关键词： 宫颈癌   半胱氨酸天冬氨酸蛋白酶1   IQ序列三磷酸鸟苷酶激活蛋白   血管内皮生长因子C  

摘要： 目的探究半胱氨酸天冬氨酸蛋白酶1(Caspase-1)、IQ序列三磷酸鸟苷酶激活蛋白(IQGAP1)及血管内皮生长因子C(VEGF-C)在宫颈癌中的表达对患者预后的预测价值。方法选取2021年6月—2022年6月于丽水市人民医院进行宫颈癌治疗的患者180例,经手术提取宫颈癌组织作为实验组,同时搜集距离癌组织3 cm处的癌旁组织作为对照组。采用免疫组化法测定Caspase-1、IQGAP1及VEGF-C阳性表达情况,并分析其与临床特征和预后之间的关系。结果癌变组织Caspase-1、IQGAP1及VEGF-C阳性表达率(66.67%、72.22%及61.11%)与癌旁组织(39.44%、42.22%及36.11%)比较均升高,差异均有统计学意义(χ^(2)=26.778、33.090及22.517,均P<0.05)。宫颈癌癌变组织中Caspase-1、IQGAP1及VEGF-C表达与分化程度、临床分期、淋巴结转移相关(均P<0.05)。将宫颈癌患者年龄、体质量指数、瘤体直径及组织类型等因素进行控制后,Caspase-1、IQGAP1及VEGF-C仍与分化程度、临床分期、淋巴结转移显著相关(均P<0.05)。受试者特征曲线(ROC)分析Caspase-1、IQGAP1、VEGF-C及联合检测对宫颈癌预后的预测价值,其曲下面积分别为0.707、0.752、0.795及0.911。结论Caspase-1、IQGAP1及VEGF-C在宫颈癌癌变组织中均呈现上调状态,并且其表达高低变化与分化程度、临床分期、淋巴结转移和预后情况之间具有一定联系,可能共同参与该疾病的发生、发展,并对患者的预后情况产生影响。

关键词： Cancer-predisposing variant   Cingulin   Epithelial-mesenchymal transition   IQGAP1   Rac1  

摘要： Background: Cingulin (CGN) is a pivotal cytoskeletal adaptor protein located at tight junctions. This study investigates the link between CGN mutation and increased cancer susceptibility through genetic and mechanistic analyses and proposes a potential targeted therapeutic approach. Methods: In a high-cancer-density family without known pathogenic variants, we performed tumor-targeted and germline whole-genome sequencing to identify novel cancer-associated variants. Subsequently, these variants were validated in a 222 cancer patient cohort, and CGN c.3560C > T was identified as a potential cancer-risk allele. Both wild-type (WT) (c.3560C > C) and variant (c.3560C > T) were transfected into cancer cell lines and incorporated into orthotopic xenograft mice model for evaluating their effects on cancer progression. Western blot, immunofluorescence analysis, migration and invasion assays, two-dimensional gel electrophoresis with mass spectrometry, immunoprecipitation assays, and siRNA applications were used to explore the biological consequence of CGN c.3560C > T. Results: In cancer cell lines and orthotopic animal models, CGN c.3560C > T enhanced tumor progression with reduced sensitivity to oxaliplatin compared to the CGN WT. The variant induced downregulation of epithelial marker, upregulation of mesenchymal marker and transcription factor, which converged to initiate epithelial-mesenchymal transition (EMT). Proteomic analysis was conducted to investigate the elements driving EMT in CGN c.3560C > T. This exploration unveiled overexpression of IQGAP1 induced by the variant, contrasting the levels observed in CGN WT. Immunoprecipitation assay confirmed a direct interaction between CGN and IQGAP1. IQGAP1 functions as a regulator of multiple GTPases, particularly the Rho family. This overexpressed IQGAP1 was consistently associated with the activation of Rac1, as evidenced by the analysis of the cancer cell line and clinical sample harboring CGN c.3560C > T. Notably, acti

关键词： IQGAP1   B cell   MAPK   IQGAP1 signalosome  

摘要： IQGAP1 is a multi-functional scaffold protein. However, its role in B cell development and function is unknown. Here, we show IQGAP1 as an essential scaffold that regulates early B cell development and function. Iqgap1-/- mice contained significantly increased numbers of B220+ B, B220+IgM- pro/pre-B, and B220LowIgM+ immature-B cells in the bone marrow. In the spleens of the Iqgap1-/- mice, newly formed and follicular B cell numbers were increased, while the marginal zone B cell numbers were significantly reduced. Lack of IQGAP1 reduced T-dependent and T-independent humoral responses. Mechanistically, the lack of IQGAP1 considerably decreased the phosphorylation of Mek1/2, Erk1/2, and Jnk1/2. B cells from Iqgap1-/- mice failed to suppress IL-7R-mediated activation of Stat5a/b, an essential step for cell-cycle exit and initiate light-chain recombination, reducing RS rearrangement frequency. Our study provides the first evidence that IQGAP1-based signalosome is necessary for the development and functions of B cells.

