This study was aimed to explore the effect of homoharringtonine in combination with AG490 on JAK2-STAT5 associated signal pathway in HEL cells, and analyze its mechanism so as to provide theoretical basis for therapy of chronic myeloproliferative neoplasma by new program. The cell survival rates were tested by MTT, apoptosis was tested by flow cytometry after HEL cells were treated by 20 ng/ml HHT, 100 µmol/L AG490 and 20 ng/ml HHT in combination with 100 µmol/L AG490, while the signal proteins such as P-JAK2, P-STAT5 and BCL-xL activated by abnormal activated JAK2 were tested by Western blot. The results showed that both HHT and AG490 could inhabit the HEL cell proliferation after being treated for 24 hours, and Annexin V-PI double staining confirmed early apoptosis while HHT effect was more obvious, Western blot showed that the expressions of P-JAK2 and P-STAT5 were down-regulated, while the total protein levels of JAK2 and STAT5 were stable. It is concluded that HHT combined with AG490 can obviously inhibit the proliferation and induce early apoptosis of HEL cells, and there is synergistic effect between the two drugs. HHT possibly acts as a broad-spectrum PTK inhibitor and synergistically with AG490 inhibits the phosphorylation of signal proteins caused by JAK2V617F, thus down-regulating the transcription of STAT5.
Cell Line, Tumor ; Harringtonines ; pharmacology ; Humans ; Janus Kinase 2 ; metabolism ; STAT5 Transcription Factor ; metabolism ; Signal Transduction ; drug effects ; Tyrphostins ; pharmacology

This study was aimed to investigate the effect of AG490, a JAK2 inhibitor, on expression of PHLPP and p-Akt in K562. K562 cells were treated with different concentrations of AG490. The proliferation of K562 cells was examined by WST-1 assay and apoptosis of K562 cells was detected by flow cytometry with Annexin V-FITC/PI double staining. The expressions of PHLPP, phosphorate-Akt (p-Akt) and total Akt protein were detected by Western blot. The results indicated that AG490 inhibited the proliferation of K562 cells in concentration-and time-dependent manners, with the IC(50) 338.0 µmol/L in 48 h. AG490 100 µmol/L also induced apoptosis of K562 cells in a time-dependent manner. AG490 100 µmol/L time-dependently down-regulated the protein expression of p-Akt and PHLPP, but without significant effect on expression of total Akt. It is concluded that AG490 can inhibit proliferation and induce apoptosis of K562 cells through down-regulation of p-Akt expression, but inhibiting efficacy of AG490 on K562 proliferation also may be limited due to the down-regulation of p-Akt regulatory protein PHLPP expression.
Cell Proliferation ; drug effects ; Down-Regulation ; Humans ; K562 Cells ; Nuclear Proteins ; metabolism ; Phosphoprotein Phosphatases ; metabolism ; 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 study the mechanism by which AG490 improves the survival rate of rats following extensive liver resection.

METHODSThirty-eight rats were randomly divided into two groups after surgery: control group (n=10), without treatment; (2) AG490 group (n=28), with AG490 (1 mg x kg(-1) x 12 h(-1)) administrated intraperitoneally immediately and 36 hours after the operation. The survival rate was observed and the serum liver functions were measured.

RESULTSThe survival rates of control group and AG490 group were 0% and 25%. AG490 group had significantly better blood glucose and aminotransferase levels (P < 0.05) than control group; serum bilirubin levels significantly decreased 48 hours after the operation. Serum protein levels in both two groups had slow decrease but without statistical significance (P > 0.05).

CONCLUSIONSAG490 can significantly increase the survival rate of rats following extensive liver resection. Such a benefit mainly results from the protection towards residual liver function rather than from the promotion of liver regeneration.

