Východiska: Proteiny STAT (signal transducer and activator of transcription) jsou cytoplazmatické transkripční faktory, které přenášejí signál cytokinů, hormonů a růstových faktorů. Proteiny STAT kontrolují základní buněčné procesy vč. přežití, proliferace a diferenciace. Nadměrná aktivace proteinů STAT může přispět k transformaci buněk a vzniku leukemie. Okolo 70 % všech solidních a hematologických nádorů vykazuje aberantní expresi a/nebo aktivaci STAT3, což dokumentuje zásadní roli STAT3 v tumorigenezi. Aberantní aktivace STAT3 byla popsána u několika solidních nádorů a hematologických malignit. Důležité je, že konstitutivní aktivace proteinů STAT byla detekována u několika typů leukemie vč. akutní myeloidní leukemie, akutní promyelocytární leukemie, akutní lymfoblastické leukemie, chronické myeloidní leukemie a chronické lymfocytární leukemie (CLL). Konstitutivně aktivovaný STAT3 hraje důležitou roli v biologii CLL. Buňky CLL jsou konstitutivně fosforylované na S727 a acetylované na K685, navíc může dojít i k fosforylaci na Y705. Exprese mediátorové RNA STAT3 je výrazně vyšší v buňkách CLL ve srovnání se zdravými B lymfocyty. Zajímavé je, že inhibice STAT3 byla popsána jako důležitý vedlejší produkt léčby ibrutinibem u pacientů s CLL. Cíl: Účelem tohoto přehledu je popsat důsledky deregulace STAT3 u buněk CLL. V práci jsou popsány procesy ovlivněné nadměrnou aktivací STAT3 jako proliferace, apoptóza, signalizace BCR (B cell receptor), sekrece cytokinů, regulace kontrolních bodů imunitního systému, regulace mikroRNA, metabolizmus mastných kyselin a elektronový transportní řetězec v mitochondriích.

Background: Signal transducer and activator of transcription (STAT) proteins are cytoplasmic transcription factors that transmit the signal of cytokines, hormones and growth factors. STAT proteins control fundamental cellular processes including survival, proliferation and differentiation. Inappropriate activation of STATs might contribute to cellular transformation and leukaemogenesis. About 70% of all solid and haematological tumours exhibit aberrant STAT3 expression and/or activation, highlighting its essential role in tumourigenesis. Aberrant STAT3 activation has been found in several solid tumours and haematologic malignancies. Importantly, constitutive activation of STAT proteins has been found in several leukaemias including acute myeloid leukaemia, acute promyelocytic leukaemia, acute lymphoblastic leukaemia, chronic myeloid leukaemia and chronic lymphocytic leukaemia (CLL). Constitutively activated STAT3 plays an important role in CLL biology. CLL cells harbour constitutive phosphorylation on S727 and acetylation on K685 and transient phosphorylation on Y705 residues. Moreover, STAT3 messenger RNA expression is significantly higher in CLL cells compared to healthy B-lymphocytes. Interestingly, STAT3 inhibition was disclosed as an important by-product of ibrutinib treatment in CLL patients. Purpose: The purpose of this review is to describe the consequences of STAT3 dysregulation in CLL cells. Here, we discuss aberrantly modified processes by STAT3 activation in CLL cells such as proliferation, apoptosis, B cell receptor signalling, cytokine secretion, immune checkpoint regulation, microRNA regulation, free fatty acid metabolism and electron transport chain in the mitochondria.

• Klíčová slova
• Ibrutinib, konstitutivní aktivace,
• MeSH
• chronická lymfatická leukemie * etiologie   farmakoterapie   MeSH
• leukemie etiologie   farmakoterapie   MeSH
• lidé MeSH
• nádorové mikroprostředí MeSH
• transkripční faktor STAT3 * MeSH
• transkripční faktory STAT * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• přehledy MeSH

