To study the preventive effect of sophocarpine (Soc) on dextran sulfate sodium (DSS)-induced colitis in mice, in order to analyze the influence of Soc on toll like receptor 4 (TLR4)/mitogen-activated protein kinases (MAPKs) and janus tyrosine kinase 2 signal transducer and activator of transcription 3 (JAK2/STAT3) signal pathways in mice intestinal tissues. The mice was given 2.5% DSS for 6 days to induce the acute colitis model. The Soc-treated group was intraperitoneally injected with sophocarpine 30 mg · kg(-1) · d(-1) since the day before the experiment to the end. The disease activity index (DAI) was assessed everyday, and the colonic morphology and histological damage were observed with HE staining. The mRNA expressions of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 (IL-6) were detected by real-time RT-PCR. The changes in key protein kinase p38 mitogen-activated protein kinase (p38MAPK), c-Jun NH2-terminal protein kinase1/2 (JNK1/2), extracellular signal-regulated kinase1/2 (ERK1/2), JAK2, STAT3 in TLR4/MAPKs and JAK2/STAT3 signaling pathways were detected by western blot. The result showed that the model group showed statistical significance in body weight, DAI, colon length and histopathological changes compared with the normal group (P <0.05); however, the Soc-treated group showed significant improvements in the above indexes compared with the model group (P <0.05). TNF-α, IL-1β and IL-6 in the model group was significantly higher than that in the normal group (P <0.05), but lowered in the Soc-treated group to varying degrees (P <0.05). In the normal group, the expressions of TLR4 and the phosphorylation of P38, JNK1/2, JAK2, STAT3 were at low levels; in the model group, the phosphorylation of P38, JNK1/2, JAK2, STAT3 increased; the Soc-treated group showed a decrease in TLR4 expression compared with the model group, with notable declines in the phosphorylation of TLR4, P38, JNK1/2, JAK2, STAT3. These findings indicate that Soc can inhibit TLR4/MAPKs, K2/STAT3 signaling pathway activation, reduce the expression of proinflammatory cytokines TNF-α, IL-1β and IL-6 and relieve inflammatory reactions, so as to effectively prevent experimental colitis.
Alkaloids ; pharmacology ; therapeutic use ; Animals ; Colitis ; drug therapy ; immunology ; pathology ; Cytokines ; genetics ; Janus Kinase 2 ; antagonists & inhibitors ; physiology ; Male ; Mice ; Mice, Inbred BALB C ; Phosphorylation ; STAT3 Transcription Factor ; antagonists & inhibitors ; physiology ; Toll-Like Receptor 4 ; antagonists & inhibitors ; physiology

OBJECTIVETo investigate the inflammatory signal transduction of high mobility group box-1 protein (HMGB1) induced inflammatory response in rat peritoneal macrophages.

METHODSPeritoneal macrophages obtained from male Wistar rats were seeded in 24-well (1 x 10(6) cells/well) tissue culture plates. The cells were incubated for 3 days before they were stimulated with HMGB1, and treated with Fludarabine [the specific inhibitor of signal transducer and activator of transcription 1 (STAT1)] or Rapamycin (the specific inhibitor of STAT3). The time-dependent and dose-dependent responses between HMGB1 stimulation and tumor necrosis factor-alpha (TNF-alpha) gene expression as well as release were analyzed respectively. Moreover, the effect of Fludarabine and Rapamycin on TNF-alpha mRNA expression and protein release were also observed.

RESULTS(1) After HMGB1 challenge, TNF-alpha mRNA expressions were up-regulated markedly, peaked at 24 hours, and decreased at 36 hours. When HMGB1 was used at a concentration of 10 microg/ml, TNF-alpha mRNA expression increased most markedly. (2) HMGB1 could induce TNF-alpha release in rat peritoneal macrophages, with peaking at 4 hours and decreasing at 8 hours later. When the concentration of HMGB1 stimulation increased from 5 microg/ml to 25 microg/ml, TNF-alpha release was persistently enhanced. (3) It was also showed that TNF-alpha mRNA expression was significantly inhibited by treatment of either Fludarabine (100 micromol/L) or Rapamycin (25 ng/ml), while TNF-alpha release was not markedly suppressed.

CONCLUSIONSSTAT1 and STAT3 might be involved in the regulation of TNF-alpha gene expression, but not in TNF-alpha early release (< 24 hours) induced by HMGB1 stimulation in rat peritoneal macrophages.

Animals ; Cells, Cultured ; Drug Interactions ; HMGB1 Protein ; pharmacology ; Macrophages, Peritoneal ; drug effects ; metabolism ; Male ; Rats ; Rats, Wistar ; STAT1 Transcription Factor ; antagonists & inhibitors ; STAT3 Transcription Factor ; antagonists & inhibitors ; Signal Transduction ; Sirolimus ; pharmacology ; Transcription, Genetic ; Tumor Necrosis Factor-alpha ; biosynthesis ; genetics ; Vidarabine ; analogs & derivatives ; pharmacology

OBJECTIVETo observe the changes in the expressions of STAT3 and NF-KB in PC-3 cells after IL-6 stimulation and to verify the effects of the NF-KB inhibitor caffeic acid phenethyl ester (CAPE) on the expressions of p-STAT3 and IL-6 in the PC-3 prostate cancer cell line.

METHODSPC-3 prostate cancer cells were treated with IL-6 at 20 ng/ml for 5, 10, 20, 30 and 45 min. The protein and mRNA expressions of STAT3 and NF-kappaB were measured by Western blot and real time PCR, respectively, and the cell cycle was detected by flow cytometry. The PC-3 cells were exposed to TNF-alpha or TNF-alpha + CAPE, followed by determination of the IL-6 expression in the supernatant of the cells by ELISA and the expression of p-STAT3 by Western blot.

RESULTSAfter IL-6 stimulation, both the expression of p-STAT3 protein and the proliferation index of the PC-3 cells were significantly increased, and so were the expressions of IL-6 and p-STAT3 protein in the supernatant after TNF-alpha treatment (P < 0.05). TNF-alpha + CAPE induced statistically lower expressions of IL-6 and p-STAT3 than TNF-alpha alone (P < 0.05).

CONCLUSIONCAPE can inhibit IL-6 secretion induced by TNF-alpha in PC-3 cells and thus suppress STAT3 translocation. Therefore, by inhibiting the expression of NF-kappaB and affecting STAT3 and other related cell signaling pathways, CAPE may become a new therapeutic option for prostate cancer.

Caffeic Acids ; pharmacology ; Cell Line, Tumor ; Humans ; Interleukin-6 ; metabolism ; pharmacology ; Male ; NF-kappa B ; antagonists & inhibitors ; Phenylethyl Alcohol ; analogs & derivatives ; pharmacology ; Prostatic Neoplasms ; metabolism ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tumor Necrosis Factor-alpha ; pharmacology

OBJECTIVETo study the role of epidermal growth factor receptor (EGFR) in the proliferation and survival of human myeloma cells.

METHODSThe inhibitor of EGFR, PD153035, was used to block the signal transduction of EGFR. The proliferation and apoptosis of myeloma cell line, XG-1, were detected by 3H-TCR incorporation assay and Annexin V staining analysis, respectively. The phosphatation of STAT3, the key activate signal to the myeloma cell proliferation, was detected with Western blot.

RESULTSPD153035 decreased the proliferation of XG-1 and induced an obvious apoptosis in XG-1. The phosphatation of STAT3 induced by HB-EGF but not by IL-6 was blocked by PD153035.

CONCLUSIONThe proliferation and survival of myeloma cells may be suppressed by PD153035 due to the blockage of phosphatation of STAT3 induced by the activation of EGFR.

Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Cell Division ; Cell Line, Tumor ; DNA-Binding Proteins ; metabolism ; Humans ; Multiple Myeloma ; pathology ; Quinazolines ; pharmacology ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; STAT3 Transcription Factor ; Trans-Activators ; metabolism

OBJECTIVELipoxin A(4) is formed by the metabolism of arachidonic acid. Anti-inflammatory and anti-proliferative effect of lipoxin A(4) has been shown in many human diseases. Recently, as a novel high affinity receptor for ligand lipoxin A(4), Lipoxin A(4) receptor-like protein (LRLP) has been identified. Currently close attention is paid to the important contribution of connective tissue growth factor (CTGF) in lung fibrosis. The purpose of the study was to transfect LRLP gene into human lung fibroblasts and investigate the mechanism of its enhancing antagonistic effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by connective tissue growth factor.

METHODSEukaryocytic expression vector pEGFP/LRLP which contained LRLP and green fluorescence protein fusion gene (GFP) was constructed and transfected into human lung fibroblasts (HLF). After selecting with G418, HLF/LRLP cell clone which stably expressed LRLP/GFP fusion protein was isolated and characterized by the laser scanning confocal microscope. Cultured HLF and HLF/LRLP were stimulated for 24 h with CTGF (1 microg/ml) in the presence and absence of pretreatment of Lipoxin A(4) (10.0 nmol/L) for 30 min. Inhibition of cell proliferation was determined by MTT assay. Cell cycle analysis was performed by flow cytometry. Western blot was used to detect the expression of cyclin D(1) protein. Electrophoretic mobility shift assay (EMSA) was employed to detect the DNA binding activity of STAT(3).

RESULTS(1) HLF/LRLP cell clone which stably expressed LRLP and GFP fusion protein was successfully obtained. (2) Proliferation of HLF and HLF/LRLP was induced by 1 microg/ml CTGF. Pretreatment with 10 nm Lipoxin A(4) inhibited the proliferation of HLF and HLF/LRLP. And the inhibitory rate of HLF/LRLP was significantly higher than that of HLF [(54.1 +/- 4.2)%, (21.2 +/- 3.7)%, P < 0.05]. (3) The flow cytometry analysis showed that compared with HLF, more HLF/LRLP were arrested at G(0)/G(1) phase in the presence of pretreatment of Lipoxin A(4). [(76.3 +/- 3.5)%, (60.8 +/- 2.0)%, P < 0.05]. (4) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of cyclin D(1) protein expression in HLF and HLF/LRLP. And its antagonistic effect on HLR/LRLP was stronger than that on HLF (P < 0.05). (5) Ten nmol/L Lipoxin A(4) antagonized CTGF induced increase of STAT(3) DNA binding activity, and its antagonistic effect on HLF/LRLP was more powerful than that on HLF (P < 0.05).

CONCLUSIONSTransfection of Lipoxin A(4) receptor-like protein gene enhanced the inhibitory effect of Lipoxin A(4) on human lung fibroblasts proliferation induced by CTGF. Its mechanism might be related to regulation of cyclin D(1) protein expression and STAT(3) DNA binding activity.

Connective Tissue Growth Factor ; antagonists & inhibitors ; Cyclin D1 ; analysis ; DNA ; metabolism ; Fibroblasts ; cytology ; drug effects ; Humans ; Lipoxins ; pharmacology ; Lung ; cytology ; drug effects ; Receptors, Formyl Peptide ; genetics ; physiology ; Receptors, Lipoxin ; genetics ; physiology ; STAT3 Transcription Factor ; metabolism ; Transfection

OBJECTIVETo observe the effect of anti-survivin oligonucleotides (ASODN) on the invasion and growth of peritoneally implanted ovarian cancer cell xenografts in nude mice.

METHODSNude mouse models bearing peritoneally implanted ovarian cancer cell (SKOV3) xenografts were established and subjected to intraperitoneal injection of survivin ASODN or saline (control). The number and weight of the intraperitoneal xenografts were compared between the two groups.The expressions of interleukin (IL-6), signal transducer and activator of transcription3 (STAT3), phosphorylated STAT3 (p-STAT3), and survivin protein in the tumor tissues were detected with Western blotting in both groups.

RESULTSCompared with those in the control group, the number and weight of the intraperitoneal xenografts were significantly reduced in ASODN group (P<0.05). ASODN treatment also resulted in significantly lowered protein levels of IL-6, STAT3, p-STAT3, and survivin in the tumor tissues (P<0.05).

CONCLUSIONSurvivin ASODN can suppress the invasion and migration capacity of ovarian cancer cells and inhibit peritoneal metastasis of the tumor in nude mice possibly though down-regulation of IL-6/STAT3 signaling pathway.

Animals ; Cell Line, Tumor ; Down-Regulation ; Female ; Humans ; Inhibitor of Apoptosis Proteins ; antagonists & inhibitors ; metabolism ; Interleukin-6 ; metabolism ; Mice ; Mice, Nude ; Neoplasm Transplantation ; Oligonucleotides ; pharmacology ; Ovarian Neoplasms ; pathology ; therapy ; STAT3 Transcription Factor ; metabolism

BACKGROUNDSignal transducer and activator of transcription 3 (STAT3) is usually constitutively activated in a variety of malignancies. It directly contributes to tumorigenesis, invasion, and metastasis. The surgical treatment of breast cancer has made no breakthroughs in terms of treatment effect, in spite of its long history. Current biotherapies bring a note of optimism to breast cancer treatment. To explore the possibility of a siRNA targeted STAT3 blocking treatment for over-activated tumor cells, we evaluated the efficacy of a STAT3 siRNA on human breast cancer cells in vitro and in vivo.

METHODSThree MCF-7 human breast cancer cell lines were tested: control MCF-7 cells, non-specific siRNA transfected MCF-7 cells and STAT3 siRNA transfected MCF-7 cells. Expression of STAT3 in MCF-7 cells was inhibited by RNA interference (RNAi). The STAT3 mRNA and protein levels were detected by semi-quantity RT-PCR and Western blotting. Cell proliferation and apoptosis were determined by MTT method and flow cytometry. The three groups of MCF-7 cells mentioned above were transplanted subcutanuously into nude mice and their tumorgenic ability observed. The STAT3 mRNA and protein levels of the samples from tumors in different groups were determined by semi-quantity RT-PCR and Western blotting and compared.

