STAT3 Research Articles

Uropathogenic Escherichia coli-induced fibrosis, leading to lower urinary tract symptoms, is associated with type 2 cytokine signaling.

Chronic inflammation and prostate fibrosis have been identified as contributors to lower urinary tract symptoms (LUTS) pathophysiology in humans. It has been shown that transurethral infection of an Escherichia coli strain named CP1, which was isolated from a patient with chronic prostatitis, can lead to the develop of differential chronic inflammation and pain in certain mouse strains. Therefore, we hypothesized that differential inflammation would influence fibrotic response in the prostate. This study showed that while prostatic infection by CP1 causes the development of chronic tactile allodynia in NOD/ShiltJ (NOD) but not C57BL/6 (B6) mice, both mice developed evidence of prostate inflammation, prostate fibrosis, and urinary dysfunction. Fibrosis was confirmed by the upregulation of fibrosis-associated messenger RNAs (mRNAs), α-smooth muscle actin immunohistochemistry, and collagen staining with picrosirius red. These findings were mainly focused on the dorsolateral lobes of the prostate. Both mouse strains also developed smaller, more frequent voiding patterns postinfection, examined via cystometry. B6 mice responded to CP1 infection with type 2 cytokines (IL-4 and IL-13), while NOD mice did not, which may explain the differing tactile allodynia responses and level of collagen deposition. When mice lacking signal transducer and activator of transcription 6 (STAT6), a transcription factor known to be important for the production and signaling of IL-4 and IL-13, were infected with CP1, fibrosis was attenuated. This study provides a potential model for studying the development of infection-induced prostatic fibrosis and LUTS. This study also demonstrates that CP1-induced prostate fibrosis has a STAT6-dependent mechanism in B6 mice.

The Association Between STAT4 rs7574865 Polymorphism and the Susceptibility of Autoimmune Thyroid Disease: A Meta-Analysis.

Objectives: The signal transducer and activator of transcription 4 (STAT4) gene encodes an important transcription factor that transmits signals induced by several cytokines associated with autoimmune diseases and has been identified as a susceptibility gene for numerous autoimmune disorders. The association between STAT4 rs7574865 polymorphism and the susceptibility of autoimmune thyroid disease (AITD) has been investigated in previous case-control studies. However, the investigation results were inconsistent. Hence, a meta-analysis was performed to draw a more reliable conclusion about it.Methods: All relevant studies were searched in Embase, PubMed, Web of Science, and China National Knowledge Infrastructure, till August 20, 2018. The pooled odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the strength of the association.Results: A total of five independent case-control studies with 1707 AITD patients and 2316 controls were included in the present meta-analysis. The overall pooled analysis indicated that STAT4 rs7574865 polymorphism was significantly associated with AITD susceptibility [TT vs. GG: OR = 1.63, 95%CI = 1.24–2.15, PZ = 0.0005; TT vs. (TG+GG): OR = 1.55, 95%CI = 1.26–1.91, PZ < 0.0001]. However, the subgroup analysis showed a significant association of STAT4 rs7574865 polymorphism with AITD susceptibility in Asian population, but not in African population. STAT4 rs7574865 polymorphism was significantly associated both with Graves’ disease (GD) and Hashimoto’s thyroiditis (HT) susceptibility.Conclusion: This meta-analysis showed a significant association between STAT4 rs7574865 polymorphism and AITD susceptibility. However, further studies with larger sample sizes and other ethnicities are still required to confirm the findings.

Analysis of IL-4/STAT6 Signaling in Macrophages.

Activation of signal transducer and activator of transcription 6 (STAT6) is a key signaling pathway in macrophage function, and is required for the so-called alternative (M2) activation of macrophages. Interleukin (IL)-4 and IL-13 are important M2 polarizing cytokines that act through STAT6 by inducing its phosphorylation and promoting transcription of STAT6-responsive genes. Inactivation of STAT6 signaling in macrophages has not been fully explored; however, a recent model suggests that inactivation of STAT6 signaling can occur via ubiquitination and proteasomal degradation. In this chapter, we describe a combination of techniques that can be used to study the activation/inactivation of STAT6 signaling in macrophages.

Regulation of Systemic Glucose Homeostasis by T Helper Type 2 Cytokines.

