关键词： endothelial injury   IQ-GTPase-activating protein   nanoparticle   platelet-derived growth factor receptor   simvastatin  

摘要： Endothelial barrier dysfunction is a critical pathophysiological process of sepsis. Impaired endothelial cell migration is one of the main reasons for endothelial dysfunction. Statins may have a protective effect on endothelial barrier function. However, the effect and mechanism of statins on lipopolysaccharide (LPS)-induced endothelial barrier dysfunction remain unclear. Simvastatin (SV) was loaded in nanostructured lipid carriers to produce SV nanoparticles (SV-NPs). Normal SV and SV-NPs were used to treat human umbilical vein vascular endothelial cells (HUVECs) injured by LPS. Barrier function was evaluated by monitoring cell monolayer permeability and transendothelial electrical resistance, and cell migration ability was measured by a wound healing assay. LY294002 and imatinib were used to inhibit the activity of PI3K/Akt and platelet-derived growth factor receptor (PDGFR) beta. IQ-GTPase-activating protein 1 (IQGAP1) siRNA was used to knockdown endogenous IQGAP1, which was used to verify the role of the PDGFR beta/PI3K/Akt/IQGAP1 pathway in SV/SV-NPs-mediated barrier protection in HUVECs injured by LPS. The results show that SV/SV-NPs promoted the migration and decreased the permeability of HUVECs treated with LPS, and the efficacy of the SV-NPs exceeded that of SV significantly. LY294002, imatinib and IQGAP1 siRNA all suppressed the barrier protection of SV/SV-NPs. SV/SV-NPs promoted the secretion of platelet-derived growth factor-BB (PDGF-BB) and activated the PDGFR beta/PI3K/Akt/IQGAP1 pathway. SV preparations restored endothelial barrier function by restoring endothelial cell migration, which is involved in the regulation of the PDGFR beta/PI3K/Akt/IQGAP1 pathway and PDGF-BB secretion. As an appropriate formulation for restoring endothelial dysfunction, SV-NPs may be more effective than SV.

关键词： 宫颈癌   免疫组织化学   预后  

摘要： 目的观察宫颈癌中IQ结构域GTP酶激活蛋白(IQGAP1)和β连环蛋白(β-catenin)联合表达与宫颈癌的发生、发展相关性,并探讨临床意义。方法收集98例宫颈癌石蜡组织作为观察组,50例癌旁组织为对照组,采用免疫组织化学的方法检测IQGAP1和β-catenin在各组中的表达与宫颈癌临床病理特征及患者预后关系的相关性。结果宫颈癌组织中IQGAP1阳性率76.5%,高于癌旁组织中的表达(28.0%,P=0.001)。β-catenin在宫颈癌组织中的阳性率高于在癌旁组织中的表达(75.5%vs 6.0%,P=0.001)。宫颈癌组织中IQGAP1阳性率与年龄、肿瘤直径无关(P>0.05),与临床分期、是否伴有淋巴结转移、分化程度有关(P=0.001)。β-catenin在宫颈癌中的表达与年龄、肿瘤直径及分化程度无关,与临床分期、是否伴有淋巴结转移有关(P=0.001)。宫颈癌中IQGAP1和β-catenin表达呈正相关(r=0.468,P=0.001)。宫颈癌中IQGAP1和β-catenin共阳性表达的患者生存时间较单阳组、全阴组缩短。结论IQGAP1和β-catenin参与了宫颈癌的发生、发展,并与其高度侵袭性和转移性相关,二者相互协同,共阳性表达提示预后不良。

