To investigate the role of spinal interleukin-6-Janus kinase 2 (IL-6-JAK2) signaling transduction pathway in regulating astrocytes activation during the maintenance of bone cancer pain (BCP).
 Methods: NCTC 2472 fibrosarcoma cells were injected into the femur marrow cavity in C3H/HeNCrlVr male mice to establish BCP model and they were replaced by the equal volume of α-MEM in the sham model. The paw withdrawal latency (PWL) was measured after inoculation of tumor cells. The lumbar enlargement of spinal cord (L3-L5) was isolated, and Real-time RT-PCR and Western blot were used to detect the expression of spinal glial fibrillary acidic protein (GFAP) and JAK2 mRNA and protein, respectively. The expression level of spinal GFAP mRNA indirectly reflect astrocytes activation level. Pain behaviors and spinal cord GFAP mRNA and protein expression were observed at the given time points after intrathecal administration of JAK2 antagonist AG-490.
 Results: The PWL at 10, 14, 21 d after operation in BCP model group were significantly shorter than that in the sham group (P<0.05); the spinal GFAP and JAK2 mRNA and protein levels were higher in the BCP model group in comparison to mice in the sham group (P<0.05); intrathecal injection of JAK2 agonist AG-490 (30 or 90 nmol) significantly alleviated PWL, and downregulated the expression of spinal GFAP mRNA and protein (P<0.05).
 Conclusion: The IL-6-JAK2 signaling pathway plays an important role in maintaining the BCP by regulating the expression of GFAP in the spinal cord. Intrathecal injection of AG-490 can reduce the BCP, and inhibit the activation of IL-6-JAK2 signaling pathway, which may be one of the mechanisms for spinal astrocyte activation.
Animals ; Astrocytes ; pathology ; Bone Neoplasms ; complications ; Hyperalgesia ; drug therapy ; etiology ; Injections, Spinal ; Male ; Mice ; Mice, Inbred C3H ; Rats, Sprague-Dawley ; Spinal Cord ; cytology ; pathology ; Tyrphostins ; administration & dosage

To investigate the role of Janus kinase (JAK) inhibitor AG490 in the anti-proliferation and cell cycle in human retinoblastoma HXO-RB44 cell lines in vitro, and to explore its effect on the expression of JAK2/signal transducer and activator of transcription 3 (STAT3).
 Methods: Cells were divided into an experiment group and a control group, and the experiment group was further divided into 6 sub-groups according to different AG490 concentrations (6.25, 12.50, 25.00, 50.00 or 100.00 μmol/L). Cell proliferation in the different groups was analyzed by cell vitality determination. Cell cycle distribution and apoptosis rate were examined by flow cytometry. The protein levels of STAT3, p-STAT3 and vascular endothelial growth factor (VEGF) were detected by Western blot.
 Results: After 48 h treatment with AG490, the viability of HXO-RB44 cells was reduced in a concentration-dependent manner. Compared with the control group, there was no significant difference in the experiment groups except the 6.25 μmol/L group (all P>0.05). The apoptosis rates in the experiment groups were significantly increased with increase in concentration of AG490 compared with that in the control group (all P<0.05). The cell ratio in the G1 phase in 50 or 100 μmol/L group was increased, whereas the cell ratio in the S phase was decreased. Western blot results showed that the expressions of STAT3 and p-STAT3 in the experiment groups were dramatically reduced with the increase in concentration of AG490 compared with that in the control group (all P<0.05). VEGF expression didn't obviously change in the experiment groups with AG490 concentration less than 12.5 μmol/L compared with that in the control group (both P>0.05), but there were significant differences in the other experiment groups (all P<0.05). 
 Conclusion: JAK inhibitor AG490 can inhibit proliferation and promote apoptosis of the retinoblastoma HXO-RB44 cells through down-regulation of JAK2/STAT3 signaling pathway.
Apoptosis ; drug effects ; Cell Line, Tumor ; Cell Proliferation ; drug effects ; Cell Survival ; drug effects ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation, Neoplastic ; drug effects ; Humans ; Janus Kinase 2 ; genetics ; metabolism ; Retinoblastoma ; STAT3 Transcription Factor ; genetics ; metabolism ; Signal Transduction ; drug effects ; Tyrphostins ; pharmacology ; Vascular Endothelial Growth Factor A ; metabolism

