• 대한임상검사과학회지
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• 제55권4호
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• pp.306-313
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• 2023

패혈증은 병원성 감염에 의해 여러 장기에 나타나는 전신성 염증 반응으로, 현재로서는 유망한 치료제가 없다. Signal transducer and activator of transcription 3 (STAT3)은 세포 신호전달 전사 인자로서 항염증 및 염증 반응과 관련된 다양한 세포의 생물학적 과정에서 중요한 역할을 한다. Niclosamide는 FDA에서 승인된 구충제로 STAT3 조절에 관여한다고 알려져 있다. C57BL/6 마우스에 복강 주사로 지질 다당체 (lipopolysaccharide, LPS)를 투여해 패혈증을 유발하였고, Niclosamide를 LPS 주사 2시간 후에 경구 투여하였다. 본 연구에서 Niclosamide가 LPS로 유발된 패혈증 모델의 생존률과 폐 손상을 완화시켰고, 혈청 내 interleukin (IL)-6, 종양괴사인자(tumor necrosis factor-α, TNF-α), IL-1β, AST, ALT, LDH 수치를 유의하게 감소시켰다. 또한 폐 조직 면역 블롯을 통해 PI3K, AKT, NF-κB, STAT3 신호 전달 경로가 Niclosamide에 의해 조절되는 것을 확인하였다. Niclosamide는 LPS를 자극한 RAW 264.7 세포주에서 IL-6, TNF-α, IL-1β와 같은 염증성 사이토카인의 발현을 감소시켰으며, 또한 STAT3의 인산화를 감소시켰다. 본 연구를 통해 Niclosamide에 의한 STAT3 조절이 염증 반응을 억제함으로써 패혈증 모델에 대한 새로운 치료 전략을 제시하였다.

• Biomolecules & Therapeutics
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• 제30권1호
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• pp.72-79
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• 2022

Licochalcone H (LCH) is a phenolic compound synthetically derived from licochalcone C (LCC) that exerts anticancer activity. In this study, we investigated the anticancer activity of LCH in human skin cancer A375 and A431 cells. The 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay was used to evaluate the antiproliferative activity of LCH. Cell cycle distribution and the induction of apoptosis were analyzed by flow cytometry. Western blotting assays were performed to detect the levels of proteins involved in cell cycle progression, apoptosis, and the JAK2/STAT3 signaling pathway. LCH inhibited the growth of cells in dose- and time-dependent manners. The annexin V/propidium iodide double staining assay revealed that LCH induced apoptosis, and the LCH-induced apoptosis was accompanied by cell cycle arrest in the G1 phase. Western blot analysis showed that the phosphorylation of JAK2 and STAT3 was decreased by treatment with LCH. The inhibition of the JAK2/STAT3 signaling pathway by pharmacological inhibitors against JAK2/STAT3 (cryptotanshinone (CTS) and S3I-201) simulated the antiproliferative effect of LCH suggesting that LCH induced apoptosis by modulating JAK2/STAT3 signaling.

• BMB Reports
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• 제46권1호
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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 Ginseng Research
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• 제46권3호
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• pp.418-425
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• 2022

Background: Sorafenib is effective in treating hepatoma, but most patients develop resistance to it. STAT3 signaling has been implicated in sorafenib resistance. Artesunate (ART) and 20(R)-ginsenoside Rg3 (Rg3) have anti-hepatoma effects and can inhibit STAT3 signaling in cancer cells. This study aimed to evaluate the effects of Rg3 in combination with ART (Rg3-plus-ART) in overcoming sorafenib resistance, and to examine the involvement of STAT3 signaling in these effects. Methods: Sorafenib-resistant HepG2 cells (HepG2-SR) were used to evaluate the in vitro anti-hepatoma effects of Rg3-plus-ART. A HepG2-SR hepatoma-bearing BALB/c-nu/nu mouse model was used to assess the in vivo anti-hepatoma effects of Rg3-plus-ART. CCK-8 assays and Annexin V-FITC/PI double staining were used to examine cell proliferation and apoptosis, respectively. Immunoblotting was employed to examine protein levels. ROS generation was examined by measuring DCF-DA fluorescence. Results: Rg3-plus-ART synergistically reduced viability of, and evoked apoptosis in HepG2-SR cells, and suppressed HepG2-SR tumor growth in mice. Mechanistic studies revealed that Rg3-plus-ART inhibited activation/phosphorylation of Src and STAT3 in HepG2-SR cultures and tumors. The combination also decreased the STAT3 nuclear level and induced ROS production in HepG2-SR cultures. Furthermore, overactivation of STAT3 or removal of ROS diminished the anti-proliferative effects of Rg3-plus-ART, and removal of ROS diminished Rg3-plus-ART's inhibitory effects on STAT3 activation in HepG2-SR cells. Conclusions: Rg3-plus-ART overcomes sorafenib resistance in experimental models, and inhibition of Src/STAT3 signaling and modulation of ROS/STAT3 signaling contribute to the underlying mechanisms. This study provides a pharmacological basis for developing Rg3-plus-ART into a novel modality for treating sorafenib-resistant hepatoma.

