关键词： choroidal neovascularization   IQGAP1   Rac1GTP   Rap1GTP   vascular endothelial growth factor  

摘要： Neovascular age-related macular degeneration (nAMD) is a leading cause of blindness. The pathophysiology involves activation of choroidal endothelial cells (CECs) to transmigrate the retinal pigment epithelial (RPE) monolayer and form choroidal neovascularization (CNV) in the neural retina. The multidomain GTPase binding protein, IQGAP1, binds active Rac1 and sustains activation of CECs, thereby enabling migration associated with vision-threatening CNV. IQGAP1 also binds the GTPase, Rap1, which when activated reduces Rac1 activation in CECs and CNV. In this study, we tested the hypothesis that active Rap1 binding to IQGAP1 is necessary and sufficient to reduce Rac1 activation in CECs, and CNV. We found that pharmacologic activation of Rap1 or adenoviral transduction of constitutively active Rap1a reduced VEGF-mediated Rac1 activation, migration, and tube formation in CECs. Following pharmacologic activation of Rap1, VEGF-mediated Rac1 activation was reduced in CECs transfected with an IQGAP1 construct that increased active Rap1-IQGAP1 binding but not in CECs transfected with an IQGAP1 construct lacking the Rap1 binding domain. Specific knockout of IQGAP1 in endothelial cells reduced laser-induced CNV and Rac1 activation in CNV lesions, but pharmacologic activation of Rap1 did not further reduce CNV compared to littermate controls. Taken together, our findings provide evidence that active Rap1 binding to the IQ domain of IQGAP1 is sufficient to interfere with active Rac1-mediated CEC activation and CNV formation.

关键词： Liver fibrosis   miR-124   IQGAP1   Inflammation   NF-kappa B  

摘要： Liver fibrosis is a health concern that leads to organ failure mediated via production of inflammatory cytokines and fibrotic biomarkers. To date, there was no direct approved antifibrotic therapy, and current treatment was mainly the removal of the causative factor. Recent studies demonstrated that aberrant expression of miR-124 was involved in the progression of various liver diseases including hepatocellular carcinoma (HCC). However, whether miR-124 could function as a transcriptional regulator in the inflammatory cytokines secretion of liver fibrosis remains unclear. In this study, we demonstrated that the expression of miR-124 was downregulated in liver fibrosis tissues and TNF-alpha-induced LX-2 cells, concomitant with the upregulated expression of IQGAP1, suggesting that miR-124 and IQGAP1 might be associated with the development of inflammation in liver fibrosis. Therefore, we demonstrated that the overexpression of miR-124 and knockdown of IQGAP1 could lead to the downregulation of TNF-alpha, IL-1 beta and IL-6. While knockdown of miR-124 or overexpression of IQGAP1 showed reversed results. Moreover, dual luciferase reporter assays demonstrated that miR-124 specifically targeted the 3 '-UTR of IQGAP1, and thus inhibited the expression of IQGAP1. Mechanistically, we found that the expression changes of miR-124 and IQGAP1 could be involved in inhibition or activation of NF-kappa B signaling pathway in response to TNF-alpha. In conclusion, these results indicated that miR-124 plays a crucial role in TNF-alpha-induced LX-2 cells via regulating NF-kappa B signaling pathway.

关键词： MAL2   IQGAP1   ERK   Pancreatic cancer  

摘要： Pancreatic cancer is a digestive tract malignancy characterized by an occult onset and rapid progression. The genetic heterogeneity of pancreatic cancer is closely related to its highly malignant biological behavior. The myelin and lymphocyte protein 2 (MAL2) is upregulated in multiple cancers at the transcriptional level. However, the exact role of MAL2 in pancreatic cancer remains elusive. In this study, we demonstrated that MAL2 protein and mRNA levels were upregulated in pancreatic cancer. MAL2 over expression was significantly associated with poor prognosis in patients with pancreatic cancer. We further showed that MAL2 interacted with IQGAP1 to increase ERK1/2 phosphorylation levels, which promoted pancreatic cancer progression. Therefore, these results suggest that MAL2 could be a novel therapeutic target for pancreatic cancer. ? 2021 Elsevier Inc. All rights reserved.

