• Journal of Physiology & Pathology in Korean Medicine
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• v.26 no.4
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• pp.437-440
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• 2012

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor that regulates various cellular processes such as cell survival, angiogenesis and proliferation. In the present study, we examined that Cryptotanshione(CT), a tanshinone from oriental traditional medicinal herb Danshen (Salvia miltiorrhiza Bunge), had the inhibitory effects on hypoxia-mediated activation of STAT3 in androgen independent human prostate cancer PC-3 cells. CT inhibited the protein expression of hypoxia-inducible factor-1alpha (HIF-$1{\alpha}$) under hypoxic condition. Consistently, CT blocked hypoxia-induced phosphorylation and nuclear accumulation of STAT3. In addition, CT reduced cellular of vascular endothelial growth factor (VEGF), a critical angiogenic factor and a target gene of STAT3 induced under hypoxia. Of note, chromatin immunoprecipitation (ChiP) assay revealed that CT inhibited binding of STAT3 to VEGF promoter. Taken together, our results suggest that CT has anti-angiogenic activity by disturbing the binding STAT3 to the VEGF promoter in PC-3 cells.

• BMB Reports
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• v.53 no.6
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• pp.335-340
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• 2020

Since cancer is the leading cause of death worldwide, there is an urgent need to understand the mechanisms underlying cancer progression and the development of cancer inhibitors. Signal transducer and activator of transcription 3 (STAT3) is a major transcription factor that regulates the proliferation and survival of various cancer cells. Here, dual-specificity phosphatase 3 (DUSP3) was identified as a regulator of STAT3 based on an interaction screening performed using the protein tyrosine phosphatase library. DUSP3 interacted with the C-terminal domain of STAT3 and dephosphorylated p-Y705 of STAT3. In vitro dephosphorylation assay revealed that DUSP3 directly dephosphorylated p-STAT3. The suppressive effects of DUSP3 on STAT3 were evaluated by a decreased STAT3-specific promoter activity, which in turn reduced the expression of the downstream target genes of STAT3. In summary, DUSP3 downregulated the transcriptional activity of STAT3 via dephosphorylation at Y705 and also suppressed the migratory activity of cancer cells. This study demonstrated that DUSP3 inhibits interleukin 6 (IL-6)/STAT3 signaling and is expected to regulate cancer development. Novel functions of DUSP3 discovered in IL-6/STAT3 signaling regulation would help expand the understanding of cancer development mechanisms.

• Korean Journal of Pharmacognosy
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• v.49 no.3
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• pp.225-230
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• 2018

3',4'-Disenecioylkhellactone is one of khellactone-type coumarins isolated from the roots of Peucedanum japonicum Thunb. However, its pharmacological effects are still little understood. In the present study, we investigated the inhibitory effect of 3',4'-disenecioylkhellactone on growth of gastric cancer cells. 3',4'-Disenecioylkhellactone strongly suppressed cell proliferation and induced caspase-mediated apoptosis in AGS human gastric cancer cells. Analysis of phospho-antibody arrays revealed 3',4'-disenecioylkhellactone effectively suppressed signal transducer and activator of transcription 3 (STAT3) tyrosine phosphorylation. 3',4'-Disenecioylkhellactone decreased STAT3 translocation to the nucleus and expression of STAT3 target genes. In addition, we examined the level of STAT3 activation in several gastric cancer cells and found that the inhibition of STAT3 phosphorylation by 3',4'-disenecioylkhellactone was associated with gastric cancer cell proliferation. Taken together, this study provides evidence for the first time that 3',4'-disenecioylkhellactone may be a potential therapeutic agent for the prevention or treatment of gastric cancer.

• 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.2
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• pp.551-560
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• 2014

Colorectal cancer (CRC) is the third most common malignancy and fourth most common cause of cancer mortality worldwide. Untreated chronic inflammation in the intestine ranks among the top three high-risk conditions for colitis-associated colorectal cancer (CAC). Signal Transducer and Activator of Transcription 3 (STAT3) protein is a member of the STAT family of transcription factors often deregulated in CRC. In this review, we try to emphasize the critical role of STAT3 in CAC as well as the crosstalk of STAT3 with inflammatory cytokines, nuclear factor (NF)-${\kappa}B$, PI3K/Akt, Mammalian Target of Rapamycin (mTOR), Notch, $Wnt/{\beta}$-catenin and microRNA (MiR) pathways. STAT3 is considered as a primary drug target to treat CAC in humans and rodents. Also we updated the findings for inhibitors of STAT3 with regard to effects on tumorigenesis. This review will hopefully provide insights on the use of STAT3 as a therapeutic target in CAC.

