eEF1A2 promotes cell migration, invasion and metastasis in pancreatic cancer by upregulating MMP-9 expression through Akt activation

eEF1A2 is a protein translation factor involved in protein synthesis that is overexpressed in various cancers, with important functions in tumor genesis and progression. We have previously showed that the ectopic expression of eEF1A2 is correlated with lymph node metastasis and perineural invasion in pancreatic cancer. In this study, we investigated the functional role of eEF1A2 in the regulation of cell migration, invasion, and metastasis in pancreatic cancer. Furthermore, we investigated the potential molecular mechanisms involved. By evaluating the invasive ability of a panel of pancreatic cancer cell lines with different metastatic potentials, eEF1A2 expression in cells was positively associated with their invasive ability. The knockdown of eEF1A2 by siRNA decreased the migration and invasion of PANC-1 cells. By contrast, the ectopic expression of exogenous eEF1A2 significantly promoted the migration and invasion of SW1990 cells. Stable eEF1A2 overexpression in a nude mouse model of peritoneal metastasis likewise dramatically enhanced the intraperitoneal metastatic ability of SW1990 cells. In addition, eEF1A2 overexpression could upregulate MMP-9 expression and activity. A significant positive correlation between the overexpression of both eEF1A2 and MMP-9 was observed in pancreatic cancer tissues. The inhibition of MMP-9 activity reduced the promoting effect of eEF1A2 on cell migration and invasion. Furthermore, eEF1A2-mediated cell migration and invasion, as well as MMP-9 expression and upregulation, were largely dependent on the eEF1A2-induced Akt activation. The findings suggested the potentially important role of eEF1A2 in pancreatic cancer migration, invasion, and metastasis. Thus, the results provide evidence of eEF1A2 as a potential therapeutic target in the treatment of aggressive pancreatic cancer.     

Claudin-1 is a strong prognostic indicator in stage II colonic cancer: a tissue microarray study.

Tight junction associated proteins are key molecular components governing cellular adhesion, polarity and glandular differentiation. Tight junction proteins also play critical roles in cellular proliferation and neoplastic pathways via their functions as couplers of the extracellular milieu to intracellular signaling pathways and the cytoskeleton. Neoplastic cells frequently exhibit structural and functional deficiencies in the tight junction. The purpose of this study was to determine the pattern of expression and prognostic value of four tight junction associated proteins, claudin-1, claudin-4, occludin and ZO-1 in a cohort of TNM stage II colon cancer using tissue microarray technology. In this study, we retrospectively analyzed, resected and otherwise untreated paraffin embedded specimens from 129 consecutive patients with TNM stage II colonic carcinomas for claudin-1, claudin-4, occludin and ZO-1 protein expression by immunohistochemistry. Seventy-five, 58, 56 and 44% of the tumors exhibited normal to elevated expression levels (+2 and +3 immunopositivity) of claudin-1, claudin-4, occludin and ZO-1 respectively. Low expression levels of claudin-1 and ZO-1 were directly associated with higher tumor grade (P=0.05 and 0.03 respectively). Multivariate analysis indicated that lymphovascular invasion (P=0.01) and low levels of claudin-1 (P=0.0001) expression were independent predictors of recurrence and that reduced claudin-1 expression (P=0.0001) was associated with poor survival. This study is the first to comprehensively examine the expression of several tight junction associated proteins in colonic neoplasms and to correlate their expression with disease progression. Loss of claudin-1 expression proved to be a strong predictor of disease recurrence and poor patient survival in stage II colon cancer.     

