Cardiovascular Diseases/genetics* ; Humans ; STAT3 Transcription Factor

In several human tumors, signal transducer and activator of transcription 3 (STAT3) and nuclear factor κB (NFκB) are activated and interact; how these STAT3–NFκB complexes are transported to the nucleus is not fully understood. In this study, we found that Rac1 was activated in starved cancer cells and that activated Rac1 coexisted with STAT3 and NFκB. Rac1 knockdown and overexpression of the dominant-negative mutant Rac1N19 inhibited the degradation of IκBα, an inhibitor of NFκB. MG132, an inhibitor of the ubiquitin proteasome pathway, increased the amount of non-phosphorylated IκBα, but not serine-phosphorylated IκBα, indicating that IκBα degradation by Rac1 in starved cancer cells is independent of IκBα serine phosphorylation by IKK. Rac1 knockdown also inhibited the nuclear translocation of STAT3–NFκB complexes, indicating that this translocation requires activated Rac1. We also demonstrated that the mutant STAT3 Y705F could form complexes with NFκB, and these unphosphorylated STAT3–NFκB complexes translocated into the nucleus and upregulated the activity of NFκB in starved cancer cells, suggesting that phosphorylation of STAT3 is not essential for its translocation. To our knowledge, this is the first study demonstrating the crucial role of Rac1 in the function of STAT3–NFκB complexes in starved cancer cells and implies that targeting Rac1 may have future therapeutic significance in cancer therapy.
Humans ; Phosphorylation ; Proteasome Endopeptidase Complex ; Serine ; STAT3 Transcription Factor ; Ubiquitin

Signal transducer and activator of transcription 3 (STAT3) take part in cell proliferation, differentiation, survival, apoptosis, transformation, cellular immunity and some other important physiological and pathological processes. Among STAT3 signaling pathways, the JAK-STAT signaling pathway has been comprehensively studied. Abnormal activation of STAT3 is frequently detected in various tumors, and the abnormal activation is closely related with the tumorigenesis. Recent studies have found that mutations and several specific genotypes of single nucleotide polymorphisms in STAT3 gene may be involved in tumor formation, also suggesting the important role of STAT3 in tumor biology. In this review, the role of STAT3 in the development of tumors is briefly summarized.
Humans ; Neoplasms ; metabolism ; pathology ; STAT3 Transcription Factor ; Signal Transduction

OBJECTIVETo explore the correlation between JAK/STAT signaling pathways and pathogenesis of immune thrombocytopenia(ITP).

METHODSTwenty-six newly-diagnosed ITP patients was included in this study. They all meet the clinical and hematological criteria for the diagnosis of ITP, and patients with coronary heart disease, severe refractory hypertension, diabetes or with severe liver or kidney function incompetence were ruled out. 24 healthy control without autoimmune diseases, viral infectious diseases and with normal liver and kidney functions were also included. The expressions of Jak3, p-Jak3 mRNA, Stat3, and p-Stat3 were tested and the changes in levels of IL-21 mRNA, IL-21 cell secretion after DEX intervention and AG490 blockade were measured.

RESULTSCompared with the healthy control, patients with ITP had significantly high expressions of Jak3, p-Jak3 mRNA, Stat3 and p-Stat3 protein, which significantly reduced after AG490 blocking (P<0.01). The expression of IL-21 mRNA and the secretion of IL-21 obviously decreased after DEX intervention, but increased after AG490 blocking(P<0.01).

CONCLUSIONThe pathogenesis of ITP associates with the activation of JAK/STAT signaling pathways, and IL-21-mediated JAK/STAT signaling pathways play regulatory role in ITP.