Obesity results in an inflammatory microenvironment in adipose tissue, leading to the deterioration of tissue protective mechanisms. Although recent studies suggested the importance of type 2 immunity in an anti-inflammatory microenvironment in adipose tissue, the regulatory effects of T helper 2 (Th2) cytokines on systemic metabolic regulation are not fully understood. Recently, we identified the roles of the Th2 cytokine (interleukin 4 [IL-4] and IL-13)-induced adipokine, growth differentiation factor 15 (GDF15), in adipose tissue in regulating systemic glucose metabolism via signal transducer and activator of transcription 6 (STAT6) activation. Moreover, we showed that mitochondrial oxidative phosphorylation is required to maintain these macrophage-regulating autocrine and paracrine signaling pathways via Th2 cytokine-induced secretion of GDF15. In this review, we discuss how the type 2 immune response and Th2 cytokines regulate metabolism in adipose tissue. Specifically, we review the systemic regulatory roles of Th2 cytokines in metabolic disease and the role of mitochondria in maintenance of type 2 responses in adipose tissue homeostasis.

Role of hypomethylation of suppressor of cytokine signaling in T helper 17 cell/regulatory T cell imbalance in children with Henoch-Schönlein purpura

To investigate the association between suppressor of cytokine signaling (SOCS) hypomethylation and T helper 17 (Th17) cell/regulatory T (Treg) cell imbalance in children with Henoch-Schönlein purpura (HSP) and the immune pathogenesis of HSP. A total of 32 children in the acute stage of HSP who were hospitalized from May 2014 to January 2015 were enrolled as subjects, and 28 children who underwent physical examination were enrolled as normal control group. ELISA was used to measure the plasma level of interleukin-6 (IL-6). Flow cytometry was used to measure the percentages of CD4+ IL-17A+ T cells (Th17 cells) and CD4+CD25+ Treg cells (Treg cells) in peripheral blood and mean fluorescence intensity (MFI) for phosphorylated-STAT3 (pSTAT3) protein in CD4+ T cells. Quantitative real-time PCR was used to measure the mRNA expression of suppressor of cytokine signaling-1 (SOCS1) and suppressor of cytokine signaling-3 (SOCS3) in CD4+ T cells. High-resolution melting (HRM) was used to evaluate the methylation level of the CpG islands in SOCS1 exon 2 and the CpG islands of the potential bind sites for STAT3 in the 5'-untranslated region (5'-UTR) of SOCS3 in peripheral blood mononucleated cells. Compared with the normal control group, the HSP group had significant increases in plasma IL-6 concentration and MFI for pSTAT3 in CD4+ T cells, as well as a significant increase in the percentage of Th17 cells and a significant reduction in the percentage of Treg cells (P<0.05). The HSP group had significantly higher mRNA expression of SOCS1 and SOCS3 in peripheral blood mononucleated cells than the normal control group (P<0.05). In the HSP group, the mRNA expression of SOCS1 and SOCS3 was negatively correlated with Th17/Treg ratio (P<0.05). The HSP group had hypomethylation of the CpG islands in SOCS1 exon 2 and the potential binding site for STAT3 in SOCS3 5'-UTR, while the normal control group had complete demethylation. Low relative expression of SOCS1 and SOCS3 caused by hypomethylation may be a factor for Th17/Treg imbalance in children with HSP.

The NADPH Oxidase Nox4 controls polarization of macrophages in a NFκB-dependent manner.

The family of NADPH oxidases represents a source of reactive oxygen species (ROS). Within this family, Nox4 is special, as it constitutively produces H2O2. The loss of Nox4 promotes inflammation. A major cellular component of inflammation is the macrophage population, which divides in several subpopulations with pro-inflammatory M1 and wound-healing M2 macrophages being extremes of the functional spectrum of these cells. As controversial findings on Nox4 expression in macrophages exist, we hypothesize that Nox4 expression is only present in a subpopulation of macrophages, where it may determine the phenotype. In a murine inflammation-driven fibro sarcoma model Nox4-deficiency results an increase in the expression of pro-inflammatory genes and cytokines and higher amounts of pro-inflammatory Ly6C+ macrophages in the tumors. Ex vivo, bone marrow-derived macrophages deficient in Nox4 displayed a reduced M2 polarization whereas M1 markers were elevated. ROS levels where augmented in Nox4-/- cells polarized to M1 accompanied by a higher expression of Nox2. Mechanistically, Nox4-deficiency reduces STAT6 activation and promotes NFκB activity, with the latter being responsible for the higher level of Nox2 in Nox4-deficient M1-polarized macrophages. Collectively the data obtained in this study propose an anti-inflammatory role of Nox4 in macrophages. This is achieved by an enhanced M2 polarization and a suppression of NFκB activity.