The aim of the present study was to investigate the mechanism of the inhibitory effect of luteolin on the proliferation of breast cancer cells induced by epidermal growth factor (EGF) in vitro. MTT assay was used to detect the inhibitory effect of luteolin on the proliferation of MCF-7 and MDA-MB-231 cells as well as the effect on the proliferation of MCF-7 cells induced by EGF. Western blotting was used to detect the effects of luteolin on the expression of epidermal growth factor receptor (EGFR), phosphatidylinositol 3-kinase (PI3K)/Akt, mitogen-activated protein kinase (MAPK)/extracellular-signal-regulated kinases (Erk) 1/2 and signal transducers and activators of transcription-3 (STAT3) in MCF-7 cells induced by EGF. The results showed that luteolin could significantly inhibit the proliferation of MCF-7 and MDA-MB-231 cells, and the inhibitory effect on MCF-7 cells was more prominent. Moreover, luteolin could inhibit the proliferation of MCF-7 cells induced by EGF. Western blotting results showed that luteolin and AG1478 (an inhibitor of EGFR signaling) could inhibit the expression of p-EGFR and p-STAT3 in MCF-7 cells induced by EGF. Luteolin, LY294002 (an inhibitor of Akt signaling) and PD98059 (an inhibitor of Erk1/2 signaling) could inhibit the expression of p-Akt and p-Erk1/2 respectively in MCF-7 cells induced by EGF. Our data suggest that luteolin may inhibit EGF-induced activities of EGFR signaling pathway in human breast cancer cell lines, and PI3K/Akt, MAPK/Erk1/2, STAT3 signal pathways may be the major pathways that mediate the inhibitory effect of luteolin on EGFR signaling. Overall, our results may provide a theoretical foundation for the development of luteolin as anti-tumor drug.
Breast Neoplasms ; Cell Line, Tumor ; Cell Proliferation ; Chromones ; Epidermal Growth Factor ; Humans ; Luteolin ; MAP Kinase Signaling System ; Mitogen-Activated Protein Kinase 1 ; Mitogen-Activated Protein Kinase 3 ; Morpholines ; Phosphatidylinositol 3-Kinases ; Quinazolines ; Receptor, Epidermal Growth Factor ; Tyrphostins

To investigate the effect of diosgenin (Dgn) on chondrocytes and its relation to JAK2/STAT3 signaling pathway in mice with osteoarthritis (OA).Fifteen male C57BL/6 mice were randomly divided into three groups:control group, OA group and OA+Dgn group. After 4 weeks of treatment, the histopathological changes of cartilage tissue were observed by toluidine blue staining under light microscopy and the ultrastructure of chondrocytes was observed under electron microscopy. The primarily cultured chondrocytes of OA mice were randomly divided into 4 groups:(1) OA group, (2) Dgn group, (3) Dgn+AG490 group, (4) AG490 group. The expression of p-JAK2, p-STAT3, Bax, succinate dehydrogenase (SDH) and cytochrome c oxidase (COX) were detected by Western blotting, and superoxide dismutase (SOD) was detected using colorimetric method.The morphological observation showed that the chondrocytes of OA group presented considerable pathological changes, while the chondrocytes in OA+Dgn group maintained intact membrane. Electron microscopy observation found obvious injury in cartilage tissues of OA group, while that in OA+Dgn group remained smooth. Compared with OA group, the expressions of p-JAK2 and p-STAT3 in chondrocytes of Dgn group were increased (all<0.05), and the expressions of Bax protein, SDH, COX and SOD were decreased (all<0.05). While compared with Dgn group, the expressions of p-JAK2, p-STAT3, SDH, COX and SOD in chondrocytes of Dgn+AG490 group were decreased (all<0.05), and the expression of Bax protein was increased (<0.05).Diosgenin can inhibit apoptosis and increase mitochondrial oxidative stress capacity of chondrocytes in mice with osteoarthritis, which is closely related to the activation of JAK2/STAT3 signaling pathway.
Animals ; Apoptosis ; drug effects ; Cartilage ; drug effects ; pathology ; Chondrocytes ; chemistry ; drug effects ; pathology ; Diosgenin ; pharmacology ; Electron Transport Complex IV ; metabolism ; Janus Kinase 2 ; drug effects ; Male ; Mice ; Mice, Inbred C57BL ; Mitochondria ; drug effects ; genetics ; Osteoarthritis ; genetics ; physiopathology ; Oxidative Stress ; drug effects ; STAT3 Transcription Factor ; drug effects ; Signal Transduction ; Succinate Dehydrogenase ; metabolism ; Superoxide Dismutase ; metabolism ; Tyrphostins ; pharmacology ; bcl-2-Associated X Protein ; metabolism