关键词： Mechanism   SP1   p300   Multiple myeloma   IQGAP1  

摘要： Our previous research had firstly shown that MM cells overexpressed IQGAP1 gene and activated Ras/Raf/MEK/ERK pathway. But the mechanism of IQGAP1 overexpression and IQGAP1 gene transcription regulation remains uncertain. The mechanism of IQGAP1 overexpression and transcriptional regulation of IQGAP1 gene in myeloma cells was explored in the study. Through bioinformatics analysis and prediction we predicted and screened transcription factor Sp1 as a possible upstream regulator of *** proliferation, cell cycle and downstream ERK1/2 and p-ERK1/2 proteins were detected after siRNA-IQGAP1 was transfected to myeloma cells. The expression of Sp1, p300, IQGAP1, p-ERK1/2 and ERK1/2 were detected after Sp1 and p300 were inhibited or overexpressed respectively. The dual-luciferase reporter system was used to detect the activity of IQGAP1 gene promoter. CHIP was used to detect the binding of the Sp1 and IQGAP1 promoter ***-IP was used to explore the interaction between Sp1 and *** mRNA expression levels of Sp1, p300 and IQGAP1 of the myeloma patients were detected, and the correlation analysis of their mRNA expression levels were carried out. The results showed IQGAP1-siRNA inhibits cell proliferation, cell cycle, IQGAP1 expression and phosphorylation of ERK1/2 protein. Inhibition of Sp1 or p300 down-regulated ERK1/2 and IQGAP1 expression;overexpression of Sp1 or p300 up-regulated ERK1/2 and IQGAP1 expression;Sp1 and p300 had a positive regulation effect on *** expression of Sp1 or p300 significantly increased activity of IQGAP1 gene promoter. The transcription factor Sp1 plays a regulatory role in the IQGAP1 promoter region. There is an interaction between Sp1 and p300 in myeloma cells. The mRNA expression levels of Sp1, IQGAP1 and p300 in MM samples showed a positive correlation. In summary IQGAP1 is required for cell proliferation in MM cells, and the transcription of Sp1/p300 complex regulates expression of IQGAP1 gene.

关键词： HPK1   Autoimmune disease   Cancer metastasis   Aging   IL-17A   PKC theta   IQGAP1   Autophagy   Verteporfin  

摘要： MAP4K3 (also named GLK) is a serine/threonine kinase, which belongs to the mammalian Ste20-like kinase family. At 22 years of age, GLK was initially cloned and identified as an upstream activator of the MAPK JNK under an environmental stress and proinflammatory cytokines. The data derived from GLK-overexpressing or shRNA-knockdown cell lines suggest that GLK may be involved in cell proliferation through mTOR signaling. GLK phosphorylates the transcription factor TFEB and retains TFEB in the cytoplasm, leading to inhibition of cell autophagy. After generating and characterizing GLK-deficient mice, the important in vivo roles of GLK in T-cell activation were revealed. In T cells, GLK directly interacts with and activates PKC theta through phosphorylating PKC theta at Ser-538 residue, leading to activation of IKK/NF-kappa B. Thus, GLK-deficient mice display impaired T-cell-mediated immune responses and decreased inflammatory phenotypes in autoimmune disease models. Consistently, the percentage of GLK-overexpressing T cells is increased in the peripheral blood from autoimmune disease patients;the GLK-overexpressing T cell population is correlated with disease severity of patients. The pathogenic mechanism of autoimmune disease by GLK overexpression was unraveled by characterizing T-cell-specific GLK transgenic mice and using biochemical analyses. GLK overexpression selectively promotes IL-17A transcription by inducing the AhR-ROR gamma t complex in T cells. In addition, GLK overexpression in cancer tissues is correlated with cancer recurrence of human lung cancer and liver cancer;the predictive power of GLK overexpression for cancer recurrence is higher than that of pathologic stage. GLK directly phosphorylates and activates IQGAP1, resulting in induction of Cdc42-mediated cell migration and cancer metastasis. Furthermore, treatment of GLK inhibitor reduces disease severity of mouse autoimmune disease models and decreases IL-17A production of human autoimmune T cells. D