Inflammation and Vascular Calcification Causing Effects of Oxidized HDL are Attenuated by Adiponectin in Human Vascular Smooth Muscle Cells.

The role of oxidized high- density lipoprotein (oxHDL) and the protective effects of adiponectin in terms of vascular calcification is not well-established. This study was conducted to investigate the effects of oxHDL with regard to inflammation and vascular calcification and to determine the protective role of adiponectin in attenuating the detrimental effects of oxHDL. Cell viability, mineralization, and calcification assays were conducted to optimize the concentration of oxHDL. Then, human vascular smooth muscle cells (HAoVSMCs) were incubated with β-glycerophosphate, HDL, oxHDL, adiponectin, or the combination of oxHDL with adiponectin for 24 h. Protein expression of IL-6, TNF-α, osterix, RUNX2, ALP, type 1 collagen, osteopontin, osteocalcin, WNT-5a, NF-ĸβ(p65), cAMP and STAT-3 were measured by ELISA kits. OxHDL induced vascular calcification by promoting the formation of mineralization nodules and calcium deposits in HAoVSMCs. This was accompanied by an increased secretion of IL-6, osterix, WNT-5a and NF-ĸβ (p65). Interestingly, these detrimental effects of oxHDL were suppressed by adiponectin. Besides, incubation of adiponectin alone on HAoVSMCs showed a reduction of inflammatory cytokines, osteoblastic markers (RUNX2, osterix and osteopontin), WNT-5a and NF-ĸβ (p65). This study exhibits the ability of oxHDL in inducing inflammation and vascular calcification and these detrimental effects of oxHDL can be attenuated by adiponectin.

Effects of IL-33 on renal tubular injury in lupus nephritis through the JAK/STAT signaling pathway

Objective To investigate the effects and mechanism of interleukin 33 (IL-33) on renal tubular injury in mice with lupus nephritis. Methods Twelve-week-old female MRL/lpr mice were randomly divided into model group, IL-33 group and solvent control group with 10 rats in each group. Ten female MRL/MP mice of the same age were used as normal control group. The mice in IL-33 group were intraperitoneally injected with 100 μL of phosphate buffer saline (PBS), containing 2 μg of recombinant mouse IL-33, once a day for 14 days. The mice in control group and the model group were intraperitoneally injected with the same dose of PBS. All the mice were sacrificed at 14 weeks of age. Serum creatinine (Cr) and urea nitrogen (BUN) concentrations were determined by serum separation. The urine in 24 hours was collected testing urinary protein creatinine ratio and urinary protein quantification. The contents of E-cadherin, α-SMA, and JAK/STAT pathway signaling proteins, including JAK2, p-JAK2, STAT1, and p-STAT1, were detected by Western blot. Results The BUN, urinary protein creatinine ratio and urine protein level of the IL-33 group were significantly higher than those of the model group (all P 0.05). Conclusions IL-33 can cause tubulointerstitial lesions in lupus mice, and its mechanism may be related to the activation of JAK/STAT pathway. Key words: Lupus nephritis; Tubular interstitial leison; JAK2; Signal transducer and activator of transcription 1

MicroRNA-135a induces prostate cancer cell apoptosis via inhibition of STAT6.

Clinical management of metastatic prostate cancer remains a challenge. Activation of apoptosis signaling pathways via signal transducer and activator of transcription 6 (STAT6) has been hypothesized to be a therapeutic strategy for patients with metastatic prostate cancer. The ONCOMINE® prostate cancer database and two Gene Expression Omnibus datasets (Gene Series 40026 and 21032) were re-analyzed to determine the expression levels of STAT6 and microRNA (miR)-135a in prostate cancer. The current study investigated the induced overexpression of miR-135a in prostate cancer cell lines to detect its function in prostate cell apoptosis using Hoechst staining and fluorescence-activated cell sorting and examined the expression levels of STAT6 and its DNA binding ability using western blotting and an electrophoretic mobility shift assay. In analysis of the ONCOMINE® database, STAT6 expression levels in prostate cancer tissue were higher compared with those in normal prostate gland tissue and were associated with the overall survival rate and biochemical relapse rate following radical prostatectomy. Additionally, there was an inverse correlation between miR-135a and STAT6 expression levels in prostate cancer cell lines. miR-135a was able to induce prostate cancer cell apoptosis via targeting STAT6 mRNA and subsequently repressing protein expression and phosphorylation, which also altered the transcriptional factor function of STAT6 through its DNA-binding capabilities. In conclusion, miR-135a may function as a tumor-suppressing miRNA in prostate cancer and its anti-oncogenic activity may involve the direct targeting and inhibition of STAT6.

STAT6 variants and non-atopic asthma in Pakistani population

Asthma a chronic airway inflammatory disease mainly characterized by airways obstruction. Airway hyper responsiveness particularly in eosinophils and inflammatory mediators affect the bronchial mucosa. Genetic association studies show the association of single nucleotide polymorphisms (SNPs) in the STAT6 gene with asthma risk. Role of Signal transducer and activator of transcription 6 (STAT6) is acute for T-helper 2 (Th2) mediated responses during allergic airway diseases. Objective was to investigate whether the two single nucleotide polymorphism (rs4559 and rs324011) in STAT6 gene are associated with non-atopic asthma risk in Pakistani population. One hundred (100) asthma patients with a positive family history with at least one-first degree asthma affected relative were enrolled. Normal healthy individuals (n=100) were also included as control subjects in the current study. STAT6 SNPs rs4559 and rs324011 were genotyped using SNaPSHOT mini-sequencing assay and the obtained data was statistically analyzed by online SHEsis software. A case-control study for association of STAT6 polymorphisms rs4559 and rs324011 with asthma risk was performed. The SNP rs4559 was found statistically significantly associated with increased susceptibility of developing non-atopic asthma in Pakistani individuals. The SNP rs324011 polymorphism in intron 2 of STAT6 gene may be associated with increased susceptibility of the development of non-atopic asthma as a strong statistically significant difference in allele frequency and genotype was observed between asthmatics and controls showing association with non-atopic asthma in Pakistani individuals. rs4559 and rs324011SNPs in STAT6 found associated with non-atopic asthma risk. We observed the statistically significant association between STAT6 polymorphisms with intrinsic (non-atopic) asthma in Pakistani population.

Fungi in Mucoobstructive Airway Diseases

Asthma, chronic rhinosinusitis, and related incurable allergic afflictions of the upper and lower airways are medically important because of their association with the disabling symptom of dyspnea and, at least for asthma, the potential to cause fatal asphyxiation. Extensive research over the past two decades has uncovered both the physiological basis of airway obstruction in asthma and key governing molecular pathways. Exaggerated airway constriction in response to diverse provocative stimuli, termed airway hyperresponsiveness, is mediated through the cytokines interleukin 4 (IL-4) and IL-13 and the transcription factor signal transducer and activator of transcription 6 (STAT6). Overproduction of mucus has long been known to be an essential second component of airway obstruction and is also mediated in part through the IL-4/IL-13/STAT6 pathway. In this review, we discuss a second major signaling pathway which underlies mucus production that is mediated through proteinase-cleaved fibrinogen signaling through Toll-like receptor 4. Unexpectedly, our analysis of human sputum and paranasal sinus fluid indicates that in most cases of severe allergic airway disease, a unique type of airway fungal infection, termed airway mycosis, is pathogenically linked to these conditions. We further discuss how fungal and endogenous proteinases mediate the fibrinogenolysis that is essential to both Toll-like receptor 4 signaling and fibrin deposition that, together with mucus, contribute to airway obstruction.