Regulation of membrane-type 1 matrix metalloproteinase expression by zonula occludens-2 in human lung cancer cells

During tumor invasion, tumor epithelial cells acquire migratory and invasive properties involving important phenotypic alterations. Among these changes, one can observe reorganization or a loss of cell–cell adhesion complexes such as tight junctions (TJs). TJs are composed of transmembrane proteins (occludin, claudins) linked to the actin cytoskeleton through cytoplasmic adaptor molecules including those of the zonula occludens family (ZO-1, -2, -3). We here evaluated the potential role of ZO-2 in the acquisition of invasive properties by tumor cells. In vivo, we showed a decrease of ZO-2 expression in bronchopulmonary cancers, with a preferential localization in the cytoplasm. In addition, in vitro, the localization of ZO-2 varied according to invasive properties of tumor cells, with a cytoplasmic localization correlating with invasion. In addition, we demonstrated that ZO-2 inhibition increases invasive and migrative capacities of invasive tumor cells. This was associated with an increase of MT1-MMP. These results suggest that ZO-2, besides its structural role in tight junction assembly, can act also as a repressor of tumor progression through its ability to reduce the expression of tumor-promoting genes in invasive tumor cells.     

CUB-domain-containing protein 1 regulates peritoneal dissemination of gastric scirrhous carcinoma

CUB-domain-containing protein 1 (CDCP1) is a type-I transmembrane protein that is highly expressed in colon, breast, and lung cancers. We recently revealed that CDCP1 is associated with and phosphorylated by Src family kinases and is involved in the regulation of anchorage independence of certain lung cancer cell lines. In this study, we examined whether CDCP1 is involved in the regulation of tumor progression of scirrhous gastric cancer, which is a diffusely infiltrative carcinoma with high invasion potential. Expression and phosphorylation levels of CDCP1 correlated with the invasive potential of scirrhous gastric cancers. Reduction of CDCP1 expression by siRNA suppressed migration, invasion, and anchorage independence without affecting the proliferation of highly invasive scirrhous gastric cancer cells. However, CDCP1 overexpression promoted gastric cancer cell migration with low potential of invasion. Loss of CDCP1 suppressed invasion and dissemination of cancer cells that were orthotopically implanted in the gastric wall of nude mice. Expression and phosphorylation of CDCP1 were also detected in cancer cells of surgically resected tissues of human scirrhous gastric cancer by immunohistochemical analysis. Our results suggest that CDCP1 promotes invasion and peritoneal dissemination of cancer cells through the regulation of cell migration and anchorage independence. Therefore, it is both a potential prognostic and therapeutic target in certain types of gastrointestinal cancers, and suppression of its phosphorylation might be a useful strategy for modulating cancer metastasis.     

Gli1 enhances migration and invasion via up-regulation of MMP-11 and promotes metastasis in ERα negative breast cancer cell lines

Gli1 is an established oncogene and its expression in Estrogen Receptor (ER) α negative and triple negative breast cancers is predictive of a poor prognosis; however, the biological functions regulated by Gli1 in breast cancer have not been extensively evaluated. Herein, Gli1 was over-expressed or down-regulated (by RNA interference and by expression of the repressor form of Gli3) in the ERα negative, human breast cancer cell lines MDA-MB-231 and SUM1315. Reduced expression of Gli1 in these two cell lines resulted in a decrease in migration and invasion. Gli1 over-expression increased the migration and invasion of MDA-MB-231 cells with a corresponding increase in expression of MMP-11. Silencing MMP-11 in MDA-MB-231 cells that over-expressed Gli1 abrogated the Gli1-induced enhancement of migration and invasion. Sustained suppression of Gli1 expression decreased growth of MDA-MB-231 in vitro by increasing apoptosis and decreasing proliferation. In addition, silencing of Gli1 reduced the numbers and sizes of pulmonary metastases of MDA-MB-231 in an in vivo experimental metastasis assay. In summary, Gli1 promotes the growth, survival, migration, invasion and metastasis of ERα negative breast cancer. Additionally, MMP-11 is up-regulated by Gli1 and mediates the migration and invasion induced by Gli1 in MDA-MB-231.     