关键词： EMT   gastric cancer   HIF1 alpha   IQGAP1   VEGF-A  

摘要： As an oncogene, IQ-domain GTPase-activating protein 1 (IQGAP1) regulates the epithelial-mesenchymal transition (EMT) of several cancers, such as breast cancer, thyroid cancer, and esophageal squamous cell carcinoma. However, the role of the scaffold protein IQGAP1 on EMT in gastric cancer remains unclear. Therefore, the present work was performed to address the question. Our results showed that IQGAP1 expression is upregulated in human gastric cancer specimens and cell lines. Furthermore, IQGAP1 knockdown inhibited the migratory ability of gastric cancer cells and reduced the expression of mesenchymal phenotype markers, including Slug, beta-catenin, Snail, Vimentin, and N-cadherin, as well as vascular endothelial growth factor-A (VEGF-A) secretion in gastric cancer cells. Conversely, IQGAP1 downregulation increased the epithelial phenotype marker E-cadherin. Furthermore, IQGAP1 silencing not only downregulated hypoxia-inducible transcription factor 1 alpha (HIF1 alpha) but also limited its translocation from the cytosol to the nucleus. Collectively, our results indicated that EMT was regulated by IQGAP1, which was associated with VEGF-A, since other data demonstrated that HIF1 alpha was involved in VEGF-A expression. Therefore, we speculated that IQGAP1 regulated EMT of gastric cancer partially via the HIF1 alpha/VEGF-A signaling pathway. IQGAP1 may serve as an effective therapeutic biomarker for gastric cancer.

关键词： Invadopodia   Endothelin-1   Endothelin-1 receptors   Ovarian cancer   beta-arr1   IQGAP1  

摘要： The invasive phenotype of serous ovarian cancer (SOC) cells is linked to the formation of actin-based protrusions, invadopodia, operating extracellular matrix (ECM) degradation and metastatic spread. Growth factor receptors might cause engagement of integrin-related proteins, like the polarity protein IQ-domain GTPase-activating protein 1 (IQGAP1), to F-actin core needed for invadopodia functions. Here, we investigated whether IQGAP1 forms a signalosome with endothelin-1 (ET-1)/beta-arrestin1 (beta-arr1) network, as signal-integrating module for adhesion components, cytoskeletal remodelling and ECM degradation. In SOC cells, ET-1 receptor (ET-1R) activation, besides altering IQGAP1 expression and localization, coordinates the binding of IQGAP1 with beta-arr1, representing a "hotspot" for ET-1R-induced invasive signalling. We demonstrated that the molecular interaction of IQGAP1 with beta-arr1 affects relocalization of focal adhesion components, as vinculin, and cytoskeleton dynamics, through the regulation of invadopodia-related pathways. In particular, ET-1R deactivates Rac1 thereby promoting RhoA/C activation for the correct functions of invasive structures. Silencing of either IQGAP1 orp-arr1, or blocking ET-1R activation with a dual antagonist macitentan, prevents matrix metalloproteinase (MMP) activity, invadopodial function, transen-dothelial migration and cell invasion. In vivo, targeting ET-1R/beta-arr1 signalling controls the process of SOC metastasis, associated with reduced levels of IQGAP1, as well as other invadopodia effectors, such as vinculin, phospho-cortactin and membrane type 1-MMP. High expression of ETAR/beta-arrl/IQGAP1 positively correlates with poor prognosis, validating the clinical implication of this signature in early prognosis of SOC. These data establish the ET-1R-driven beta-arr1/IQGAP1 interaction as a prerequisite for the dynamic integration of pathways in fostering invadopodia and metastatic process in human SOC. (C) 2018 The Author

关键词： acetylcholine   coronary spastic angina   IQ motif-containing GTPase-activating protein 1   p122RhoGTPase-activating protein (GAP)/deleted in liver cancer-1   phospholipase C  

摘要： Phospholipase C (PLC)-delta 1, activated by p122RhoGTPase-activating protein (GAP)/deleted in liver cancer-1 (p122RhoGAP/DLC-1), contributes to the coronary spastic angina (CSA) pathogenesis. The present study aims to further investigate the p122RhoGAP/DLC-1 protein. We examined molecules assisting this protein and identified a scaffold protein-IQ motif-containing GTPase-activating protein 1 (IQGAP1). IQGAP1-C binds to the steroidogenic acute regulatory-related lipid transfer (START) domain of p122RhoGAP/DLC-1, and PLC-delta 1 binds to IQGAP1-N, forming a complex. In fluorescence microscopy, small dots of PLC-delta 1 created fine linear arrays like microtubules, and IQGAP1 and p122RhoGAP/DLC-1 were colocated in the cytoplasm with PLC-delta 1. Ionomycin induced the raft recruitment of the PLC-delta 1, IQGAP1, and p122RhoGAP/DLC-1 complex by translocation to the plasma membrane (PM), indicating the movement of this complex is along microtubules with the motor protein kinesin. Moreover, the IQGAP1 protein was elevated in skin fibroblasts obtained from patients with CSA, and it enhanced the PLC activity and peak intracellular calcium concentration in response to acetylcholine. IQGAP1, a novel stimulating protein, forms a complex with p122RhoGAP/DLC-1 and PLC-delta 1 that moves along microtubules and enhances the PLC activity.

