Protein Expression Levels Of p-ERK Research Articles

Glucagon-Like Peptide Receptor Agonist Inhibits Angiotensin II-Induced Proliferation and Migration in Vascular Smooth Muscle Cells and Ameliorates Phosphate-Induced Vascular Smooth Muscle Cells Calcification.

Glucagon-like peptide-1 receptor agonist (GLP-1RA), which is a therapeutic agent for the treatment of type 2 diabetes mellitus, has a beneficial effect on the cardiovascular system. To examine the protective effects of GLP-1RAs on proliferation and migration of vascular smooth muscle cells (VSMCs), A-10 cells exposed to angiotensin II (Ang II) were treated with either exendin-4, liraglutide, or dulaglutide. To examine the effects of GLP-1RAs on vascular calcification, cells exposed to high concentration of inorganic phosphate (Pi) were treated with exendin-4, liraglutide, or dulaglutide. Ang II increased proliferation and migration of VSMCs, gene expression levels of Ang II receptors AT1 and AT2, proliferation marker of proliferation Ki-67 (Mki-67), proliferating cell nuclear antigen (Pcna), and cyclin D1 (Ccnd1), and the protein expression levels of phospho-extracellular signal-regulated kinase (p-Erk), phospho-c-JUN N-terminal kinase (p-JNK), and phospho-phosphatidylinositol 3-kinase (p-Pi3k). Exendin-4, liraglutide, and dulaglutide significantly decreased the proliferation and migration of VSMCs, the gene expression levels of Pcna, and the protein expression levels of p-Erk and p-JNK in the Ang II-treated VSMCs. Erk inhibitor PD98059 and JNK inhibitor SP600125 decreased the protein expression levels of Pcna and Ccnd1 and proliferation of VSMCs. Inhibition of GLP-1R by siRNA reversed the reduction of the protein expression levels of p-Erk and p-JNK by exendin-4, liraglutide, and dulaglutide in the Ang II-treated VSMCs. Moreover, GLP-1 (9-36) amide also decreased the proliferation and migration of the Ang II-treated VSMCs. In addition, these GLP-1RAs decreased calcium deposition by inhibiting activating transcription factor 4 (Atf4) in Pi-treated VSMCs. These data show that GLP-1RAs ameliorate aberrant proliferation and migration in VSMCs through both GLP-1Rdependent and independent pathways and inhibit Pi-induced vascular calcification.

Stress regulation of WFS1 and PERK-p-eIF2α-ATF4 signaling pathway in placental tissue cells of intrahepatic cholestasis of pregnancy

IntroductionThe placental tissue stress of intrahepatic cholestasis of pregnancy (ICP) is activated by ERS under hypoxia condition. PERK signaling pathway is the key pathway for UPR regulation, and is first to activated during ERS. WFS1, as an important regulatory gene of UPR pathway, participates in ERS regulation. The purpose of our study is to explore the expression level and mutual regulation mechanisms of WFS1 and PERK-mediated UPR pathway in ICP placental tissue cell under stress. MethodsBlood and placenta samples were obtained from the ICP patients and ethinylestradiol (EE)-induced intrahepatic cholestasis pregnant rats. IHC and WB were used to detect the expression of WFS1, key factors of PERK pathway (GRP78, PERK, eIF2a, P-eIF2α, ATF4) and placental stress peptides (CRH, UCN). Furthermore, qPCR was carried out to detect mRNA expression of above indicators. ResultsThe expression levels of WFS1 and key factors of PERK pathway were significantly increased in severe ICP placental tissues. Moreover, qPCR and WB showed that relative mRNA and protein expression levels of WFS1 and key factors of PERK pathways in placenta tissues of severe ICP and EE-induced intrahepatic cholestasis pregnant rats were higher than those in control group to varying degrees, while CRH and UCN were descended. Meanwhile, after WFS1-siRNA targeted silencing of the WFS1 gene, the protein expression levels of PERK, P-eIF2α, ATF4 were significantly increased, while CRH and UCN protein were significantly decreased. DiscussionOur study revealed that the activation of WFS1 and PERK-p-eIF2α-ATF4 signaling pathway may contribute to stress regulation in placental tissue cells of intrahepatic cholestasis of pregnancy, thereby avoiding adverse pregnancy outcomes.

