Time dependent expression profiling of PTK2B and its relationship with Aβ, Tau and LRP-1 in hippocampus and blood of APPswe/PS1dE9 double-transgenic mouse / 中国应用生理学杂志

Objective: To uncover the time-dependent expression pattern of ptk2b gene and ptk2b-encoded protein, protein tyrosine kinase 2 beta(PTK2B), in the brain tissues of transgenic animal models of Alzheimer's disease (AD) and its relationship with the levels of Aβ1-42, phosphorylation of Tau (p-Tau) and low density lipoprotein receptor-related protein-1(LRP-1) in blood and brain tissues. Methods: In this study, 5-, 10- and 15-month-old APPswe/PS1dE9 double-transgenic mice harboring the genotype of AD confirmed by the gene test were divided into the 5-, 10- and 15-month-old experiment groups, and simultaneously, age-matched C57BL/6J mice were placed into the corresponding control groups, with 8 mice in each group. All mice were subjected to the Morris Water Maze for test of cognitive and behavioral ability. Expression profiles of PTK2B, Aβ1-42, p-Tau/Tau and LRP-1 in the hippocampus or blood of mice were quantified by using the immunohistochemistry staining, Western blot or enzyme-linked immunosorbent assay (ELISA), while the mRNA expression of ptk2b in the hippocampus was quantified by using the real-time quantitative polymerase chain reaction (qRT-PCR). Results: Results of experiment groups demonstrated that as mice aged, the expression levels of PTK2B, ptk2b mRNA, Aβ1-42 and p-Tau/Tau in the hippocampus were increased, and the expression of LRP-1 was decreased gradually. While in the blood, the level of Aβ1-42 was decreased, and the cognitive and behavioral ability was decreased in an age-dependent manner (all P＜ 0.05). However, comparisons among the control groups, only the age-dependent downregulation of LRP-1 were observed in hippocampus(P＜0.05), but other indicators had no significant differences (P＞0.05). Conclusion: In the hippocampus of APP/PS1 double-transgenic mice, the expressions of PTK2B, Aβ1-42 and p-Tau/Tau are upregulated, LRP-1 is downregulated, while cognitive and behavioral ability is decreased, and such changes are presented in a time-dependent manner.

PTK2B affects the levels of Aβ in blood and brain and behavioral functions via targeting LRP-1 transporter in Aβ-induced cognitive dysfunction mice / 生理学报

The aim of the present study was to explore the correlation between ptk2b/PTK2B (protein tyrosine kinase 2 beta, a ptk2b-encoded protein) and the level of low density lipoprotein receptor-related protein-1 (LRP-1), as well as to uncover the relationship between the changes in beta amyloid protein (Aβ) levels in blood and brain and the expression of ptk2b in Aβ-induced cognitive dysfunction mice. A total of 64 3-month-old C57BL/6J mice were divided randomly into the experimental group and control group. All mice underwent the intracerebroventricular (i.c.v.) intubation. Mice in the experimental group received the i.c.v. infusion of oligomeric Aβ

Expression and clinical significance of proline-rich tyrosine kinase 2 and phospho-protein kinase B in tongue squamous cell carcinoma / 华西口腔医学杂志

OBJECTIVE@#This study aimed to investigate the expression and clinical significance of proline-rich tyrosine kinase 2 (Pyk2) and phospho-protein kinase B (p-AKT) in tongue squamous cell carcinoma (TSCC) and adjacent nontumor tissues.@*METHODS@#The Pyk2 and p-AKT protein levels were detected via immunohistochemistry in 45 cases of TSCC tissues and 30 cases of adjacent nontumor tissues. The relationships of the two protein levels and clinicopathological characteristics were also analyzed.@*RESULTS@#Pyk2 and p-AKT levels were significantly higher in the TSCC tissues than in the adjacent nontumor tissues (P<0.05). Nontumor tissues showed poor or no expression. The expression levels of the two proteins were positively correlated (γs=0.412). The expression of Pyk2 was associated with histopathological differentiation type, regional lymph node metastasis, and TNM staging (P<0.05), but not with age and gender. The expression of p-AKT was only related to histopathological differentiation types (P<0.05).@*CONCLUSIONS@#The abnormal expression of Pyk2 and p-AKT proteins might be closely related to the development and progression of TSCC. Joint detection can be used as an indicator to estimate the degree of TSCC.

