关键词： 子宫颈肿瘤   IQGAP1   免疫组织化学  

摘要： 目的 探讨子宫颈癌组织和癌旁组织中IQ结构域GTP酶激活蛋白1（IQ-domain GTPase-activating protein1,IQGAP1）的表达及其意义。方法 采用免疫组化SP法检测48例子宫颈癌组织和23例癌旁组织中IQGAP1的表达,并分析IQGAP1表达与子宫颈癌临床病理特征的关系。结果 IQGAP1在子宫颈癌中的阳性率为77.1%（37/48）,明显高于癌旁组织（30.4%,7/23）,两组相比差异有统计学意义（χ2=14.285,P〈0.01）。IQGAP1表达与子宫颈癌组织分化程度（χ2=3.102,P〈0.05）、临床分期（χ2=7.111,P〈0.05）和淋巴结转移（χ2=6.553,P〈0.05）相关;与患者年龄（χ2=0.112,P〉0.05）无关。结论 子宫颈癌组织中IQGAP1蛋白阳性率明显高于癌旁组织,且与肿瘤分化程度、临床分期及有无淋巴结转移密切相关,有望成为子宫颈癌生物学行为的有效指标之一。

关键词： Myeloproliferative neoplasms   Erythrocyte proteome   IQGAP1   Rho GTPases  

摘要： Besides genetic abnormalities in MPN patients, several studies have reported alterations in protein expression that could contribute towards the clinical phenotype. However, little is known about protein modifications in Ph- MPN erythrocytes. In this context, we used a quantitative mass spectrometry proteomics approach to study the MPN erythrocyte proteome. LC-MS/MS (LTQ Orbitrap) analysis led to the identification of 51 and 86 overexpressed proteins in Polycythemia Vera and Essential Thrombocythemia respectively, compared with controls. Functional comparison using pathway analysis software showed that the Rho GTPase family signaling pathways were deregulated in MPN patients. In particular, IQGAP1 was significantly overexpressed in MPNs compared with controls. Additionally, Western-blot analysis not only confirmed IQGAP1 overexpression, but also showed that IQGAP1 levels depended on the patient's genotype. Moreover, we found that in JAK2V617F patients IQGAP1 could bind RhoA, Rac1 and Cdc42 and consequently recruit activated GTP-Rac1 and the cytoskeleton motility protein PAK1. In CALR( +) patients, IQGAP1 was not overexpressed but immunoprecipitated with RhoGDI. In JAK2V617F transduced Ba/F3 cells we confirmed JAK2 inhibitor-sensitive overexpression of IQGAP1/PAK1. Altogether, our data demonstrated alterations of IQGAP1/Rho GTPase signaling in MPN erythrocytes dependent on JAIC2/CALR status, reinforcing the hypothesis that modifications in erythrocyte signaling pathways participate in Ph- MPN pathogenesis. (C) 2016 Elsevier B.V. All rights reserved.

关键词： Erythrocyte proteome   IQGAP1   Myeloproliferative neoplasms   Rho GTPases  

摘要： Besides genetic abnormalities in MPN patients, several studies have reported alterations in protein expression that could contribute towards the clinical phenotype. However, little is known about protein modifications in Ph − MPN erythrocytes. In this context, we used a quantitative mass spectrometry proteomics approach to study the MPN erythrocyte proteome. LC-MS/MS (LTQ Orbitrap) analysis led to the identification of 51 and 86 overexpressed proteins in Polycythemia Vera and Essential Thrombocythemia respectively, compared with controls. Functional comparison using pathway analysis software showed that the Rho GTPase family signaling pathways were deregulated in MPN patients. In particular, IQGAP1 was significantly overexpressed in MPNs compared with controls. Additionally, Western-blot analysis not only confirmed IQGAP1 overexpression, but also showed that IQGAP1 levels depended on the patient's genotype. Moreover, we found that in JAK2V617F patients IQGAP1 could bind RhoA, Rac1 and Cdc42 and consequently recruit activated GTP-Rac1 and the cytoskeleton motility protein PAK1. In CALR(+) patients, IQGAP1 was not overexpressed but immunoprecipitated with RhoGDI. In JAK2V617F transduced Ba/F3 cells we confirmed JAK2 inhibitor-sensitive overexpression of IQGAP1/PAK1. Altogether, our data demonstrated alterations of IQGAP1/Rho GTPase signaling in MPN erythrocytes dependent on JAK2/CALR status, reinforcing the hypothesis that modifications in erythrocyte signaling pathways participate in Ph − MPN pathogenesis. [ABSTRACT FROM AUTHOR]

关键词： IQGAP1   Dvl   免疫组化   人非小细胞肺癌  

摘要： 目的探讨非小细胞肺癌细胞中IQ-domain GTPase-activatingprotein 1(IQGAP1)与Dishevelled(Dvl)的相关性。方法应用免疫组化法检测109例非小细胞肺癌组织中IQGAP1和Dvl的表达,分析与临床病理因素的关联。结果 IQGAP1在肺癌组织中的表达水平显著高于癌旁正常组织。IQGAP1与Dvl在肺癌细胞浆及核的共定位表达显著正相关,而核共定位组的c-myc和cyclin D1表达率明显高于浆共定位组(P<0.05)。淋巴结转移组中二者浆/核共定位表达率明显高于未转移组(P<0.05),且与生存时间呈正比。结论 IQGAP1可能在胞浆促进Dvl入核从而激活经典Wnt通路,促进市癌的恶性表型。