Estrogenic Activity of 4-Hydroxy-Benzoic Acid from Acer tegmentosum via Estrogen Receptor α-Dependent Signaling Pathways.

Acer tegmentosum, a deciduous tree belonging to Aceraceae, has been used in traditional oriental medicine for treating hepatic disorders, such as hepatitis, cirrhosis, and liver cancer. We evaluated the estrogen-like effects of A. tegmentosum using an estrogen receptor (ER)-positive breast cancer cell line, namely MCF-7, to identify potential phytoestrogens and found that an aqueous extract of A. tegmentosum promoted cell proliferation in MCF-7 cells. Five phenolic compounds (1-5) were separated and identified from the active fraction using bioassay-guided fractionation of crude A. tegmentosum extract and phytochemical analysis. The chemical structures of the compounds were characterized as vanillic acid (1), 4-hydroxy-benzoic acid (2), syringic acid (3), isoscopoletin (4), and (E)-ferulic acid (5) based on the analysis of their nuclear magnetic resonance spectra and liquid chromatography-mass spectrometry data. All five compounds were evaluated using an E-screen assay for their estrogen-like effects on MCF-7 cells. Among the tested compounds, only 4-hydroxy-benzoic acid (2) promoted the proliferation of MCF-7 cells, which was mitigated by the ER antagonist, ICI 182,780. The mechanism underlying the estrogen-like effect of 4-hydroxy-benzoic acid (2) was evaluated via western blotting analysis to determine the expression levels of extracellular signal-regulated kinase (ERK), phosphoinositide 3-kinase (PI3K), serine/threonine kinase (AKT), and ERα. Our results demonstrated that 4-hydroxy-benzoic acid (2) induced the increase in the protein expression levels of p-ERK, p-AKT, p-PI3K, and p-Erα, concentration dependently. Collectively, these experimental results suggest that 4-hydroxy-benzoic acid (2) is responsible for the estrogen-like effects of A. tegmentosum and may potentially aid in the control of estrogenic effects during menopause.

Effect of porous tantalum on promoting the osteogenic differentiation of bone marrow mesenchymal stem cells in vitro through the MAPK/ERK signal pathway

BackgroundAs an ideal new graft material, porous tantalum (pTa) has excellent mechanical properties and corrosion resistance and has received increased attention in the biomedical field because of its excellent cytocompatibility and ability to induce bone formation. However, the molecular mechanism of its potential to promote osteogenesis remains unclear, and very few reports have been published on this topic. MethodsIn this study, we first produced porous Ti6Al4V (pTi6Al4V) and pTa with the same pore size by three-dimensional printing combined with chemical vapour deposition. The number of adhesions between pTa and pTi6Al4V and bone marrow mesenchymal stem cells (BMSCs) after 1 day of culture was detected by the live/dead cell staining method. The proliferation activity of the two groups was determined after culture for 1, 3, 5 and 7 days by the cell counting kit-8 method. In addition, the osteogenic activity, mRNA expression levels of osteogenic genes alkaline phosphatase (ALP), osterix (OSX), collagen-I (Col-I), osteonectin (OSN) and osteocalcin (OCN) and protein expression levels of the mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) signalling pathway marker p-ERK of the two groups cultured for 7, 14 and 21 days were determined by the ALP activity assay, real-time quantitative polymerase chain reaction (Q-PCR) and Western blotting, respectively. Subsequently, the two groups were treated with the MAPK/ERK–specific inhibitor U0126, and then, the mRNA expression levels of osteogenic genes and protein expression levels of p-ERK in the cultures were determined by Q-PCR and Western blotting, respectively. ResultsThe live/dead cell staining and cell counting kit-8 assays showed that the adhesion and proliferation activities of BMSCs on pTa were significantly better than those on pTi6Al4V. In addition, the ALP activity assay and Q-PCR showed that pTa harboured osteogenic activity and that the osteogenic genes ALP, OSX, Col-I, OSN and OCN were highly expressed, and by Western blotting, the expression of p-ERK protein in the pTa group was also significantly higher than that in the pTi6Al4V group. Subsequently, using the MAPK/ERK–specific inhibitor U0126, Western blotting showed that the expression of p-ERK protein was significantly inhibited and that there was no difference between the two groups. Furthermore, Q-PCR showed that osteogenic gene expression and ALP expression levels were significantly increased in the pTa group, and there were no differences in the OSX, Col-I, OSN and OCN mRNA expression levels between the two groups. ConclusionOverall, our research found that compared with the widely used titanium alloy materials, our pTa can promote the adhesion and proliferation of BMSCs, and the molecular mechanism of pTa may occur via activation of the MAPK/ERK signalling pathway to regulate the high expression of OSX, Col I, OSN and OCN osteogenic genes and promote the osteogenic differentiation of BMSCs in vitro.The translational potential of this article: Our self-developed pTa material produced by three-dimensional printing combined with the chemical vapour deposition method not only retains excellent biological activity and osteoinductive ability of the original tantalum metal but also saves considerably on material costs to achieve mass production of personalised orthopaedic implants with pTa as a stent and to accelerate the wide application of pTa implants in clinical practice, which have certain profound significance.

