• Biomolecules & Therapeutics
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• v.29 no.3
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• pp.273-281
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• 2021

Severe acute respiratory syndrome CoV-2 (SARS-CoV-2) is responsible for the current coronavirus disease 2019 (COVID-19) pandemic. Signaling pathways that are essential for virus production have potential as therapeutic targets against COVID-19. In this study, we investigated cellular responses in two cell lines, Vero and Calu-3, upon SARS-CoV-2 infection and evaluated the effects of pathway-specific inhibitors on virus production. SARS-CoV-2 infection induced dephosphorylation of STAT1 and STAT3, high virus production, and apoptosis in Vero cells. However, in Calu-3 cells, SARS-CoV-2 infection induced long-lasting phosphorylation of STAT1 and STAT3, low virus production, and no prominent apoptosis. Inhibitors that target STAT3 phosphorylation and dimerization reduced SARS-CoV-2 production in Calu-3 cells, but not in Vero cells. These results suggest a necessity to evaluate cellular consequences upon SARS-CoV-2 infection using various model cell lines to find out more appropriate cells recapitulating relevant responses to SARS-CoV-2 infection in vitro.

• The Korean Journal of Physiology and Pharmacology
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• v.12 no.5
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• pp.281-286
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• 2008

Although the interaction between gp130 and the ErbB family has frequently been shown in cancer cells, the mechanism of this interaction remains unclear and controversial. In the present study, we found that specific tyrphostin inhibitors of ErbB2 (AG825 and AG879), but not ErbB1 inhibitor (AG1478), suppressed IL-6-induced tyrosine phosphorylation of STAT3 in schwannoma cells. However, biochemical evidence for transactivation of ErbB2 by IL-6 was not observed. Additionally, the inhibition of ErbB2 expression, with either a specific RNAi or transfection of an ErbB2 mutant lacking the intracellular domain did not inhibit the IL-6-induced tyrosine phosphorylation of STAT3. Thus, it seems that tyrphostins, which are known as specific inhibitors of the ErbB2 kinase, may have non-specific suppressive effects on the IL-6/STAT3 pathway.

• Korean Journal of Clinical Laboratory Science
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• v.55 no.4
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• pp.306-313
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• 2023

Sepsis is a systemic inflammatory response, with manifestations in multiple organs by pathogenic infection. Currently, there are no promising therapeutic strategies. Signal transducer and activator of transcription 3 (STAT3) is a cell signaling transcription factor. Niclosamide is an anti-helminthic drug approved by the Food and Drug Administration (FDA) as a potential STAT3 inhibitor. C57BL/6 mice were treated with an intraperitoneal injection of lipopolysaccharide (LPS). Niclosamide was administered orally 2 hours after the LPS injection. This study found that Niclosamide improved the survival and lung injury of LPS-induced mice. Niclosamide decreased the levels of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β), aspartate aminotransferase (AST), alanine aminotransferase (ALT), and lactate dehydrogenase (LDH) in serum. The effects of Niclosamide on phosphoinositide 3-kinase (PI3K), AKT, nuclear factor-κB (NF-κB), and STAT3 signaling pathways were determined in the lung tissue by immunoblot analysis. Niclosamide reduced phosphorylation of PI3K, AKT, NF-κB, and STAT3 significantly. Furthermore, it reduced the phosphorylation of STAT3 by LPS stimulation in RAW 264.7 macrophages. Niclosamide also reduced the LPS-stimulated expression of proinflammatory mediators, including IL-6, TNF-α, and IL-1β. Niclosamide provides a new therapeutic strategy for murine sepsis models by suppressing the inflammatory response through STAT3 inhibition.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5071-5076
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• 2014

Cholangiocarcinoma (CCA) is one of the aggressive cancers with a very poor prognosis. Several efforts have been made to identify and develop new agents for prevention and treatment of this deadly disease. In the present study, we examined the anticancer effect of luteolin on human CCA, KKU-M156 cells. Sulforhodamine B assays showed that luteolin had potent cytotoxicity on CCA cells with IC50 values of $10.5{\pm}5.0$ and $8.7{\pm}3.5{\mu}M$ at 24 and 48 h, respectively. Treatment with luteolin also caused a concentration-dependent decline in colony forming ability. Consistent with growth inhibitory effects, luteolin arrested cell cycle progression at the G2/M phase in a dose-dependent manner as assessed by flow cytometry analysis. Protein expression of cyclin A and Cdc25A was down-regulated after luteolin treatment, supporting the arrest of cells at the G2/M boundary. Besides evident G2/M arrest, luteolin induced apoptosis of KKU-M156 cells, demonstrated by a distinct sub-G1 apoptotic peak and fluorescent dye staining. A decrease in the level of anti-apoptotic Bcl-2 protein was implicated in luteolin-induced apoptosis. We further investigated the effect of luteolin on JAK/STAT3, which is an important pathway involved in the development of CCA. The results showed that interleukin-6 (IL-6)-induced JAK/STAT3 activation in KKU-M156 cells was suppressed by treatment with luteolin. Treatment with a specific JAK inhibitor, AG490, and luteolin diminished IL-6-stimulated CCA cell migration as assessed by wound healing assay. These data revealed anticancer activity of luteolin against CCA so the agent might have potential for CCA prevention and therapy.

