Signal Transducer And Activator Of Transcription 3 Signaling Pathway Research Articles

Impact of STAT-signaling pathway on cancer-associated fibroblasts in colorectal cancer and its role in immunosuppression

Colorectal cancer (CRC) remains one of the most commonly diagnosed and deadliest types of cancer worldwide. CRC displays a desmoplastic reaction (DR) that has been inversely associated with poor prognosis; less DR is associated with a better prognosis. This reaction generates excessive connective tissue, in which cancer-associated fibroblasts (CAFs) are critical cells that form a part of the tumor microenvironment. CAFs are directly involved in tumorigenesis through different mechanisms. However, their role in immunosuppression in CRC is not well understood, and the precise role of signal transducers and activators of transcription (STATs) in mediating CAF activity in CRC remains unclear. Among the myriad chemical and biological factors that affect CAFs, different cytokines mediate their function by activating STAT signaling pathways. Thus, the harmful effects of CAFs in favoring tumor growth and invasion may be modulated using STAT inhibitors. Here, we analyze the impact of different STATs on CAF activity and their immunoregulatory role.

PLAU promotes cell proliferation and migration of head and neck cancer via STAT3 signaling pathway

It was reported that within the head and neck cancer (HNC) cell line CAL21 the epithelial-mesenchymal transition (EMT) and cell proliferation were promoted by Urokinase-Type Plasminogen Activator (PLAU) proteinase through TNFRSF12A. Additionally, in this paper HNC cell lines refer to Fadu and Tu686. A novel PLAU-STAT3 axis was found to be involved in HNC cell line proliferation and metastasis. PLAU expression in HNC samples was upregulated, besides, the elevated expression of PLAU was linked to the lower overall survival (OS) and disease-free survival (DFS). Ectopic PLAU expression promoted cell proliferation and migration, while PLAU knockdown exhibited opposite results. RNA-seq data identified the JAK-STAT signaling pathway, confirmed by western blotting. A recovery assay using S3I-201, a selective inhibitor of signal transducer and activator of transcription 3 (STAT3), indicated that PLAU promoted HNC cell line progression via STAT3 signaling in vitro. The oncogenic role of PLAU in HNC tumor growth in vivo was confirmed using xenograft models. In summary, we identified the tumorigenic PLAU function in the HNC progress. PLAU may represent a potential prognostic biomarker of HNC and the PLAU-STAT3 pathway might be considered a therapeutic target of HNC.

STAT protein family and cardiovascular diseases: overview of pathological mechanisms and therapeutic implications.

Globally, cardiovascular diseases (CVD) are one of the significant causes of death and are considered a major concern of human society. One of the most crucial objectives of scientists is to reveal the mechanisms associated with the pathogenesis of CVD, which has attracted the attention of many scientists. Accumulating evidence showed that the signal transducer and activator of transcription (STAT) signaling pathway is involved in various physiological and pathological processes. According to research on the molecular mechanisms of CVDs, the STAT family of proteins is one of the most crucial players in these diseases. Numerous studies have demonstrated the undeniable relevance of STAT family proteins in various CVDs. The aim of this review is to shed light on how STAT signaling pathways are related to CVD and the potential for using these signaling pathways as therapeutic targets.

Inhibition of PRMT1 Suppresses the Growth of U87MG-Derived Glioblastoma Stem Cells by Blocking the STAT3 Signaling Pathway.

Glioblastoma stem cells (GSCs) play a pivotal role in the initiation, progression, resistance to treatment, and relapse of glioblastoma multiforme (GBM). Thus, identifying potential therapeutic targets and drugs that interfere with the growth of GSCs may contribute to improved treatment outcomes for GBM. In this study, we first demonstrated the functional role of protein arginine methyltransferase 1 (PRMT1) in GSC growth. Furamidine, a PRMT1 inhibitor, effectively inhibited the proliferation and tumorsphere formation of U87MG-derived GSCs by inducing cell cycle arrest at the G0/G1 phase and promoting the intrinsic apoptotic pathway. Moreover, furamidine potently suppressed the in vivo tumor growth of U87MG GSCs in a chick embryo chorioallantoic membrane model. In particular, the inhibitory effect of furamidine on U87MG GSC growth was associated with the downregulation of signal transducer and activator of transcription 3 (STAT3) and key GSC markers, including CD133, Sox2, Oct4, Nanog, aldehyde dehydrogenase 1, and integrin α6. Our results also showed that the knockdown of PRMT1 by small interfering RNA significantly inhibited the proliferation of U87MG GSCs in vitro and in vivo through a molecular mechanism similar to furamidine. In addition, combined treatment with furamidine and berbamine, a calcium/calmodulin-dependent protein kinase II gamma (CaMKIIγ) inhibitor, inhibited the growth of U87MG GSCs more strongly than single-compound treatment. The increased antiproliferative effect of combining the two compounds resulted from a stronger downregulation of STAT3-mediated downstream GBM stemness regulators through dual PRMT1 and CaMKIIγ function blockade. In conclusion, these findings suggest that PRMT1 and its inhibitor, furamidine, are potential novel therapeutic targets and drug candidates for effectively suppressing GSC growth.