An Experimental Analysis of the Molecular Effects of Trastuzumab (Herceptin) and Fulvestrant (Falsodex), as Single Agents or in Combination, on Human HR+/HER2+ Breast Cancer Cell Lines and Mouse Tumor Xenografts.

PurposeTo investigate the effects of trastuzumab (herceptin) and fulvestrant (falsodex) either in combination or alone, on downstream cell signaling pathways in lab-cultured human HR+/HER2+ breast cancer cell lines ZR-75-1 and BT-474, as well as on protein expression levels in mouse xenograft tissue.MethodsCells were cultivated in the presence of trastuzumab or fulvestrant or both. Molecular events that resulted in an inhibition of cell proliferation and cell cycle progression or in an increased rate of apoptosis were studied. The distribution and abundance of the proteins p-Akt and p-Erk expressed in these cells in response to single agents or combinatorial treatment were also investigated. In addition, the effects of trastuzumab and fulvestrant, either as single agents or in combination on tumor growth as well as on expression of the protein p-MED1 expressed in in vivo mouse xenograft models was also examined.ResultsCell proliferation was increasingly inhibited by trastuzumab or fulvestrant or both, with a CI<1 and DRI>1 in both human cell lines. The rate of apoptosis increased only in the BT-474 cell line and not in the ZR-75-1 cell line upon treatment with fulvestrant and not trastuzumab as a single agent (P<0.05). Interestingly, fulvestrant, in combination with trastuzumab, did not significantly alter the rate of apoptosis (in comparison with fulvestrant alone), in the BT-474 cell line (P>0.05). Cell accumulation in the G1 phase of cell cycle was investigated in all treatment groups (P<0.05), and the combination of trastuzumab and fulvestrant reversed the effects of fulvestrant alone on p-Akt and p-Erk protein expression levels. Using ZR-75-1 or BT-474 to generate in vivo tumor xenografts in BALB/c athymic mouse models, we showed that a combination of both drugs resulted in a stronger inhibition of tumor growth (P<0.05) and a greater decrease in the levels of activated MED1 (p-MED1) expressed in tumor issues compared with the use of either drug as a single agent.ConclusionsWe demonstrate that the administration of trastuzumab and fulvestrant in combination results in positive synergistic effects on both, ZR-75-1 and BT-474 cell lines. This combinatorial approach is likely to reduce physiological side effects of both drugs, thus providing a theoretical basis for the use of such combination treatment in order to resolve HR+/HER2+ triple positive breast cancer that has previously been shown to be resistant to endocrine treatment alone.