OBJECTIVE: To investigate the effects of combined inhibition of signal transducer and activator of transcription 3 (STAT3) and hypoxia-inducible factor-1α (HIF-1α) in the enhancement of chemosensitivity of the model of human laryngeal squamous cacinoma in nude mice. METHOD: Model nude mice were divided into six groups randomly: control group(A) , cisplatin group(B) , cisplatin and AG490 group(C) , cisplatin and HIF-1α⁻/⁻ group (D), cisplatin combined AG490 and HIF-1α⁻/⁻ group (E), HIF-1α⁻/⁻ group (F) (only in calculating tumor inhibition rate). 3mg/kg cisplatin was administered by peritoneal injection for 3 days. Then cisplatin and 10 mg/kg AG490 were administered every other day for 12 days. The expression of Ki67 and HIF-1α was detected by immunocytochemical method. Western blot was used to detect the expression of p-STAT3. RESULT: The expression of HIF-1α in group C and group D were lower than that in group B, and there were significant difference respectively (t₁ = 2.782, t₂ = 3.873, P < 0.05); The expression of HIF-1α in group E was lower than that in group C and group D respectively, and there were significant difference respectively (t₁ = 6.140, t₂ = 3.667, P < 0.01). The expression level of p-STAT3 in group C was markedly lower compared with that in group B, and there were significant difference between them (t = 17.840, P < 0.01); There were no difference between the expression level of p-STAT3 in group D and that in group B (t = 0.038, P > 0.05); The expression level of p-STAT3 in group E was significantly lower compared with that in group C and group D respectively (P < 0.01). Tumor inhibition rate of group E was higher than that in group B, group C , as well as group D respectively and there were significant difference respectively (t₁ = 5.509, P < 0.01; t₂ = 3.422, P < 0.05; t₃ = 2.718, P < 0.05 ). Ki67 index of group E was lower than that in group B, group C as well as group D respectively and there were significant difference respectively(t₁ = 8.307, P < 0.01; t₂ = 3.736, P < 0.05; t₃ = 4.524, P < 0.01). CONCLUSION Combined inhibition of STAT3 and HIF-1α could enhance chemo-sensitivity in the model of human laryngeal squamous cacinoma in nude mice.
Animals ; Antineoplastic Agents ; pharmacology ; Carcinoma, Squamous Cell ; drug therapy ; metabolism ; Cisplatin ; pharmacology ; Drug Resistance, Neoplasm ; Hypoxia-Inducible Factor 1, alpha Subunit ; genetics ; metabolism ; Ki-67 Antigen ; metabolism ; Laryngeal Neoplasms ; drug therapy ; metabolism ; Mice ; Mice, Nude ; Neoplasms, Experimental ; drug therapy ; metabolism ; STAT3 Transcription Factor ; genetics ; metabolism ; Tyrphostins ; pharmacology

The type 1 insulin-like growth factor receptor (IGF-1R) and its downstream signaling components have been increasingly recognized to drive the development of malignancies, including non-small cell lung cancer (NSCLC). This study aimed to investigate the effects of IGF-1R and its inhibitor, AG1024, on the progression of lung cancer. Tissue microarray and immunohistochemistry were employed to detect the expressions of IGF-1 and IGF-1R in NSCLC tissues (n=198). Western blotting was used to determine the expressions of IGF-1 and phosphorylated IGF-1R (p-IGF-1R) in A549 human lung carcinoma cells, and MTT assay to measure cell proliferation. Additionally, the expressions of IGF-1, p-IGF-1R and IGF-1R in a mouse model of lung cancer were detected by Western blotting and real-time fluorescence quantitative polymerase chain reaction (FQ-PCR), respectively. The results showed that IGF-1 and IGF-1R were overexpressed in NSCLC tissues. The expression levels of IGF-1 and p-IGF-1R were significantly increased in A549 cells treated with IGF-1 as compared to those treated with IGF-1+AG1024 or untreated cells. In the presence of IGF-1, the proliferation of A549 cells was significantly increased. The progression of lung cancer in mice treated with IGF-1 was significantly increased as compared to the group treated with IGF-1+AG1024 or the control group, with the same trend mirrored in IGF-1/p-IGF-1R/IGF-1R at the protein and/or mRNA levels. It was concluded that IGF-1 and IGF inhibitor AG1024 promotes lung cancer progression.
Adult ; Aged ; Animals ; Carcinoma, Non-Small-Cell Lung ; metabolism ; pathology ; Cell Proliferation ; Disease Models, Animal ; Disease Progression ; Female ; Humans ; Insulin-Like Growth Factor I ; metabolism ; Lung Neoplasms ; metabolism ; pathology ; Male ; Mice ; Middle Aged ; Receptor, IGF Type 1 ; antagonists & inhibitors ; physiology ; Tyrphostins ; pharmacology

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 antitumour molecular mechanisms of WP1066 (STAT-3 inhibitor ) to human tongue squamous cell carcinoma in vitro and in vivo.