Ursolic acid alleviates cancer cachexia by inhibiting STAT3 signaling pathways in C2C12 myotube and CT26 tumor-bearing mouse model

Cancer cachexia, a multi-organ disorder resulting from tumor and immune system interactions, prominently features muscle wasting and affects the survival of patients with cancer. Ursolic acid (UA) is known for its antioxidant, anti-inflammatory, and anticancer properties. However, its impact on cancer cachexia remains unexplored. This study aimed to assess the efficacy of UA in addressing muscle atrophy and organ dysfunction in cancer cachexia and reveal the mechanisms involved. UA dose-dependently ameliorated C2C12 myotube atrophy. Mechanistically, it inhibited the expression of muscle-specific RING finger containing protein 1 (MURF1) and the phosphorylation of signal transducer and activator of transcription 3 (STAT3), and upregulated the mRNA or protein levels of myogenic differentiation antigen and myogenin in cultured C2C12 myotubes treated with conditioned medium. In vivo, UA protected CT26 tumor-bearing mice against loss of body weight, as well as increased skeletal muscle and epididymal fat without affecting tumor growth. Additionally, UA increased food intake in CT26 tumor-bearing mice. The mRNA expression of tumor necrosis-α and interleukin 6 was significantly downregulated in the intestine, gastrocnemius, and heart tissues following 38 d UA administration. UA treatment reversed the levels of myocardial function indicators, including creatine kinase, creatine kinase-MB, lactate dehydrogenase, car-dial troponin T, and glutathione. Finally, UA treatment significantly inhibited the expression of MURF1, the phosphorylation of nuclear factor kappa-B p65, and STAT3 in the gastrocnemius muscle and heart tissues of cachexic mice. Our findings suggest that UA is a promising natural compound for developing dietary supplements for cancer cachexia therapy owing to its anti-catabolic effects.

Oncostatin M Reduces Pathological Neovascularization in the Retina Through Müller Cell Activation.

Continuous vision loss due to vasoproliferative eye disease still represents an unsolved issue despite anti-vascular endothelial growth factor (VEGF) therapy. The impact of signal transducer and activator of transcription 3 (STAT3) signaling on retinal angiogenesis and its potential use as a therapeutic target remain controversial. In vitro, oncostatin M (OSM), as a strong STAT3 activator, possesses robust proangiogenic activity. This study investigated to what extent the proangiogenic effects of OSM translate to the in vivo setting of vasoproliferative eye disease. The in vitro effect of OSM on endothelial cells was investigated in the spheroid sprouting assay and through RNA sequencing. The mouse model for oxygen-induced retinopathy (OIR) was used to evaluate the impact of OSM in vivo. Signaling patterns were measured by western blot and retinal cryosections. Primary Müller cell cultures were used to evaluate the effect of OSM on the Müller cell secretome. Murine retinal vascular endothelial cells were isolated from OIR retinas using fluorescence-activated cell sorting (FACS) and were used for RNA sequencing. Although OSM induced pro-angiogenic responses in vitro, in the OIR model intravitreal injection of OSM reduced retinal neovascularization by 65.2% and vaso-obliteration by 45.5% in Müller cells. Injecting OSM into the vitreous activated the STAT3 signaling pathway in multiple retinal cell types, including Müller cells. In vitro, OSM treatment increased CXCL10 secretion. RNA sequencing of sorted vascular endothelial cells at OIR P17 following OSM treatment indicated downregulation of angiogenesis- and mitosis-associated genes. In vivo, OSM reveals a beneficial angiomodulatory effect by activating Müller cells and changing their secretome. The data highlight contradictions between cytokine-induced effects in vitro and in vivo depending on the cell types mediating the effect.

Research progress on the STAT signaling pathway in pregnancy and pregnancy-associated disorders.

