Overexpression Of Signal Transducer And Activator Of Transcription 3 Research Articles

2'-Hydroxycinnamaldehyde Alleviates Intestinal Inflammation by Attenuating Intestinal Mucosal Barrier Damage Via Directly Inhibiting STAT3.

The currently available clinical therapeutic drugs for ulcerative colitis (UC) are considered inadequate owing to certain limitations. There have been reports on the anti-inflammatory effects of 2'-hydroxycinnamaldehyde (HCA). However, whether HCA can improve UC is still unclear. Here, we aimed to investigate the pharmacological effects of HCA on UC and its underlying molecular mechanisms. The pharmacological effects of HCA were comprehensively investigated in 2 experimental setups: mice with dextran sulfate sodium (DSS)-induced colitis and lipopolysaccharide (LPS)-treated fetal human colon (FHC) cells. Furthermore, the interaction between HCA and signal transducer and activator of transcription 3 (STAT3) was investigated using molecular docking. The FHC cells with STAT3 knockdown or overexpression and mice with intestinal epithelium-specific STAT3 deletion (STAT3ΔIEC) were used to evaluate whether STAT3 mediated the pharmacological effects of HCA. 2'-Hydroxycinnamaldehyde attenuated dysregulated expression of inflammatory cytokines in a dose-dependent manner while increasing the expression of tight junction proteins, reducing the apoptosis of intestinal epithelial cells, and effectively alleviating inflammation both in vivo and in vitro. 2'-Hydroxycinnamaldehyde bound directly to STAT3 and inhibited its activation. The modulation of STAT3 activation levels due to STAT3 knockdown or overexpression influenced the mitigating effects of HCA on colitis. Further analysis indicated that the remission effect of HCA was not observed in STAT3ΔIEC mice, indicating that STAT3 mediated the anti-inflammatory effects of HCA. We present a novel finding that HCA reduces colitis severity by attenuating intestinal mucosal barrier damage via STAT3. This discovery holds promise as a potential new strategy to alleviate UC.

MicroRNA-124 negatively regulates STAT3 to alleviate hypoxic-ischemic brain damage by inhibiting oxidative stress.

MicroRNA-124 (miR-124) is implicated in various neurological diseases; however, its significance in hypoxic-ischaemic brain damage (HIBD) remains unclear. This study aimed to elucidate the underlying pathophysiological mechanisms of miR-124 in HIBD. In our study performed on oxygen-glucose deprivation followed by reperfusion (OGD)/R-induced primary cortical neurons, a substantial reduction in miR-124 was observed. Furthermore, the upregulation of miR-124 significantly mitigated oxidative stress, apoptosis, and mitochondrial impairment. We demonstrated that miR-124 interacts with the signal transducer and activator of transcription 3 (STAT3) to exert its biological function using the dual-luciferase reporter gene assay. As the duration of OGD increased, miR-124 exhibited a negative correlation with STAT3. STAT3 overexpression notably attenuated the protective effects of miR-124 mimics, while knockdown of STAT3 reversed the adverse effects of the miR-124 inhibitor. Subsequently, we conducted an HIBD model in rats. In vivo experiments, miR-124 overexpression attenuated cerebral infarction volume, cerebral edema, apoptosis, oxidative stress, and improved neurological function recovery in HIBD rats. In summary, the neuroprotective effects of the miR-124/STAT3 axis were confirmed in the HIBD model. MiR-124 may serve as a potential biomarker with significant therapeutic implications for HIBD.

Ascorbic acid induces ferroptosis via STAT3/GPX4 signaling in oropharyngeal cancer

Ferroptosis is recognized as a new type of regulated cell death initiated by iron-dependent accumulation of lipid peroxidation. Recent studies have shown that the administration of ascorbic acid (AA) preferentially kills tumor cells by impairing iron metabolism and exerting pro-oxidant effects. Despite mounting evidence indicating the anticancer potential of AA, the underlying molecular mechanisms remain unknown. In this study, we demonstrated that AA decreased cell viability and Ki67 expression, along with its accumulation in the G0/G1 phase in FaDu and SCC-154 cell lines. Furthermore, AA exposure induced morphological changes in mitochondria associated with ferroptosis. AA-induced ferroptosis is accompanied by depletion of glutathione (GSH) and increased levels of ferrous ions (Fe2+), reactive oxygen species (ROS), and malondialdehyde (MDA). However, these ferroptotic effects were ameliorated by deferoxamine and N-acetylcysteine. Network pharmacology results showed that signal transducer and activator of transcription 3 (STAT3) is a key target of AA against oropharyngeal cancer. AA markedly downregulates the relative mRNA expression of STAT3 and glutathione peroxidase 4 (GPX4). Immunoblotting indicated that the protein levels of p-STAT3, STAT3, and GPX4 in FaDu and SCC-154 cells decreased significantly in response to AA treatment. Mechanistically, a chromatin immunoprecipitation assay confirmed that AA exposure reduced STAT3 expression in the GPX4 promoter region. Additionally, AA-induced inhibition of cell growth and ferroptosis was suppressed by STAT3 and GPX4 overexpression, respectively. In summary, AA inhibited oropharyngeal cancer cell growth in vitro by regulating STAT3/GPX4-mediated ferroptosis, which may provide a novel theoretical basis for the clinical treatment of oropharyngeal cancer with AA.