METHODSWP1066 was used to inhibit the p-STAT-3 expression in Tscca human tongue squamous cell carcinoma cell line .Real-time PCR was used to detect the microRNA-21 expression after treatment with DMSO and WP1066. Methyl thiazolyl tatrozolium (MTT) assay was employed to determine cell survival. Flow cytometry (FCM) was used to measure apoptosis. The expression level of STAT-3/p-STAT-3, programmed cell death protein 4 (PDCD-4), antigen 67 (Ki-67), B cell lymphoma 2 (Bcl-2) and cleaved cysteinyl aspartate specific proteinase-3 (CCASP-3) was examined by Western blotting. Luciferase reporter gene assay was conducted to verify the regulation of STAT-3 to microRNA-21. Tscca xenograft tumor model was established in BALB/c nude mice and the tumors were divided into control, DMSO and WP1066 treated groups. The tumor tissues were measured by immunohistochemistry stain and terminal-deoxynucleoitidyl transferase mediated nick end labeling (TUNEL) assay.

RESULTSSTAT-3/p-STAT-3 protein was suppressed after treatment with WP1066 (STAT-3:F = 15.336, P = 0.004, p-STAT-3: F = 52.837, P = 0.000). MicroRNA-21 relative expression level was down-regulated (F = 8.197, P = 0.019). Cell survival rate was significantly reduced after treatment with WP1066 than control groups (F = 94.388, P = 0.000). Early apoptosis rate increased after treatment with WP1066 (F = 217.080, P = 0.000) . PDCD-4 and cleaved cysteinyl aspartate specific proteinase-3 (CCASP-3) protein expression was increased after treatment with WP1066 (PDCD-4:F = 8.771, P = 0.017; CCASP-3: F = 26.611, P = 0.001) .Ki-67 and Bcl-2 protein was down regulated (Ki-67:F = 5.854, P = 0.039; Bcl-2:F = 125.502, P = 0.000). Luciferase reporter gene assay proved that STAT-3 combined with specific promoter region of microRNA-21.In vivo, the tumor volume after treatment with WP1066 was significantly smaller than control groups by the end of observation (F = 15.390, P = 0.000) .Immunological histological chemistry indicated that PDCD-4 and CCASP-3 protein expression was up-regulated simultaneously while Ki-67 and Bcl-2 protein of tumor tissue was down-regulated after treatment with WP1066 than control groups. TUNEL assay suggested that apoptosis index rose after treatment with WP1066 than control groups (F = 133.368, P = 0.000) .

CONCLUSIONSWP1066 affected Tscca cancer cell proliferation and apoptosis via inhibiting STAT-3/microRNA-21.WP1066 provided new direction and possibility to human tongue squamous cell carcinoma therapy.

Animals ; Apoptosis ; Apoptosis Regulatory Proteins ; biosynthesis ; Carcinoma, Squamous Cell ; pathology ; Cell Line, Tumor ; Cell Proliferation ; Down-Regulation ; Heterografts ; Humans ; In Vitro Techniques ; Mice ; Mice, Nude ; Pyridines ; pharmacology ; Real-Time Polymerase Chain Reaction ; STAT3 Transcription Factor ; biosynthesis ; Signal Transduction ; Tongue Neoplasms ; pathology ; Tyrphostins ; pharmacology

OBJECTIVETo study the relationship of basic fibroblast growth factor (bFGF) and signal transducer and activator of transcription 3(STAT3) in glioma apoptosis and possible mechanisms of its interaction.

METHODSTwo glioblastomamultiforme (GBM) cell lines: U87 (wild-type p53) and U251 (mutant p53) were used in this study and divided into normal control group, mock group and experiment group.Small interfering RNA-carried recombinant lentivirus, LV-bFGFsiRNA and LV-STAT3siRNA, targeting bFGF and STAT3 were constructed respectively. After 48 hours of lentivirus transfection, small molecular inhibitors were used to block specific signaling pathways, AG490 20 µmol/L blocking JAK, LY294002 20 µmol/L blocking PI3K/Akt pathways for 24 hours, 48 hours and 72 hours, respectively. Then, apoptosis, changes in apoptosis-related proteins and mitochondrial membrane potential were detected through the methods of flow cytometry, protein chip and confocal microscopy, respectively.Groups were compared using single factor analysis of variance (One-way ANOVA).