紫杉醇联合顺铂化疗对人卵巢浆液性囊腺癌组织occludin和ZO-1表达以及线粒体超微结构的影响

 目的：观察紫杉醇联合顺铂化疗对人卵巢浆液性囊腺癌（serous cystadenocarcinoma, SC）组织紧密连接蛋白occludin和zonula occludens-1(ZO-1)表达以及线粒体超微结构的影响。方法：取紫杉醇联合顺铂化疗和未化疗的卵巢癌患者SC组织,用电镜观察其线粒体超微结构,用免疫组织化学法观察癌组织occludin和ZO-1蛋白的表达,并以子宫肌瘤患者的正常卵巢组织为正常对照。结果：SC细胞线粒体明显肿胀,呈现巨线粒体,且嵴断裂十分显著;化疗后的SC细胞线粒体肿胀减轻,形态接近正常。SC细胞较正常卵巢上皮细胞occludin和ZO-1蛋白表达明显降低（P<005或P<001）;化疗组较未化疗组SC细胞occludin和ZO-1蛋白表达明显增多（P<001）。结论: 紧密连接蛋白occludin 和 ZO-1的低表达可能是SC浆液生成增多和细胞代谢异常的关键所在,而化疗可促进紧密连接蛋白表达,从而减轻线粒体结构肿胀并改善细胞功能。     

MicroRNA-374a promotes pancreatic cancer cell proliferation and epithelial to mesenchymal transition by targeting SRCIN1

MicroRNAs (miRNAs) play a vital role in the progress of cancer. Whereas the expression and function of miR-374a in pancreatic cancer remain largely unknown. In this study, pancreatic cancer samples and its adjacent normal tissues were obtained from 30 clinical patients with pancreatic cancer. Quantitative real-time PCR (qRT-PCR) was used to measure miR-374a and SRC Kinase Signaling Inhibitor 1 (SRCIN1) expression. Western blotting assay was performed to measure the levels of SRCIN1, E-cadherin, N-cadherin, Vimentin, Zonula occludens-1 (ZO-1) and β-catenin in PANC-1 cells. Luciferase reporter assay was conducted to confirm the direct targeting of SRCIN1 by miR-374a. Cell proliferation and migration assays were utilized to analyze the role of miR-374a in PANC-1 cells. We found that miR-374a expression was upregulated in pancreatic cancer tissues and cell lines. Over-expression of miR-374a promoted cell proliferation, migration and epithelial-mesenchymal transition (EMT) in pancreatic cancer. While, SRCIN1 expression was downregulated in pancreatic cancer tissues and cells. SRCIN1 was found to be a potential targets of miR-374a by dual-luciferase reporter assay. And SRCIN1 was down-regulated after miR-374a transfection. More than that, over-expression of SRCIN1 inhibited cell proliferation, migration and EMT in pancreatic cancer cell. Therefore, this study revealed that miR-374a promoted cell proliferation, migration and EMT via targeting SRCIN1 in pancreatic cancer.     

miR-34c-3p inhibits cell proliferation,migration and invasion of hepatocellular carcinoma by targeting MARCKS

Recent studies have shown that microRNA-34c-3p (miR-34c-3p) is down-regulated in various types of cancers and involved in tumor growth, invasion and metastasis. However, the roles of miR-34c-3p in hepatocellular carcinoma (HCC) are poorly understood. In this study, the expression profile of miR-34c-3pin HCC tissues and cell lines were examined by quantitative real-time polymerase chain reaction (qRT-PCR). The correlations of miR-34c-3p expression and clinicopathological characteristics were analyzed. The biological role of MiR-34c-3pin cell proliferation, migration and invasion was examined. In addition, the targets of miR-34c-3p were identified. The results showed that miR-34c-3p expression was significantly down-regulated in HCC tissues and cell lines; low expression level of miR-34c-3p was correlated with vascular invasion and advanced TNM stage. In vitro functional assays showed that overexpression of miR-34c-3pin HepG2 and Huh7 cells significantly reduced cell proliferation, migration and invasion. Furthermore, target analysis and luciferase assay identified myristoylated alanine-rich protein kinase c substrate (MARCKS) as a specific target of miR-34c-3p. Knockdown of MARCKS in HepG2 cells reduced cell migration and invasion, but not cell proliferation. Taken together, our findings implicate the potential application of miR-34c-3p as a tumor suppressor in cancer therapy.     