Chronic inflammation represents a major threat to human health since long-term systemic inflammation is known to affect distinct tissues and organs. Recently, solid evidence demonstrated that chronic inflammation affects hematopoiesis; however, how chronic inflammation affects hematopoietic stem cells (HSCs) on the mechanistic level is poorly understood. Here, we employ a mouse model of chronic multifocal osteomyelitis (CMO) to assess the effects of a spontaneously developed inflammatory condition on HSCs. We demonstrate that hematopoietic and nonhematopoietic compartments in CMO BM contribute to HSC expansion and impair their function. Remarkably, our results suggest that the typical features of murine multifocal osteomyelitis and the HSC phenotype are mechanistically decoupled. We show that the CMO environment imprints a myeloid gene signature and imposes a pro-inflammatory profile on HSCs. We identify IL-6 and the Jak/Stat3 signaling pathway as critical mediators. However, while IL-6 and Stat3 blockage reduce HSC numbers in CMO mice, only inhibition of Stat3 activity significantly rescues their fitness. Our data emphasize the detrimental effects of chronic inflammation on stem cell function, opening new venues for treatment.

• MeSH
• hematopoetické kmenové buňky metabolismus   MeSH
• hematopoéza MeSH
• interleukin-6 * genetika   metabolismus   MeSH
• lidé MeSH
• myši MeSH
• signální transdukce MeSH
• transkripční faktor STAT3 genetika   metabolismus   MeSH
• zánět * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Activation of fibroblast growth factor receptor 3 (FGFR3) leads to attenuation of cartilage growth. The members of the STAT family of transcription factors are believed to participate in FGFR3 signaling in cartilage, however the molecular mechanism of this action is poorly understood. Here, we demonstrate that a chronic FGF stimulus leads to accumulation of STAT1, 3, 5 and 6, evident in both in vitro chondrocyte model and murine limb explant cultures. Despite the accumulation, both endogenous and cytokine-induced activation of STAT1 and STAT3 is impaired by FGF, as demonstrated by imaging of active STAT nuclear translocation and analyses of STAT activatory phosphorylation and transcriptional activation. Further, we demonstrate that FGF induces expression of CIS, SOCS1 and SOCS3 inhibitors of gp130, a common receptor for the IL6-family of cytokines. Since cytokine-gp130 signaling represents an important positive regulator of cartilage, its inhibition may contribute to the growth-inhibitory effect of FGFR3 in cartilage.

• MeSH
• chondrocyty metabolismus   účinky léků   MeSH
• cytokinový receptor gp130 metabolismus   MeSH
• fibroblastový růstový faktor 2 farmakologie   MeSH
• financování organizované MeSH
• interferon gama antagonisté a inhibitory   farmakologie   MeSH
• interleukin-6 antagonisté a inhibitory   farmakologie   MeSH
• myši MeSH
• polymerázová řetězová reakce s reverzní transkripcí MeSH
• proteiny SOCS metabolismus   MeSH
• receptor fibroblastových růstových faktorů, typ 3 metabolismus   MeSH
• sekvence nukleotidů MeSH
• signální transdukce MeSH
• transkripční faktor STAT1 antagonisté a inhibitory   metabolismus   MeSH
• transkripční faktor STAT3 antagonisté a inhibitory   metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH

Adiponectin (APN), an adipose tissue-excreted adipokine, plays protective roles in metabolic and cardiovascular diseases. In this study, the effects and mechanisms of APN on biological functions of rat vascular endothelial progenitor cells (VEPCs) were investigated in vitro. After administrating APN in rat VEPCs, the proliferation was measured by methyl thiazolyl tetrazolium (MTT) method, the apoptotic rate was test by Flow cytometry assay, mRNA expression of B-cell lymphoma-2 (Bcl-2) and vascular endothelial growth factor (VEGF) was determined by real-time reverse transcriptase polymerase chain reaction (RT-PCR), and protein expression of mechanistic target of rapamycin (mTOR), signal transducer and activator of transcription 3 (STAT3) and phospho-STAT3 (pSTAT3) was analyzed by Western blot. It was suggested that APN promoted the optical density (OD) value of VEPCs, enhanced mRNA expression of Bcl-2 and VEGF, and inhibited cell apoptotic rate. Furthermore, protein expression of pSTAT3 was also increased in the presence of APN. Moreover, APN changed-proliferation, apoptosis and VEGF expression of VEPCs were partially suppressed after blocking the mTOR-STAT3 signaling pathway by the mTOR inhibitor XL388. It was indicated that APN promoted biological functions of VEPCs through targeting the mTOR-STAT3 signaling pathway.