• Journal of Digestive Cancer Research
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• v.6 no.1
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• pp.6-10
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• 2018

The importance of signal transducer and activator of transcription 3 (STAT3) signaling in gastric carcinogenesis was firmly evaluated in the previous studies. Fully activated STAT3 induces various target genes involving tumor invasion and epithelial-mesenchymal transition (EMT), and mediates interaction between cancer cells and microenvironmental immune cells. Thus, suppression of STAT3 activity is an important issue for inhibition of gastric carcinogenesis and invasion. Unfortunately, data from clinical studies of direct inhibitor targeting STAT3 have been disappointing. SH2-containing protein tyrosine phosphatase 1 (SHP-1) effectively dephosphorylates and inhibits STAT3 activity, which has not been extensively studied gastric cancer research field. However, by summarizing recent data, it is evident that protein and gene expression of SHP-1 are minimal in gastric cancer cells, and induction of SHP-1 effectively downregulates phosphorylated STAT3 and inhibits cellular invasion in gastric cancer cells. Several SHP-1 inducers have been investigated in the experimental studies, including proton pump inhibitor, arsenic trioxide, and other natural compounds. Taken together, we suggest that modulation of SHP-1/STAT3 signaling axis may present a new way for treatment of gastric cancer, and development of effective SHP-1 inducer may be an important task in the future search field of gastric cancer.

• Parasites, Hosts and Diseases
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• v.47 no.2
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• pp.117-124
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• 2009

Toxoplasma gondii provokes rapid and sustained nuclear translocation of the signal transducer and activator of transcription 6 (STAT6) in HeLa cells. We observed activation of STAT6 as early as 2hr after infection with T. gondii by the nuclear translocation of fluorescence expressed from exogenously transfected pDsRed2-STAT6 plasmid and by the detection of phosphotyrosine-STAT6 in Western blot. STAT6 activation occurred only by infection with live tachyzoites but not by co-culture with killed tachyzoites or soluble T. gondii extracts. STAT6 phosphorylation was inhibited by small interfering RNA of STAT6 (siSTAT6). In view of the fact that STAT6 is a central mediator of IL-4 induced gene expression, activation of STAT6 by T. gondii infection resembles that infected host cells has been stimulated by IL-4 treatment. STAT1 was affected to increase the transcription and expression by the treatment of siSTAT6. STAT6 activation was not affected by any excess SOCS's whereas that with IL-4 was inhibited by SOCS-1 and SOCS-3. T. gondii infection induced Eotaxin-3 gene expression which was reduced by $IFN-{\gamma}$. These results demonstrate that T. gondii exploits host STAT6 to take away various harmful reactions by $IFN-{\gamma}$. This shows, for the first time, IL-4-like action by T. gondii infection modulates microbicidal action by $IFN-{\gamma}$ in infected cells.

• The Mathematical Education
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• v.50 no.3
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• pp.383-394
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• 2011

This paper analyzes subjects related to Math/Stat and studies teaching effect on subject development connected Math/Stat in software curriculum. Among many subjects related to the software, this paper shows exemplary applications of Math/Stat in the software curriculum. Thereby this opens potential application fields of Math/Stat. This confirms that Math/Stat is not only an essential subject to improve competitiveness but also a strategic element in the field of software. Therefore, by maximizing the academic outcome through the interdisciplinary combination of software and Math/Stat, it is possible to educate more competitive and skilled professionals.

• BMB Reports
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• v.46 no.1
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• pp.59-64
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• 2013

Signal transducer and activator of transcription 3 (STAT3) and telomerase are considered attractive targets for anticancer therapy. The in vitro anticancer activity of the gold(I) compound auranofin was investigated using MDA-MB 231 human breast cancer cells, in which STAT3 is constitutively active. In cell culture, auranofin inhibited growth in a dose-dependent manner, and N-acetyl-L-cysteine (NAC), a scavenger of reactive oxygen species (ROS), markedly blocked the effect of auranofin. Incorporation of 5-bromo-2'-deoxyuridine into DNA and anchorage-independent cell growth on soft agar were decreased by auranofin treatment. STAT3 phosphorylation and telomerase activity were also attenuated in cells exposed to auranofin, but NAC pretreatment restored STAT3 phosphorylation and telomerase activity in these cells. These findings indicate that auranofin exerts in vitro antitumor effects in MDA-MB 231 cells and its activity involves inhibition of STAT3 and telomerase. Thus, auranofin shows potential as a novel anticancer drug that targets STAT3 and telomerase.

• Journal of dental hygiene science
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• v.19 no.2
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• pp.141-146
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• 2019

Background: Oral cancer has a high incidence worldwide and has been closely associated with smoking, alcohol, and infection by the human papillomavirus. Metastasis is highly important for oral cancer survival. Lysophosphatidic acid (LPA) is a bioactive lipid mediator that promotes various cellular processes, including cell survival, proliferation, metastasis, and invasion. Signal transducer and activator of transcription (STATs) are transcription factors that mediate gene expression. Among the seven types of STATs in mammals, STAT3 is involved in invasion and metastasis of numerous tumors. However, little is known about the role of STAT3 in oral tumor invasion. In the present study, we hypothesized that STAT3 mediates LPA-induced oral cancer invasion. Methods: Immunoblotting was performed to analyze LPA-induced STAT3 activation. 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay was performed to assess the survival rates of YD-10B cells. STAT3 levels in LPA-treated oral tumor cells were evaluated by performing in vitro invasion assay. Results: To the best of our knowledge, this is the first study to demonstrate that LPA enhances STAT3 phosphorylation in oral cancer. In addition, treatment with WP1066, a selective inhibitor of STAT3, at a concentration that does not cause severe reduction in cell viability, significantly attenuated LPA-induced YD-10B cancer cell invasion. Conclusion: The results suggested that LPA induces oral tumor cells with greater invasive potential via STAT3 activation. Our findings provided important insights into the mechanisms underlying mouth neoplasms.