A STAT3 Degrader Demonstrates Pre-Clinical Efficacy in Venetoclax Resistant Acute Myeloid Leukemia

Introduction: Acute Myeloid leukemia (AML) is an aggressive hematological malignancy resulting from the transformation of immature myeloid progenitor cells followed by an uncontrolled clonal proliferation and accumulation of the transformed cells. AML is the most common myeloid malignancy in the elderly [1]. Venetoclax (Ven) is a selective inhibitor of the anti-apoptotic BCL2 protein. Ven is FDA approved in combination with hypomethylating agents (HMA's) or low dose cytarabine for the treatment of de-novo AML in patients > 75 years or those ineligible for standard induction therapies. Despite the recent FDA approval of HMA/Ven and other novel therapies, 5-year survival in newly diagnosed AML remain less than 30% and disease relapse is inevitable without a bridge to allogeneic stem cell transplantation [2]. Signal transducer and activator of transcription 3 (STAT3) belonging to the STAT family of transcription factors is well known to be inappropriately activated in several malignancies [3]. On stimulation by cytokines such as IL-6, STAT3 undergoes dimerization and phosphorylation. Phosphorylation at Tyr 705 leads to its translocation to the nucleus whereas phosphorylation at Ser 727 translocates it to the mitochondria [4]. Previous data from our lab demonstrated de-methylation and overexpression of STAT3 in MDS & AML stem cells, that is associated with an adverse prognosis [5]. We have also reported that STAT3 controls several important leukemic drivers such as the anti-apoptotic protein myeloid cell leukemia-1 (MCL1). MCL1 overexpression is the central mechanism of resistance to BCL2 inhibition (Ven) in AML [5]. While MCL1 is a well-known direct transcriptional target of STAT3, the role of STAT3 in venetoclax resistance (Ven-res) is unknown. Methods & Results: To understand the role of STAT3 in Venetoclax resistance (Ven-res), Ven-res AML cell lines (MOLM-13, MV-4-11) as well as a Ven-res large cell lymphoma cell line (SU-DHL-1) were generated, which exhibited increased levels of both total STAT3, phospho-STAT3 and its downstream effector, MCL1, when compared to their parental cell lines (Fig. 1A). Data from > 90 AML patients treated with prior Ven also showed high expression of total STAT3 along with enhanced phosphorylation for p Ser727 and p Tyr-705 STAT3, that strongly correlated with worse overall survival (OS) and reduced remission duration (RemDur) (p<0.05). A highly specific potent heterobifunctional degrader of STAT3 (degrader) resulted in a dose dependent and selective degradation of STAT3 in both parental and Ven-res hematological malignancy cell lines. Treatment with degrader showed a significant (>60%) decrease in p Tyr-705 as wellas p Ser-727 STAT3 levels in MOLM-13 parental as well as MOLM-13 Ven-res cells. STAT3 degradation also led to induction of apoptosis in both parental and Ven-res AML cell lines (p < 0.001). Importantly, colony assay of Ven-res AML patient samples showed effective degradation of STAT3 (>90%) together with the increased erythroid and myeloid differentiation (~ 2 fold) on treatment with degrader. Interestingly, no differentiation was observed in healthy samples, suggesting the specificity of the degrader to AML stem and progenitor cells. In patients with Ven-res AML, erythroid colony counts were seen to increase (~1.5 fold) with a concomitant decrease in myeloid colony counts (>2.5 fold), on treatment with degrader. This observation supports the clinical significance of our studies in AML patients with anemia. Although BH3 profiling of Ven-res MOLM-13 supports an increased dependency on MCL1, we have observed that treatment with degrader led to ~20% reduction in the MCL1 dependent mitochondrial depolarization. Additionally, cell derived xenograft (CDX) models of Ven-res showed significant reduction of p Tyr-705 STAT3(~60%), total STAT3 (>90%) and MCL1 (~70%), on treatment with STAT3 degrader - KT-333 (currently in an early phase clinical trial:NCT05225584), as early as week 2 (Fig 1B). Significant decrease in intracellular STAT3 in the spleen cells was also observed (p < 0.05), with ongoing survival analysis. Conclusion: Our study suggests that targeting STAT3 and the downstream MCL1 represents a novel and effective strategy for Ven-resistant AML patients in clinic, with strong mechanistic rationales that can spur further clinical development of STAT3 degraders especially given the significant side effects of direct MCL1 inhibitors.