• MeSH
• adiponektin farmakologie   MeSH
• buněčné linie MeSH
• cévní endotel účinky léků   metabolismus   MeSH
• endoteliální progenitorové buňky účinky léků   fyziologie   MeSH
• krysa rodu rattus MeSH
• proliferace buněk účinky léků   fyziologie   MeSH
• signální transdukce účinky léků   fyziologie   MeSH
• sulfony farmakologie   MeSH
• TOR serin-threoninkinasy antagonisté a inhibitory   biosyntéza   MeSH
• transkripční faktor STAT3 antagonisté a inhibitory   biosyntéza   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu rattus MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

The present study was designed to examine effects of Sinomenine (SM) on glioma cells growth in vivo and in vitro. Cells growth and apoptosis were detected by MTT assay, TUNEL assay and flow cytometric analysis. In the study, SM treatment led to growth inhibition on a series of glioma cell lines, including U87, U373, U251, Hs683 and T98G. SM prevented U87 growth in the nude mice as well. Inhibitory effects of SM on U87 cells proliferation in vitro and in vivo were more effective than that of temozolomide (TMZ), and SM has synergistic effects with TMZ in the glioma therapy. SM induced apoptotic death in U87 cells via activation of caspase-3, caspase-8 and caspase-9, and down-regulation of HIAP, Bcl-2 and survivin. Moreover, we observed SM decreased the expression of phosphorylated STAT3 (p-STAT3) both in vivo and in vitro. Interestingly, using a specific activator of STAT3, we demonstrated overexpression of p-STAT3 impaired, SM mediated growth inhibition and apoptosis induction in the U87 cells. In summary, our results indicate SM induced growth suppression of human glioma cells through inhibiting phosphorylation of STAT3.

• MeSH
• alkaloidy farmakologie   terapeutické užití   MeSH
• apoptóza genetika   imunologie   účinky léků   MeSH
• astrocyty účinky léků   MeSH
• gliom farmakoterapie   patologie   ultrastruktura   MeSH
• kaspasy analýza   metabolismus   MeSH
• kultivované buňky MeSH
• nádorové buněčné linie imunologie   metabolismus   účinky léků   MeSH
• signální transdukce MeSH
• Sinomenium chemie   MeSH
• techniky in vitro MeSH
• transkripční faktor STAT3 antagonisté a inhibitory   metabolismus   účinky léků   MeSH

Introduction: IgA nephropathy is a chronic renal disease characterized by mesangial immunodeposits that contain autoantigen, which is aberrantly glycosylated IgA1 with some hinge-region O-glycans deficient in galactose. Macroscopic hematuria during an upper respiratory tract infection is common among patients with IgA nephropathy, which suggests a connection between inflammation and disease activity. Interleukin-6 (IL-6) is an inflammatory cytokine involved in IgA immune response. We previously showed that IL-6 selectively increases production of galactose-deficient IgA1 in IgA1-secreting cells from patients with IgA nephropathy. Methods: We characterized IL-6 signaling pathways involved in the overproduction of galactose-deficient IgA1. To understand molecular mechanisms, IL-6 signaling was analyzed by kinomic activity profiling and Western blotting, followed by confirmation assays using siRNA knock-down and small-molecule inhibitors. Results: STAT3 was differentially activated by IL-6 in IgA1-secreting cells from patients with IgA nephropathy compared with those from healthy control subjects. Specifically, IL-6 induced enhanced and prolonged phosphorylation of STAT3 in the cells from patients with IgA nephropathy, which resulted in overproduction of galactose-deficient IgA1. This IL-6-mediated overproduction of galactose-deficient IgA1 could be blocked by small molecule inhibitors of JAK/STAT signaling. Discussion: Our results revealed that IL-6-induced aberrant activation of STAT3-mediated overproduction of galactose-deficient IgA1. STAT3 signaling pathway may thus represent a new target for disease-specific therapy of IgA nephropathy.

