OBJECTIVE: To study the effects of oligodeoxynucleotides complementary Stat3 on apoptosis in laryngeal carcinoma Hep-2 cell. METHOD: Oligodeoxynucleotides complementary Stat3 was designed, which was transferred into laryngeal carcinoma Hep-2 cell by lipofection. Expression of Stat3 and p-Stat3 were detected by Western blot and PCR. MTT was used to observe the growth-inhibiting ratio. DNA ladder, AO/EB and FCM were used to observe the apoptosis of laryngeal carcinoma cell Hep-2 in vitro. RESULT: Western blot and PCR results demonstrated that oligodeoxynucleotides complementary Stat3 could significantly inhibit the expression of Stat3 and p-Stat3 in Hep-2 cell. MTT results showed that it could significantly suppress the growth of Hep-2 cell. The DNA ladder, AO/EB and FCM results showed it could inhibit the expression of Stat3 and induce the apoptosis of Hep-2 cell in a concentration-dependent manner. CONCLUSION Oligodeoxynucleotides complementary Stat3 could induce the apoptosis and suppress cell proliferation in laryngeal carcinoma Hep-2 cell.
Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Humans ; Oligodeoxyribonucleotides ; genetics ; pharmacology ; STAT3 Transcription Factor ; genetics ; Transfection

OBJECTIVETo investigate the anti-cancer efficacy and mechanism of sorafenib and 5-fluorouracil (5-FU) therapy in vitro using the HCC cell line MHCCLM3.

METHODSThe effects of sorafenib and 5-FU, alone or in combination, on the proliferation of MHCCLM3 cells were evaluated by cell viability assays. Combined-effects analyses were conducted according to the median-effect principle established by Chou and Talalay. Effects on cell cycle distributions were tested by flow cytometry and expression of proteins related to the RAF/MEK/ERK and STAT3 signaling pathways and cyclinD1 were tested by western blotting.

RESULTSSorafenib and 5-FU alone or in combination displayed significant efficacy in inhibiting proliferation of the MHCCLM3 cells, with the following inhibition rates: sorafenib: 46.16% +/- 2.52%, 5-FU: 28.67% +/- 6.16%, and sorafenib + 5-FU: 22.59% +/- 6.89%. The sorafenib + 5-FU combination did not provide better results than treatment with either drug alone. The combination index values of the sorafenib and 5-FU treatments were mainly greater than 1, indicating that the two agents induced antagonistic, instead of synergistic, effects on the MHCCLM3 cells. In addition, the MHCCLM3 cells were less sensitive to 5-FU when administrated in combination with sorafenib, as evidenced by the half inhibitory concentration (IC50) significantly increasing from (102.86 +/- 27.84) mg/L to (178.61 +/- 20.73) mg/L (P = 0.003). Sorafenib alone induced G1 phase arrest (increasing from 44.73% +/- 1.63% to 65.80% +/- 0.56%; P less than 0.001) and significantly decreased the proportion of cells in S phase (decreasing from 46.63% +/- 0.65% to 22.83% +/- 1.75%; P less than 0.01), as well as down-regulated cyclinD1 expression (0.57 +/- 0.03-fold change vs. untreated control group; P less than 0.01). 5-FU alone up-regulated cyclinD1 expression (1.45 +/- 0.12-fold change vs. untreated control group; P less than 0.01). Moreover, sorafenib alone significantly inhibited the RAF/MEK/ERK and STAT3 pathways, with the fold-changes of p-C-RAF, p-ERK1/2 and p-STAT3 being 0.56 +/- 0.05, 0.54 +/- 0.02 and 0.36 +/- 0.02, respectively (all P less than 0.01); 5-FU alone produced no significant effects on these pathways.