Alanine Transaminase ; blood ; Animals ; Aspartate Aminotransferases ; blood ; Bilirubin ; blood ; Blood Glucose ; metabolism ; Enzyme Inhibitors ; pharmacology ; Hepatectomy ; methods ; Male ; Protein-Tyrosine Kinases ; antagonists & inhibitors ; Random Allocation ; Rats ; Rats, Sprague-Dawley ; Survival Rate ; Tyrphostins ; pharmacology

1) A beta agonist stimulated Na+ transport and decreased the intracellular Cl concentration ([Cl]c) associated with cell shrinkage via an increase in cytosolic cAMP level by activating adenylate cyclase in rat fetal distal lung epithelial (FDLE) cells. 2) Lowering [Cl-]c activated a 28-pS nonselective cation (NSC) channel by elongating the open time of the channel. 3) cAMP signals were converted to a protein tyrosine kinase (PTK)-mediated signal. 4) The PTK-mediated signal was involved in the cAMP-stimulated Na+ transport in rat FDLE cells.
Adrenergic beta-Agonists/pharmacology* ; Animal ; Biological Transport/physiology ; Biological Transport/drug effects ; Cell Size/physiology ; Chlorides/metabolism* ; Cyclic AMP/metabolism ; Cytosol/metabolism ; Enzyme Inhibitors/pharmacology ; Female ; Fetus/cytology ; Forskolin/pharmacology ; Nitrobenzoates/pharmacology ; Pregnancy ; Protein-Tyrosine Kinase/metabolism* ; Rats ; Rats, Wistar ; Respiratory Mucosa/enzymology* ; Respiratory Mucosa/embryology ; Respiratory Mucosa/cytology ; Sodium/metabolism* ; Tyrphostins/pharmacology

OBJECTIVETo investigate the effect of angiotensin (Ang)II and its Janns-activated kinase-2 (JAK2) signal pathway in transdifferentiation of renal tubular cells under the challenge of acute ischemic reperfusion injury.

METHODSModels of acute ischemic reperfusion injury were established and the level of local AngII, a key element of renin-angiotensin system (RAS), in kidney was measured using radioimmunity technique. The expression of alpha-smooth muscle actin (alpha-SMA), a phenotype of mesenchymal cells, was detected by RT-PCR and immunohistochemistry methods. Renal tubule cells (NRK-52E) were cultured with various concentration of AngII, followed by blocking of PD123319, AngII receptor 2 antagonist, and AG490, an inhibitor of JAK2 signal pathway.

RESULTSAngII of kidney tissue increased immediately after acute ischemic-reperfusion injury, in time dependent fashion. Expression of alpha-SMA in renal tubule cells was found at 48 hours after ischemic-reperfusion injury and in NRK-52E cells treated by high concentration of AngII and was dose and time dependent. The peak of alpha-SMA expression was seen after 30 minute treatment at the dose of 10(-9) mol/L, which was interrupted by both of PD123319 and AG490.

CONCLUSIONSTransdifferentiation of renal tubular epithelial cells occurs under acute ischemic-reperfusion injury. Local renin-angiotensin system may play a role in the transdifferentiation of TEC through AT2 receptor and its JAK2 signal pathway.

Actins ; genetics ; metabolism ; Angiotensin II ; administration & dosage ; metabolism ; pharmacology ; Angiotensin II Type 1 Receptor Blockers ; pharmacology ; Animals ; Cell Differentiation ; drug effects ; Cell Line ; Dose-Response Relationship, Drug ; Imidazoles ; pharmacology ; Janus Kinase 2 ; antagonists & inhibitors ; Kidney Tubules ; cytology ; metabolism ; Male ; Pyridines ; pharmacology ; RNA, Messenger ; metabolism ; Rats ; Rats, Wistar ; Renin-Angiotensin System ; Reperfusion Injury ; metabolism ; pathology ; Signal Transduction ; drug effects ; Tyrphostins ; pharmacology

OBJECTIVETo study the regulatory effect of Helicobacter pylori CagA protein on gastrin promoter and the related signaling pathways as to further elucidate the mechanism of the development and progression of human gastric carcinoma.