关键词： apical protein endocytosis   epithelial cell polarity   IQGAP1   MDCK cells   polarity reorientation   Rac1   Tiam1   two-cell stage  

摘要： A single epithelial cell embedded in extracellular matrix (ECM) can proliferate to form an apical lumen-harboring cyst, whose formation is a fundamental step in epithelial organ development. At an early two-cell stage after cell division, the cell doublet typically displays "inverted" polarity, with apical and basolateral proteins being located to the ECM-facing and cell-cell-contacting plasma membranes, respectively. Correct cystogenesis requires polarity reorientation, a process containing apical protein endocytosis from the ECM-abutting periphery and subsequent apical vesicle delivery to a cell-cell contact site for lumen formation. Here, we show that downstream of the ECM-signal-transducer beta 1-integrin, Rac1, and its effector IQGAP1 promote apical protein endocytosis, contributing to polarity reorientation of mammalian epithelial Madin-Darby canine kidney (MDCK) cells at a later two-cell stage in three-dimensional culture. Rac1-GTP facilitates IQGAP1 interaction with the Rac-specific activator Tiam1, which also contributes to the endocytosis and enhances the effect of IQGAP1. These findings suggest that Tiam1 and IQGAP1 form a positive feedback loop to activate Rac1. With Rac1-GTP, IQGAP1 also binds to AP2 alpha, an adaptor protein subunit for clathrin-mediated endocytosis;depletion of the AP2 complex impairs apical protein endocytosis in MDCK doublets. Thus, Rac1 likely participates in polarity reorientation at the two-cell stage via its interaction with IQGAP1.

关键词： IQGAP   EGFR   fluorescence imaging   protein oligomerization   cell signaling  

摘要： IQGAP1 is a large, multi-domain scaffold that connects and modulates different signaling networks including the one initiated by epidermal growth factor (EGF). In this study, we have used live cell fluorescence imaging methods along with other biochemical techniques to follow the mechanisms used by IQGAP1 to enhance EGF signaling. We show that IQGAP1 enhances EGF signaling by promoting the oligomerization of its receptor, EGFR, upon EGF addition along with concurrent IQGAP oligomerization. Using cellular markers, we find that IQGAP1 promotes the plasma membrane localization of EGFR and promotes association to one of its phosphoinositide lipid pathway ligands, PI(3,4,5)P3. Additionally, we find that binding of EGFR to IQGAP1 protects EGFR from lysosomal degradation. Taken together, our results show that IQGAP1 enhances EGF-mediated pathway progression through mechanisms that augment simple scaffolding activities.

关键词： Glioblastoma   Scaffold proteins   Precision medicine   IQGAP1  

摘要： Glioblastoma (GB) is a highly heterogeneous type of incurable brain cancer with a low survival rate. Intensive ongoing research has identified several potential targets;however, GB is marred by the activation of multiple pathways, and thus common targets are highly sought. The signal regulatory scaffold IQGAP1 is an oncoprotein implicated in GB. IQGAP1 nucleates a myriad of pathways in a contextual manner and modulates many of the targets altered in GB like MAPK, NF-kappa B, and mTOR/PI3K/Akt1, thus positioning it as a plausible common therapeutic target. Here, we review the targets that are subjects of GB treatment clinical trials and the commonly used animal models that facilitate target identification. We propose a model in which the dysfunction of various IQGAP1 pathways can explain to a larger extent some of the GB heterogeneity and offer a platform for personalized medicine.

关键词： IQGAP1   Mycobacteria   Phthiocerol dimycocerosate (PDIM)   VEGF   Granuloma  

摘要： Tuberculosis, caused by Mycobacterium tuberculosis (Mtb), still ranks among the leading causes of annual human death by infectious disease. Mtb has developed several strategies to survive for years at a time within the host despite the presence of a robust immune response, including manipulating the progression of the inflammatory response and forming granulomatous lesions. Here we demonstrate that IQGAP1, a highly conserved scaffolding protein, compartmentalizes and coordinates multiple signaling pathways in macrophages infected with Mycobacterium marinum (Mm or ***), the closest relative of Mtb. Upregulated IQGAP1 ultimately suppresses TNF-alpha production by repressing the MKK3 signal and reducing NF-kappa Bp65 translocation, deactivating the p38MAPK pathway. Accordingly, IQGAP1 silencing and overexpression significantly alter p38MAPK activity by modulating the production of phosphorylated MKK3 during mycobacterial infection. Pharmacological inhibition of IQGAP1-associated microtubule assembly not only alleviates tissue damage caused by *** infection but also significantly decreases the production of VEGF-a critical player for granuloma-associated angiogenesis during pathogenic mycobacterial infection. Similarly, IQGAP1 silencing in Mm-infected macrophages diminishes VEGF production, while IQGAP1 overexpression upregulates VEGF. Our data indicate that mycobacteria induce IQGAP1 to hijack NF-kappa Bp65 activation, preventing the expression of proinflammatory cytokines as well as promoting VEGF production during infection and granuloma formation. Thus, therapies targeting host IQGAP1 may be a promising strategy for treating tuberculosis, particularly in drug-resistant diseases.