CONCLUSIONAdministered alone, both sorafenib and 5-FU exert anti-tumoral activity on in vitro cultured HCC cells. The sorafenib + 5-FU combination treatment produces antagonistic, rather than synergistic, effects. Sorafenib-inhibited RAF/MEK/ERK and STAT3 signaling and cyclinD1 expression may have induced the observed G1phase arrest and S phase reduction, thereby reducing the cells' sensitivity to 5-FU.

Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cyclin D1 ; metabolism ; Drug Antagonism ; Fluorouracil ; pharmacology ; Humans ; Niacinamide ; analogs & derivatives ; pharmacology ; Phenylurea Compounds ; pharmacology ; STAT3 Transcription Factor ; metabolism ; Signal Transduction

OBJECTIVETo investigate the role of TGF-beta1 and STAT3 signaling in liver fibrosis using a rat model system and to determine the therapeutic mechanism of AG490 in relation to this signaling pathway.

METHODSRats were randomly divided into a control group and DENA-induced liver fibrosis model group, and then subdivided into AG490 treatment groups. During fibrosis development, liver tissue samples were collected at different time points (0, 4 and 8 weeks) and evaluated according to the Scheuer scoring system. Expression of STAT3, TGFbeta1, alpha-SMA, E-cadherin, MMP2 and TIMP1 was measured by PCR (mRNA) and immunohistochemistry and western blotting (protein).

RESULTSIncreasing degrees of inflammation and fibrosis were observed in liver tissues of DENA-treated rats throughout model establishment. The mRNA expression of TGFbeta1 and STAT3 was significantly increased in DENA-induced rats with advanced fibrosis (AF) compared to those with early fibrosis (EF) (P = 0.034 and P = 0.012 respectively). The protein expression of TGF-beta1, phospho-Smad2, alpha-SMA, E-cadherin, STAT3 and phospho-STAT3 was significantly increased in DENA-induced rats with AF compared to the unmodeled control group (P = 0.048, P = 0.003, P = 0.002, P = 0.028, P = 0.009 and P = 0.039). The protein expression of E-cadherin was lower in the DENA-induced rats with AF than in those with EF (P = 0.026). STAT3 and TGF-beta1 co-expression was detected in AF tissues. DENA-induced AG490-treated rats with AF showed substantially lower protein expression of STAT3, TGF-beta1, MMP2 and TIMP1 compared to DENA-induced untreated rats with AF (P = 0.006, P = 0.018, P = 0.010 and P = 0.005); in addition, the degrees of fibrosis and inflammation were also greatly reduced in the DENA-induced AG490-treated rats with AF compared to DENA-induced untreated rats with AF (P = 0.042 and P = 0.021). Conclusions STAT3 signal transduction may regulate the TGF-beta1 pathway and affect liver fibrosis, especially in the advanced phase. AG490 can inhibit TGFbeta1-STAT3 signaling, resulting in reversal of liver fibrosis.

Animals ; Disease Models, Animal ; Liver Cirrhosis ; chemically induced ; metabolism ; Rats ; Rats, Sprague-Dawley ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Transforming Growth Factor beta1 ; metabolism ; Tyrphostins ; pharmacology

OBJECTIVETo investigate the effects of cycle-dependent kinase (CDK) inhibitor SNS-032 on apoptosis in human acute myeloid leukemia (AML) HL-60 cells and its molecular mechanisms.

METHODSCultured AML HL-60 cells were treated with various concentrations of SNS-032. Cell apoptosis was determined with flow cytometry;cell viability was measured by MTT assay; the profiles of microRNA expression of HL-60 cells were analyzed by microRNA microarray;the protein expressions of JAK2/STAT3 pathway were detected by Western blotting.

RESULTSApoptosis of AML HL-60 cells was induced by SNS-032; the rate of apoptosis was (5.9±1.7)%, (12.1±3.1)% and (59.4±3.6)% when HL-60 cells were treated with 0,100 and 200 nmol/L SNS-032. MicroRNA microarray analysis revealed that the levels of miR-30a, miR-183, miR-20b, miR-26b, miR-20a, miR-589, miR-107, miR-181a, miR-106a, miR-17 and miR-378c were down-regulated by SNS-032,whereas the levels of miR-320a and miR-H7* were up-regulated. Western blotting showed that SNS-032 strongly inhibited phosphorylation of STAT3 and protein expression of JAK2,C-MYC and MCL-1.

CONCLUSIONCDK inhibitor SNS-032 can induce apoptosis of AML HL-60 cells, which is associated with the inhibition of MCL-1,C-MYC and JAK2/STAT3, and down-regulation of miR-17-92 family.

Apoptosis ; Cell Survival ; Down-Regulation ; Flow Cytometry ; HL-60 Cells ; Humans ; Janus Kinase 2 ; metabolism ; MicroRNAs ; metabolism ; Oxazoles ; pharmacology ; Phosphorylation ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Thiazoles ; pharmacology

BACKGROUNDAdvances in the understanding of cardiovascular pathogenesis have highlighted that inflammation plays a central role in atherosclerotic coronary heart disease. Therefore, exploring pharmacologically based anti-inflammatory treatments to be used in cardiovascular therapeutics is worthwhile to promote the discovery of novel ways of treating cardiovascular disorders.

METHODSThe myocardial cell line H9c2(2-1) was exposed to lipopolysaccharide (LPS) in culture and resulted in a cellular pro-inflammation status. miR-21 microRNA levels were detected using quantitative real-time polymerase chain reaction (Q-RT-PCR). The influence of lovastatin on miR-21 under normal and pro-inflammatory conditions was tested after being added to the cell culture mixture for 24 hours. Conditional gene function of two predicted cardiovascular system relevant downstream targets of miR-21, protein phosphatase 1 regulatory subunit 3A (PPP1R3A) and signal transducer and activator of transcription 3 (STAT3), were analyzed with immunoblotting.

RESULTSForty-eight hours of LPS treatment significantly increased the miR-21 to 170.71%± 34.32% of control levels (P = 0.002). Co-treatment with lovastatin for 24 hours before harvesting attenuated the up-regulation of miR-21 (P = 0.013). Twenty-four hours of lovastatin exposure up-regulated PPP1R3A to 143.85%± 21.89% of control levels in cardiomyocytes (P = 0.023). Lovastatin up-regulated the phosphorylation level of STAT3 compared to the background LPS pretreatment (P = 0.0077), this effect was significantly (P = 0.018) blunted when miR-21 was functionally inhibited.

CONCLUSIONSmiR-21 plays a major role in the regulation of the cellular anti-inflammation effects of lovastatin.

Blotting, Western ; Cell Line ; Humans ; Lipopolysaccharides ; pharmacology ; Lovastatin ; pharmacology ; MicroRNAs ; genetics ; Myocardium ; metabolism ; Myocytes, Cardiac ; drug effects ; metabolism ; Phosphoprotein Phosphatases ; metabolism ; Phosphorylation ; STAT3 Transcription Factor ; metabolism

OBJECTIVETo study the effect of matrine and oxymatrine on proliferation and the expression of Stat3, Stat5 mRNA in SMMC-7721 cell line.

METHODTreated with matrine and oxymatrine, the inhibitory effect on SMMC-7721 cell proliferation was detected by MTT, double fluorescence labeling was applied to measure the apotosis ratios of SMMC-7721cells, the expression of Stat3 and Stat5 mRNA in SMMC-7721 cell line were assessed with RT-PCR.

RESULTMatrine and oxymatrine could inhibit the proliferation and induce the apoptosis of SMMC-7721 cells and it was time and dose dependent, the expression of Stat3 and Stat5 mRNA in SMMC-7721 cell with matrine and oxymatrine were significantly lower than those in control group (P<0.05 or P<0.01). Compared with the same dose of matrine and oxymatrine, matrine showed stronger effect on cell proliferation, apoptosis, and Stat3 and Stat5 mRNA (P<0.05 or P<0.01).

CONCLUSIONMatrine and oxymatrine inhibited the proliferation and induced the of SMMC-7721 cells significantly, the mechanism of which might be related to the down-regulation of stat3 and stat5 mRNA and inhibition of the signaling transduction pathway.

Alkaloids ; pharmacology ; Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Drugs, Chinese Herbal ; pharmacology ; Gene Expression Regulation ; drug effects ; Humans ; Quinolizines ; pharmacology ; Reverse Transcriptase Polymerase Chain Reaction ; STAT3 Transcription Factor ; genetics ; STAT5 Transcription Factor ; genetics

OBJECTIVETo investigate the effect of cardiotrophin-1 (CT-1) on the GATA4 expression and related signaling pathways (JAK-STAT3, ERK1/2 and PI3-K) in rat cardiomyocytes.

METHODSUsing semi-quantitative RT-PCR and EMSA, we measured the dose and time dependent effects of CT-1 on GATA4 mRNA and binding activity in cultured rat cardiomyocytes. Parthenolide (a STAT inhibitor), U-0126 (an ERK inhibitor) and LY-294002 (a PI3-K inhibitor) alone or in combination were added to the culture medium to assess the role of above signaling pathways in CT-1 mediated effects.

RESULTSGATA4 mRNA expression significantly increased at 3 h post 0.1 nmol/L CT-1 exposure, peaked at 6 h and remained high till 24 h post exposure. The GATA4 binding activity began to increase at 10 min and peaked at 60 min and returned to baseline level 180 min. Six hours post CT-1 (0.01 nmol/L, 0.1 nmol/L, 1 nmol/L) exposure, the GATA4 mRNA expression increased in a dose-dependent manner. The GATA4 binding activity peaked with 0.1 nmol/L CT-1 and higher dose did not further increase the binding activity. U-0126 increased the GATA4 mRNA expression and enhanced the GATA4 binding activity and these effects could be partially attenuated with addition of Parthenolide. Parthenolide also prevented the increase of GATA4 mRNA and binding activity induced by CT-1. LY-294002 had no effects GATA4 mRNA and binding activity.

CONCLUSIONCT-1 increases the GATA4 mRNA expression and binding activity in rat cardiomyocytes via STAT3/ERK1/2 pathways and these effects are independent of PI3-K pathway.

Animals ; Cell Line ; Cytokines ; pharmacology ; GATA4 Transcription Factor ; biosynthesis ; genetics ; Myocytes, Cardiac ; metabolism ; RNA, Messenger ; biosynthesis ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; STAT3 Transcription Factor ; pharmacology ; Signal Transduction

This study was aimed to investigate the activation of P38MAPK/STAT3 and expression of telomerase reverse transcriptase during sodium nitroprusside (SNP) inducing apoptosis of human leukemia cell line K562 and to explore the molecular mechanisms of SNP-inducing apoptosis in K562 cells. The K562 cell were treated with different concentrations of SNP and were cultured for different time. Cell apoptosis was analysed by cell morphology, DNA agarose gel electrophoresis, DNA content, and Annexin-V/PI labeling method. The TdT-mediated dUTP nick end labeling (TUNEL) assay was used to quantitate the in situ cell apoptosis. The expressions of phosphorylated p38MAPK or STAT3 were analysed by flow cytometry, while the expression of hTERT mRNA in transcriptional level was measured by fluorescence quantitative RT-PCR. The results showed that SNP inhibited K562 cell growth. The K562 cell apoptosis was confirmed by typical cell morphology and DNA fragment, peak of sub-G1 phase, TUNEL and Annexin-V/PI labeling. A majority of K562 cells were arrested in G0/G1 phase. After treatment with SNP at 0.5-3.0 mmol/L, the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 increased first and decreased afterwards. Incubation of K562 cell with SNP (2 mmol/L) could increase the expression of phosphorylated-P38MAPK and phosphorylated-STAT3 at 12 hours and 24 hours respectively, and down-regulated at 72 hours and 48 hours. SNP could decrease the expression of hTERT-mRNA in time-and dose-dependent manner. It is concluded that SNP can significantly induce K562 cells apoptosis, its mechanism may be related to the activation of P38MAPK and suppression of phosphorylated-STAT3 and hTRET-mRNA.
Apoptosis ; drug effects ; Humans ; K562 Cells ; Nitroprusside ; pharmacology ; RNA, Messenger ; biosynthesis ; genetics ; STAT3 Transcription Factor ; genetics ; metabolism ; Telomerase ; biosynthesis ; genetics ; p38 Mitogen-Activated Protein Kinases ; genetics ; metabolism

We investigated the effect of phenylephrine (PE)- and isoproterenol (ISO)-induced cardiac hypertrophy on subcellular localization and expression of caveolin-3 and STAT3 in H9c2 cardiomyoblast cells. Caveolin-3 localization to plasma membrane was attenuated and localization of caveolin-3 to caveolae in the plasma membrane was 24.3% reduced by the catecholamine-induced hypertrophy. STAT3 and phospho-STAT3 were up-regulated but verapamil and cyclosporin A synergistically decreased the STAT3 and phospho-STAT3 levels in PE- and ISO-induced hypertrophic cells. Both expression and activation of STAT3 were increased in the nucleus by the hypertrophy. Immunofluorescence analysis revealed that the catecholamine-induced hypertrophy promoted nuclear localization of pY705-STAT3. Of interest, phosphorylation of pS727-STAT3 in mitochondria was significantly reduced by catecholamine-induced hypertrophy. In addition, mitochondrial complexes II and III were greatly down-regulated in the hypertrophic cells. Our data suggest that the alterations in nuclear and mitochondrial activation of STAT3 and caveolae localization of caveolin-3 are related to the development of the catecholamine-induced cardiac hypertrophy.
Animals ; Catecholamines/*pharmacology ; Caveolae/*metabolism ; Caveolin 3/*metabolism ; Cell Line ; Hypertrophy/metabolism ; Mitochondria/*metabolism ; Myocardium/cytology/*pathology ; Myocytes, Cardiac/cytology/*drug effects/metabolism ; Rats ; STAT3 Transcription Factor/*metabolism

OBJECTIVETo investigate the effects of dexamethasone on the expression of interleukin-21 (IL-21) and phospho- STAT3 (p-STAT3) in a murine model of chronic asthma.

METHODSThirty-three female BALB/C mice were randomly divided into control group, asthmatic group and dexamethasone-treated group (n=11). In the latter two groups, asthmatic models were established by ovalbumin administration. The cells in the broncho-alveolar lavage fluid (BALF) were counted and classified. The airway inflammation was evaluated by HE staining, and the expressions of IL-21 and p-STAT3 in the lung tissue were detected by immunohistochemistry and Western blotting.

RESULTSThe total cell number and lymphocyte number in the BALF were significantly higher in asthmatic group than in the control group and dexamethasone group (P/0.01). Compared with the control group, the asthmatic group showed significantly increased protein expressions of IL-21 and p-STAT3 (P<0.05), which were reduced by dexamethasone intervention (P/0.05).

CONCLUSIONDexamethasone can inhibit the expression of IL-21 and p-STAT3 in the murine model of chronic asthma, suggesting the importance of IL-21/STAT3 signaling pathway in the therapeutic mechanisms of dexamethasone for asthma.

Animals ; Asthma ; metabolism ; Dexamethasone ; pharmacology ; Disease Models, Animal ; Female ; Interleukins ; metabolism ; Lung ; drug effects ; metabolism ; Mice ; Mice, Inbred BALB C ; Phosphorylation ; STAT3 Transcription Factor ; metabolism ; Signal Transduction