• BMB Reports
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• v.57 no.5
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• pp.238-243
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• 2024

Bone marrow-derived mesenchymal stem cells (BM-MSCs) can differentiate into endothelial cells in an inflammatory microenvironment. However, the regulatory mechanisms underlying this process are not entirely understood. Here, we found that TIE2 in BM-MSCs was upregulated at the transcriptional level after stimulation with tumor necrosis factor-alpha (TNFα), a major pro-inflammatory cytokine. Additionally, the STAT-binding sequence within the proximal region of TIE2 was necessary for TNFα-induced TIE2 promoter activation. TIE2 and STAT3 knockdown reduced TNFα-induced endothelial tube formation in BM-MSCs. Among the major TNFα-activated MAP kinases (ERK1/2, JNK1/2, and p38 MAPK) in BM-MSCs, only inhibition of the p38 kinase abrogated TNFα-induced TIE2 upregulation by inhibiting the JAK-STAT signaling pathway. These findings suggest that p38 MAP contributes to the endothelial differentiation of BM-MSCs by activating the JAK-STAT-TIE2 signaling axis in the inflammatory microenvironment.

• Biomolecules & Therapeutics
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• v.23 no.3
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• pp.238-244
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• 2015

Macrophage-derived chemokine, C-C motif chemokine 22 (MDC/CCL22), is one of the inflammatory chemokines that controls the movement of monocytes, monocyte-derived dendritic cells, and natural killer cells. Serum and skin MDC/CCL22 levels are elevated in atopic dermatitis, which suggests that the chemokines produced from keratinocytes are responsible for attracting inflammatory lymphocytes to the skin. A major signaling pathway in the interferon-${\gamma}$ (IFN-${\gamma}$)-stimulated inflammation response involves the signal transducers and activators of transcription 1 (STAT1). In the present study, we investigated the anti-inflammatory effect of dieckol and its possible action mechanisms in the category of skin inflammation including atopic dermatitis. Dieckol inhibited MDC/CCL22 production induced by IFN-${\gamma}$ (10 ng/mL) in a dose dependent manner. Dieckol (5 and $10{\mu}M$) suppressed the phosphorylation and the nuclear translocation of STAT1. These results suggest that dieckol exhibits anti-inflammatory effect via the down-regulation of STAT1 activation.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.10
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• pp.5825-5831
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• 2013

Background/Objectives: Maintenance of cellular function in culture is vital for transfer and development following adoptive immunotherapy. Dual properties of IL-21 in activating T cells and reducing activation induced cell death led us to explore the mechanism of action of IL-21 enhanced proliferation and cytotoxic potential of CIK cells. Method: CIK cells cultured from PBMCs of healthy subjects were stimulated with IL-21 and cellular viability and cytotoxicity to K562 cells were measured. To elucidate the mechanism of action of IL-21, mRNA expression of cytotoxic factors was assessed by RT-PCR and protein expression of significantly important cytotoxic factors and cytokine secretion were determined through flow cytometry and ELISA. Western blotting was performed to check the involvement of the JAK/STAT pathway following stimulation. Results: We found that IL-21 did not enhance in vitro proliferation of CIK cells, but did increase the number of cells expressing the CD3+/CD56+ phenotype. Cytotoxic potential was increased with corresponding increase in perforin ($0.9831{\pm}0.1265$ to $0.7592{\pm}0.1457$), granzyme B ($0.4084{\pm}0.1589$ to $0.7319{\pm}0.1639$) and FasL ($0.4015{\pm}0.2842$ to $0.7381{\pm}0.2568$). Interferon gamma and TNF-alpha were noted to increase ($25.8{\pm}6.1ng/L$ to $56.0{\pm}2.3ng/L$; and $5.64{\pm}0.61{\mu}g/L$ to $15.14{\pm}0.93{\mu}g/L$, respectively) while no significant differences were observed in the expression of granzyme A, TNF-alpha and NKG2D, and NKG2D. We further affirmed that IL-21 signals through the STAT-3 and STAT-5b signaling pathway in the CIK cell pool. Conclusion: IL-21 enhances cytotoxic potential of CIK cells through increasing expression of perforin, granzyme B, IFN-gamma and TNF-alpha. The effect is brought about by the activation of STAT-3 and STAT-5b proteins.