Signal transducer and activator of transcription (STAT) proteins, pivotal regulators of signaling cascades, undergo activation in response to the stimulation of cytokines and growth factors, and participate in biological processes, including inflammation, immune responses, cell proliferation, and differentiation. During the process of pregnancy, STAT signaling is involved in regulating embryonic implantation, endometrial decidualization, and establishing and maintaining maternal-fetal immune tolerance. Increasing evidence suggests that aberrant STAT signaling contributes to the occurrence and development of pregnancy disorders, including repeated implantation failure (RIF), preeclampsia (PE), recurrent spontaneous abortion (RSA), preterm birth (PTB) and gestational diabetes mellitus (GDM). Elucidating the molecular mechanisms of the STAT signaling pathway holds promise for further understanding the establishment and maintenance of normal pregnancy, and thereby providing potent targets and strategic avenues for the prevention and management of ailments associated with pregnancy. In this review, we summarized the roles of the STAT signaling pathway and its related regulatory function in embryonic implantation, endometrial decidualization, and maternal-fetal immune tolerance. In conclusion, in-depth research on the mechanism of the STAT signaling pathway not only enhances our understanding of normal pregnancy processes but also offers STAT-based therapeutic approaches to protect women from the burden of pregnancy-related disorders.

Hepatic vagotomy blunts liver regeneration after hepatectomy by downregulating the expression of interleukin-22.

Rapid regeneration of the residual liver is one of the key determinants of successful partial hepatectomy (PHx). At present, there is a lack of recognized safe, effective, and stable drugs to promote liver regeneration. It has been reported that vagus nerve signaling is beneficial to liver regeneration, but the potential mechanism at play here is not fully understood. To explore the effect and mechanism of hepatic vagus nerve in liver regeneration after PHx. A PHx plus hepatic vagotomy (Hv) mouse model was established. The effect of Hv on liver regeneration after PHx was determined by comparing the liver regeneration levels of the PHx-Hv group and the PHx-sham group mice. In order to further investigate the role of interleukin (IL)-22 in liver regeneration inhibition mediated by Hv, the levels of IL-22 in the PHx-Hv group and the PHx-sham group was measured. The degree of liver injury in the PHx-Hv group and the PHx-sham group mice was detected to determine the role of the hepatic vagus nerve in liver injury after PHx. Compared to control-group mice, Hv mice showed severe liver injury and weakened liver regeneration after PHx. Further research found that Hv downregulates the production of IL-22 induced by PHx and blocks activation of the signal transducer and activator of transcription 3 (STAT3) pathway then reduces the expression of various mitogenic and anti-apoptotic proteins after PHx. Exogenous IL-22 reverses the inhibition of liver regeneration induced by Hv and alleviates liver injury, while treatment with IL-22 binding protein (an inhibitor of IL-22 signaling) reduce the concentration of IL-22 induced by PHx, inhibits the activation of the STAT3 signaling pathway in the liver after PHx, thereby hindering liver regeneration and aggravating liver injury in PHx-sham mice. Hv attenuates liver regeneration after hepatectomy, and the mechanism may be related to the fact that Hv downregulates the production of IL-22, then blocks activation of the STAT3 pathway.

LncRNA-CCAT5-mediated crosstalk between Wnt/β-Catenin and STAT3 signaling suggests novel therapeutic approaches for metastatic gastric cancer with high Wnt activity.

Although the constitutively activated Wnt/β-catenin signaling pathway plays vital roles in gastric cancer (GC) progression, few Wnt inhibitors are approved for clinical use. Additionally, the clinical significance of long non-coding RNAs (lncRNAs) in GC intraperitoneal dissemination (IPD) remains elusive. Here, we investigated the function and therapeutic potential of Wnt-transactivated lncRNA, colon cancer-associated transcript 5 (CCAT5), in GC metastasis. LncRNA-sequencing assay was performed to document abundance changes of lncRNAs induced by Wnt family member 3A (Wnt3a) and degradation-resistant β-catenin (S33Y mutated) in ascites-derived GC cells with low Wnt activity. Luciferase reporter, Chromatin immunoprecipitation (ChIP)-re-ChIP assays were performed to determine how CCAT5 was transcribed. The clinical significance of CCAT5 was examined in 2 cohorts of GC patients. The biological function of CCAT5 was investigated through gain- and loss-of-function studies. The molecular mechanism was explored through RNA-sequencing, mass spectrometry, and CRISPR/Cas9-knocknout system. The therapeutic potential of CCAT5 was examined through RNAi-based cell xenograft model and patient-derived xenograft (PDX) model of IPD. We identified a novel Wnt-regulated lncRNA, CCAT5, which was transactivated by the β-catenin/transcription factor 3 (TCF3) complex. CCAT5 was significantly upregulated in GC and predicted poor prognosis. Functional studies confirmed the promotive role of CCAT5 in GC growth and metastasis. Mechanistically, CCAT5 bound to the C-end domain of signal transducer and activator of transcription 3 (STAT3) and blocks Src homology 2 domain-containing protein tyrosine phosphatase 1 (SHP-1)-mediated STAT3Y705 dephosphorylation, leading to STAT3 nuclear entry and transactivation, thus accelerating GC progression. Furthermore, we demonstrated that both Wnt3a and β-catenin acted as activator of STAT3 signaling pathway, and the interplay between CCAT5 and STAT3 was functionally essential for Wnt-drived STAT3 signaling and tumor evolution. Finally, we revealed in vivo si-CCAT5 selectively attenuated growth and metastasis of Wnthigh GC, but not Wntlow GC. The combination of si-CCAT5 and oxaliplatin displayed obvious synergistic therapeutic effects on Wnthigh PDX mice. We identified a novel Wnt-transactivated lncRNA, CCAT5. Our study revealed a mechanism of STAT3 signaling regulation via canonical Wnt signaling and the functional significance of CCAT5 as critical mediator. We provided conceptual advance that lncRNAs serve as therapeutic targets reversing GC progression.