METHODSAfter pcDNA3.1ZEO(-)/CagAand PGL/GP were identified by double restriction enzyme digestion, PCR and sequencing, the gastric cancer cell lines AGS and SGC-7901 cells were co-transfected with pcDNA3.1ZEO(-)/CagA and PGL/GP for 48 h. Alternatively, AGS and SGC-7901 cells were transfected by PGL/GP for 36 h later, and infected with Helicobacter pylori for additional 12 h. Meanwhile, the transfected and infected cells were treated using the JAK2 signaling pathway inhibitor AG490 and the ERK signaling pathway inhibitor U0126. The untreated cells and empty-vector-transfected cells were used as the control. Finally, luciferase activity was detected using the luciferase reporter assay system in transfected and infected cells. The levels of gastrin mRNA was determined by TaqMan® real-time quantitative PCR.

RESULTSAfter co-transfection with pcDNA3.1ZEO(-)/CagA and PGL/GP, the activities of luciferase were increased by 251.3, 106.1 and 2.4 times in AGS cells and 35.8, 22.7 and 13.4 times in SGC-7901 cells, respectively, as compared with that of the control, pcDNA3.1 ZEO(-)/CagA + PGL3/Basic and pcDNA3.1 ZEO(-) + PGL/GP groups. The activities of luciferase in PGL/GP transfection and HP infection group were also increased by 1673.2, 33.5, 1.4 times in AGS cells and 1180.2, 72.2 and 1.5 times in SGC-7901 cells, respectively, as compared with that of the control, PGL3/Basic + HP and PGL/GP groups. There were statistically significant differences between them (P < 0.05), which suggested that the transcription activity of gastrin promoter increased significantly. But after adding the inhibitor AG490 and U0126, respectively, the activities of luciferase were significantly decreased by 95.7% (U0126) and 33.0% (AG490) in co-transfected AGS cells and 94.8% (U0126) and 86.2% (AG490) in co-transfected SGC-7901 cells with pcDNA3.1ZEO(-)/CagA and PGL/GP (P < 0.05). In the PGL/GP transfection and HP infection group, the activities of luciferase were significantly decreased by 24.6% (U0126) and 25.8% (AG490) in AGS cells and 57.3% (U0126) and 14.1% (AG490) after adding the inhibitor AG490 and U0126, respectively (P < 0.05). The results showed that the gastrin promoter activities were significantly inhibited. The gastrin mRNA levels were 3.0 and 4.5 times higher in HP-infected AGS and SGC-7901 cells, respectively, than that in the control groups. In the cells transfected with pcDNA3.1ZEO(-)/CagA, the gastrin mRNA levels were raised 10.8 and 2.3 times (AGS cells) and 10.9 and 16.2 times (SGC-7901 cells), respectively, as compared with that of control and pcDNA3.1ZEO(-) groups. All of the differences were statistically significant (P < 0.05).

CONCLUSIONThese results suggest that CagA may activate the gastrin promoter and up-regulate the expression of gastrin gene, and CagA is one of the important proteins in regulating gastrin gene expression. The ERK/MAPK and JAK/STAT signaling pathways may be involved in the controlling of gastrin gene expression by CagA.

Antigens, Bacterial ; genetics ; metabolism ; Antineoplastic Agents ; pharmacology ; Bacterial Proteins ; genetics ; metabolism ; Butadienes ; pharmacology ; Cell Line, Tumor ; Enzyme Inhibitors ; pharmacology ; Gastrins ; biosynthesis ; genetics ; Gene Expression Regulation, Neoplastic ; Genetic Vectors ; Helicobacter Infections ; Helicobacter pylori ; isolation & purification ; Humans ; Nitriles ; pharmacology ; Promoter Regions, Genetic ; RNA, Messenger ; metabolism ; Stomach Neoplasms ; metabolism ; pathology ; virology ; Transfection ; Tyrphostins ; pharmacology ; Up-Regulation

AIMTo investigate mechanisms of tryptase-induced reduction of sperm motility and explore whether epidermal growth factor receptor (EGF-R) and protease activated receptor 2 (PAR-2)- associated pathways are involved.