RESULTSIn STAT3 siRNA transfected MCF-7 cells, the expressions (STAT3/β-actin) of STAT3 mRNA (0.327 ± 0.020) and protein (0.153 ± 0.006) were significantly lower than that in control MCF-7 cells (mRNA 1.093 ± 0.018, protein 1.374 ± 0.022) and non-specific siRNA transfected MCF-7 cells (mRNA 1.035 ± 0.050, protein 1.320 ± 0.033) (P < 0.05). MTT showed that cell proliferation was significantly reduced and the cell growth inhibition ratio in the STAT3-siRNA group was (44.00 ± 5.10)%, significantly higher than that in non-specific siRNA transfected MCF-7 cells ((16.10 ± 1.05)%, P < 0.05). Flow cytometry results showed that more apoptosis was observed in the STAT3-siRNA group. The rate of apoptosis was (14.79 ± 0.22)%, much higher than in control MCF-7 cells (7.06 ± 0.71) and non-specific siRNA transfected MCF-7 cells (8.45 ± 0.43) (P < 0.05). The tumor growth in the STAT3 siRNA transfected MCF-7 cells was significantly slower than in the two control groups. On the 22th day after transplantation the tumor weight ((21.40 ± 10.57) mg) and volume ((41.15 ± 12.17) mm(3)) in the STAT3 siRNA transfected group were significantly lower than in control group (weight (88.60 ± 12.16) mg, volume (118.45 ± 24.68) mm(3)) and non-specific siRNA transfected group (weight (57.20 ± 21.86) mg, volume (101.36 ± 21.90) mm(3)) (P < 0.05). Both the STAT3 mRNA and protein levels in the tumors from the STAT3 siRNA transfected group were significantly lower than in the tumors from the two control groups.

CONCLUSIONSSTAT3 siRNA can effectively silence the STAT3 gene in vitro and in vivo, increase cell apoptosis rate and significantly decrease cell proliferation, which inhibits the growth of breast cancer cell in vitro. Tumor growth of xenograft mice is significantly inhibited. The results obtained in vivo are in consistency with those in vitro. STAT3 may be a novel therapeutic target for breast cancer and RNA interference has potential clinical application.

Animals ; Apoptosis ; Cell Line, Tumor ; Female ; Humans ; Mammary Neoplasms, Experimental ; pathology ; therapy ; Mice ; Mice, Nude ; RNA, Small Interfering ; genetics ; STAT3 Transcription Factor ; antagonists & inhibitors ; genetics ; Xenograft Model Antitumor Assays

Interleukin-6 (IL-6) is an important cytokine that participates in inflammation reaction and cell growth and differentiation in the immune and nervous systems. However, the neuroprotection of IL-6 against N-methyl-D-aspartate (NMDA)-induced neurotoxicity and the related underlying mechanisms are still not identified. In the present study, the cultured cerebellar granule neurons (CGNs) from postnatal (8-day) infant rats were chronically exposed to IL-6 for 8 d, and then NMDA (100 micromol/L) was applied to the cultured CGNs for 30 min. Methyl-thiazole-tetrazolium (MTT) assay, terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) method and confocal laser scanning microscope (CLSM) were used to detect neuronal vitality, apoptosis and dynamic changes of intracellular Ca(2+) levels in the neurons, respectively. Anti-gp130 monoclonal antibody (75 ng/mL) was employed to the cultured CGNs with IL-6 to inhibit IL-6 activity so as to evaluate the role of gp130 (a 130 kDa glucoprotein transducing IL-6 signal) in mediating IL-6 neuroprotection. Western blot was used to measure the expressions of phospho-signal transducer and activator of transcription 3 (STAT3) and phospho-extracellular signal regulated kinase 1/2 (ERK1/2) in the cultured CGNs. The NMDA stimulation of the cultured CGNs without IL-6 pretreatment resulted in a significant reduction of the neuronal vitality, notable enhancement of the neuronal apoptosis and intracellular Ca(2+) overload in the neurons. The NMDA stimulation of the CGNs chronically pretreated with IL-6 caused a remarkable increase in the neuronal vitality, marked suppression of neuronal apoptosis and intracellular Ca(2+) overload in the neurons, compared with that in the control neurons without IL-6 pretreatment. Furthermore, anti-gp130 antibody blocked the inhibitory effect of IL-6 on NMDA-induced intracellular Ca(2+) overload in the neurons. The levels of phospho-STAT3 and phospho-ERK1/2 were significantly higher in IL-6-pretreated CGNs than those in IL-6-untreated neurons. The results suggest that chronic IL-6 pretreatment of CGNs protects the neurons against NMDA-induced neurotoxicity. The neuroprotective effect of IL-6 is closely related to its suppression of NMDA-induced intracellular Ca(2+) overload and is possibly mediated by gp130/JAK-STAT3 and gp130/RAS-ERK1/2 transduction pathways.
Animals ; Animals, Newborn ; Cells, Cultured ; Cerebellum ; cytology ; drug effects ; metabolism ; Interleukin-6 ; physiology ; MAP Kinase Signaling System ; N-Methylaspartate ; antagonists & inhibitors ; toxicity ; Neurons ; cytology ; drug effects ; metabolism ; Neuroprotective Agents ; Rats ; Rats, Sprague-Dawley ; STAT3 Transcription Factor ; metabolism