Objective: To observe the effect of meisoindigo on apoptosis and proliferation of JAK2/V617F heterozygous mutation cell line-SET2 cell line to further explore the role of JAK-STAT pathway in this effect. Methods: Cell apoptosis after treated with different concentration of meisoindigo (0, 5, and 10 μmol/L) was evaluated by flow cytometry at different time points (24, 48, 72 h). Cell proliferation with CCK8 test was evaluated at different time points (24, 48, 72, 96 h) after administered with different concentration of meisoindigo (0, 5, 10, and 20 μmol/L). After treatment with different concentration of meisoindigo (0, 5, 10, and 20 μmol/L), SET2 cells were collected after 12 h, and then cultured in incomplete methylcellulose-based medium for clone formation. JAK-STAT signaling pathway and apoptosis related protein by Western blot test were evaluated 12 h after administered with different concentration of meisoindigo (0, 5, 10, and 20 μmol/L). Results: At different time points after treated with meisoindigo, the apoptosis rate of SET2 cell lines increased (P<0.01) with the inhibited proliferation (P<0.01), and the decreased clone formation rate of SET2 cell lines [0 μmol/L meisoindigo: (4.48±1.19)%, 20 μmol/L meisoindigo: (2.55±0.36)%; Dunnett P=0.020] in the presence of augmented concentrations of meisoindigo. At 12 hours after administration with meisoindigo, the reduced expressions of JAK2, P-JAK2, P-STAT1, P-STAT3, P-STAT3, STAT5, the decreased anti-apoptosis proteins BCL-2, BCL-XL and the increased pro-apoptosis protein BID, BIM were observed in the presence of increased concentrations of meisoindigo. Conclusion: Meisoindigo played an important role during the apoptosis and the inhibition of proliferation in ph-negative myeloproliferative neoplasm cell-SET2 cell lines, which might be related to the inhibition of JAK-STAT signaling pathway with up-regulation of pro-apoptosis protein and down-regulation of anti-apoptosis protein.
Apoptosis ; Cell Line ; Cell Proliferation ; Indoles ; STAT3 Transcription Factor

To explore the changes of serum miR-375 and its target genes in patients with allergic rhinitis (AR) before and after treatment and its significance.
 Methods: A total of 120 AR patients treated in Wuhan Fourth Hospital were selected as an observation group (AR group), and 120 healthy volunteers served as a control group. Real-time quantitative polymerase chain reaction was used to detect the expression changes of miR-375 and its predicted target genes, such as 3-phosphoinositide-dependent protein kinase-1 (PDK1), protein kinase B (AKT1), Janus kinase 2 (JAK2), and signal transducer and activator of transcription 3 (STAT3), as well as inflammatory factors, such as tumor necrosis factor-α (TNF-α), interleukin-6 (IL-6), interleukin-10 (IL-10), and interleukin-13 (IL-13) in the AR group before and after treatment. According to the relative expression levels of miR-375 and target genes, the AR patients were also subdivided into a high expression group and a low expression group for comparative analysis.
 Results: Before treatment, the level of miR-375 in the serum in the AR group was higher than that in the control group (P<0.01); the expressions of PDK1, AKT1, JAK2 and STAT3 in the plasma in the AR group were lower than those in the control group (all P<0.01); the plasma levels of TNF-α, IL-6, IL-10, and IL-13 in the AR group were higher than those in the control group (all P<0.05). After treatment, compared with the control group, the level of miR-375 in the serum was down-regulated (P<0.01), while the levels of target genes (PDK1, AKT1, JAK2 and STAT3) were up-regulated (all P<0.05), and the levels of TNF-α, IL-6, IL-10, and IL-13 were down-regulated in the AR group (all P<0.05). The total effective rate, total nasal symptom score (TNSS), symptom improvement time, and incidence of adverse reactions in the AR groups with high expression of miR-375 and low expression of target genes before treatment were better than those in the correspending groups with low expression of miR-375 and high expression of target genes (all P<0.05).
 Conclusion: MiR-375 might be a potential predictor of treatment response for AR patient, which might be related to the plasma levels of its target genes and inflammatory factors.
Humans ; Interleukin-6 ; MicroRNAs ; Rhinitis, Allergic ; STAT3 Transcription Factor ; Tumor Necrosis Factor-alpha