METHODSFresh semen was collected from healthy donors (n = 15). Semen parameters and quality were assessed in accordance with the World Health Organization (WHO) criteria. Swim-up sperm were fixed and subjected to immunocytochemistry and immunoelectronmicroscopy with specific antibodies directed against PAR-2 and EGF-R. Protein extractions from swim-up spermatozoa were analyzed by Western blotting with antibodies for both receptors. Motility of spermatozoa was evaluated by computer-assisted semen analysis.

RESULTSImmunocytochemistry found PAR-2 and EGF-R in approximately 30% of examined human ejaculated spermatozoa. Both receptors were localized in the plasma membrane. Like tryptase, the PAR-2 synthetic agonist SLIGKV reduced sperm motility, and this effect was inhibited by application of two specific EGF-R pathway blockers (AG1478 and PD168393).

CONCLUSIONThe observed reduction of sperm motility by tryptase through the PAR-2 receptor involves EGF-R pathways.

Ejaculation ; Enzyme Inhibitors ; pharmacology ; Humans ; Male ; Microscopy, Immunoelectron ; Oligopeptides ; pharmacology ; Quinazolines ; pharmacology ; Receptor, Epidermal Growth Factor ; antagonists & inhibitors ; drug effects ; physiology ; Receptor, PAR-2 ; physiology ; Reference Values ; Semen ; physiology ; Sperm Motility ; drug effects ; physiology ; Spermatozoa ; drug effects ; physiology ; ultrastructure ; Tyrphostins ; pharmacology

OBJECTIVETo examine how the thymidine phosphorylase (TP) gene expression is upregulated by interferon-alpha (IFN-alpha) in human hepatocellular carcinoma SMMC-7721 cells.

METHODSTP mRNA levels were determined by RT-PCR. Whether the JAK-STAT cascade mediates IFN-alpha-induced TP mRNA expression was studied by pretreatment with Janus Kinase (JAK) inhibitor, AG-490. Effects of IFN-alpha on TP mRNA stability were detected with additional actinomycin D.

RESULTSThe expression of TP mRNA was induced by IFN-alpha in a dose- and time-dependent manner in SMMC-7721 (human hepatocellular carcinoma) cells. TP mRNA levels rose at 8 h, reached the peak value at 12 h, and remained at a high level up to 72 h in SMMC-7721 cells treated with IFN-alpha 10000 U/ml. IFN-alpha at a dose of 5000 or 10000 U/ml up-regulated TP expression about 3 fold compared with that of non-treated cells (P < 0.05). Induction of TP mRNA expression by IFN-alpha was significantly inhibited in SMMC-7721 cells by pretreatment with AG-490, in comparison with that treated with IFN-alpha alone. Pretreatment of SMMC-7721 cells with IFN-alpha 10000 U/ml for 24 h caused a substantial stabilization of TP mRNA, with a half-live of 35.8 h, compared with 8.5 hr in the control SMMC-7721 cells.

CONCLUSIONIFN-alpha at certain doses upregulates TP mRNA expression via both JAK-STAT transcriptional activation and post-transcriptional mRNA stabilization in human hepatocellular carcinoma SMMC-7721 cells.

Carcinoma, Hepatocellular ; enzymology ; pathology ; Cell Line, Tumor ; Dose-Response Relationship, Drug ; Enzyme Inhibitors ; pharmacology ; Gene Expression Regulation, Neoplastic ; Humans ; Interferon-alpha ; administration & dosage ; pharmacology ; Janus Kinases ; metabolism ; Liver Neoplasms ; enzymology ; pathology ; RNA, Messenger ; metabolism ; STAT1 Transcription Factor ; metabolism ; Thymidine Phosphorylase ; biosynthesis ; genetics ; Transcriptional Activation ; drug effects ; Tyrphostins ; pharmacology

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