Focal Adhesion Kinase Induces Matrix Metalloproteinase-2 by Involving α5β1-Mediated Signaling in Breast Cancer Cell, MCF-7.

Introduction: Focal adhesion kinase (FAK) is a non-receptor tyrosine kinase that plays a pivotal role in cell invasion. Matrix metalloproteinases (MMPs) are implicated as the key players in cancer cell invasion. Hence, the role of FAK in MMP regulation is very important in understanding tumor progression. Materials and Methods: Here, we studied the role of FAK, its association with other signaling kinases and involvement in the α5β1 integrin receptor-mediated regulation of MMP-2 activity and expression in human breast cancer cell line MCF-7. Results: Immuno blot analysis revealed that FN treatment causes phosphorylation of FAK and FAK gets localized at the cell attachment focal point of MCF-7 cells. FN treatment did not change the mRNA status of FAK but enhanced mRNA level of MMP-2 and MT1-MMP, also caused downregulation of TIMP-2. Co-imunoprecipitation and inhibitor studies revealed the association of FAK with α5β1, Paxillin, PI3K and ERK. siRNA studies revealed that FAK is critical in regulation of activity and expression of MMP-2 and downstream signaling kinases. Conclusion: Th e interaction of α5β1 integrin with FN initiates a signaling cascade with FAK as its central player. FAK gets phosphorylated and in turn associates with tyrosine kinases like PI3K and ERK. FAK also activates PI3K and ERK that serve as very crucial mediators of the signaling pathway leading to induction of MMP-2 activity and resulting invasion of breast cancer cell, MCF-7.

Effects of prednisone on renal FAK and Pyk2 expressions in rats with adriamycin- induced nephritis / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the effects of prednisone on the expressions of FAK and Pyk2 in the kidneys of rats with adriamycin-induced nephritis.</p><p><b>METHODS</b>Thirty SD rats were randomized into normal control group, adriamycin-induced nephritic model group, and prednisone treatment group (n=10). Prednisone was administered at 10 mg/kg once daily in nephritic rats starting since the 7th day after adriamycin injection. Twenty-four-hour proteinuria was measured in the rats at different time points, and renal tissue histology was examined using transmission electron microscope. The expression levels of Pyk2, FAK and nephrin mRNA in the renal tissue were detected tested by RT-PCR, and the protein expressions of FAK, Pyk2, phosphorylated Pyk2 and phosphorylated FAK-Tyr397 were detected by Western blotting; immunohistochemistry was used for detecting nephrin protein expression in the kidney.</p><p><b>RESULTS</b>Compared with the normal control group, the rats with adriamycin-induced nephritis showed significantly increased proteinuria (P<0.01), which was obviously lowered by prednisone treatment (P<0.01). Transmission electron microscopy revealed extensive fusion of the foot processes of the podocytes in the model group. Prednisone treatment promoted nephrin expression in the kidney (P<0.05). Compared with the control group, the model and prednisone treated groups showed significantly lowered nephrin mRNA expression (P<0.01) but increased FAK mRNA expression (P<0.01), but prednisone-treated group had a higher nephrin mRNA expression than the model group (P<0.05). The model group exhibited significantly increased expressions of FAK total and phosphorylated proteins, P-FAK/FAK, and P-Pyk2/Pyk2 (P<0.01), which were all lowered in the treatment group (P<0.01). Correlation analysis suggested that the expressions of FAK mRNA, FAK, pFAK, Pyk2 mRNA and pPyk2/Pyk2 were positively correlated with proteinuria (r=0.819, 0.750, 0.838, 0.762, 0.934, respectively, P<0.01).</p><p><b>CONCLUSIONS</b>Adriamycin increases phosphorylated FAK and Pyk2 expressions to mediate kidney injury in rats. Prednisone inhibits Pyk2 and FAK activation, decreases proteinuria, and alleviates podocyte lesions to protect the glomerular filtration barrier.</p>