关键词： adipocyte   caveolae   caveolin-1   cytoskeletal proteins   IQGAP1  

摘要： The ubiquitously expressed IQ motif-containing GTPase activating protein-1 (IQGAP1) is a scaffolding protein implicated in an array of cellular functions, in particular by binding to cytoskeletal elements and signaling proteins. A role of IQGAP1 in adipocytes has not been reported. We therefore investigated the cellular IQGAP1 interactome in primary human adipocytes. Immunoprecipitation and quantitative mass spectrometry identified caveolae and caveolae-associated proteins as the major IQGAP1 interactors alongside cytoskeletal proteins. We confirmed co-localization of IQGAP1 with the defining caveolar marker protein caveolin-1 by confocal microscopy and proximity ligation assay. Most interestingly, insulin enhanced the number of IQGAP1 interactions with caveolin-1 by fivefold. Moreover, we found a significantly reduced abundance of IQGAP1 in adipocytes from patients with type 2 diabetes compared with cells from nondiabetic control subjects. Both the abundance of IQGAP1 protein and mRNA were reduced, indicating a transcriptional defect in diabetes. Our findings suggest a novel role of IQGAP1 in insulin-regulated interaction between caveolae and cytoskeletal elements of the adipocyte, and that this is quelled in the diabetic state.

关键词： IQGAP1   Nucleus   MAP kinase pathway   Podocytes   Slit diaphragm proteins  

摘要： IQGAP1, a protein that links the actin cytoskeleton to slit diaphragm proteins, is involved in podocyte motility and permeability. Its regulation in glomerular disease is not known. We have exposed human podocytes to puromycin aminonucleoside (PAN), an inducer of nephrotic syndrome in rats, and studied the effects on IQGAP1 biology and function. In human podocytes exposed to PAN, a nuclear translocation of IQGAP1 was observed by immunocytolocalization and confirmed by Western blot after selective nuclear/cytoplasmic extraction. In contrast to IQGAP1, IQGAP2 expression remained cytoplasmic. IQGAP1 nuclear translocation was associated with a significant decrease in its interaction with nephrin and podocalyxin. Activation of the ERK pathway was observed in PAN treated podocytes with a preponderant nuclear localization of the phosphorylated form of ERK (P-ERK). The interaction between IQGAP1 and P-ERK increased upon podocyte exposure to PAN. Inhibitors of ERK pathway activation blocked IQGAP1 nuclear translocation (p < 0.02). Chromatin interaction protein assays demonstrated an interaction of IQGAP1 with chromatin and with Histone H3, which increased in response to PAN. In summary, PAN induces the ERK dependent translocation of IQGAP1 into the nuclei in human podocytes which leads to the interaction of IQGAP1 with chromatin and Histone H3, and decreased interactions between IQGAP1 and slit-diaphragm proteins. Therefore, IQGAP1 may have a role in podocyte gene regulation in glomerular disease. (C) 2016 Elsevier Inc. All rights reserved.

关键词： IQGAP1   RAS   siRNA   Apoptosis   HepG2 cells  

摘要： IQ motif-containing GTPase-activating proteins (IQGAPs) belong to a conserved family, and they are involved in various intracellular processes. IQGAP1 is expressed in all cells, while IQGAP2 and IQGAP3 are mainly expressed in hepatic cells. IQGAP1 has been suggested to be an oncogene, while IQGAP2 is considered a tumor-suppressor gene. However, the relationship between RAS family genes and IQGAP genes remains unclear. We recently demonstrated this interaction in a chemically induced mouse liver cancer. In this study, IQGAP1 expression was partially silenced in human hepatocellular carcinoma (HepG2) cells. We investigated the impact of IQGAP1 silencing on the interactions of IQGAP and RAS with several apoptotic proteins, including caspase-3 (CASP3), BCL2-associated X protein (BAX), and B-cell leukemia/lymphoma 2 (BCL2). Additionally, we investigated the effects of the interactions of these genes on cell viability, proliferation, apoptosis, and invasive capacity. IQGAP1 siRNA-treated HepG2 cells showed lower invasive capacity than the control cells, and this reduction was time- and vector concentration-dependent. In addition, IQGAP1 silencing resulted in significantly lower IQGAP1 level and subsequently higher IQGAP2 and IQGAP3 expression in HepG2 cells than in the control. Flow cytometry analyses indicated that the silencing of IQGAP1 can induce early and late apoptosis in HepG2 cells. Additionally, IQGAP2, IQGAP3, CASP3, and BAX were upregulated whereas IQGAP1 and BCL2 were downregulated in the siRNA-treated cells. Furthermore, we observed that the mRNA levels of HRAS, KRAS, NRAS, and MRAS decreased upon IQGAP1 silencing. These findings indicate that IQGAP1 potentially regulates the expression of IQGAP and RAS gene families and demonstrate its regulatory role in the apoptotic network. Taken together, our findings suggest that IQGAP1 silencing plays crucial roles in the apoptosis of HepG2 cells and lowers their proliferative and invasive capacities.