Identification of novel STAT3 inhibitors for liver fibrosis, using pharmacophore-based virtual screening, molecular docking, and biomolecular dynamics simulations

The signal transducer and activator of transcription 3 (STAT3) plays a fundamental role in the growth and regulation of cellular life. Activation and over-expression of STAT3 have been implicated in many cancers including solid blood tumors and other diseases such as liver fibrosis and rheumatoid arthritis. Therefore, STAT3 inhibitors are be coming a growing and interesting area of pharmacological research. Consequently, the aim of this study is to design novel inhibitors of STAT3-SH3 computationally for the reduction of liver fibrosis. Herein, we performed Pharmacophore-based virtual screening of databases including more than 19,481 commercially available compounds and in-house compounds. The hits obtained from virtual screening were further docked with the STAT3 receptor. The hits were further ranked on the basis of docking score and binding interaction with the active site of STAT3. ADMET properties of the screened compounds were calculated and filtered based on drug-likeness criteria. Finally, the top five drug-like hit compounds were selected and subjected to molecular dynamic simulation. The stability of each drug-like hit in complex with STAT3 was determined by computing their RMSD, RMSF, Rg, and DCCM analyses. Among all the compounds Sa32 revealed a good docking score, interactions, and stability during the entire simulation procedure. As compared to the Reference compound, the drug-like hit compound Sa32 showed good docking scores, interaction, stability, and binding energy. Therefore, we identified Sa32 as the best small molecule potent inhibitor for STAT3 that will be helpful in the future for the treatment of liver fibrosis.

Mitigation of Sepsis-Induced Acute Lung Injury by BMSC-Derived Exosomal miR-125b-5p Through STAT3-Mediated Suppression of Macrophage Pyroptosis.

Sepsis is a syndrome characterized by high morbidity and mortality rates. One of its most severe complications is acute lung injury, which exhibits a multitude of clinical and biological features, including macrophage pyroptosis. This study investigates the regulatory effects of exosomes derived from Bone Marrow-Derived Mesenchymal Stem Cells (BMSCs) on sepsis-associated acute lung injury (ALI) and explores the potential mechanisms mediated by exosomal miRNAs. Exosomes were isolated from primary BMSCs of adult C57BL/6J mice using differential centrifugation. Their uptake and distribution in both in vitro and in vivo contexts were validated. Key sepsis-associated hub gene signal transducer and activator of transcription 3 (STAT3) and its upstream non-coding miR-125b-5p were elucidated through a combination of bioinformatics, machine learning, and miRNA sequencing. Subsequently, the therapeutic potential of BMSC-derived exosomes in alleviating sepsis-induced acute lung injury was substantiated. Moreover, the functionalities of miR-125b-5p and STAT3 were corroborated through miR-125b-5p inhibitor and STAT3 agonist interventions, employing gain and loss-of-function strategies both in vitro and in vivo. Finally, a dual-luciferase reporter assay reaffirmed the interaction between miR-125b-5p and STAT3. We isolated exosomes from primary BMSCs and confirmed their accumulation in the mouse lung as well as their uptake by macrophages in vitro. This study identified the pivotal sepsis-associated hub gene STAT3 and demonstrated that exosomes derived from BMSCs can target STAT3, thereby inhibiting macrophage pyroptosis. MiR-125b-5p inhibition experiments showed that exosomes mitigate macrophage pyroptosis and lung injury by delivering miR-125b-5p. STAT3 overexpression experiments validated that miR-125b-5p reduces macrophage pyroptosis and lung injury by suppressing STAT3. Furthermore, a dual-luciferase reporter assay confirmed the binding interaction between miR-125b-5p and STAT3. Exosomes derived from BMSCs, serving as carriers for delivering miR-125b-5p, can downregulate STAT3, thereby inhibiting macrophage pyroptosis and alleviating sepsis-associated ALI. These significant findings provide valuable insights into the potential development of ALI therapies centred around exosomes derived from BMSC.

A pan-cancer analysis of STAT3 expression and genetic alterations in human tumors.

Combined cancer immunotherapy and targeted therapy have proven to be effective against various cancers and therefore have recently become the focus of cancer research. Signal transducer and activator of transcription 3 (STAT3) is a member of the STAT protein family of transcription factors. Several studies have shown that STAT3 can affect the prognosis of cancer patients by regulating immune microenvironment (IME). Therefore, STAT3 may have high research value for the development of combined immunotherapy/targeted therapy approaches for the treatment of cancer patients. We found differences in STAT3 expression between tumor and normal tissues. Kaplan-Meier survival and Cox regression analyses showed that high expression of STAT3 is associated with poor prognosis in low-grade glioma (LGG) patients. The results of the analysis of the area under the curve of the receiver operating characteristic curve further suggested that the expression of STAT3 is an effective way to evaluate the prognosis of patients with glioma. The results of the IME analysis revealed that the immune and matrix scores of LGGs were positively correlated with the expression of STAT3 (P < 0.05). The results of immune cell infiltration analysis showed that STAT3 was positively correlated with resting dendritic cells, eosinophils, neutrophils, M0 macrophages, M1 macrophages, CD4 memory resting T cells, and CD8 T cells in LGG patients, but negatively correlated with activated mast cells and M2 macrophages (P < 0.05). Our gene set enrichment analysis identified 384 enriched pathways. According to the enrichment scores, the top ten most significantly upregulated pathways were related to immune response. The top ten most significantly downregulated pathways were related to cell signal transduction and the regulation of cell survival, proliferation, and metabolism. Genetic alteration analysis showed that missense mutations in STAT3 account for the majority of mutations, and STAT3 mutations mostly occur in the Src homology domain. In conclusion overexpression of STAT3 can promote the development and growth of tumors by regulating IME, which is significantly related to the poor prognosis of cancer patients. Therefore, targeted inhibition of STAT3 expression may have high research value for the development of combined immunotherapy/targeted therapy approaches for the treatment of cancer patients.