关键词： 胰腺肿瘤   IQ结构域GTP酶激活蛋白1   癌性锚蛋白重复序列   预后   病理特征  

摘要： 目的:探讨胰腺癌组织中IQ结构域GTP酶激活蛋白1(IQGAP1)、癌性锚蛋白重复序列(Gankyrin)的表达及临床意义。方法:回顾性分析2011年1月—2014年1月武威市人民医院行胰腺癌根治术治疗的95例胰腺癌患者的病历及随访资料,免疫组织化学染色法检测正常胰腺组织、胰腺癌组织及癌旁组织中IQGAP1和Gankyrin的表达,分析IQGAP1和Gankyrin表达与胰腺癌临床病理参数的关系,采用Kaplan-Meier生存曲线分析不同IQGAP1和Gankyrin表达患者的总生存率的差异,Cox比例风险回归模型分析患者预后的影响因素。结果:与癌旁组织和正常胰腺组织相比,胰腺癌组织中IQGAP1和Gankyrin表达均上调(P<0.05)。IQGAP1和Gankyrin表达均与胰腺癌TNM分期、分化程度和糖类抗原199(CA199)表达相关(P<0.05)。IQGAP1阳性、Gankyrin阳性患者的5年生存率均明显低于阴性患者(P<0.05);Cox比例风险回归分析结果显示,TNM分期、IQGAP1表达、Gankyrin表达和CA199表达均是胰腺癌患者预后的独立危险因素(HR=1.250、13.316、3.542、4.089,P<0.05)。结论:胰腺癌组织中IQGAP1和Gankyrin表达上调,IQGAP1和Gankyrin表达与胰腺癌患者生存以及预后相关,可能作为胰腺癌患者的预后预测因子,辅助胰腺癌的诊断和临床治疗。

关键词： circ‐   IQGAP1   miR‐   671‐   5p   Osteoarthritis   TCF4  

摘要： Objective To explore the function of circular RNA IQ motif-containing GTPase-activating protein 1 (circ-IQGAP1) in interleukin (IL)-1 beta-induced osteoarthritis (OA) model and to explore whether circ-IQGAP1 can modulate microRNA-671-5p (miR-671-5p) and transcription factor 4 (TCF4) to regulate chondrocyte apoptosis, inflammatory injury, and extracellular matrix degradation. Methods The cartilage tissues were collected from 32 OA patients or normal subjects. Human chondrocyte CHON-001 cells were challenged via different doses of IL-1 beta for 24 hours. CHON-001 cells were transfected with circ-IQGAP1 overexpression vector, TCF4 overexpression vector, small interfering RNA (siRNA) for circ-IQGAP1, miR-671-5p mimic, miR-671-5p inhibitor or corresponding negative controls. Circ-IQGAP1, miR-671-5p and TCF4 abundances in cartilage tissues or CHON-001 cells were examined via quantitative reverse transcription polymerase chain reaction (qRT-PCR) or western blot. Cell viability was investigated by 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT). Cell apoptosis was measured by flow cytometry. The inflammatory injury was analyzed by the secretion levels of inflammatory cytokines (IL-6, IL-8 and tumor necrosis factor-alpha [TNF-alpha]) by enzyme-linked immunosorbent assay (ELISA). The extracellular matrix degradation was evaluated by expression of aggrecan and matrix metalloproteinase 13 (MMP13) via western blot. The target relationship of miR-671-5p and circ-IQGAP1 or TCF4 was analyzed via dual-luciferase reporter and RNA immunoprecipitation (RIP) analyses. Results Circ-IQGAP1 abundance was enhanced in the cartilage tissues from OA patients compared with normal subjects (n = 32), and its expression was increased in CHON-001 cells after treatment of IL-1 beta in a dose-dependent pattern. MiR-671-5p expression was decreased in the cartilage tissues from OA patients (n = 32) and IL-1 beta-challenged CHON-001 cells. MiR-671-5p expression was negatively associ