Electroacupuncture improves cognitive dysfunction in rats with Alzheimer's disease by regulating microglial cells.

To observe the effect of electroacupuncture (EA) on microglia (MG), Janus kinase-2 (JAK2) and signal transducer and activator of transcription-3 (STAT3) in hippocampal CA1 region of Alzheimer's di-sease (AD) rats, so as to explore its mechanisms in the treatment of AD. Thirty-six male SD rats were randomly divided into sham operation, model and EA groups, with 12 rats in each group. The AD rat model was established by intraperitoneal injection of D-galactose combined with intrahippocampal injection of aggregated Aβ25-35. The rats in the EA group were given EA (2 Hz/20 Hz, 2 mA) at "Baihui"(GV20) and"Shenting"(GV24) for 30 min, once daily, 6 days a week for 4 weeks. Morris water maze test was used to detect the learning and memory ability and spatial exploration ability of rats. HE staining was used to observe the pathological changes of hippocampus. The ultrastructure of hippocampal neurons was observed by transmission electron microscopy. The positive expression of MG marker io-nized calcium adaptor protein (Iba-1) in hippocampus was observed by immunofluorescence staining. The expression levels of serum inflammatory factor interferon-γ (IFN-γ) and transforming growth factor beta 1 (TGF-β1) were detected by ELISA. The mRNA expression levels of JAK2, STAT3, inducible nitric oxide synthase (iNOS) and arginase-1 (Arg-1) in hippocampal CA1 region were detected by real-time quantitative PCR. The protein and phosphorylation levels of JAK2 and STAT3 in hippocampal CA1 region were detected by Western blot. Compared with the sham operation group, the escape latency of the model group was significantly prolonged (P<0.01), and the number of crossing the original platform was significantly reduced (P<0.01), the positive expression of Iba-1 in CA1 region, the content of serum IFN-γ, the relative mRNA expressions of JAK2, STAT3 and iNOS, and the protein and phosphorylation levels of JAK2 and STAT3 were significantly increased (P<0.01), while the content of serum TGF-β1 and the relative expression of Arg-1 mRNA were significantly decreased (P<0.01). Compared with the model group, the escape latency of rats in the EA group was significantly shortened (P<0.01), the number of crossing the original platform was significantly increased (P<0.01), the positive expression of Iba1, the content of serum IFN-γ, the mRNA expressions of JAK2, STAT3 and iNOS, and the protein and phosphorylation levels of JAK2 and STAT3 were significantly decreased (P<0.05, P<0.01), while the content of serum TGF-β1 and the expression of Arg-1 mRNA were significantly increased (P<0.01). Moreover, pathological and ultrastructural observation showed a reduction in the number of hippocampal neurons, changement of nuclear morphology, dilation of intercellular space, and decreased number of mitochondria in the model group；these situations were relatively milder in the EA group. EA can improve the learning and memory function of AD rats, which may be associated with its functions in decreasing MG activities, and inhibiting the JAK2 / STAT3 signaling pathway in the hippocampus.

Nuciferine Inhibits Oral Squamous Cell Carcinoma Partially through Suppressing the STAT3 Signaling Pathway.

Oral squamous cell carcinoma (OSCC) poses a significant obstacle to the worldwide healthcare system. Discovering efficient and non-toxic medications is crucial for managing OSCC. Nuciferine, an alkaloid with an aromatic ring, is present in the leaves of Nelumbo nucifera. It has been proven to play a role in multiple biological processes, including the inhibition of inflammation, regulation of the immune system, formation of osteoclasts, and suppression of tumors. Despite the demonstrated inhibitory effects of nuciferine on different types of cancer, there is still a need for further investigation into the therapeutic effects and potential mechanisms of nuciferine in OSCC. Through a series of in vitro experiments, it was confirmed that nuciferine hindered the growth, movement, and infiltration, while enhancing the programmed cell death of OSCC cells. Furthermore, the administration of nuciferine significantly suppressed the signal transducer and activator of transcription 3 (STAT3) signaling pathway in comparison to other signaling pathways. Moreover, the activation of the STAT3 signaling pathway by colivelin resulted in the reversal of nuciferine-suppressed OSCC behaviors. In vivo, we also showed the anti-OSCC impact of nuciferine using the cell-based xenograft (CDX) model in nude mice. Nonetheless, colivelin diminished the tumor-inhibiting impact of nuciferine, suggesting that nuciferine might partially impede the advancement of OSCC by suppressing the STAT3 signaling pathway. Overall, this research could offer a fresh alternative for the pharmaceutical management of OSCC.

(−)-Guaiol inhibit epithelial-mesenchymal transition in lung cancer via suppressing M2 macrophages mediated STAT3 signaling pathway

In the context of cancer expansion, epithelial-mesenchymal transition (EMT) plays an essential role in driving invasion and metastasis potential of cancer cells. Tumor-associated macrophages (TAMs)-derived factors involved in the initiation and progression of EMT. We assess the role of M2 macrophage in suppressing lung tumors of a natural compound (−)-Guaiol by using macrophage depleted model. Bone marrow-derived monocytes (BMDMs) were extracted and induced to M2-like phenotype in vitro. The co-culture of M2 macrophage and lung cancer cells was established to observe that inhibition of lung tumor growth by (−)-Guaiol requires presence of macrophages. This suppressed effect of (−)-Guaiol was alleviated when mice macrophage was depleted. The expression of M2-like macrophages was strongly reduced by (−)-Guaiol treated mice, but not the changes of M1-like macrophages. In vitro studies, we demonstrated that (−)-Guaiol suppressed M2 polarization of BMDMs, as well as migration, invasion, and EMT of lung cancer cells in co-culture. M2 macrophage-derived interleukin 10 (IL-10) was investigated as a critical signaling molecule between M2 macrophage and lung cancer cells. We have also verified that the mechanism of (−)-Guaiol inhibiting the EMT process of lung cancer is related to the activation of IL-10-mediated signal transducer and activator of transcription 3 (STAT3). These results suggested that the suppressive effect role of (−)-Guaiol in M2 macrophage promoting EMT of lung cancer, which was associated with inhibition of IL-10 mediated STAT3 signaling pathway.

Inhibition of PRMT1 alleviates sepsis-induced acute kidneyinjury in mice by blocking the TGF-β1 and IL-6 trans-signaling pathways.

Sepsis-induced acute kidney injury (SI-AKI) causes renal dysfunction and has a high mortality rate. Protein arginine methyltransferase-1 (PRMT1) is a key regulator of renal insufficiency. In the present study, we explored the potential involvement of PRMT1 in SI-AKI. A murine model of SI-AKI was induced by cecal ligation and perforation. The expression and localization of PRMT1 and molecules involved in the transforming growth factor (TGF)-β1/Smad3 and interleukin (IL)-6/signal transducer and activator of transcription 3 (STAT3) signaling pathways were detected in mouse kidney tissues by western blot analysis, immunofluorescence, and immunohistochemistry. The association of PRMT1 with downstream molecules of the TGF-β1/Smad3 and IL-6/STAT3 signaling pathways was further verified in vitro in mouse renal tubular epithelial cells. Cecal ligation and perforation caused epithelial-mesenchymal transition, apoptosis, and inflammation in renal tissues, and this was alleviated by inhibition of PRMT1. Inhibition of PRMT1 in SI-AKI mice decreased the expression of TGF-β1 and phosphorylation of Smad3 in the renal cortex, and downregulated the expression of soluble IL-6R and phosphorylation of STAT3 in the medulla. Knockdown of PRMT1 in mouse renal tubular epithelial cells restricted the expression of Cox-2, E-cadherin, Pro-caspase3, and phosphorylated Smad3 (involved in the TGF-β1-mediated signaling pathway), and also blocked IL-6/soluble IL-6R, inducing the expression of Cox-2 and phosphorylated-STAT3. In conclusion, our findings suggest that inhibition of PRMT1 mitigates SI-AKI by inactivating the TGF-β1/Smad3 pathway in the cortex and the IL-6/STAT3 pathway in the medulla. Our findings may aid in the identification of potential therapeutic target molecules for SI-AKI.

A novel imidazo[1,2-a]pyridine derivative and its co-administration with curcumin exert anti-inflammatory effects by modulating the STAT3/NF-κB/iNOS/COX-2 signaling pathway in breast and ovarian cancer cell lines.

Imidazo[1,2-a]pyridine derivatives with diverse pharmacological properties and curcumin, as a potential natural anti-inflammatory compound, are promising compounds for cancer treatment. This study aimed to synthesize a novel imidazo[1,2-a]pyridine derivative, (MIA), and evaluate its anti-inflammatory activity and effects on nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 3 (STAT3) pathways, and their target genes, alone and in combination with curcumin, in MDA-MB-231 and SKOV3 cell lines. We evaluated the interaction between imidazo[1,2-a]pyridine ligand, curcumin, and NF-κB p50 protein, using molecular docking studies. MTT assay was used to investigate the impacts of compounds on cell viability. To evaluate the NF-κB DNA binding activity and the level of inflammatory cytokines in response to the compounds, ELISA-based methods were performed. In addition, quantitative polymerase chain reaction (qPCR) and western blotting were carried out to analyze the expression of genes and investigate NF-κB and STAT3 signaling pathways. Molecular docking studies showed that MIA docked into the NF-κB p50 subunit, and curcumin augmented its binding. The MTT assay results indicated that MIA and its combination with curcumin reduced cell viability. According to the results of the ELISA-based methods, MIA lowered the levels of inflammatory cytokines and suppressed NF-κB activity. In addition, real-time PCR and Griess test results showed that the expression of cyclooxygenase-2 (COX-2) and inducible NO synthase (iNOS) genes, and nitrite production were reduced by MIA. Furthermore, the western blotting analysis demonstrated that MIA increased the expression of inhibitory κB (IκBα) and B-cell lymphoma 2 (Bcl-2)-associated X proteins (BAX), and suppressed the STAT3 phosphorylation, and Bcl-2 expression. Our findings revealed that curcumin had a potentiating role and enhanced all the anti-inflammatory effects of MIA. This study indicated that the anti-inflammatory activity of MIA is exerted by suppressing the NF-κB and STAT3 signaling pathways in MDA-MB-231 and SKOV3 cancer cell lines.

FTO promotes proliferation and migration of bladder cancer via enhancing stability of STAT3 mRNA in an m6A-dependent manner

ABSTRACT N6-Methyladenosine (m6A) plays a key role in the occurrence and development of various cancers. Fat mass and obesity‐associated protein (FTO) was is involved in multiple cancers owing to its demethylase activity, and the molecular mechanism underlying FTO-promoted bladder cancer proliferation and migration via the regulation of RNA stability requires further investigation. In the present study, FTO was upregulated in bladder cancer and related to poor prognosis. Gain- and loss-of-function experiments showed that the upregulation of FTO promoted bladder cancer proliferation and migration. Mechanistic studies showed that FTO enhanced the stability of signal transducer and activator of transcription 3 (STAT3) mRNA in an m6A-dependent manner, thereby increasing STAT3 expression, which subsequently promoted P-STAT3 expression and activated STAT3 signalling pathway. Overall, this study revealed that the critical role of FTO in the progression of bladder cancer and could provide a novel avenue to regulate oncogene STAT3.

The Role of STAT3 Signaling Pathway Activation in Subconjunctival Scar Formation after Glaucoma Filtration Surgery.

Scar formation resulting from overly active wound healing is a critical factor in the success rate of glaucoma filtration surgery (GFS). IL-6 and TGF-β have been implicated in the pathogenesis of fibrogenesis. In addition, the signal transducer and activator of transcription 3 (STAT3) can be activated by numerous cytokines and growth factors, including IL-6 and TGF-β1. Thus, STAT3 activation may integrate common profibrotic pathways to promote fibrosis. In this study, an increase in p-STAT3 was observed in activated HTFs. Inhibiting STAT3 in cultured HTFs by pharmacological inactivation reversed the fibrotic responses, such as fibroblast migration, the differentiation of resting fibroblasts into myofibroblasts and the deposition of ECM, mediated by IL-6 and TGF-β1. Moreover, the expression of suppressor of cytokine signaling 3 (SOCS3) was decreased in HTFs cultured with IL-6 and TGF-β1, and SOCS3 overexpression rescued ECM deposition, α-SMA expression and migration in IL-6- and TGF-β1-stimulated HTFs by inactivating STAT3. Finally, S3I-201 treatment inhibited profibrotic gene expression and subconjunctival fibrosis in a rat model of GFS. In conclusion, our data suggests that STAT3 plays a central role in fibrosis induced by different profibrotic pathways and that STAT3 is a potential target for antifibrotic therapies following GFS.

Curcumin potentiates the anti-inflammatory effects of Tehranolide by modulating the STAT3/NF-κB signaling pathway in breast and ovarian cancer cell lines.

Studies have demonstrated thatnatural products, such as curcumin and artemisinin,possess anti-inflammatory effects, which can be beneficial for cancer treatment.Tehranolide, as a novel natural product, has a wide range of biological activities, including anti-cancer effects. However,many properties of Tehranolide, like its anti-inflammatory activity and its combination with curcumin, have not been investigated yet. This investigation examined the anti-inflammatory activity of Tehranolide, either alone or in combination with curcumin, via modulating the NF-κB (nuclear factor kappa-light-chain-enhancer of activated B cells) and STAT3 (signal transducer and activator of transcription 3) signaling pathways in MDA-MB-231 and SKOV3, breast and ovarian cancer cell lines. ELISA-based methods were employed to measure the pro-inflammatory cytokine levels and the NF-κB activity in lipopolysaccharide (LPS)-induced cells. The real-time PCR experiment and Griess test were performed to evaluate inducible nitric oxide synthase (iNOS) gene expression and nitrite levels, respectively. The STAT3 and NF-κB signaling pathways were investigated by Western blotting analysis. Tehranolide's anti-cancer activity was also assessed in a mouse model of breast cancer using the TUNEL (terminal deoxynucleotidyl transferase nick-end labeling) assay. Tehranolide diminished levels of pro-inflammatory cytokines in cancer cells. Additionally, it suppressed NF-κB DNA binding and STAT3 phosphorylation, reducing iNOS gene expression and nitrite production. Moreover, Western blotting showed that Tehranolide enhanced the inhibitory κB (IκBα) and Bcl-2 (B-cell lymphoma 2)-associated X (BAX) expression, and downregulated the expression of Bcl-2 proteins. Furthermore, the TUNEL assay demonstrated that Tehranolide induced apoptosis in a breast cancer mouse model. Curcumin potentiated all the anti-inflammatory effects of Tehranolide. This investigation indicated for the first time that Tehranolide, either alone or in combination with curcumin, exerted its anti-inflammatory effects by suppressing NF-κB and STAT3 signaling pathways in SKOV3 and MDA-MB-231 cells.

Mechanisms of Si-Wu Decoction in the treatment of ulcerative colitis revealed by network pharmacology and experimental verification

Ethnopharmacological relevanceSi-Wu Decoction (SWD) is a traditional Chinese medicine decoction. SWD is commonly used to treat blood deficiency syndrome. It is also used to treat some ulcerative colitis (UC) patients now, but the mechanism of action remains unclear. Aim of the studyThis study explored the efficacy and mechanism of action of SWD in treating UC based on network pharmacology and related experimental validation. Materials and MethodsSeveral databases were used to screen SWD for major active ingredients, targets of the ingredients, and UC disease genes. Cytoscape 3.8.2 software was used for topological analysis to construct the drug-compound-disease gene-target relationship network. The String database platform was used to construct the target protein interaction network. The DAVID (Database for Annotation, Visualization and Integrated Discovery) database was used to perform the GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analysis for the key targets. DSS (Dextran Sulfate Sodium)-induced UC mouse model was used to evaluate the in-vivo activity of SWD. Western Blot analysis and quantitative polymerase chain reaction were performed to verify the targets in the related pathways. ResultsNetwork pharmacology revealed that the SWD targeted pathway network involved 12 core targets and 15 major pathways. SWD may play a part by targeting key targets such as nuclear factor-kappaB (NF-κB), Janus kinase (JAK)-signal transducer and activator of transcription 3 (STAT3) pathway, and several mitogenic pathways. We showed that SWD largely restored the colorectal structure in UC model mice. Compared to the model group, the SWD group showed reduced infiltration of inflammatory cells. SWD significantly decreased the mRNA levels of IL-6 (Interleukin-6), TNF-α (Tumor necrosis factor-alpha), IL-1b (Interleukin-1beta) and other pro-inflammatory factors. Western Blot results showed that SWD concentration-dependently inhibited STAT3 and NF-κB activation in DSS-treated colon tissue. ConclusionOur findings suggest that SWD treats UC by inhibiting STAT3 and NF-κB signaling pathways, reducing the expression of inflammatory cytokines, and improving epithelial repair in experimental colitis, thus shedding light on the mechanisms by which SWD exerts its effects on UC.

Renoprotective Effect of TP0472993, a Novel and Selective 20-Hydroxyeicosatetraenoic Acid Synthesis Inhibitor, in Mouse Models of Renal Fibrosis.

Kidney fibrosis is considered the essential pathophysiological process for the progression of chronic kidney disease (CKD) toward renal failure. 20-Hydroxyeicosatetraenoic acid (20-HETE) has crucial roles in modulating the vascular response in the kidney and the progression of albuminuria. However, the roles of 20-HETE in kidney fibrosis are largely unexplored. In the current research, we hypothesized that if 20-HETE has important roles in the progression of kidney fibrosis, 20-HETE synthesis inhibitors might be effective against kidney fibrosis. To verify our hypothesis, this study investigated the effect of a novel and selective 20-HETE synthesis inhibitor, TP0472993, on the development of kidney fibrosis after folic acid- and obstructive-induced nephropathy in mice. Chronic treatment with TP0472993 at doses of 0.3 and 3 mg/kg twice a day attenuated the degree of kidney fibrosis in the folic acid nephropathy and the unilateral ureteral obstruction (UUO) mice, as demonstrated by reductions in Masson's trichrome staining and the renal collagen content. In addition, TP0472993 reduced renal inflammation, as demonstrated by markedly reducing interleukin-1β (IL-1β) and tumor necrosis factor alpha (TNF-α) levels in the renal tissue. Chronic treatment with TP0472993 also reduced the activity of extracellular signal-regulated kinase 1/2 (ERK1/2) and signal transducer and activator of transcription 3 (STAT3) in the kidney of UUO mice. Our observations indicate that inhibition of 20-HETE production with TP0472993 suppresses the kidney fibrosis progression via a reduction in the ERK1/2 and STAT3 signaling pathway, suggesting that 20-HETE synthesis inhibitors might be a novel treatment option against CKD. SIGNIFICANCE STATEMENT: In this study, we demonstrate that the pharmacological blockade of 20-hydroxyeicosatetraenoic acid (20-HETE) synthesis using TP0472993 suppresses the progression of kidney fibrosis after folic acid- and obstructive-induced nephropathy in mice, indicating that 20-HETE might have key roles in the pathogenesis of kidney fibrosis. TP0472993 has the potential to be a novel therapeutic approach against chronic kidney disease.

β-defensin-1 regulates influenza virus infection in human bronchial epithelial cells through the STAT3 signaling Pathway

Abstract To develop intervention strategies it is necessary to understand the host response to influenza A virus (IAV) infection. The primary barriers for invading respiratory pathogens are the airway epithelial cells of the respiratory tract and several antimicrobial peptides are produced by these cells. The antimicrobial peptide, β-defensin-1, has antiviral activity against both enveloped and non-enveloped viruses. Significant downregulation of β-defensin-1 gene (DEFB1) expression was observed when human bronchial epithelial cells (HBEpCs) were exposed to IAV. HBEpCs overexpressing DEFB1caused a significant reduction in IAV, that was confirmed by IAV matrix gene analysis, plaque assay, and confocal microscopy. DEFB1expression after transfection with two micro RNAs (miRNAs), hsa-miR-186-5p and hsa-miR-340-5p, provided evidence that DEFB1expression could be modulated by these miRNAs and hsa-miR-186-5p had a higher binding efficiency with DEFB1. Overexpression of DEFB1in IAV infected HBEpCs led to increased NF-κB expression. In a PCR array analysis of 84 transcription factors, either overexpressing DEFB1or siRNA silencing of DEFB1expression significantly modulated the expression of signal transducer and activator of transcription 3 (STAT3). In addition, Ingenuity Pathway Analysis (IPA) integrated with PCR array data showed that the JAK1/STAT3 pathway was significantly altered in cells overexpressing DEFB1, suggesting this to be one of the pathways by which defensin regulates IAV replication in HBEpCs. In conclusion, the reduction in IAV copy number in DEFB1overexpressing cells suggests that β-defensin-1 plays a key role in regulating IAV survival through STAT3 and is a potential target for antiviral drug development. No funding