RESULTSWestern blot results revealed the levels of Tyr705 and Ser727 phosphorylationin reduced in a time dependent manner by blocking JAK and PI3K/Akt pathway respectively. The results of flow cytometry showed that the apoptosis rate in normal control group, mock group, experiment group were 17.97% ± 0.24%, 18.26% ± 0.88%, 46.57% ± 1.63% in U87 cells and 15.94% ± 1.18%, 16.88% ± 0.17%, 39.34% ± 0.87% in U251 cells, respectively. There was no statistically significant change between the normal control group and the mock group (P > 0.05) , while when compared with the experiment group, both group showed statistically significant difference (F = 697.41, 729.58, both P < 0.05). The results of protein chip demonstrated that protein expression of Bad, Caspase3, Cytochrome C, p27 were higher and XIAP was lower in the experiment group compared with the normal control group and mock group. Also, confocal microscopy could detect apoptosis and mitochondrial membrane potential reduced significantly in the experimental group compared with the normal control group and the mock group.

CONCLUSIONSbFGF mainly interacts with STAT3 tyrosine site-pSTAT3(Tyr705) to influence the level of STAT3 phosphorylation;blocking bFGF/STAT3 signaling pathway can induce glioma cell apoptosis through mitochondrial pathway.

Apoptosis ; Brain Neoplasms ; metabolism ; Cell Line, Tumor ; Cytochromes c ; Fibroblast Growth Factor 2 ; metabolism ; Glioma ; metabolism ; Humans ; Mitochondria ; Phosphatidylinositol 3-Kinases ; Phosphorylation ; RNA, Small Interfering ; STAT3 Transcription Factor ; metabolism ; Signal Transduction ; Transfection ; Tyrphostins

Our previous studies indicate that phosphatidylinositol 4-kinase IIα can promote the growth of multi-malignant tumors via HER-2/PI3K and MAPK pathways. However, the molecular mechanisms of this pathway and its potential for clinical application remain unknown. In this study, we found that PI4KIIα could be an ideal combinatorial target for EGFR treatment via regulating EGFR degradation. Results showed that PI4KIIα knockdown reduced EGFR protein level, and the expression of PI4KIIα shows a strong correlation with EGFR in human breast cancer tissues (r = 0.77, P < 0.01). PI4KIIα knockdown greatly prolonged the effects and decreased the effective dosage of AG-1478, a specific inhibitor of EGFR. In addition, it significantly enhanced AG1478-induced inhibition of tumor cell survival and strengthened the effect of the EGFR-targeting anti-cancer drug Iressa in xenograft tumor models. Mechanistically, we found that PI4KIIα suppression increased EGFR ligand-independent degradation. Quantitative proteomic analysis by stable isotope labeling with amino acids in cell culture (SILAC) and LC-MS/MS suggested that HSP90 mediated the effect of PI4KIIα on EGFR. Furthermore, we found that combined inhibition of PI4KIIα and EGFR suppressed both PI3K/AKT and MAPK/ERK pathways, and resulted in downregulation of multiple oncogenes like PRDX2, FASN, MTA2, ultimately leading to suppression of tumor growth. Therefore, we conclude that combined inhibition of PI4KIIα and EGFR exerts a multiple anti-tumor effect. Dual inhibition of EGFR at protein and activity level via combinatorial blocking of PI4KIIα presents a novel strategy to combat EGFR-dependent tumors.
Animals ; Antineoplastic Agents ; pharmacology ; Breast Neoplasms ; metabolism ; pathology ; Cell Line, Tumor ; Cell Survival ; drug effects ; ErbB Receptors ; antagonists & inhibitors ; metabolism ; Female ; HSP90 Heat-Shock Proteins ; metabolism ; Humans ; MCF-7 Cells ; Male ; Mice ; Mice, Inbred BALB C ; Mice, Nude ; Minor Histocompatibility Antigens ; Mitogen-Activated Protein Kinases ; metabolism ; Phosphatidylinositol 3-Kinases ; metabolism ; Phosphotransferases (Alcohol Group Acceptor) ; antagonists & inhibitors ; genetics ; metabolism ; Proto-Oncogene Proteins c-akt ; metabolism ; Quinazolines ; pharmacology ; Transplantation, Heterologous ; Tyrphostins ; pharmacology