Inhibition of PTB-associated splicing factor on IGF-1/VEGF signaling pathway in retinal vascular endothelial cells

Background Retinal neovascularization (RNV) is common findings of many fundus diseases.Research showed that insulin-like growth factor-1 (IGF-1) induces the proliferation of vascular endothelial cells and therefore promotes the formation of new blood vessel.Polypyrimidine tract-binding protein-associated splicing factor (PSF) is determined to play the inhibitory effect on the gene trancription in IGF-1 signal pathway, but its effect on RNV is still unelucidated. Objective This study was to observe the regulation of PSF on IGF-1/vascular endothelial growth factor(VEGF) signaling pathway in vitro. Methods RF/6A cells were cultured and divided into four groups.Pegfp-C2-PSF plasmid, Pegfp-C2 plasmid, pGenesil-PSF-RNAi plasmid and pGenesil-RNAi plasmid were transfected into the cells with the PSF dose of 0.00, 0.25, 0.50 and 1.00 μg respectively.The cells were cultured with or without IGF-1.The proliferation rates of the cells were detected by using MTT assay to determine the optimal PSF dose.Reverse-transceiption PCR (RT-PCR) was employed to assay and compare the relative expression levels of VEGF mRNA in the cells among different PSF plasmid tranfected groups or between the treated groups with and without U0126, and the levels of phosphorylized extracellular signal-regulation kinase (pERK) in the cells were detected by Western blot assay. Results After IGF-1 stimulation, 0.50 μg and 1.00 μg PSF appeared to be the optimal dose in the Pegfp-C2-PSF plasmid group and the pGenesil-PSF-RNAi plasmid group, respectively.The cell proliferation rates and VEGF mRNA levels in the cells were (0.22±0.02) and (0.79±0.07), respectively, in the Pegfp-C2-PSF plasmid group, which were significantly lower than 0.260±0.006 in the Pegfp-C2 plasmid group and 1.26±0.19 in the untransfected group (P=0.040, 0.016). The mean cell proliferative rate was 0.32±0.03, and the mean expression level of VEGF mRNA was 2.29±0.43 in the pGenesil-PSF-RNAi plasmid group, showing significant increases in comparison with 0.210±0.019 of the pGenesil-RNAi plasmid group and 1.26±0.19 of the untransfected group (P=0.003, 0.019). The expression levels of pERK protein in the cells were evidently reduced in the Pegfp-C2-PSF plasmid group compared with the untransfected group 1 hour, 3, 6 hours after addition of IGF-1 (P=0.017, 0.000, 0.000). After treated by U0126, the relative expression level of VEGF mRNA in the Pegfp-C2-PSF plasmid group was 0.93±0.21, which was significantly lower than 1.32±0.08 in the untransfected group (P=0.037) and 1.23±0.09 in the non-U0126 treated cells of the Pegfp-C2-PSF plasmid group (P=0.002). Conclusions PSF inhibits the activation of ERK signal pathway in the IGF-1-stimulated RF/6A cells and down-regulates the expression level of VEGF in RF/6A cells and thus suppresses the growth and proliferation of RF/6A cells. Key words: Polypyrimidine tract-binding protein; RNA splicing; Insulin-like growth factor; Cell line; Endothelial cells/drug effect; Retinal vessels/cytology; Vascular endothelial growth factor; Extracellular signal-regulation kinase

Prednisone inhibits the focal adhesion kinase/receptor activator of NF-κB ligand/mitogen-activated protein kinase signaling pathway in rats with adriamycin-induced nephropathy.