• Publikační typ
• časopisecké články MeSH

Despite the development of novel targeted drugs, the molecular heterogeneity of diffuse large B-cell lymphoma (DLBCL) still poses a substantial therapeutic challenge. DLBCL can be classified into at least 2 major subtypes (germinal center B cell [GCB]-like and activated B cell [ABC]-like DLBCL), each characterized by specific gene expression profiles and mutation patterns. Here we demonstrate a broad antitumor effect of dimethyl fumarate (DMF) on both DLBCL subtypes, which is mediated by the induction of ferroptosis, a form of cell death driven by the peroxidation of phospholipids. As a result of the high expression of arachidonate 5-lipoxygenase in concert with low glutathione and glutathione peroxidase 4 levels, DMF induces lipid peroxidation and thus ferroptosis, particularly in GCB DLBCL. In ABC DLBCL cells, which are addicted to NF-κB and STAT3 survival signaling, DMF treatment efficiently inhibits the activity of the IKK complex and Janus kinases. Interestingly, the BCL-2-specific BH3 mimetic ABT-199 and an inhibitor of ferroptosis suppressor protein 1 synergize with DMF in inducing cell death in DLBCL. Collectively, our findings identify the clinically approved drug DMF as a promising novel therapeutic option in the treatment of both GCB and ABC DLBCLs.

• MeSH
• dánio pruhované MeSH
• difúzní velkobuněčný B-lymfom farmakoterapie   genetika   metabolismus   patologie   MeSH
• dimethyl fumarát farmakologie   MeSH
• ferroptóza účinky léků   MeSH
• lidé MeSH
• myši MeSH
• nádorové proteiny genetika   metabolismus   MeSH
• NF-kappa B genetika   metabolismus   MeSH
• peroxidace lipidů účinky léků   genetika   MeSH
• regulace genové exprese u nádorů účinky léků   MeSH
• signální transdukce účinky léků   genetika   MeSH
• transkripční faktor STAT3 genetika   metabolismus   MeSH
• xenogenní modely - testy antitumorózní aktivity MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Nitro-oleic acid (NO2-OA), pluripotent cell-signaling mediator, was recently described as a modulator of the signal transducer and activator of transcription 3 (STAT3) activity. In our study, we discovered new aspects of NO2-OA involvement in the regulation of stem cell pluripotency and differentiation. Murine embryonic stem cells (mESC) or mESC-derived embryoid bodies (EBs) were exposed to NO2-OA or oleic acid (OA) for selected time periods. Our results showed that NO2-OA but not OA caused the loss of pluripotency of mESC cultivated in leukemia inhibitory factor (LIF) rich medium via the decrease of pluripotency markers (NANOG, sex-determining region Y-box 1 transcription factor (SOX2), and octamer-binding transcription factor 4 (OCT4)). The effects of NO2-OA on mESC correlated with reduced phosphorylation of STAT3. Subsequent differentiation led to an increase of the ectodermal marker orthodenticle homolog 2 (Otx2). Similarly, treatment of mESC-derived EBs by NO2-OA resulted in the up-regulation of both neural markers Nestin and β-Tubulin class III (Tubb3). Interestingly, the expression of cardiac-specific genes and beating of EBs were significantly decreased. In conclusion, NO2-OA is able to modulate pluripotency of mESC via the regulation of STAT3 phosphorylation. Further, it attenuates cardiac differentiation on the one hand, and on the other hand, it directs mESC into neural fate.