PROGRESSIVE DECREASE IN T CELL QUANTITY AND FUNCTION IN A PATIENT WITH IL-12 PATHWAY DEFECT

Introduction T helper 1 (TH1) and IFN-g are key players in the cell-mediated immune response. Furthermore, IL-12 is an important cytokine that promotes TH1 cell differentiation and mediates its affects through signal transducer and activator of transcription 4 (STAT4). Mutations in the gene encoding the IL-12 receptor beta1 subunit have been identified in patients with disseminated Salmonella and nontuberculous mycobacterial (NTM) infections or disseminated Bacillus Calmette-Guerin (BCG) infection following vaccine administration. Case Description 5-month old female with history of recurrent salmonella enteritis and meningitis at 3 weeks and 3 months of age who presented to our Immunology clinic for an immune evaluation. Initial T cell lymphocyte subsets showed elevated CD3, CD4, CD8 and CD16/CD56 absolute values. Her mitogen culture proliferation assay was reported as low lymphocyte proliferation to ConA and PHA, however based on our assessment she had greater than tenfold response to stimulus and therefore normal function. The patient's lymphocyte subsets have been reassessed on a yearly basis and have showed progressive decline. This year, her CD4 and CD8 were 754 and 338 respectively. Mitogen proliferation culture re-assessment this year also showed significant decline in her T cell function and she was therefore started on Bactrim prophylaxis. Discussion Our patient showed progressive decline in her T cell subset values and decrease in overall function. Although classically MSMD (mendelian susceptibility to mycobacterial disease) patients showed increase susceptibility to disseminated BCG and Salmonella disease and is managed with interferon gamma and azithromycin prophylaxis, our patient now requires additional Bactrim prophylaxis. IL-12 Signaling Pathway

Role of STAT1 signaling pathway in osteoblast apoptosis and effect of blocking the path

Objective To investigate the role of signal transducer and activator of transcription (STAT1) signaling pathway in osteoblast apoptosis, and to study the effect of STAT1 inhibitor (fludarabine) on osteoblast. Methods The viability of the osteoblasts in different concentration of fludarabine was detected by cell counting kit-8 (CCK-8) assay. Osteoblasts were divided into 4 groups: control group, dexamethasone (Dex) group, fludarabine (Flu) group, and Dex + Flu group. Enzyme linked immunosorbent (ELISA) was used for determining the protein expression of Bcl-2 Associated X Protein (BAX), STAT1 and phosphorylation-signal transducers and activators of transcription 1 (p-STAT1), and cleaved caspase-3 to reflect the apoptosis in all groups. Results Treatment with Dex increased the protein expression of apoptosis-related proteins and p-STAT1 in time-dependent and dose-dependent manner. Exposure of the cells to Flu, which was a selective STAT1 inhibitor, resulted in a decreased the protein levels of apoptosis-related proteins. Conclusions Our results suggest that fludarabine could suppress Dex-induced apoptosis through the inhibition of STAT1-mediated up-regulation cleaved caspase-3 expression in osteoblasts. Key words: Osteoblasts/DE; Vidarabine/AA; Vidarabine/PD; Apoptosis; STAT1 transcription factor

Behçet's disease: An immunogenetic perspective.

Behçet's disease (BD) is a chronic and rare multisystemic disorder defined byautoimmunity and inflammatory characteristics, manifested by ocular lesions, recurrent genital and oral ulcers, skin symptoms and arthritis as well as neurological, intestinal, and vascular involvement. Despite the unknown cause of BD, there issome strong documentationfor immunological, genetic, environmental, and infectious factors playing a role in the pathogenesis of BD. While the nature of the genetic variants remains unidentified, many genetic risk factors are considered to contribute to BD susceptibility. Along with human leukocyte antigen gene encoding B*51 (HLA-B*51) and areas including the major histocompatibility complex class I, genome-wide association studies have recognized numerous other BD susceptibility genes including those encoding interleukin (IL)-10, IL-12 receptor β 2 (IL-12RB2), IL-23 receptor (IL-23R), C-C chemokine receptor 1 gene, signal transducer and activator of transcription 4 (STAT4), endoplasmic reticulum aminopeptidase (ERAP1), and genes encoding killer cell lectin-like receptor family members (KLRC4-KLRK1). It is believed that BD could be considered as a disorder lyingin between autoimmune and autoinflammatory syndromes. The positive responses to classical immunosuppressive agents like azathioprine and cyclosporineand involvement of autoantigens in the initiation of the disorder are the main BD features that reflect the autoimmune nature of the disorder. In this review, we address recent findings on the role of common cytokines, antibodies and immunogenetic factors in BD.

The transcription factor STAT6 plays a critical role in promoting beta cell viability and is depleted in islets of individuals with type 1 diabetes

Aims/hypothesisIn type 1 diabetes, selective beta cell loss occurs within the inflamed milieu of insulitic islets. This milieu is generated via the enhanced secretion of proinflammatory cytokines and by the loss of anti-inflammatory molecules such as IL-4 and IL-13. While the actions of proinflammatory cytokines have been well-studied in beta cells, the effects of their anti-inflammatory counterparts have received relatively little attention and we have addressed this.MethodsClonal beta cells, isolated human islets and pancreas sections from control individuals and those with type 1 diabetes were employed. Gene expression was measured using targeted gene arrays and by quantitative RT-PCR. Protein expression was monitored in cell extracts by western blotting and in tissue sections by immunocytochemistry. Target proteins were knocked down selectively with interference RNA.ResultsCytoprotection achieved with IL-4 and IL-13 is mediated by the early activation of signal transducer and activator of transcription 6 (STAT6) in beta cells, leading to the upregulation of anti-apoptotic proteins, including myeloid leukaemia-1 (MCL-1) and B cell lymphoma-extra large (BCLXL). We also report the induction of signal regulatory protein-α (SIRPα), and find that knockdown of SIRPα is associated with reduced beta cell viability. These anti-apoptotic proteins and their attendant cytoprotective effects are lost following siRNA-mediated knockdown of STAT6 in beta cells. Importantly, analysis of human pancreas sections revealed that STAT6 is markedly depleted in the beta cells of individuals with type 1 diabetes, implying the loss of cytoprotective responses.Conclusions/interpretationSelective loss of STAT6 may contribute to beta cell demise during the progression of type 1 diabetes.

STAT6 and IL-10 are required for the anti-arthritic effects of Schistosoma mansoni via different mechanisms.

To investigate possible roles of T helper type 2 (Th2) cytokines in the anti-arthritic effects of a blood fluke, Schistosoma mansoni (Sm), for mouse collagen-induced arthritis (CIA), wild-type (WT), signal transducer and activator of transcription 6 (STAT6) knock-out (KO) and interleukin (IL)-10 KO mice were infected with Sm. Three weeks after infection, the mice were immunized with bovine type II collagen (IIC). Arthritis severity was monitored by scoring, measurement of paw thickness and the presence of ankylosis. Serum anti-IIC IgG levels, splenic cytokine production and cytokine gene expression in the popliteal lymph nodes (PLNs) were measured and compared among WT and gene-KO mice. Consistent with our previous findings, Sm infection reduced the arthritis severity in WT mice. Splenic production of IL-17A and tumor necrosis factor (TNF)-α was reduced by the infection. In contrast, Sm infection markedly exacerbated CIA in STAT6 KO mice. In the KO mice, IL-17A production was increased by the infection. Conversely, Sm infection did not affect the exacerbated arthritis in IL-10 KO mice, although IL-17A production was reduced by the helminth. Our results suggest that signaling via STAT6 (presumably IL-4 and/or IL-13) and IL-10 is required for the suppression of CIA by Sm infection, but through different mechanisms. STAT6 was essential for helminth-induced reduction of IL-17A, whereas regulation of the basal arthritis severity by IL-10 was needed in order for it to be sufficiently suppressed by the helminth.

Deceleration of glycometabolism impedes IgG-producing B-cell-mediated tumor elimination by targeting SATB1.

B lymphocytes, known as antibody producers, mediate tumor cell destruction in the manner of antibody-dependent cell-mediated cytotoxicity; however, their anti-tumor function seems to be weakened during tumorigenesis, while the underlying mechanisms remain unclear. In this study, we found that IgG mediated anti-tumor effects, but IgG-producing B cells decreased in various tumors. Considering the underlying mechanism, glycometabolism was noteworthy. We found that tumor-infiltrating B cells were glucose-starved and accompanied by a deceleration of glycometabolism. Both inhibition of glycometabolism and deprivation of glucose through tumor cells, or glucose-free treatment, reduced the differentiation of B cells into IgG-producing cells. In this process, special AT-rich sequence-binding protein-1 (SATB1) was significantly silenced in B cells. Down-regulating SATB1 by inhibiting glycometabolism or RNA interference reduced the binding of signal transducer and activator of transcription 6 (STAT6) to the promoter of germline Cγ gene, subsequently resulting in fewer B cells producing IgG. Our findings provide the first evidence that glycometabolic inhibition by tumorigenesis suppresses differentiation of B cells into IgG-producing cells, and altering glycometabolism may be promising in improving the anti-tumor effect of B cells.

Effect of flotillin-1 gene small interfering RNA combined with curcumin on apoptosis of renal cell carcinoma in vitro

Objective To investigate the effect of flotillin-1 (FLOT1) small interfering RNA (siRNA) combined with curcumin on the apoptosis of renal cell carcinoma. Methods FLOT1-siRNA was transfected into 786-0 cells of human renal carcinoma by Lipofectamine™ 2000. The protein expression of FLOT1 in the cells transfected with siRNA was detected by Western blotting. Thereafter, FLOT1-siRNA, curcumin and FLOT1-siRNA+ curcumin were used for cell intervention, and a blank control group was set up. The cell viability and apoptosis rate of four groups were detected by cell counting kit-8 (CCK-8) assay and flow cytometry. H2DCFHDA probe was used to detect the content of ROS in four groups. The expression levels of phosphorylated signal transducer and activators of transcription 3 (p-STAT3), proliferating cell nuclear antigen (PCNA) and B cell lymphoma/leukemia-2 associated X protein (bax) protein were detected by Western blotting. Results The expression of FLOT1 (0.087±0.010) was significantly inhibited in 786-0 cells transfected with FLOT1-siRNA, and the difference was statistically significant as compared with the blank control group (0.454±0.038) (t=16.177, P=0.000). Si-FLOT1 (0.491±0.053) or curcumin (0.542±0.058) could inhibit the activity of 786-0 cells, induce 786-0 cell apoptosis [(18.22±1.07)% and (12.39±0.86)%] and ROS production [(189.5±8.2) and (147.7±7.1)], down-regulate the expression of p-STAT3 [(0.118±0.014) and (0.110±0.012)] and PCNA [(0.229±0.025) and (0.302±0.034)] and up-regulate the expression of bax [(0.206±0.021) and (0.123±0.014)], and the difference was statistically significant as compared with NC group [(0.792±0.065), (1.62±0.25)%, (57.7±3.5), (0.202±0.023), (0.577±0.049), (0.069±0.010)] (t=6.736, 7.378, 12.796, 10.112, 7.186, 2.832, P=0.000, 0.000, 0.000, 0.000, 0.000, 0.022). Combined use of si-FLOT1 and curcumin could inhibit the activity of 786-0 cells [(0.378±0.044)], induce apoptosis [(24.18±1.22)%] and ROS production [(249.3±9.4)], down-regulate the expression of p-STAT3 [(0.054±0.008)] and PCNA [(0.135±0.016)] and up-regulate the expression of bax [(0.411±0.038)], with the difference being statistically significant as compared with single si-FLOT1 group or curcumin group (t=5.132, 4.491, 3.456, 6.140, 10.752, 15.106, P=0.001, 0.002, 0.009, 0.000, 0.000, 0.000). Conclusion FLOT1 siRNA or curcumin can inhibit the viability of renal cell carcinoma cells and induce apoptosis, and the combined use of FLOT1 siRNA and curcumin can be more obvious to cell viability and apoptosis. The mechanism may be related to the increases in intracellular ROS and the inhibition of STAT3 signal. Key words: Renal cell carcinoma; Flotillin-1 gene; Curcumin; Apoptosis; Signal transducer and activators of transcription 3 signaling pathway

GW29-e0335 Hyperglycemia induces formation of LMP7 in cardiomyocytes: involvement of STAT3

GW29-e0335 Hyperglycemia induces formation of LMP7 in cardiomyocytes: involvement of STAT3

Correction: The ratio of STAT1 to STAT3 expression is a determinant of colorectal cancer growth.

[This corrects the article DOI: 10.18632/oncotarget.9315.].