Head and neck squamous cell carcinomas (HNSCC) are common human malignancies with poor clinical outcomes. The 5-year survival rates for patients with advanced stage HNSCC have not changed appreciably in the past few decades, underscoring a dire need for improved therapeutic options. Recent studies have elucidated a key signaling axis, the EGFR-STAT3-Bcl-XL signaling axis, that is aberrantly activated in a majority of HNSCC and contributes to the proliferation and survival of malignant cells. Considerable effort is being placed on developing highly specific inhibitors of different components of this pathway. This review highlights the progress that is being made towards achieving potent inhibition of the EGFR-STAT3-Bcl-XL signaling axis in HNSCC and the promising therapeutic strategies that are currently under development for this disease.
Animals ; Antibodies, Monoclonal ; pharmacology ; Antineoplastic Agents ; pharmacology ; Apoptosis ; Biphenyl Compounds ; pharmacology ; Cell Proliferation ; Head and Neck Neoplasms ; metabolism ; pathology ; Humans ; Nitrophenols ; pharmacology ; Piperazines ; pharmacology ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; STAT3 Transcription Factor ; antagonists & inhibitors ; metabolism ; Signal Transduction ; drug effects ; Sulfonamides ; pharmacology ; bcl-X Protein ; antagonists & inhibitors ; metabolism

Persistently activated JAK/STAT3 signaling pathway plays a pivotal role in various human cancers including major carcinomas and hematologic tumors, and is implicated in cancer cell survival and proliferation. Therefore, inhibition of JAK/STAT3 signaling may be a clinical application in cancer therapy. Here, we report that 2-cyclohexylimino-6-methyl-6,7-dihydro-5H-benzo [1,3]oxathiol-4-one (BOT-4-one), a small molecule inhibitor of JAK/STAT3 signaling, induces apoptosis through inhibition of STAT3 activation. BOT-4-one suppressed cytokine (upd)-induced tyrosine phosphorylation and transcriptional activity of STAT92E, the sole Drosophila STAT homolog. Consequently, BOT-4-one significantly inhibited STAT3 tyrosine phosphorylation and expression of STAT3 downstream target gene SOCS3 in various human cancer cell lines, and its effect was more potent in JAK3-activated Hodgkin's lymphoma cell line than in JAK2-activated breast cancer and prostate cancer cell lines. In addition, BOT-4-one-treated Hodgkin's lymphoma cells showed decreased cell survival and proliferation by inducing apoptosis through down-regulation of STAT3 downstream target anti-apoptotic gene expression. These results suggest that BOT-4-one is a novel small molecule inhibitor of JAK3/STAT3 signaling and may have therapeutic potential in the treatment of human cancers harboring aberrant JAK3/STAT3 signaling, specifically Hodgkin's lymphoma.
Animals ; Antineoplastic Agents/chemistry/*pharmacology ; Apoptosis/drug effects ; Bicyclo Compounds, Heterocyclic/chemistry/*pharmacology ; Cell Line ; Cell Proliferation/drug effects ; Cell Survival/drug effects ; Drosophila/enzymology/metabolism ; Drosophila Proteins/antagonists & inhibitors/metabolism ; Enzyme Activation/*drug effects ; Gene Expression Regulation, Neoplastic/*drug effects ; Humans ; Janus Kinase 3/*antagonists & inhibitors/metabolism ; Lymphoma/enzymology/*metabolism ; Phosphorylation/drug effects ; STAT Transcription Factors/antagonists & inhibitors/metabolism ; STAT3 Transcription Factor/*antagonists & inhibitors/metabolism ; Signal Transduction/*drug effects