• MeSH
• biologické markery metabolismus   MeSH
• buněčná diferenciace * účinky léků   MeSH
• dusíkaté sloučeniny farmakologie   MeSH
• embryoidní tělíska účinky léků   metabolismus   MeSH
• kardiomyocyty účinky léků   metabolismus   MeSH
• kyseliny olejové farmakologie   MeSH
• myší embryonální kmenové buňky cytologie   účinky léků   metabolismus   MeSH
• myši MeSH
• neurony cytologie   účinky léků   metabolismus   MeSH
• organogeneze účinky léků   MeSH
• pluripotentní kmenové buňky účinky léků   metabolismus   MeSH
• signální transdukce účinky léků   MeSH
• transkripční faktor STAT3 metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

Osteosarcoma (OS), a severe malignant bone tumour, usually occurs in adolescents and children and has a poor prognosis. Asiatic acid (AA), an active component isolated from Centella asiatica (L.) Urb., exhibits appreciable anti-oxidant and anti-tumour activities. So far, the effects and underlying mechanisms of AA against OS have not been clarified. Here, we explored the anti-tumour effects of AA against human OS and the involved mechanism mediating its actions. To evaluate effects of AA on the cell proliferation of human OS cells, cell viability and colony formation assays were performed. Flow cytometry was used to evaluate apoptosis in OS cells exposed to AA and mitochondrial membrane potential. Western blotting and RT-PCR were applied to determine expression of the relevant proteins and their mRNA levels. Our explorations showed that AA inhibits proliferation of human OS cells in a concentration- and time-dependent manner, and induces apoptosis of OS cells by the intrinsic (mitochondrial) pathway. Importantly, we found that inhibition of the AA-induced phosphorylation of JAK2/STAT3 signalling molecules and the decrease in MCL-1 contributed to the anti-tumour efficacy of AA. Collectively, our results suggest that AA could evoke mitochondrial- induced apoptosis in human OS cells by suppression of the JAK2/STAT3 pathway and MCL-1 expression. These results strongly demonstrate that AA could be a potential anti-tumour agent for OS treatment.

• MeSH
• apoptóza * MeSH
• Janus kinasa 2 MeSH
• lidé MeSH
• mladiství MeSH
• nádorové buněčné linie MeSH
• osteosarkom * farmakoterapie   MeSH
• pentacyklické triterpeny farmakologie   MeSH
• proliferace buněk MeSH
• transkripční faktor STAT3 MeSH
• Check Tag
• lidé MeSH
• mladiství MeSH
• Publikační typ
• časopisecké články MeSH

Signal transducer and activator of transcription 3 (STAT3) signalling serves an important role in carcinogenesis and cellular senescence, and its inhibition in tumour cells represents an attractive therapeutic target. Premature cellular senescence, a process of permanent proliferative arrest of cells in response to various inducers, such as cytostatic drugs or ionizing radiation, is accompanied by morphological and secretory changes, and by altered susceptibility to chemotherapeutic agents, which can thereby complicate their eradication by cancer therapies. In the present study, the responsiveness of proliferating and docetaxel (DTX)‐induced senescent cancer cells to small molecule STAT3 inhibitor Stattic and its analogues was evaluated using tumour cell lines. These agents displayed cytotoxic effects in cell viability assays on both proliferating and senescent murine TRAMP‐C2 and TC‐1 cells; however, senescent cells were markedly more resistant. Western blot analysis revealed that Stattic and its analogues effectively inhibited constitutive STAT3 phosphorylation in both proliferating and senescent cells. Furthermore, whether the Stattic‐derived inhibitor K1836 could affect senescence induction or modulate the phenotype of senescent cells was evaluated. K1836 treatment demonstrated no effect on senescence induction by DTX. However, the K1836 compound significantly modulated secretion of certain cytokines (interleukin‐6, growth‐regulated oncogene α and monocyte chemoattractant protein‐1). In summary, the present study demonstrated differences between proliferating and senescent tumour cells in terms of their susceptibility to STAT3 inhibitors and demonstrated the ability of the new STAT3 inhibitor K1836 to affect the secretion of essential components of the senescence‐associated secretory phenotype. The present study may be useful for further development of STAT3 inhibitor‐based therapy of cancer or age‐related diseases.

• MeSH
• cytokiny * metabolismus   MeSH
• docetaxel farmakologie   MeSH
• exprese genu MeSH
• fosforylace MeSH
• myši MeSH
• stárnutí buněk MeSH
• transkripční faktor STAT3 * metabolismus   MeSH
• zvířata MeSH
• Check Tag
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH