Effects of extract of Oratosquilla on expression of P53, COX-2 and VEGF in human nasopharyngeal carcinoma cell line

AIM: To study the inhibitory effect of the extract of Oratosquilla(EOS) on the expression of P53, cyclooxygenase-2(COX-2) and vascular endothelial growth factor(VEGF) in nasopharyngeal carcinoma cell line CNE-2Z.METHODS: CNE-2Z cells were treated with different concentrations of EOS for 24 h. The methods of RT-PCR and immunocytochemistry were used to detect the expression of COX-2 and VEGF at mRNA and protein levels, respectively. The protein expression of P53 was determined by Western blotting.RESULTS: After treated with EOS, the protein expression of P53 in CNE-2Z cells was decreased(P<0.01), and the expression of COX-2 and VEGF at mRNA and protein levels was also significantly decreased in a dose-dependent manner(P<0.01). The expression of COX-2 was positively correlated with that of VEGF(P<0.05), and a positive correlation between the expression of COX-2 and P53 protein(P<0.05) was also observed.CONCLUSION: EOS may play its antitumor effect by inhibiting the expression of P53, COX-2 and VEGF in nasopharyngeal carcinoma cell line CNE-2Z.     

Effect of extract of Oratosquilla oratoria on telomerase activity in human nasopharyngeal carcinoma cell line

AIM: To study the inhibitory effect and its mechanisms of the extract of Oratosquilla oratoria (EOS) on the activity of telomerase in human nasopharyngeal carcinoma cell line CNE-2Z. METHODS: MTT assay was used to determine the effect of different doses of EOS on the proliferation of CNE-2Z cells. The activity of telomerase was analyzed by TRAP-ELISA. The mRNA expression of hTERT was determined by RT-PCR, and the protein expression of c-Myc was detected by Western blotting. RESULTS: EOS inhibited the proliferation of CNE-2Z cells in a dose-dependent manner (P<0.01). Telomerase activity was decreased, the mRNA expression of hTERT and c-Myc in CNE-2Z cells was also decreased (P<0.01) by the treatment of EOS. The correlation between the down-regulatory expression of hTERT mRNA and inhibitory expression of c-Myc protein (P<0.05) under the condition of EOS exposure was observed. CONCLUSION: EOS inhibits the proliferation of CNE-2Z cells by reducing the activity of telomerase, which is related with the inhibitory expression of hTERT mRNA caused by the decrease in c-Myc production.     

GM-CSF induces human vascular endothelial cells to form vessel-like structure and the role of VEGF

AIM: To investigate the influence of GM-CSF on human vascular endothelial cells induced to form new blood vessels and the role of VEGF. METHODS: HUVECs were cultured by Matrigel to set up a stable angiogenesis system with the stimulating factors. The rhGM-CSF concentration-dependent and time-dependent effects and the role of VEGF165 were detected. CD34 was measured by immunochemical staining and numbers of vessel formation was calculated under microscopic observation. RESULTS: After treatment with rhGM-CSF at various concentrations and at different time points, the numbers of vessel formation increased in a dose-dependent and time-dependent manner. In the presence of VEGF165, the numbers of vessel formation increased evidently. CONCLUSION: HUVECs were induced to develop tubular structure in vitro cultured with Matrigel. GM-CSF promotes human vascular endothelial cells to form vessel-like structure in vitro in a dose-dependent and time-dependent manner. VEGF also in vitro promotes human vascular endothelial cells to form new vessel-like structure.     

Inhibitory role of epigallocatechin-3-gallate in proliferation of human nasopharyngeal carcinoma cells by targeting P53/miR-34a

AIM: To study the effect of epigallocatechin-3-gallate(EGCG) on the proliferation of human nasopharyngeal carcinoma(NPC) cells, and to explore its mechanism by targeting miR-34a.METHODS: Nasopharyngeal carcinoma CNE-2Z cells were treated with various concentrations of EGCG. The ability of cell proliferation was detected by CCK-8 assay, 5-ethynyl-2-deoxyuridine(EdU) incorporation assay and colony-forming assay. The cell cycle distributions were analyzed by flow cytometry. The protein levels of P53 and Notch1 were detected by Western blot. The expression of miR-34a and Notch1 mRNA was measured by real-time PCR.RESULTS: EGCG effectively inhibited the proliferation and colony formation of CNE-2Z cells in a dose-dependent manner, which was related to its induction of cell cycle arrest at G₀/G₁ phase. The expression of P53 and miR-34a in CNE-2Z cells was significantly increased after treated with EGCG, while the expression of Notch1 at mRNA and protein levels was markedly suppressed.CONCLUSION: EGCG induces cell cycle arrest and suppresses cell proliferation by regulating the P53/miR-34a/Notch1 pathway in NPC cells.     

Role of ClC-3 chloride channel in inhibition of nasopharyngeal carcinoma cell cycle by metformin

AIM: To study the roles of ClC-3 chloride channel in the inhibition of nasopharyngeal carcinoma cell cycle by metformin. METHODS: The CNE-2Z cells were treated with metformin at different concentrations. The viability of CNE-2Z cells was measured by CCK-8 assay. The cell cycle distribution was detected by flow cytometry. The protein expression of ClC-3 was determined by Western blot. The Cl^- currents was record by the patch-clamp technique. In addition, the cell cycle distribution was analyzed in the nasopharyngeal carcinoma CNE-2Z cells which over-expressed ClC-3 by pEZ-M03-ClC-3 plasmid transfection. RESULTS: Metformin inhibited the viability of CNE-2Z cells at 5, 10 and 20 mmol/L. Metformin at 10 mmol/L prevented the activation of chloride currents induced by hypotonicity, inhibited the protein expression of ClC-3 chloride channel and arrested the nasopharyngeal carcinoma CNE-2Z cells at G₀/G₁ phases. ClC-3 chloride channel protein over-expression reversed the effect of metformin on the cell cycle distribution of CNE-2Z cells. CONCLUSION: Metformin inhibits the CNE-2Z cell cycle, which may be related to the inhibition of ClC-3 chloride channel function and protein expression.     

Effects of curcumin analogue B50 on proliferation and apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM: To compare the effects of B50, a mono-carbonyl analogue of curcumin, on the proliferation and apoptosis between homologous nasopharyngeal carcinoma cells CNE-2R and CNE-2 with different radioresistance.METHODS: The effects of B50 on cell viability and cell growth were detected by MTT assay and colony-forming experiment, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential (MMP) were determined by flow cytometry.RESULTS: B50 inhibited the cell viability of CNE-2R cells in a time-and dose-dependent manner with the IC₅₀ of (8.06±0.14) μmol/L (24 h), (2.49±0.02)μmol/L (48 h) and (1.42±0.02) μmol/L (72 h), which was more effective than that in CNE-2 cells . The inhibitory effect of B50 on CNE-2R cell growth was more effective than that on CNE-2 cells . After treated with B50 for 48 h, the proportion of CNE-2R cells in G₂/M stage was increased from 7.1% to 34.9%, which was better than that of CNE-2 cells (from 12.4% to 35.7%). After treated with B50 for 24 h, the early apoptotic rate in CNE-2R cells was increased from 3.7% to 19.5%, which was better than that in CNE-2 cells (from 4.4% to 14.8%), and the MMP in CNE-2R cells was decreased by (43.17±3.11)%, which was better than that in CNE-2 cells .CONCLUSION: B50 is more effective on inhibiting the cell viability and cell growth, blocking the cell cycle at G₂/M stage, inducing apoptosis and decreasing MMP in CNE-2R cells than those in CNE-2 cells, indicating that B50 may enhance the radio-sensitivity of CNE-2R cells by blocking the cell cycle and inducing apoptosis through mitochondrial pathway.     

Effects of PKC-α asODN and PKA-ⅠasODN on growth and proliferation of the CNE-2Z cells of nasopharyngeal carcinoma

AIM:To investigate the effects of antisense oligonucleotides (asODN) of PKC-α and PKA-Ⅰon growth and proliferation of the CNE-2Z cells.METHODS:The expression of PKC-α and PKA-Ⅰ was observed with immunohistochemistry method. The asODNs of (1)PKC-α, (2)PKA-Ⅰ, (3)PKC-α and PKA-Ⅰ, were transfected into CNE-2Z cells by lipofectin (LP), and a random sequence as a control was used. The cell growth index (GI) and the clone formation rate of CNE-2Z were detected by MTT colorimetric assay and soft agar assy, respectively.RESULTS:The expression of PKC-α or PKA-Ⅰin CNE-2Z in experimental group were both significantly lower than that of control group(P<0.05). The GI and clone formation rates of CNE-2Z cells transfected by PKC-α and PKA-ⅠasODN with concentrations ranging from 0.05 μM to 1.00 μM were lower significantly than that of control groups(P<0.05), and there was a dose-dependent relationship among them. The inhibitory effects of PKC-α and PKA-ⅠasODNs both on the cell growth index (GI) and clone formation rates were more significant than that of control group(P<0.01),and the GI were significantly lower than that of the other experimental groups(P<0.05).CONCLUSION:PKC-α asODN and PKA-ⅠasODN inhibited CNE-2Z growth and proliferation in vitro, and a synergetic inhibitory effect of PKC-α asODN and PKA-ⅠasODN was also observed.     

Curcumin analogue B67 induces apoptosis and G2/M arrest to suppress radioresistant nasopharyngeal carcinoma cells

AIM: To study the effect of curcumin analogues B67 on radioresistant nasopharyngeal carcinoma cells (CNE-2R). METHODS: The effects of B67 on the cell viability and proliferation of CNE-2R and the parent cells CNE-2 were detected by MTT assay and colony formation assay, respectively. The changes of cell cycle, apoptosis and mitochondrial membrane potential were determined by flow cytometry. The morphological changes of the cells were observed under fluorescence microscope. Node mice were subcutaneously inoculated with the cells to determine the tumorigenic ability. RESULTS: The IC₅₀ of B67 on the viability of CNE-2R cells after treatment for 24 h, 48 h and 72 h were 3.96,2.59 and 0.89 μmol/L, respectively, and those of CNE-2 cells were 8.84, 3.55 and 1.10 μmol/L,respectively. The IC₅₀ of B67 on the proliferation of CNE-2R cells after treatment for 48 h was 0.55 μmol/L, and that of CNE-2 cells was 0.73 μmol/L. After treated with B67 for 24 h, CNE-2R and CNE-2 cells at G₂/M stage increased from 5.32% to 40.01% and from 9.07% to 15.73%,respectively. After treated with B67 for 48 h, the apoptosis of CNE-2R and CNE-2 cells increased from 5.49% to 38.06% and from 4.99% to 35.74%, respectively. The mitochondrial membrane potential in CNE-2R and CNE-2 cells was decreased by 66.76% and 72.09%, respectively. After treated with B67 for 24 h, the tumorigenic rate of CNE-2R cells was 0%, while the rates of CNE-2 cells in low- and high-concentration groups were 100% and 0%, respectively.CONCLUSION: Curcumin analogue B67 exhibits enhanced suppressive activity on radioresistant nasopharyngeal carcinoma cells by inducing G₂/M-phase arrest, promoting cell apoptosis and changing mitochondrial membrane potential.     

Roles of chloride channels in the migration of nasopharyngeal carcinoma cells at different stages of the cell cycle

AIM: To clarify the migration capability of nasopharyngeal carcinoma cells (CNE-2Z) at different stages of the cell cycle and the roles of chloride channels in cell migration. METHODS: Synchronous cells were obtained by the serum deprivation，double chemical-block, mitotic arrest and shake-off techniques. Cell cycle distribution of CNE-2Z cells was analyzed by the flow cytometry. Migration rate was assayed by transwell chambers and by image analysis. The cytotoxicity of chemicals on cells was tested by MTT assay. RESULTS: CNE-2Z cells at different stages of the cell cycle exhibited different migratory ability. The migration rate of the three stages was G1>M> S. The migration of CNE-2Z cells was inhibited by chloride channel blockers (ATP, NPPB and tamoxifen), but the inhibitory effect of the blockers varied with cells at different stages. CONCLUSIONS: The migratory ability is associated with the cell cycle in CNE-2Z cells. Chloride channels play an important role in cell migration of CNE-2Z cells.     

Inhibitory effect of polypeptide from Buthus martensii Karsch on neoplasm cells

AIM: To observe the inhibitory effects of polypeptide from Buthus martensii venom (PBMV) on human tumor cell lines and the influence of PBMV on cell cycle migration, expression of tumor-suppressor gene p53 and the membrane potential of CNE-2Z cells. METHODS: MTT colorimetric method, the colony formation and mitosis index, flow cytometry assay and intracellular recording with glass microelectrodes were used. RESULTS: PBMV had obvious cytotoxicity on several tumor cell lines. The cells grow was inhibited by PBMV, colony formation rate and mitotic index of tumor cells were reduced and the number of polykaryocyte was decreased. CNE-2Z cells in S phase were reduced evidently after they were treated with PBMV (P<0.01). After CNE-2Z cells were incubated with PBMV, P53 protein expression in the cells decreased obviously. Differences were very distinct (P<0.01). The negative potential of cell membrane reduced evidently and cell membrane was in depolarization state. CONCLUSION: PBMV probably possesses the effects of the "membrane toxin". By decreasing the membrane potential, the growth and proliferation of tumor cells were interfered by PBMV.     

Transforming growth factor α promotes the proliferation,migration and adhesion of human endothelial progenitor cells

AIM: To explore the effects of transforming growth factor-α (TGF-α) in the monoclonal formation, proliferation, migration and adhesiveness of human endothelial progenitor cells (EPCs). METHODS: The isolated and cultured EPCs were treated with various concentrations of TGF-α (final concentrations of 1, 5, 10 μg/L, respectively). At the same time, the PBS control and epidermal growth factor receptor-tyrosine kinase inhibitor (EGFR-TKI) group (10 μg/L TGF-α plus 1: 1 000 EGFR-TKI) were set. The effects of TGF-α on monoclonal formation, proliferation, migration and adhesiveness of EPCs were determined by clone formation experiment, thiazolyl blue tetrazolium bromide (MTT), EdU, Transwell and adhesion assays, respectively. The expression of epithelial growth receptor (EGFR) and vascular endothelial growth factor (VEGF) were measured by Western blotting. RESULTS: Different concentrations of TGF-α all significantly induced the monoclonal formation, proliferation, migration and adhesiveness of EPCs (P<0.01), which were inhibited by EGFR-TKI. The results of Western blotting showed that TGF-α also induced the expression of EGFR and VEGF with a certain concentration effect (P<0.01). CONCLUSION: By combining with EGFR induced the expression of VEGF, TGF-α significantly promotes the related cell function of monoclonal formation, proliferation, migration, adhesiveness in EPCs.     

Effects of curcumin analogue T83 on apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance

AIM：To compare the effect of T83 (a 4-arylidene curcumin analogue) on the apoptosis of homologous nasopharyngeal carcinoma cells with different radioresistance. METHODS：The effects of T83 on the viability, apoptosis, mitochondrial membrane potential (MMP), expression of procaspase-3/procaspase-9/Cyt-C proteins and relative PTEN/Akt/p27 mRNA expression in CNE-2R cells and CNE-2 cells were detected and compared by the methods of MTT assay, Hoechst staining, flow cytometry, Western blotting and qRT-PCR. RESULTS：T83 inhibited the viability of CNE-2R cells with the IC50 of 0.9,0.4 and 0.2 μmol/L for 24 h, 48 h and 72 h,respectively, which was more effective than that inhibiting the viability of CNE-2 cells with the IC50 of 1.8,0.5 and 0.4 μmol/L, respectively. After treated with T83 for 48 h, chromatin condensation, margination and splitting into a massive structure were observed in CNE-2R cells and CNE-2 cells,and the late apoptotic rate of CNE-2R cells was increased from 1.57% to 27.26%, which was higher than that of CNE-2 cells (1.74% to 8.15%). After treated with T83 for 36 h, the MMP in CNE-2R cells decreased by 87.71% and that decreased by 50.47% in CNE-2 cells. After treated with T83 for 48 h, the protein levels of procaspase-3 and procaspase-9 were decreased, and the protein level of Cyt-C was increased, which were more susceptible in CNE-2R cells than those in CNE-2 cells. After treated with T83 for 24 h, the relative mRNA expression of PTEN and p27 was significantly up-regulated, and the mRNA expression of Akt was down-regulated, which were more susceptible in CNE-2R cells than those in CNE-2 cells. CONCLUSION：Compared with CNE-2 cells, the inhibitory effect of T83 on the viability of CNE-2R cells is more specific by starting the mitochondrial apoptotic pathway, which is due to the inhibition of PTEN/Akt/p27 signaling pathway.     

Fasudil reduces formation of urethral stricture after injury via inhibiting Rho/ROCK pathway activation in rabbit urethra fibroblasts

AIM: To investigate the role of Rho-associated kinase (ROCK) inhibitor fasudil in the formation of rabbit urethral stricture after injury and to observe the cell activity, migration and extracellular matrix synthesis in the rabbit urethra fibroblasts. METHODS: The rabbit model of urethral stricture was established by microsurgical techniques. The rabbits were divided into sham operation group, operation group and fasudil (3 mg/kg, 10 mg/kg, 30 mg/kg) groups. The diameter of the stenosis was measured by retrograde urethrography 3 months after surgery. The fibroblasts were isolated from urethral scar, and then incubated with fasudil (12.5 μmol/L, 25 μmol/L, 50 μmol/L) in the presence of transforming growth factor-β1 (TGF-β1, 10 μg/L). The untreated cells were used for control. The cell activity was measured by MTT assay. The cell migration ability was tested by the method of Transwell chambers. The protein expression of ROCK, α-smooth muscle actin (α-SMA), collagen I and collagen III was determined by Western blot analysis. RESULTS: Fasudil significantly reduced formation of urethral stricture after injury (P<0.05). Cultured rabbit fibroblasts with different concentrations of fasudil inhibited the cell activity and cell migration ability (P<0.05). The protein expression of ROCK, α-SMA, collagen I and collagen III was also inhibited by treatment with fasudil in a dose-dependent manner (P<0.05). CONCLUSION: Fasudil inhibits the formation of extracellular matrix and reduces the incidence of urethral stricture after injury by down-regulating TGF-β1-induced Rho/ROCK pathway activation in the rabbit urethra fibroblasts.     

X-ray ionizing radiation induces epithelial-mesenchymal transition in human nasopharyngeal carcinoma CNE-2 cells

AIM:To investigate the effect of X-ray ionizing radiation on epithelial-mesenchymal transition (EMT) in human nasopharyngeal carcinoma CNE-2 cells and its involved potential signaling pathway. METHODS:The nasopharyngeal carcinoma CNE-2 cells were irradiated with different doses (0 Gy, 2 Gy, 4 Gy and 8 Gy) of X-ray. The morphological changes of the cells were observed under inverted microscope after 24 h. The migration and invasion abilities were detected by wound healing and Transwell assays. The mRNA and protein levels of E-cadherin, N-cadherin and vimentin in nasopharyngeal carcinoma CNE-2 cells were determined by real-time PCR and Western blot, respectively. The protein levels of Akt and p-Akt were detected by Western blot. RESULTS:After X-ray irradiation, the CNE-2 cells exhibited typical ‘cobblestone’ or spindle-like shape, with extended pseudopodia and dilated intercellular space. The invasiveness and metastatic abilities of the CNE-2 cells were enhanced (P<0.01). The mRNA and protein expression levels of E-cadherin were significantly decreased (P<0.01), while the mRNA and protein expression levels of N-cadherin and vimentin were markedly increased after irradiation as compared with the control group (no irradiation) (P<0.05). The protein level of p-Akt was significantly enhanced (P<0.01), while the protein level of Akt showed little change after irradiation. CONCLUSION:X-ray ionizing radiation induces EMT in nasopharyngeal carcinoma CNE-2 cells, which may be related to the activation of PI3K/Akt signaling pathway.     

T63 enhances radiotherapeutic sensitivity of nasopharyngeal carcinoma cells through apoptosis and G2/M arrest

AIM: To explore the antitumor effect of a curcumin analogue T63 in human nasopharyngeal carcinoma (NPC) cell lines CNE-2 and CNE-2R. METHODS: Cell viability was monitored by the methods of MTT and colony formation assay. Cell cycle distribution was detected by flow cytometry. Apoptosis was examined using the annexin V-FITC/PI staining assay. RESULTS: A growth inhibitory effect was observed with T63 treatment in a dose-dependent manner. Either T63 or ionizing radiation (IR) significantly induced G2/M arrest and apoptosis in NPC cells. In addition, T63 treatment combined with IR induced significantly higher apoptosis and G2/M arrest in NPC cells. CONCLUSION: T63 exhibits potent inhibitory activity on NPC cells and induces the radiotherapeutic sensitivity. Therefore, T63 has a potential as a preventive or therapeutic agent for treating NPC.     

Inhibitory effect of propolis on proliferation of K562 cells in vitro

AIM: To study the effect of propolis on the proliferation of K562 cells.METHODS: K562 cells were cultured in vitro. Cell proliferation was measured by MTT method. The apoptotic rate was determined by flow cytometry. RT-PCR was applied to detect mRNA expression of Nup98. The protein level of Nup98 was determined by Western blotting. RESULTS: The inhibitory rates of proliferation induced by propolis at the concentrations of 2 mg/L, 20 mg/L and 200 mg/L were obviously higher than that in control cells in a time-and dose-dependent manner. The apoptotic rate was increased in a dose-dependent manner. High concentration of propolis down-regulated the expression of Nup98 at mRNA and protein levels. CONCLUSION: Propolis inhibits the proliferation and induces apoptosis in K562 cells. The mechanism may be related with down-regulation of Nup98.     

NBP promotes angiogenesis of HUVECs by activating VEGF/VEGFR2-Notch1/Dll4 signal pathway

AIM: To investigate the effects of DL-3-n-butylphthalidle (NBP) on angiogenesis of human umbilical vein endothelial cells (HUVECs) and the role of vascular endothelial growth factor (VEGF)/VEGF receptor 2(VEGFR2)-Notch1/Delta-like ligand 4 (Dll4) signaling pathway in this process. METHODS: The serum-free medium and anoxic tank were used to simulate the conditions of hypoxia and ischemia (H/I). HUVECs were divided into control group, H/I group, H/I+NBP_high group and H/I+NBP_low group. The HUVECs in control group were conventionally cultured, and those in H/I group were cultured under H/I intervention. The HUVECs in H/I+NBP_high group were treated with NBP at 20 μmol/L under H/I intervention. The HUVECs in H/I+NBP_low group were treated with NBP at 5 μmol/L under H/I intervention. The cell viability of each group was measured by CCK-8 assay. The migration ability of the HUVECs in each group was detected by cell scratch test. The vessel formation ability of the HUVECs was examined by in vitro angiogenesis assay. The expression of VEGFR2, Notch1 and Dll4 at mRNA and protein levels was determined by qPCR and Western blot, and the expression of VEGF was determined by qPCR and ELISA. RESULTS: NBP increased the viability of HUVECs, and promoted the migration ability and the formation of blood vessels in vitro under H/I intervention. These effects of NBP at high dose were more significant than those at low dose. NBP increased the expression of VEGF, VEGFR2, Notch1 and Dll4 at mRNA and protein levels (P<0.05). CONCLUSION: NBP promotes HUVECs to form blood vessels under H/I intervention. The mechanism may be related to the activation of VEGF/VEGFR2-Notch1/Dll4 signaling pathway.     

Effect of AG490 on expression of VEGF and HIF-1α in HEL cells

AIM: To investigate the effect of AG490 on the expression of VEGF and HIF-1α, and the capacity of invasion in human erythroleukemia (HEL) cells. METHODS: The HEL cells were treated with AG490 at different concentrations. The cell viability was detected by CCK-8 assay. The apoptosis was detected by Hoechst staining. The apoptosis and the cell cycle were analyzed by flow cytometry. The capacity of migration was evaluated by Transwell assay. The mRNA expression level of JAK2 was measured by RT-PCR. The protein levels of p-JAK2, VEGF and HIF-1α were determined by Western blot. RESULTS: The HEL cell viabilities were 88%, 75%, 48%, 10% and 0.12% after treated with AG490 at 20, 40, 60, 80 and 100 μmol/L for 48 h, respectively. The results of Hoechst staining showed that brilliant blue cells in 80 μmol/L AG490 group was significantly increased compared with control group for 48 h. The apoptosis rate of 80 μmol/L AG490 group was significantly increased compared with control group at 48 h after AG490 treatment. The number of membrane-permeating HEL cells in 20 μmol/L AG490 group at 24 h after AG490 treatment was significantly lower than that in control group (P<0.05). The mRNA level of JAK2 decreased in a concentration-dependent manner after the HEL cells were treated with different concentrations of AG490 for 48 h. The protein levels of p-JAK2, VEGF and HIF-1α were lower in AG490 treatment groups than those in control group (P<0.05). CONCLUSION: AG490 inhibits the expression of VEGF and HIF-1α in HEL cells by inhibiting JAK2 pathway.