• BMB Reports
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• v.55 no.9
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• pp.447-452
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• 2022

Neurogenic differentiation 1 (NeuroD1) is an essential transcription factor for neuronal differentiation, maturation, and survival, and is associated with inflammation in lipopolysaccharide (LPS)-induced glial cells; however, the concrete mechanisms are still ambiguous. Therefore, we investigated whether NeuroD1-targeting miRNAs affect inflammation and neuronal apoptosis, as well as the underlying mechanism. First, we confirmed that miR-30a-5p and miR-153-3p, which target NeuroD1, reduced NeuroD1 expression in microglia and astrocytes. In LPS-induced microglia, miR-30a-5p and miR-153-3p suppressed pro-inflammatory cytokines, reactive oxygen species, the phosphorylation of c-Jun N-terminal kinase, extracellular-signal-regulated kinase (ERK), and p38, and the expression of cyclooxygenase and inducible nitric oxide synthase (iNOS) via the NF-κB pathway. Moreover, miR-30a-5p and miR-153-3p inhibited the expression of NOD-like receptor pyrin domain containing 3 (NLRP3) inflammasomes, NLRP3, cleaved caspase-1, and IL-1β, which are involved in the innate immune response. In LPS-induced astrocytes, miR-30a-5p and miR-153-3p reduced ERK phosphorylation and iNOS expression via the STAT-3 pathway. Notably, miR-30a-5p exerted greater anti-inflammatory effects than miR-153-3p. Together, these results indicate that miR-30a-5p and miR-153-3p inhibit MAPK/NF-κB pathway in microglia as well as ERK/STAT-3 pathway in astrocytes to reduce LPS-induced neuronal apoptosis. This study highlights the importance of NeuroD1 in microglia and astrocytes neuroinflammation and suggests that it can be regulated by miR-30a-5p and miR-153-3p.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3117-3120
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• 2015

Objective: Interferon-${\gamma}$ (IFN-${\gamma}$) and signal transducers and activators of transcription (STATs) each play an important role in carcinogenesis associated with viral infection. Cervical cancer is almost invariably associated with infection by human papillomavirus (HPV), and previous studies suggested that dysregulation of the signal pathway involved in IFN-${\gamma}$ and STATs is associated. Our objective was to evaluate the association of SNPs in STAT2, STAT3, and IFN-${\gamma}$ with cervical cancer susceptibility in Chinese Han women in Hunan province. Materials and Methods: Genomic DNA was extracted from peripheral blood samples of 234 cervical cancer patients and 216 healthy female controls. STAT2 and STAT3 genotyping was performed using polymerase chain reaction-restriction enzyme (PCR-RE) analysis. IFN-${\gamma}$ genotyping was detected by PCR-amplification of specific allele (PASA). Results: For STAT2 rs2066807 polymorphisms, there was no significant difference of genotype distribution (P=0.827) and allele frequencies (P=0.830, OR=1.09, 95% CI: 0.51-2.31) between cases and controls. For STAT3 rs957970 polymorphisms, there was no significant difference of genotype distribution (P=0.455) and allele frequencies (P=0.560, OR=0.92, 95% CI: 0.71-1.20) between cases and controls. For IFN-${\gamma}$ +874A/T polymorphisms, there was no significant difference of genotype distribution (P=0.652) and allele frequencies (P=0.527, OR=1.12, 95% CI: 0.79-1.59) between cases and controls. Conclusion: These results suggest that polymorphisms in STAT2, STAT3 and IFN-${\gamma}$ genes are not likely to be strong predictors of cervical cancer in Han women in southern China.

• Biomolecules & Therapeutics
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• v.26 no.5
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• pp.464-473
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• 2018

Cripto is a small glycosylphosphatidylinositol-anchored signaling protein that can detach from the anchored membrane and stimulate proliferation, migration, differentiation, vascularization, and angiogenesis. In the present study, we demonstrated that Cripto positively affected proliferation and survival of mesenchymal stem cells (MSCs) without affecting multipotency. Cripto also increased expression of phosphorylated janus kinase 2 (p-JAK2), phosphorylated signal transducer and activator of transcription 3 (p-STAT3), 78 kDa glucose-regulated protein (GRP78), c-Myc, and cyclin D1. Notably, treatment with an anti-GRP78 antibody blocked these effects. In addition, pretreatment with STAT3 short interfering RNA (siRNA) inhibited the increase in p-JAK2, c-Myc, cyclin D1, and BCL3 levels caused by Cripto and attenuated the pro-survival action of Cripto on MSCs. We also found that incubation with Cripto protected MSCs from apoptosis caused by hypoxia or $H_2O_2$ exposure, and the level of caspase-3 decreased by the Cripto-induced expression of B-cell lymphoma 3-encoded protein (BCL3). These effects were sensitive to down-regulation of BCL3 expression by BCL3 siRNA. Finally, we showed that Cripto enhanced expression levels of vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF), and hepatocyte growth factor (HGF). In summary, our results demonstrated that Cripto activated a novel biochemical cascade that potentiated MSC proliferation and survival. This cascade relied on phosphorylation of JAK2 and STAT3 and was regulated by GRP78. Our findings may facilitate clinical applications of MSCs, as these cells may benefit from positive effects of Cripto on their survival and biological properties.