摘要： The Ras family of small GTPases modulates numerous essential processes. Activating Ras mutations result in hyper-activation of selected signaling cascades, which leads to human diseases. The high frequency of Ras mutations in human malignant neoplasms has led to Ras being a desirable chemotherapeutic target. The IQGAP family of scaffold proteins binds to and regulates multiple signaling molecules, including the Rho family GTPases Rac1 and Cdc42. There are conflicting data in the published literature regarding interactions between IQGAP and Ras proteins. Initial reports showed no binding, but subsequent studies claim associations of IQGAP1 and IQGAP3 with K-Ras and H-Ras, respectively. Therefore, we set out to resolve this controversy. Here we demonstrate that neither endogenous IQGAP1 nor endogenous IQGAP3 binds to the major Ras isoforms, namely H-, K-, and N-Ras. Importantly, Ras activation by epidermal growth factor is not altered when IQGAP1 or IQGAP3 proteins are depleted from cells. These data strongly suggest that IQGAP proteins are not functional interactors of H-, K-, or N-Ras and challenge the rationale for targeting the interaction of Ras with IQGAP for the development of therapeutic agents.

关键词： AmotL2   astrocytoma cells   FKBP51   glioblastoma microenvironment   glioma stem cells   IQGAP1   pericytes   scaffold proteins   tumor-associated macrophages (TAMs)  

摘要： Glioblastoma (GB) is the most frequently occurring and aggressive primary brain tumor. Glioma stem cells (GSCs) and astrocytoma cells are the predominant malignant cells occurring in GB besides a highly heterogeneous population of migrating, neovascularizing and infiltrating myeloid cells that forms a complex tumor microenvironment (TME). Cross talk between the TME cells is pivotal in the biology of this tumor and, consequently, adaptor proteins at critical junctions of signaling pathways may be crucial. Scaffold proteins (scaffolins or scaffoldins) integrate external and internal stimuli to regulate various signaling pathways, interacting simultaneously with multiple proteins involved. We investigated by double and triple immunofluorescence the localization of IQGAP1, AmotL2, and FKBP51, three closely related scaffoldins, in malignant cells and TME of human GB tumors. We found that IQGAP1 is preferentially expressed in astrocytoma cells, AmotL2 in GSCs, and FKBP51 in white blood cells in human GB tumors. As GSCs are specially the target for novel therapies, we will investigate in further studies whether AmotL2 inhibition is effective in the treatment of GB.

关键词： IQ domain GTPase-activating protein 1   Nephrin   Endocytosis   Podocyte injury   Diabetic kidney disease  

摘要： Diabetic kidney disease (DKD) is a complication associated with diabetes and is a major public health problem in modern society. Podocyte injury is the central target of the development of DKD, and the loss or dysregulation of nephrin, a key structural and signalling molecule located in the podocyte slit diaphragm (SD), initiates potentially catastrophic downstream events within podocytes. IQGAP1, a scaffold protein containing multiple-binding domains that regulates endocytosis, can interact with nephrin in podocytes. It is hypothesized that IQGAP1 contributes to nephrin endocytosis and may participate in the pathogenesis of DKD. The dramatically increased histo-nephrin granularity score in DKD glomeruli showed a significant positive correlation with increased IQGAP1-nephrin interaction without changes in the total protein content of nephrin and IQGAP1. In cultured human podocytes, hyperglycaemia induced the intracellular translocation of IQGAP1 from the cytosol to the vicinity of the cytomembrane, reinforced the IQGAP1-nephrin interaction, and augmented nephrin endocytosis. Moreover, impaired podocyte function, such as migration, extensibility and permeability, were further aggravated by wild-type IQGAP1 plasmid transfection, and these effects were partially restored by siRNA-mediated IQGAP1 downregulation. Collectively, these findings show that IQGAP1, an intracellular partner of nephrin, is involved in nephrin endocytosis and the functional regulation of podocytes in DKD.