Expression of SOCS3 and Pyk2 and their correlation in non-small cell lung cancer / 中华病理学杂志

<p><b>OBJECTIVE</b>To investigate the expression of SOCS3 and Pyk2 and their correlations in non-small cell lung cancer (NSCLC).</p><p><b>METHODS</b>The expression of SOCS3 and Pyk2 was detected in 100 cases of NSCLC, human bronchial epithelial cells (HBE) and 6 lung cancer cell lines by immunohistochemistry and immunofluorescence staining. The methylation status of SOCS3 was investigated in A549 cells by methylation-specific PCR. A549 cells were either treated with a demethylation agent 5-aza-2'-deoxycytidine (5-aza) or transfected with three SOCS3 mutants with various functional domains deleted. Besides, the cells were pretreated with a proteasome inhibitor β-lactacystin where indicated. The effects of SOCS3 on Pyk2 expression, Pyk2 Tyr 402 and ERK1/2 phosphorylations were assessed by Western blot. RT-PCR was used to estimate Pyk2 mRNA levels. Transwell experiments were performed to evaluate cell migration.</p><p><b>RESULTS</b>SOCS3 (43.0%, 43/100) and Pyk2 (65.0%, 65/100) were expressed in NSCLC. A significant negative correlation was found between SOCS3 and Pyk2 in both NSCLC tissues and cell lines. SOCS3 was aberrantly methylated and 5-aza restored SOCS3 expression. Transfection studies indicated that exogenous SOCS3 interacted with Pyk2, and both Src homology 2 (SH2) and kinase inhibitory region (KIR) domains contributed to Pyk2 binding. Furthermore, SOCS3 was found to inhibit Pyk2-associated ERK1/2 activity in A549 cells. SOCS3 possibly promoted degradation of Pyk2 in a SOCS-box-dependent manner and interfered with cell migration.</p><p><b>CONCLUSIONS</b>The data indicates that SOCS3 definitely plays roles in regulating Pyk2 signaling, and cell motility. Decreased SOCS3 induced by methylation may confer a migration advantage to A549 cells.</p>

CD98 activation increases surface expression and clusteringof beta 1 integrins in MCF-7 cells through FAK/Src- and cytoskeleton-independent mechanisms

CD98, a disulfide-linked 125-kDa heterodimeric type II transmembrane glycoprotein, regulates beta 1 integrin- mediated cell adhesion. However, the molecular mechanisms underlying CD98-mediated activation of beta 1 integrin are presently unclear. In this study, the effects of CD98 signaling on the expression and clustering of beta 1 integrin were investigated. Activation of CD98 augmented surface expression of beta 1 integrin on MCF-7 cells. Cross-linking CD98 induced clustering of beta 1 integrins. Inhibition of phosphorylation of focal adhesion kimase (FAK) by PP2, an inhibitor of Src family kinase, reduced cell-extracellular matrix adhesion, but not surface expression and clustering of beta1 integrin on MCF-7 cells. This result was confirmed by over-expression of dominant negative forms of FAK. In addition, phalloidin or cytochalasin D inhibited CD98-mediated induction of cell-ECM adhesion, but not surface expression and clustering of b1 integrins. The inhibitory effects of PP2, cytochalasin D or phalloidin on CD98-stimulated cell adhesion were diminished by pretreatment of cells with Mn2+, which is shown to induce conformational change of integrins. These results provide the first evidence that CD98 activation increases not only beta1 integrin affinity but also its surface expression and clustering and the latter is independent of FAK/Src and cytoskeleton.