• Parasites, Hosts and Diseases
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• 제54권1호
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• pp.31-38
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• 2016

Specific gene expressions of host cells by spontaneous STAT6 phosphorylation are major strategy for the survival of intracellular Toxoplasma gondii against parasiticidal events through STAT1 phosphorylation by infection provoked $IFN-{\gamma}$. We determined the effects of small molecules of tyrosine kinase inhibitors (TKIs) on the growth of T. gondii and on the relationship with STAT1 and STAT6 phosphorylation in ARPE-19 cells. We counted the number of T. gondii RH tachyzoites per parasitophorous vacuolar membrane (PVM) after treatment with TKIs at 12-hr intervals for 72 hr. The change of STAT6 phosphorylation was assessed via western blot and immunofluorescence assay. Among the tested TKIs, Afatinib (pan ErbB/EGFR inhibitor, $5{\mu}M$) inhibited 98.0% of the growth of T. gondii, which was comparable to pyrimethamine ($5{\mu}M$) at 96.9% and followed by Erlotinib (ErbB1/EGFR inhibitor, $20{\mu}M$) at 33.8% and Sunitinib (PDGFR or c-Kit inhibitor, $10{\mu}M$) at 21.3%. In the early stage of the infection (2, 4, and 8 hr after T. gondii challenge), Afatinib inhibited the phosphorylation of STAT6 in western blot and immunofluorescence assay. Both JAK1 and JAK3, the upper hierarchical kinases of cytokine signaling, were strongly phosphorylated at 2 hr and then disappeared entirely after 4 hr. Some TKIs, especially the EGFR inhibitors, might play an important role in the inhibition of intracellular replication of T. gondii through the inhibition of the direct phosphorylation of STAT6 by T. gondii.

• Genomics & Informatics
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• 제2권3호
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• pp.126-130
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• 2004

T helper-type 2 cytokines, such as IL-4 and IL-13, may play a central role in allergic diseases. The protein known as signal transducers and activators of transcription 6 (STAT6) is a key transcription factor involved in both IL-4- and -13-mediated biological responses. Two polymorphisms of the STAT 6 gene (exon 1 and G2964A variant) have been found. We investigated whether these STAT6 gene polymorph isms were associated with allergic rhinitis. Blood samples for genetic analysis were obtained from 285 individuals with allergic rhinitis and from 271 healthy subjects without atopic disease. The G2964A variant of the STAT6 gene was genotyped using PCR-RFLP analysis. The GT repeat polymorphism in exon 1 of the STAT6 gene was genotyped by fragment analysis. There was no association between the 2964A variant and GT repeat polymorphism in exon 1 of the STAT6 and allergic rhinitis in a Korean population (both p > 0.05). Our results suggest that a combination of STAT6 gene polymorphisms is not a useful marker for predicting allergic rhinitis.

