cascades, NㆍFB, IㆍB kinase, PKA, PKB, PKC, c-jun, c-fos, c-myc, cdks, cyclins, and related transducing proteins by tea polyphenols has been studied in our laboratory and others. The IㆍB kinase (IKK) activity in LPS-activated murine macrophages (RAW 264.7 cells) was found to be inhibited by various tea polyphenols including (-) epigallocatechin-3-gallate (EGCG), theaflavin (TF-1), theaflavin-3-gal-late (TF-2) and theaflavin-3,3'-digallate (TF-3). TF-3 inhibited IKK activity in activated macrophages more strongly than did the other tea polyphenols. TF-3 inhibited both IKK1 and IKK2 activity and prevented the degradation of IㆍBㆍand IㆍBㆍin activated macrophage cells. The results suggested that the inhibition of IKK activity by TF-3 and other tea polyphenols could occur by a direct effect on IKKs or on upstream events in the signal transduction pathway. TF-3 and other tea polyphenols blocked phosphorylation of IB from the cytosolic fraction, inhibited NFB activity and inhibited increases in inducible nitric oxide synthase levels in activated macrophage. TF-3 and other tea polyphenols also inhibited strongly the activities of xanthine oxidase, cyclooxygenase, EGF-receptor tyrosine kinase and protein kinase C. These results suggest that TF-3 and other tea polyphenols may exert their cancer chemoprevention through suppressing tumor promotion and inflammation by blocking signal transduction. The mechanisms of this inhibition may be due to the blockade of the mitogenic and differentiating signals through modulating EGFR function, MAPK cascades, NFkB activation as wll as c-myc, c-jun and c-fos expression.