The aim of the present study was to investigate the mechanisms underlying the effects of prednisone on adriamycin-induced nephritic rat kidney damage via the focal adhesion kinase (FAK)/receptor activator of nuclear factor-κB ligand (RANKL)/mitogen‑activated protein kinase (MAPK) signaling pathway. An adriamycin‑induced nephritic rat model was established to investigate these mechanisms. A total of 30 healthy male Sprague‑Dawley rats were randomly assigned to the normal, model or prednisone group. Samples of urine were collected over the course of 24 h at days 7, 14, and 28, and renal cortex tissue samples were harvested at days 14, and 28 following nephritic rat model establishment. The total urinary protein content was measured by biuret colorimetry. Pathological changes in the kidney tissue samples were observed using an electron microscope. The mRNA expressions levels of FAK, RANKL, p38, extracellular signal‑regulated kinase (ERK), c‑Jun N‑terminal kinase (JNK), and nephrin were then quantified by reverse transcription‑quantitative polymerase chain reaction. In addition, the protein expressions levels of FAK, RANKL, p38, ERK, JNK, phosphorylated (p)‑FAK, p‑ERK, and p‑JNK were quantified by western blotting. As compared with the normal group, the protein expression levels of FAK, RANKL, p-FAK, p38 and p-ERK in the model group were increased. In the prednisone group, the protein expression levels of p-ERK decreased, as compared with the normal group. In the prednisone group, the urinary protein levels, the protein expression levels of FAK, RANKL, p38, p-FAK, p-p38 and the mRNA expression levels of FAK, p38, RANKL, ERK, JNK decreased, as compared with the model group. In the prednisone group, the mRNA and protein expression levels of nephrin and the serum expression levels of RANKL increased, the serum expression levels of osteoprotegerin (OPG) were decreased, as compared with the model group. No significant changes in the protein expression levels of JNK were observed among the groups. These results suggested that prednisone is able to protect podocytes from apoptosis, and reduce urinary protein levels by inhibiting the FAK/RANKL/MAPK signaling pathway in kidney tissue samples. Serum prednisone may induce osteoporosis via the OPG/RANK/RANKL signaling pathway.

Effect of PI3Kδ inhibitor CAL-101 on myeloma cell lines and preliminary study of synergistic effects with other new drugs

To investigate the proliferation inhibitory role and mechanism of PI3Kδ inhibitor CAL-101 on multiple myeloma (MM) cells, and to provide new therapeutic options for MM treatment. MM cell lines U266 and RPMI8226 cells were treated with various concentrations of CAL-101. MTT assay and CalcuSyn software were performed to determine the inhibitory effect of CAL-101 and the synergistic effect with PCI- 32765, SAHA (suberoylanilide hydroxamic acid), BTZ (Bortezomib) on MM cells. The protein expression level of p-AKT, p-ERK, AKT, ERK and PI3Kδ processed by CAL-101 were analyzed by Western blot. CAL-101 at concentration of 15, 20, 25, 30 and 40 μmol/L could induce significant dose-dependent proliferation inhibition on U266 cells after treatment for 48 hours. The cell proliferation inhibition rates were (33.54 ± 1.23)%, (41.72 ± 1.78)%, (53.67 ± 2.01)%, (68.97 ± 2.11)% and (79.25 ± 1.92)%, respectively. Similar results were found in RPMI8226 cell line. Western blots showed high expression level of p-AKT, p-ERK, AKT, ERK and PI3Kδ in cell lines and MM primary cells. p-AKT and p-ERK protein expression levels were down-regulated significantly by CAL-101 treatment. Synergistic effect has been verified between CAL-101 and PCI-32765, SAHA and Bortezomib in U266 cell line, and PCI-32765, Bortezomib in RPMI8226 cell line with CI values less than 1. CAL-101 could inhibit proliferation of MM cell lines. High levels of p-AKT, p-ERK, AKT, ERK and PI3Kδ protein expression were observed in both cell lines and primary cells. Down-regulation of p-AKT and p-ERK probably related with the mechanism of CAL-101 in MM cell proliferation inhibition. CAL-101 has significant synergistic effect with PCI-32765, SAHA and BTZ.

Paeoniflorin attenuates allergic inflammation in asthmatic mice.

Paeoniflorin (PF), one of the major active ingredients of Chinese peony, has demonstrated anti-inflammatory and immunoregulatory effects. However, it has remained unclear whether PF treatment can inhibit allergic inflammation in asthma. In this study, we evaluated the effects of PF on pulmonary function and airway inflammation in asthmatic mice. The allergic asthma models were established in BALB/c mice. The mice were sensitized and challenged with ovalbumin. Airway hyperresponsiveness was detected by direct airway resistance analysis. Lung tissues were examined for inflammatory cell infiltration. IL-5, IL-13, IL-17, and eotaxin in bronchoalveolar lavage fluid (BALF) and their mRNA expression in lung tissue were examined by ELISA and realtime PCR, respectively. The total IgE level in serum was measured by ELISA. The protein expression of p-ERK and p-JNK was detected by western blot. Our data showed that PF oral administration significantly reduced airway hyperresponsiveness to aerosolized methacholine and decreased IL-5, IL-13, IL-17 and eotaxin levels in the BALF, and decreased IgE level in the serum. Histological studies showed that PF administration markedly decreased inflammatory infiltration. Similarly, treatment with PF significantly inhibited IL-5, IL-13, IL-17 and eotaxin mRNA expression in lung tissues. The protein expression levels of p-ERK and p-JNK were substantially decreased after oral administration of PF. In summary, PF displayed anti-inflammatory effects in the OVA-induced asthmatic model by decreasing the expression of IL-5, IL-13, IL-17 and eotaxin. These effects were mediated at least partially by inhibiting the activation of MAPK pathway.

Abstract 3543: Activation of the ERK pathways overcome the cisplatin-resistance in ovarian carcinoma cells

Abstract Objective: Cisplatin (CDDP) is a key drug used to treat ovarian carcinoma that activates the mitogen-activated protein kinase kinase (MEK)-extracellular signal-regulated kinase (ERK) signaling cascade and a phosphatidylinositol 3′-kinase (PI3K)-Akt pathway, both of which are considered pathways for cell proliferation and survival. The present study aimed to elucidate the roles of the MEK-ERK and PI3K-Akt pathways in regulating cytotoxicity in ovarian carcinoma cells induced by CDDP. Methods: Seven human ovarian serous adenocarcinoma cell lines were used in this study (KF, KFr, KOC-2S, SK-OV-3, SHIN-3, TU-OS-3, and TU-OS-4). We treated the cell lines with CDDP combined with PI3K inhibitor (LY294002 [LY]), MEK inhibitor (PD98059 [PD]), or ERK activator (phorbol 12-myristate 13-acetate [PMA]), then assessed cell viability by a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The levels at which proteins expressed MEK, phosphorylated (p)MEK, ERK, pERK, Akt, pAkt, and cleaved caspase-9 were detected by western blotting. Cell cycle distribution and apoptotic cells were determined by flow cytometry, 5-bromo-2-deoxyuridine (BrdU) incorporation, and staining with Annexin V. Results: The range of IC50 to CDDP was 2.4 to 26.9 μM for those cell lines. KFr, a CDDP-resistant cell line, was established from KF cells, and the IC50 to CDDP was 9.6 μM. We defined the cell lines which had 9.6 μM or higher IC50 value as CDDP-resistance. Proteins MEK, pMEK, Akt, pAkt, ERK and pERK were expressed in all cell lines. CDDP combined with LY had an additive effect on inhibiting growth of cells in all lines. In contrast, we observed an antagonism for all cell lines when CDDP was combined with PD. Interestingly, growth of cells was dramatically suppressed when CDDP was combined with PMA in the CDDP-resistant cells (KFr, SK-OV-3, SHIN-3, TU-OS-3, TU-OS-4). Treatment with PMA upregulated protein expression levels of pERK and cleaved caspase-9 only in the CDDP-resistant cells. CDDP combined with PMA increased the S-phase fraction and apoptotic cells in the CDDP-resistant cells. Conclusion: ERK activated by PMA may overcome resistance to CDDP in ovarian carcinoma cells. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3543.