• Journal of Acupuncture Research
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• 제29권1호
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• pp.37-45
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• 2012

목적 : 최근 NF-${\kappa}B$와 STAT3의 활성억제와 관련된 항암제 연구가 주목받고 있으며, 본 연구는 사독(蛇毒)이 세포자멸사 관련 단백질의 발현 조절을 통하여 세포자멸사를 유도하고, NF-${\kappa}B$와 STAT3의 활성억제를 유도하여 난소암 PA-1 세포의 성장을 억제하는지를 확인하고, 해당 기전을 살펴보고자 하였다. 방법 : 사독을 처리한 후 난소암 PA-1 세포의 세포자멸사의 관찰에는 DAPI, TUNEL staining assay를 시행하였고, 세포자멸사 조절단백질 및 NF-${\kappa}B$, STAT3의 활성 변동 관찰에는 western blot analysis를 시행하였다. 결과 : 1. 사독을 처리한 후 난소암 PA-1 세포에서 세포자멸사가 유도되어 암세포성장이 억제되었다. 2. 사독을 처리한 후 세포자멸사 관련 단백질 중 세포자멸사 촉진 단백질인 cleaved caspase-3, Bax의 발현은 증가되었고, 세포자멸사 억제 단백질인 Bcl-2의 발현은 감소되었다. 3. 사독을 처리한 후 난소암 PA-1 세포의 NF-${\kappa}B$와 STAT3 발현은 감소되었고, 각각의 길항제인 salicylic acid와 stattic 처리 후 NF-${\kappa}B$와 STAT3 발현은 더욱 감소되었다. 결론 : 사독은 난소암 세포의 세포자멸사 유발과, NF-${\kappa}B$와 STAT3의 활성억제를 통해 치료 효율이 높고, 내성이 적은 난소암 치료제의 개발에 도움이 될 것으로 기대된다.

• Parasites, Hosts and Diseases
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• 제52권5호
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• pp.459-469
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• 2014

Entamoeba histolytica is a tissue-invasive protozoan parasite causing dysentery in humans. During infection of colonic tissues, amoebic trophozoites are able to kill host cells via apoptosis or necrosis, both of which trigger IL-8-mediated acute inflammatory responses. However, the signaling pathways involved in host cell death induced by E. histolytica have not yet been fully defined. In this study, we examined whether calpain plays a role in the cleavage of pro-survival transcription factors during cell death of colonic epithelial cells, induced by live E. histolytica trophozoites. Incubation with amoebic trophozoites induced activation of m-calpain in a time- and dose-dependent manner. Moreover, incubation with amoebae resulted in marked degradation of STAT proteins (STAT3 and STAT5) and NF-${\kappa}B$ (p65) in Caco-2 cells. However, $I{\kappa}B$, an inhibitor of NF-${\kappa}B$, was not cleaved in Caco-2 cells following adherence of E. histolytica. Entamoeba-induced cleavage of STAT proteins and NF-${\kappa}B$ was partially inhibited by pretreatment of cells with a cell-permeable calpain inhibitor, calpeptin. In contrast, E. histolytica did not induce cleavage of caspase-3 in Caco-2 cells. Furthermore, pretreatment of Caco-2 cells with a calpain inhibitor, calpeptin (but not the pan-caspase inhibitor, z-VAD-fmk) or m-calpain siRNA partially reduced Entamoeba-induced DNA fragmentation in Caco-2 cells. These results suggest that calpain plays an important role in E. histolytica-induced degradation of NF-${\kappa}B$ and STATs in colonic epithelial cells, which ultimately accelerates cell death.

• Biomolecules & Therapeutics
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• 제19권2호
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• pp.141-148
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• 2011

Osteoclasts are bone-resorbing cells of monocyte/macrophage origin and are culprits of bone destruction associated with osteoporosis, rheumatoid arthritis, and cancer bone metastasis. Recent advances in osteoclast biology revealed central roles of various cytokines in regulating osteoclastogenesis both in vitro and in vivo. However, exact underlying mechanisms including signaling pathways downstream of receptor ligation are still under pursuit. In the present review, the role of Jak/STAT proteins and their regulators will be discussed in connection with osteoclastogenesis, since growing evidence indicates that a number of cytokines and growth factors utilizing Jak/STAT signaling pathways affect osteoclastogenesis. A better understanding on the role of Jak/STAT pathways in osteoclast differentiation will not only strengthen our knowledge on osteoclast biology but also provide invaluable insights into the development of anti-resorptive strategies for treating bone-lytic diseases.

• 한국작물학회:학술대회논문집
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• 한국작물학회 1987년도 추계 학술대회지
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• pp.14-15
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• 1987