BACKGROUND: Signal transducers and activators of transcription 3 (STAT3) and protein kinase substrate p36 may be involved in cell proliferation, differentiation and growth. METHODS: Immunohistochemistry for STAT3 and p36 was performed in 46 patients with hepatocellular carcinoma (HCC). RESULTS: STAT3 staining was present in the cytoplasm and/or nucleus, while p36 staining was present in the nucleus. STAT3 and p36 expression occurred in 78.3% (36/46) and 47.8% (22/46) of HCC patients, respectively. However, no correlation was found between STAT3 and p36 protein expression (p>0.05). Enhanced expression of STAT3 was negatively correlated with portal vein invasion (p=0.033). Expression of STAT3 in the nucleus was correlated with tumor grade (p=0.004). Enhanced expression of p36 was correlated with tumor grade (p=0.031). HCC was correlated with HBV infection (p=0.032). The patients'5-year survival was related to expression of p36 (p=0.044), but not to total STAT3 or nuclear STAT3 (p>0.05). CONCLUSIONS: The enhanced expression of STAT3 in the nucleus and the enhanced expression of p36 are associated with the aggressive phenotype of HCC. Enhanced p36 expression may contribute to poor survival of patients with HCC.
Carcinoma, Hepatocellular ; Cell Proliferation ; Cytoplasm ; Humans ; Immunohistochemistry ; Phenotype ; Portal Vein ; Protein Kinases ; STAT3 Transcription Factor ; Transducers

In order to investigate the mechanism of stat3 nuclear import. positioned a characterized NLS of the SV40 large T antigen into Stat3-GFP, Dstat3-GFP respectively between the C-terminus of Stat3 and the N-terminus of GFP to create Stat3-NLS-GFP and Dstat3-NLS-GFP. With NLS-GFP as the positive control, Expression of the Stat3-NLS-GFP without IL-6 stimulation and Stat3-GFP with IL-6 stimulation resulted in a predominantly nuclear localization in 293T cell. Expression of Stat3-GFP and Dstat3-NLS-GFP without IL-6 stimulation resulted in predominantly cytoplasm localization in 293T cell. The results suggest that latent Stat3 is not anchored in the cytoplasm, and that nuclear localization in response to IL-6 is facilitated by gain of an NLS function.
Active Transport, Cell Nucleus ; Cell Nucleus ; metabolism ; Nuclear Localization Signals ; Plasmids ; metabolism ; STAT3 Transcription Factor ; metabolism

Cell Line, Tumor ; Gene Silencing ; Hep G2 Cells ; Humans ; RNA, Small Interfering ; STAT3 Transcription Factor ; genetics

PURPOSE: To investigate the effect of oncostatin M (OSM) on protein expression levels and enzymatic activities of matrix metalloprotainase (MMP)-2 and MMP-9 in primary trophoblasts and the invasiveness thereof under normoxia and hypoxia conditions. MATERIALS AND METHODS: Protein expression levels and enzymatic activities of MMP-2 and MMP-9 in primary trophoblasts under normoxia and hypoxia conditions were examined by Western blot and zymography, respectively. Effects of exogenous OSM on the in vitro invasion activity of trophoblasts according to oxygen concentration were also determined. Signal transducer and activator of transcription 3 (STAT3) siRNA was used to determine whether STAT3 activation in primary trophoblasts was involved in the effect of OSM. RESULTS: OSM enhanced protein expression levels and enzymatic activities of MMP-2 and MMP-9 in term trophoblasts under hypoxia condition, compared to normoxia control (p < 0.05). OSM-induced MMP-2 and MMP-9 enzymatic activities were significantly suppressed by STAT3 siRNA silencing under normoxia and hypoxia conditions (p < 0.05). Hypoxia alone or OSM alone did not significantly increase the invasiveness of term trophoblasts. However, the invasion activity of term trophoblasts was significantly increased by OSM under hypoxia, compared to that without OSM treatment under normoxia. CONCLUSION: OSM might be involved in the invasiveness of extravillous trophoblasts under hypoxia conditions via increasing MMP-2 and MMP-9 enzymatic activities through STAT3 signaling. Increased MMP-9 activity by OSM seems to be more important in primary trophoblasts.
Anoxia* ; Blotting, Western ; In Vitro Techniques ; Oncostatin M* ; Oxygen ; RNA, Small Interfering ; STAT3 Transcription Factor ; Trophoblasts*