Pinocembrin inhibits migration and invasion of nonsmall cell lung cancer cells by inhibiting STAT3 signaling

Background: In cancer treatment, targeting the activation of signal transducer and activator of transcription 3 (STAT3) is crucial as it promotes tumor progression and metastasis through the process of epithelial-mesenchymal transition (EMT). Pinocembrin, a dihydroxyflavanone found naturally in propolis and honey, is known for its antioxidant and vasodilating properties. The objective of this study is to explore the potential of pinocembrin in regulating the STAT3 signaling pathway to inhibit migration and invasion of nonsmall cell lung cancer (NSCLC) cells.&#x0D; Methods: Hematoxylin staining was used to determine the migration and invasion of A549 cells. The relative expression of EMT-related proteins and invasive proteins in A549 cells was determined by Western blot analysis. STAT3 activity was evaluated using a luciferase assay. Overexpression of STAT3 was utilized to assess the role of pinocembrin in regulating STAT3.&#x0D; Results: Pinocembrin treatment (50 μM) significantly reduced the number of migrating and invasive cells. Pinocembrin upregulated the protein level of E-cadherin and downregulated the protein levels of N-cadherin and vimentin. Additionally, pinocembrin blocked the phosphorylation and activation of STAT3. Overexpression of STAT3 reversed the inhibitory effects of pinocembrin on cell migration and invasion.&#x0D; Conclusion: Our study demonstrates that pinocembrin can inhibit the activation of STAT3, which is associated with EMT and thereby attenuate migration and invasion in NSCLC cells.

High‑throughput screening identification of a small‑molecule compound that induces ferroptosis and attenuates the invasion and migration of hepatocellular carcinoma cells by targeting the STAT3/GPX4 axis.

Hepatocellular carcinoma (HCC) is a lethal malignancy. Although considerable efforts have been made in recent years regarding treatments, effective therapeutic drugs for HCC remain insufficient. In the present study, polyphyllin VI was identified as a potential therapeutic drug for HCC by screening natural herbal compounds. The therapeutic effects of polyphyllin VI were assessed using Cell Counting Kit‑8, lactate dehydrogenase release and colony formation assays. The occurrence of ferroptosis was determined by assessing lipid peroxidation by reactive oxygen species, malondialdehyde levels, intracellular ferrous iron levels, and the mRNA and protein levels of glutathione peroxidase 4 (GPX4). The migratory and invasive abilities of HCC cells were examined using wound healing and Transwell assays. The results revealed that polyphyllin VI inhibited the proliferation, invasion and metastasis of HCC cells (HCCLM3 and Huh7 cells) by inducing ferroptosis. In addition, through a network pharmacology‑based approach and molecular docking analyses, it was found that polyphyllin VI may target the signal transducer and activator of transcription 3 (STAT3). HCC cells were treated with polyphyllin VI or a STAT3 inhibitor (Stattic), both of which exerted similar inhibitory effects on protein expression. Furthermore, immunofluorescence staining revealed that polyphyllin VI significantly inhibited the nuclear translocation of p‑STAT3 in HCC cells. Mechanistically, by the overexpression of STAT3, it was confirmed that STAT3 binds to GPX4 and promotes its protein expression and transcription, whereas polyphyllin VI induces ferroptosis by inhibiting the STAT3/GPX4 axis. Subsequently, invivo experiments revealed that polyphyllin VI inhibited the growth of subcutaneously transplanted tumors. On the whole, findings of the present study suggest that polyphyllin VI inhibits STAT3 phosphorylation, which inhibits GPX4 expression and induces the ferroptosis of HCC cells, eventually inhibiting their invasion and metastasis. These data suggest that polyphyllin VI may be a candidate for the prevention and treatment of HCC.

Gracillin exerts anti-melanoma effects in vitro and in vivo: role of DNA damage, apoptosis and autophagy

BackgroundMelanoma is an aggressive cancer. Gracillin has been reported to treat various types of cancer, such as colorectal and lung cancer. However, there is a paucity of research on the anti-melanoma effects of gracillin. PurposeThe aim of this study was to assess the anti-melanoma effects and mechanisms of action of gracillin in vitro and in vivo. MethodsCell viability was detected using MTT and crystal violet staining assays. Cell proliferation was examined by EdU staining assays. Cell cycle arrest and apoptosis were analyzed by flow cytometry. Autophagic flux was monitored under a confocal microscope. Protein levels were determined by immunoblotting. LY294002 and rapamycin (Rapa) were used to determine the involvement of PI3K/AKT/mTOR signaling in gracillin-mediated autophagy. Signal transducer and activator of transcription 3 (STAT3) was overactivated to explore the contribution of the STAT3 signaling pathway in the anti-melanoma effects of gracillin. A B16F10 allograft mouse model was developed to evaluate the anti-melanoma effects of gracillin in vivo. ResultsWe demonstrated that in melanoma cells, gracillin inhibited proliferation, induced G0/G1 phase cell cycle arrest, evoked apoptosis, and triggered autophagic cell death. Gracillin induced DNA damage in melanoma cells. Moreover, it suppressed the phosphorylation/activation of PI3K, AKT, mTOR, and 4E-BP1 in melanoma cells. Inhibiting PI3K/AKT and mTOR activity using LY294002 and Rapa, respectively, increased the protein level of LC3B-II in gracillin-treated melanoma cells. Furthermore, gracillin downregulated the protein levels of p-JAK2 (Tyr1007/1008), p-Src (Tyr416), and p-STAT3 (Tyr705) in melanoma cells. Over-expression of STAT3 in A375 cells significantly mitigated the cytotoxic and apoptotic effects of gracillin. In vivo studies showed that gracillin (1 mg/kg or 8 mg/kg, administered intraperitoneally for 16 consecutive days) suppressed B16F10 tumor growth and Src/STAT3 and AKT/mTOR signaling in tumors. No overt toxicity was observed in mice. ConclusionInduction of DNA damage, inhibition of PI3K/AKT/mTOR signaling and suppression of STAT3 signaling are involved in gracillin-mediated cell cycle arrest, autophagic cell death and apoptosis, respectively, in melanoma cells. These findings provide novel insights into the anti-melanoma molecular mechanisms of gracillin, and suggest a potential role of gracillin in melanoma management.

Cirsiliol regulates mitophagy in colon cancer cells via STAT3 signaling

BackgroundMitophagy is a type of selective autophagy for dysfunctional mitochondria and plays a key role in tumorigenesis and cancer progression. However, whether mitophagy plays a role in colon cancer remains unclear. Cirsiliol is a natural product and has been found to exert anti-cancer effects in multiple tumors. The effects of cirsiliol in the tumorigenesis and progression of colon cancer remain unknown.MethodsCCK8 assay, plate cloning assay, and cell scratch assay were performed to determine cell viability, colony formation, and wound healing abilities of HCT116 and SW480 cells. JC-1 staining, H2DCFDA staining, and Mito-Tracker Red staining were carried out to evaluate mitochondrial membrane potential (Δψm), intracellular reactive oxygen species (ROS) level, and mitochondrial morphology. Molecular docking technology was utilized to predict interaction of cirsiliol and signal transducer and activator of transcription 3 (STAT3). Immunofluorescence staining was used to measure nuclear translocation of STAT3. The protein levels of phosphorylated STAT3 (Y705), total STAT3, and mitophagy proteins were detected by western blot.ResultsIn this study, we first found that cirsiliol inhibited cell viability, colony formation, and wound healing abilities of HCT116 and SW480 colon cancer cells. Moreover, cirsiliol suppressed Δψm, increased ROS production, and disrupted mitochondrial morphology via inhibiting the levels of mitophagy proteins including PINK1, Parkin, BNIP3, and FUNDC1. Application of mitophagy activator improved the levels of mitophagy-related proteins, and ameliorated Δψm and ROS levels. According to the result of molecular docking, we found that cirsiliol potentially bound to the SH2 domain of STAT3, the key domain for the functional activation of STAT3. Moreover, it was found that cirsiliol inhibited constitutive and IL‑6‑induced STAT3 phosphorylation and nuclear translocation by western blot and immunofluorescence analysis. Comparing with cirsiliol group, we found that overexpression of STAT3 restored the expressions of mitophagy proteins.ConclusionsCirsiliol targets STAT3 to inhibit colon cancer cell proliferation by regulating mitophagy.

Forced Overexpression of Signal Transducer and Activator of Transcription 3 (STAT3) Activates Yes-Associated Protein (YAP) Expression and Increases the Invasion and Proliferation Abilities of Small Cell Lung Cancer (SCLC) Cells.

Background: We sought to investigate the interaction between signal transducer and activator of transcription 3 (STAT3) and the Yes-associated protein (YAP) signaling pathway in human small cell lung cancer (SCLC) cells. Methods: The STAT3-overexpressing SCLC cell lines H146 and H446 were established by plasmid DNA transfection for in vitro and in vivo experiments. Results: Overexpression of STAT3 increased YAP protein expression in H146 and H446 cells. STAT3 overexpression significantly increased YAP mRNA expression and the mRNA expression of the YAP signaling downstream genes CTGF and CYR61 in H146 and H446 cells (p < 0.05). We showed that STAT3 overexpression promoted EMT (epithelial–mesenchymal transition) with increased matrix metalloproteinase (MMP)-2 and MMP9 expression. Transwell assays showed that STAT3 overexpression increased the invasion ability of H146 and H446 cells. In addition, STAT3-overexpressing H146 cells grew significantly more rapidly than control H146 cells in the xenograft mouse model (p < 0.05). Immunohistochemistry (IHC) staining and Western blotting (WB) showed that STAT3-overexpressing H146 tumors had increased p-STAT3 and YAP staining and protein expression compared with control tumors. Increased EMT was also observed in STAT3-overexpressed xenograft tumors. Conclusions: The results of our study suggest that the overexpression of STAT3 promotes SCLC EMT, invasion, and proliferation through the activation of the YAP signaling pathway.

Signal transducer and activator of transcription 3 cooperates with androgen receptor/cell cycle-related kinase signalling pathway in the progression of hepatitis B virus infection and gender differences.

The study aimed to investigate the role of androgen receptor (AR)/cell cycle-related kinase (CCRK) signalling pathway in chronic hepatitis B virus (HBV) infection and gender differences, and the contribution of AR regulatory factor signal transducer and activator of transcription 3 (STAT3) in it. AR, CCRK, and phosphorylated STAT3 expressions in liver tissues of chronic HBV-infected patients and non-HBV controls were determined by western blot and compared between genders. The relationships of expression levels with serum HBV DNA levels, liver inflammation activity, and fibrosis score were analysed in chronic HBV-infected patients. The relationships between expression levels of three proteins were also analysed. HBV-infected patients had significantly higher expression levels of AR, CCRK, and p-STAT3Tyr705 compared with controls (p < .01). The expression levels of AR, CCRK, and p-STAT3Tyr705 in chronic HBV-infected patients with severe inflammation were significantly higher than those with mild inflammation (p < .05). Expression levels in patients with heavier fibrosis (stage F4) were higher than in those with less fibrosis (stages F0-3) (p < .01). No gender differences were observed in AR, CCRK, and p-STAT3Tyr705 levels in non-HBV controls; higher levels were observed in HBV-infected males than in HBV-infected females (p < .05). AR, CCRK, and p-STAT3Tyr705 levels in liver tissues positively correlated with each other (p < .0001) and with serum HBV DNA levels (p < .0001). In conclusion, in this study, we first found concordant over-expression of AR, CCRK, and STAT3 in liver tissues of chronic HBV-infected patients who have not yet developed HCC, significantly correlated with the severity of the disease and showed gender differences. STAT3 may be a potential therapeutic co-target for chronic HBV infection.

Cell migration inducing hyaluronidase 1 promotes growth and metastasis of papillary thyroid carcinoma

ABSTRACT Cell migration inducing hyaluronidase 1 (CEMIP) mediates catabolism of hyaluronan, and participates in the cell metastasis, invasion, and motility. Dysregulated CEMIP expression was associated with progression and prognosis of tumors. The role of CEMIP in papillary thyroid carcinoma (PTC) remains unknown. Our study showed that CEMIP was upregulated in both tissues and cells of PTC. Silencing of CEMIP reduced cell proliferation and suppressed migration and invasion of PTC. Protein expression of phosphorylated STAT3 (Signal Transducer And Activator Of Transcription 3) (p-STAT3), AKT (p-AKT) and p65 (p-p65) were decreased by CEMIP silencing in PTC cells. Pyruvate dehydrogenase kinase 4 (PDK4) over-expression attenuated CEMIP silencing-induced decrease in p-STAT3, p-AKT and p-p65. Silencing of CEMIP-induced decrease in cell proliferation and metastasis in PTC were restored by over-expression of STAT3. CEMIP functioned as an oncogenic gene in PTC through PDK4-mediated activation of STAT3/AKT/NF-κB pathway.

Adipose-Derived Mesenchymal Stem Cell-Derived Exosomal miR-301a-3p Regulates Airway Smooth Muscle Cells During Asthma by Targeting STAT3.

BackgroundAsthma is a chronic inflammatory disease featured by inflammation and remodeling of airway. Adipose-derived mesenchymal stem cell (ADSCs)-derived exosomal miRNAs have been suggested as promising therapeutic manners for diseases.MethodsADSCs and airway smooth muscle cells (ASMCs) were isolated from SD rats. Flow cytometry was conducted to detect the surface biomarkers of isolated cells. Exosomes were extracted by sequentially centrifuge method and identified by Western blotting and nanoparticle tracking analysis (NTA). Uptake of exosomes by ASMCs was detected by confocal assay. ASMCs were treated with platelet-derived growth factor-BB (PDGF-BB) to mimic cell remodeling and inflammation. Cell counting 8 (CCK-8), Transwell, and flow cytometry were performed to determine the viability, migration, and apoptosis of ASMCs. Release of inflammatory factors was detected by enzyme-linked immunosorbent assay (ELISA). Levels of RNAs and proteins were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. Interaction between miR-301a-3p and signal transducer and activator of transcription 3 (STAT3) was determined by luciferase reporter gene assay. The effect of Exosomal miR-301a-3p was analyzed in ovalbumin (OVA)-induced asthma mouse model.ResultsADSCs-derived exosomes could be effectively internalized by ASMCs. Exosomal miR-301a-3p notably suppressed the PDGF-BB-stimulated proliferation and migration of ASMCs, and enhanced apoptosis, as well as decreased the secretion of inflammatory factors. MiR-301a-3p directly targeted the 3ʹUTR region of STAT3. STAT3 overexpression reversed the suppressive effects of exosomal miR-301a-3p on ASMCs under PDGF-BB stimulation. The expression of miR-301a-3p and STAT3 was negative correlation in specimen from patients with asthma. Exosomal miR-301a-3p inhibited OVA-induced lung injury by targeting STAT3 in mice.ConclusionThis study exposed that exosomal miR-301a-3p from ADSCs could effectively alleviate PDGF-BB-stimulated remodeling and inflammation of ASMCs via targeting STAT3, presented ADSCs-derived exosomal miR-301a-3p as a promising therapeutic approach for asthma.

STAT3 Promotes Cell Proliferation by Potentiating the CCL4 Transcriptional Activity in Diffuse Large B-Cell Lymphoma

Signal transducer and activator of transcription 3 (STAT3) is a transcription factor and a candidate therapeutic option for human cancers. However, the underlying mechanism of STAT3 in the pathogenesis of diffuse large B-cell lymphoma (DLBCL) is yet to be established. We studied here whether STAT3 contributes to C-C motif chemokine ligand (CCL4) transcription elevation in DLBCL. Our established protein-protein interactions network revealed the overexpression of STAT3 and CCL4 in DLBCL. Mechanistically, STAT3 activated CCL4 transcription to induce the Wnt/β-catenin pathway. The prognostic analysis exhibited that the overall survival of patients with high STAT3 and CCL4 were poorer than those with low STAT3 and CCL4 expression. In addition, silencing of STAT3 reverted the malignant phenotype in DLBCL cells. CCL4 overexpression partly weakened the si-STAT3-mediated antitumor effects on DLBCL cells. Tumor xenograft models showed that si-STAT3 inhibited tumor growth in vivo and decreased proliferative and mitogenic activities in tumor tissues, which was consistent with the in vitro data. Hence, this study provides new evidence that STAT3 and CCL4 may be new prognostic biomarkers and therapeutic targets for treating DLBCL.

Glaucocalyxin A suppresses multiple myeloma progression in vitro and in vivo through inhibiting the activation of STAT3 signaling pathway

BackgroundMultiple myeloma (MM) is the most common malignant hematological disease in the people worldwide. Glaucocalyxin A (GLA) is a bioactive ent-kauranoid diterpenoid, that is derived from Rabdosia japonica var. GLA has been demonstrated that it had various pharmacological activities, such as anti-coagulation, anti-bacterial, anti-tumor, anti-inflammation, antioxidant activities. Although GLA has effective anti-tumor properties, its effects on multiple myeloma remain unclear. The aim of this study was to examine the possible anti-cancer effects of GLA and their molecular mechanisms on MM cells in vitro and in vivo.MethodsTo evaluate the role of GLA on the proliferation of MM cells in vitro and in vivo, we used MTT method to detect the role of GLA on the proliferation of MM cells. Cell apoptosis and cell cycle assay were evaluated by flow cytometry. Protein expressions in GLA-treated and untreated MM cells were evaluated by western blot analyses. MM xenograft nude mice model was used to investigate the role of GLA on the proliferation of MM cells in vivo. IHC assay was used to examine the role of GLA on the MM xenograft model in vivo.ResultsIn the present study, we firstly reported the potent anti-myeloma activity of GLA on MM cells. We found that GLA could induce apoptosis in vitro and in vivo. GLA could inhibit the phosphorylation of the signal transducer and activator of transcription 3 (STAT3) and downregulate interleukin IL-6 induced STAT3 phosphorylation in MM. Overexpression of STAT3 could significantly prevent apoptosis induced by GLA; while knockdown of STAT3 enhanced it. Moreover, GLA could inhibit cell proliferation by inducing the cell cycle arrest. GLA reduced the expression of cell cycle-related proteins CCNB1, CCND1, CCND2, and CCND3 and increased the expression of p21 in MM cell lines. In addition, in the MM xenograft nude mice model, GLA exhibited very good anti-myeloma activity. Administration of GLA almost completely inhibited tumor growth within 19 days without physical toxicity. And the IHC results showed GLA significantly inhibited cell proliferation and interfered STAT3 pathway on MM xenograft model tumor tissues.ConclusionsTaken together, our present research indicated that GLA inhibits the MM cell proliferation, induces MM cell apoptosis and cell cycle arrest through blocking the activation of STAT3 pathway. Thus, GLA may be a potential therapeutic candidate for MM patients in the future.

The inhibition of circular RNA circNOLC1 by propofol/STAT3 attenuates breast cancer stem cells function via miR-365a-3p/STAT3 signaling