关键词： MALAT1   IQGAP1   Proliferation   Invasion   Thyroid cancer  

摘要： Background: Increasing evidence indicated that metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) acted as a key regulator in the proliferation and invasion of several cancers. However, the function of MALAT1 in the development of thyroid cancer has not been experimentally established. Methods: The expression of MALAT1 and IQGAP1 in thyroid cancer tissues and cells were detected by quantitative real-time PCR and western blot. The effects of MALAT1 and IQGAP1 on the cell proliferation and invasion of thyroid cancer cells were detected with a 3-(4,5-dimethylthiazol)-2,5-diphenyl tetrazolium 4 (MTT) assay and a Transwell assay, respectively. FTC-133 or SW1736 transfected with siMALAT1 or pcDNA-MALAT1 were injected subcutaneously into 4-week-olds BALB/c mice to examine the impact of MALAT1 on the tumor development of thyroid cancer in vivo. Results: In this study, we discovered the higher level of MALAT-1 and expression of IQGAP1 in thyroid cancer tissues and in thyroid cancer cells compared to that in the control. MTT and Transwell assay showed that the proliferation and invasion of FTC-133 cells with MALAT-1 knockdown were inhibited. Moreover, MALAT-1 could upregulate the expression of IQGAP1 in thyroid cancer cells. In addition, IQGAP1 knockdown reversed the decreasing cell proliferation and invasion of thyroid cancer induced by MALAT-1 overexpression. Finally, the study in vivo verified that MALAT-1 promoted the tumor growth of thyroid cancer. Conclusion: Our study indicated that MALAT1 promoted the proliferation and invasion of thyroid cancer cells via regulating the expression of IQGAP1. (C) 2016 Elsevier Masson SAS. All rights reserved.

关键词： cell signaling   Hippo pathway   protein complex   transcription factor   yes-associated protein (YAP)   IQGAP1  

摘要： During development, the Hippo signaling pathway regulates key physiological processes, such as control of organ size, regeneration, and stem cell biology. Yes-associated protein (YAP) is a major transcriptional co-activator of the Hippo pathway. The scaffold protein IQGAP1 interacts with more than 100 binding partners to integrate diverse signaling pathways. In this study, we report that IQGAP1 binds to YAP and modulates its activity. IQGAP1 and YAP co-immunoprecipitated from cells. In vitro analysis with pure proteins demonstrated a direct interaction between IQGAP1 and YAP. Analysis with multiple fragments of each protein showed that the interaction occurs via the IQ domain of IQGAP1 and the TEAD-binding domain of YAP. The interaction between IQGAP1 and YAP has functional effects. Knock-out of endogenous IQGAP1 significantly increased the formation of nuclear YAP-TEAD complexes. Transcription assays were performed with IQGAP1-null mouse embryonic fibroblasts and HEK293 cells with IQGAP1 knockdown by CRISPR/Cas9. Quantification demonstrated that YAP-TEAD-mediated transcription in cells lacking IQGAP1 was significantly greater than in control cells. These data reveal that IQGAP1 binds to YAP and modulates its co-transcriptional function, suggesting that IQGAP1 participates in Hippo signaling.

关键词： IQGAP1   肿瘤   Meta分析  

摘要： [目的]应用Meta分析探讨IQGAP1基因的表达与肿瘤分化程度、淋巴结转移情况和临床分期的相关性。[方法]在中国知网（CNKI）、中国生物医学文献数据库（CBM）、万方医学网、维普、Medline及PubMed等数据库中,中文以＂IQGAP1,肿瘤或癌症＂、英文以＂IQGAP1,tumor或cancer＂为检索词,检索建库至今已发表的中英文文献资料和学位论文,根据纳入排除标准筛选文献,采用RevMan5.2和Stata13.0软件分析纳入文献资料中IQGAP1蛋白的表达与肿瘤分化程度、淋巴结转移、临床分期的相关性。[结果]（1）IQGAP1在中低分化组及高分化组肿瘤组织中表达的比较：合并OR值为1.85,95%CI：1.23-2.80,P=0.003;（2）IQGAP1在有无淋巴结转移的肿瘤组织中表达的比较：合并OR值为1.57,95%CI：1.06-2.32,P=0.02;（3）IQGAP1在临床分期为Ⅰ-Ⅱ期和Ⅲ-Ⅳ期肿瘤组织中表达的比较：合并OR值为3.40,95%CI：2.27-5.10,P〈0.0001。[结论 ]IQGAP1蛋白的表达与肿瘤分化程度、临床分期及淋巴结转移密切相关。IQGAP1可以作为临床评估肿瘤恶性程度的重要指标。