关键词： IQ结构域GTP酶活化蛋白1   糖尿病肾病   足细胞凋亡   免疫组织化学法  

摘要： 目的探讨IQ结构域GTP酶活化蛋白1(IQGAP1)在2型糖尿病肾病患者足细胞凋亡中的作用及机制探究。方法采用免疫组织化学法完成两组肾脏组织中IQGAP1、p-ERK1/2、ERK1/2表达水平;采用SPSSPearson相关性分析软件分析IQGAP1与p-ERK1/2、ERK1/2表达及分布关系。结果实验组糖尿病肾病组织中IQGAP1阳性率低于对照组(P<0.05);实验组糖尿病肾病组织中p-ERK1/2、ERK1/2阳性率均高于对照组(P<0.05);免疫组化结果表明:实验组糖尿病肾病组织中足细胞裂隙变窄,足突缩小及伴有节段性融合,可见足细胞凋亡小体形成,IQGAP1分布在肾小球足细胞、系膜细胞、血管内皮细胞中;对照组肾脏组织中未见肾脏病变改变,IQGAP1表达水平较高;SPSSPearson相关性分析结果表明:实验组肾脏组织中IQGAP1与p-ERK1/2、ERK1/2蛋白阳性率呈正相关性(P<0.05)。结论IQGAP1在2型糖尿病肾病患者中呈低表达,且表达水平与p-ERK1/2、ERK1/2存在相关性,可能由于p-ERK1/2、ERK1/2能引起足细胞凋亡,从而引起大量蛋白尿,导致糖尿病肾病的发生。

关键词： AMD1   FTO   hepatocellular carcinoma   IQGAP1   N6‐   methyladenosine   polyamination   stemness  

摘要： Background S-adenosylmethionine decarboxylase proenzyme (AMD1) is a key enzyme involved in the synthesis of spermine (SPM) and spermidine (SPD), which are associated with multifarious cellular processes. It is also found to be an oncogene in multiple cancers and a potential target for tumor therapy. Nevertheless, the role AMD1 plays in hepatocellular carcinoma (HCC) is still unknown. Methods HCC samples were applied to detect AMD1 expression and evaluate its associations with clinicopathological features and prognosis. Subcutaneous and orthotopic tumor mouse models were constructed to analyze the proliferation and metastasis of HCC cells after AMD1 knockdown or overexpression. Drug sensitive and tumor sphere assay were performed to investigate the effect of AMD1 on HCC cells stemness. Real-time quantitative PCR (qRT-PCR), western blot, immunohistochemical (IHC) and m6A-RNA immunoprecipitation (Me-RIP) sequencing/qPCR were applied to explore the potential mechanisms of AMD1 in HCC. Furthermore, immunofluorescence, co-IP (Co-IP) assays, and mass spectrometric (MS) analyses were performed to verify the proteins interacting with AMD1. Results AMD1 was enriched in human HCC tissues and suggested a poor prognosis. High AMD1 level could promote SRY-box transcription factor 2 (SOX2), Kruppel like factor 4 (KLF4), and NANOG expression of HCC cells through obesity-associated protein (FTO)-mediated mRNA demethylation. Mechanistically, high AMD1 expression increased the levels of SPD in HCC cells, which could modify the scaffold protein, Ras GTPase-activating-like protein 1 (IQGAP1) and enhance the interaction between IQGAP1 and FTO. This interaction could enhance the phosphorylation and decrease the ubiquitination of FTO. Conclusions AMD1 could stabilize the interaction of IQGAP1 with FTO, which then promotes FTO expression and increases HCC stemness. AMD1 shows prospects as a prognostic predictor and a therapeutic target for HCC.

关键词： IQGAP1   GTPase   Cancer metastasis   Cytoskeleton  

摘要： The metastatic spread of tumor cells to distant anatomical locations is a critical cause for disease progression and leads to more than 90 % of cancer-related deaths. IQ motif-containing GTPase-activating protein 1 (IQGAP1), a prominent regulator in the cancer metastasis process, is a scaffold protein that interacts with components of the cytoskeleton. As a critical node within the small GTPase network, IQGAP1 acts as a binding partner of several small GTPases, which in turn function as molecular switches to control most cellular processes, including cell migration and invasion. Given the significant interaction between IQGAP1 and small GTPases in cancer metastasis, we briefly elucidate the role of IQGAP1 in regulating cancer metastasis and the varied interactions existing between IQGAP1 and small GTPases. In addition, the potential regulators for IQGAP1 activity and its interaction with small GTPases are also incorporated in this review. Overall, we comprehensively summarize the role of IQGAP1 in cancer tumorigenicity and metastasis, which may be a potential anti-tumor target to restrain cancer progression.