BackgroundBreast cancer remains one of the most dreadful female malignancies globally, in which cancer stem cells (CSCs) play crucial functions. Circular RNAs have drawn great attention in cancer research area and propofol is a widely applied intravenous anesthetic agent. Methods: In the current study, we explored the function of circular RNA nucleolar and coiled-body phosphoprotein 1 (circNOLC1) in CSCs of breast cancer and the inhibitory impact of propofol on circNOLC1.ResultsThe expression of circNOLC1 was induced in breast cancer tissues compared with the non-tumor tissues. The silencing of circNOLC1 was able to repress the viability of breast cancer cells. Meanwhile, the numbers of colony formation were suppressed by circNOLC1 knockdown in breast cancer cells. The inhibition of circNOLC1 reduced the invasion and migration ability of breast cancer cells. The mRNA and protein levels of E-cadherin were enhanced but Vimentin levels were reduced by the silencing of circNOLC1. The repression of circNOLC1 decreased the side population (SP) ratio in breast cancer cells. Meanwhile, the sphere formation ability of breast cancer cells was attenuated by the silencing of circNOLC1. The levels of ATP-binding cassette (ABC) superfamily G member 2 (ABCG2), c-Myc, B cell-specific Moloney murine leukemia virus integration site 1 (Bmi1), and SRY-box transcription factor 2 (Sox2) were repressed by the depletion of circNOLC1 in the cells. Regarding to the mechanism, circNOLC1 functioned as a competing endogenous RNAs (ceRNAs) for microRNA-365a-3p (miR-365a-3p) and the inhibition of miR-365a-3p rescued circNOLC1 depletion-repressed proliferation and cancer stem cell activity of breast cancer. MiR-365a-3p targeted signal transducer and activator of transcription 3 (STAT3) in breast cancer cells and circNOLC1 enhanced STAT3 expression by sponging miR-365a-3p. The overexpression of STAT3 could reverse miR-365a-3p or circNOLC1 depletion-inhibited proliferation and cancer stem cell properties of breast cancer. Interestingly, the expression of circNOLC1 and STAT3 was repressed by the treatment of propofol. The enrichment of STAT3 on circNOLC1 promoter was inhibited by propofol. The expression of circNOLC1 was suppressed by the silencing of STAT3 in the cells. The inhibition of circNOLC1 expression by propofol was rescued under the co-treatment of STAT3 overexpression. The overexpression of circNOLC1 rescued propofol-attenuated proliferation and cancer stem cell functions in vitro and in vivo.ConclusionsThus, we concluded that circNOLC1 contributes to CSCs properties and progression of breast cancer by targeting miR-365a-3p /STAT3 axis and propofol inhibited circNOLC1 by repressing STAT3 in a feedback mechanism.

Transfection of STAT3 overexpression plasmid mediated through recombinant lentivirus promotes differentiation of bone marrow mesenchymal stem cells into neural cells in fetal rats with spina bifida aperta.

We investigated the influence of signal transducer and activator of transcription-3 (STAT3) on the spinal cord tissue grafts of rat fetuses with spina bifida aperta. In particular, we hoped to identify whether transfection of the STAT3 overexpression plasmid increases the survival of spinal cord transplantation in order to improve therapeutic efficacy. The fetal rat model of spina bifida aperta was established using retinoic acid and treated with a microsurgical injection of bone marrow mesenchymal stem cells (BMSCs). The animals were divided into either the blank control group, negative control group or the experimental group. The optical density (OD) value of BMSCs viability was determined using the Cell Counting Kit-8 (CCK-8). The expression of STAT3, phosphorylated STAT3 (pSTAT3), neural markers and apoptosis-related factors were evaluated using real-time PCR and Western blot. The OD value in the experimental group was highest at eight hours after transplantation using CCK-8. The expression of pSTAT3, glial fibrillary acidic protein, neuron-specific enolase, neurofilament and nestin in the experimental group was significantly higher compared to the blank control group and negative control group (P<0.05). However, STAT3 expression in the experimental group was statistically significantly decreased (P<0.05). The relative expression of caspase-8 and bcl-2 in the experimental group were significantly lower compared to the blank control group and negative control group (P<0.05). Transfection of the recombinant lentivirus-mediated STAT3 overexpression plasmid with BMSCs can help improve the efficiency of transforming into neural cells and provide new seed cells for the treatment of congenital spina bifida aperta.

Propofol induces the ferroptosis of colorectal cancer cells by downregulating STAT3 expression.

Propofol is a commonly used intravenous anesthetic agent that can also suppress the proliferation of various human cancer types, including colorectal cancer (CRC). The present study aimed to investigate whether propofol could induce the ferroptosis of CRC cells by regulating signal transducer and activator of transcription 3 (STAT3). STAT3 expression in normal and CRC tissues was measured. Human normal colonic epithelial NCM460 cells and human CRC SW480 cells were exposed to different concentrations of propofol and then cell viability was detected. SW480 cells were transfected with a vector overexpressing STAT3 and treated with propofol, and the cell viability, colony formation, cell proliferation, iron level, ROS production and ferroptosis of these cells and control cells were evaluated. Overall, the results showed that STAT3 was highly expressed in CRC tissues. Propofol exerted no marked effect on NCM460 cell viability, but inhibited SW480 cell viability in a concentration-dependent manner. Meanwhile, STAT3 was downregulated by propofol in a concentration-dependent manner. Propofol also inhibited CRC cell proliferation and colony formation, and enhanced cellular iron and ROS levels. Additionally, the expression of proteins involved in ferroptosis was also altered by propofol, including the upregulation of CHAC1 and PTGS2 expression in CRC cells, and the inhibition of GPX4 expression. However, STAT3 overexpression blocked the effect of propofol on CRC cells. In conclusion, propofol may trigger the ferroptosis of CRC cells by downregulating STAT3 expression.