The influence of bortezomib on HL-60 cell function induced by all-trans retinoic acid plus bufalin and its mechanism / 中华血液学杂志

<p><b>OBJECTIVE</b>To investigate changes in the adherent ability, the expression of adhesion related proteins Pyk2 and paxillin during HL-60 cells differentiation into granulocyte-monocyte induced by low-dose (LD) bufalin in combination with all-trans retinoic acid (ATRA), and to explore the effects of bortezomib on cellular adhesion and the expression of Pyk2 and paxillin.</p><p><b>METHODS</b>The expression of CD11b was detected by flow cytometry, cellular adherence ability by MTT assay, and the expressions of Pyk2, paxillin and tubulin by Western blot.</p><p><b>RESULTS</b>The combination of 5 nmol/L bufalin and 30 nmol/L ATRA induced HL-60 cells differentiation in a time-dependent manner, the percentages of CD11b positive cells treated for 2 d and 4 d being (20.0 +/- 2.8)% and (75.0 +/- 5.3)%, respectively, with the increasing of cellular adherence ability. Meanwhile the expressions of Pyk2 and Paxillin were also up-regulated in a time-dependent manner. Bortezomib suppressed HL-60 cell adhesion in a dose-dependent manner. At concentrations of 1 nmol/L and 10 nmol/L the adherence level were (7.8 +/- 0.1)% and (5.3 +/- 0.3)%, respectively, with down-regulation of Pyk2 but not Paxillin.</p><p><b>CONCLUSION</b>Pyk2 is involved in the regulation of cellular adherence function. Bortezomib might inhibit HL-60 cells adhension function by down-regulation of Pyk2 expression.</p>

Expression of proline-rich tyrosine kinase-2 in human primary colorectal carcinoma and its prognostic implication / 中华外科杂志

<p><b>OBJECTIVE</b>To investigate the expression of proline-rich tyrosine kinase-2 (Pyk2) in human primary colorectal carcinoma (CRC) and it's prognostic significance.</p><p><b>METHODS</b>The expression of Pyk2 was retrospectively examined with immunohistochemistry (IHC) in 108 tissues of primary CRC. The correlation of Pyk2 expression to prognosis and relevant clinical factors were analyzed.</p><p><b>RESULTS</b>The rate of Pyk2 low-expression in CRC was 56.5% (61/108). The expression of Pyk2 correlated significantly to the histological grade (P < 0.05) and the TNM stage (P < 0.05), while no correlation between Pyk2 expression and age, tumor size (P > 0.05). Patients with Pyk2 over-expression had significantly higher 5-year survival rate (66.0%) than those with Pyk2 low-expression (31.4%). Pyk2 expression, together with carcinoma histologic grade and TNM stage were prognostic factors to CRC on the multivariate analysis.</p><p><b>CONCLUSIONS</b>Pyk2 expression can be a prognostic factor to the CRC patients together with other predictors.</p>

Signal Transduction of Ras-like GTPase Activation in the Nervous System / 대한해부학회지

Synaptic plasticity has been thought to be a mechanism of synaptic maturation, learning and memory. In this study, the possible involvement of Rac, RhoA, proline-rich tyrosine kinase 2 (PYK2) and focal adhesion kinase (FAK) in the synaptic plasticity was investigated using PC12 cells and rat brains. The followings are the results. 1. Depolarization induced extracellular signal-regulated kinase (ERK) activation but did not activate Rac and RhoA in PC12 cells. 2. ERK activation and c-fos expression were observed after electroconvulsive shock (ECS) but the activity of Rac and RhoA was not changed following ECS. 3. PYK2 not FAK activation was observed after ECS. 4. The activity of PYK2 was increased with postnatal development but that of FAK was decreased with ages. 5. The expression of Rac and PYK2 was clearly observed in the postsynaptic density but that of RhoA and FAK was not. These findings indicate that PYK2 seems to play an important role in activity-dependent synaptic plasticity in vivo brain.