Tight junctions in lung cancer and lung metastasis: a review

Tight junctions are structures located in the apicobasal region of the cell membranes. They regulate paracellular solute and electrical permeability of cell layers. Additionally, they influence cellular polarity, form a paracellular fence to molecules and pathogens and divide the cell membranes to apical and lateral compartments. Tight junctions adhere to the corresponding ones of neighbouring cells and by this way also mediate attachment of the cells to one other. Molecules forming the membranous part of tight junctions include occludin, claudins, tricellulin and junctional adhesion molecules. These molecules are attached to scaffolding proteins such as ZO-1, ZO-2 and ZO-3 through which signals are mediated to the cell interior. Expression of tight junction proteins, such as claudins, may be up- or downregulated in cancer and they are involved in EMT thus influencing tumor spread. Like in tumors of other sites, lung tumors show changes in the expression in tight junction proteins. In this review the significance of tight junctions and its proteins in lung cancer is discussed with a focus on the proteins forming the membranous part of these structures.     

Correlation of the presence of blood-brain barrier tight junctions and expression of zonula occludens protein ZO-1 in vitro: a freeze-fracture and immunofluorescence study

Tight junctions are regarded as the primary anatomical structure responsible for the blood-brain barrier (BBB). The molecular components that have been defined include ZO-1, a peripheral membrane protein associated with the cytoplasmic surface of the tight junction in epithelial and endothelial cells. It has been localized to the points of membrane contact with the fibrils seen by freeze-fracture. Examination of passaged endothelial cells with freeze-fracture failed to locate the intramembrane specializations associated with tight junctions. For this reason, immunocytochemistry and freeze-fracture were used to study the correlation of ZO-1 expression with the presence of tight junctions in bovine brain and aorta endothelial cells. Indirect immunofluorescence analysis showed ZO-1 to be localized at sites of cell-cell contact. Images of freeze-fractured sites of endothelial cell-cell contacts in identical passage numbers did not display characteristic tight junctions. When bovine aorta endothelial cells were cultured in astrocyte-conditioned medium on a complete extracellular matrix, platinum replicas displayed profiles of tight junctions. The elements of tight junctions were arranged as parallel ridges which displayed free ends. The immunofluorescence staining of ZO-1 was identical to that obtained on the endothelial cells that displayed no tight junction profiles. These results suggest that ZO-1 may be present at putative junction-containing sites before the junctional structures appear in the surface membrane. Therefore, ZO-1 expression does not a priori reflect assembly of the tight junctions identified by freeze-fracture.     

尿酸钠结晶影响肾小管上皮细胞的紧密连接

背景：目前研究来看,尿酸性结石与紧密连接蛋白及肾间质纤维化的关系仍未明确。 目的：观察尿酸钠结晶对肾小管上皮细胞紧密连接的影响。 方法：配制单钠尿酸钠晶体。将正常大鼠肾小管上皮细胞随机分为对照组和尿酸钠结晶组,分别用无血清培养基和尿酸钠结晶进行培养。免疫荧光和RT-PCR方法检测24,48,72 h紧密连接蛋白的表达。 结果与结论：与对照组比较,尿酸钠结晶于不同时相刺激NRK-52E细胞后,紧密连接蛋白和mRNA表达下降(P < 0.05),72 h时下降显著(P < 0.01),蛋白表达出现重新分布现象。说明尿酸钠结晶可破坏肾小管上皮细胞紧密连接蛋白的结构、功能及导致分布异常。     

Expression of occludin, tight-junction-associated protein, in human digestive tract.

The tight junction seals cells together at a subapical location and functionally separates the plasma membrane into an apical and a basolateral domain. This junction is one of the most characteristic structural markers of the polarized epithelial cell. Recently, occludin has been identified as an integral transmembrane protein localizing at the tight junction and directly associated with ZO-1, an undercoat-constitutive cytoplasmic protein. We have investigated occludin expression in conjunction with ZO-1 in normal epithelia and cancers of human digestive tract by immunostaining with a new antibody raised against human occludin. In the normal simple columnar epithelium, occludin was expressed together with ZO-1 as a single line at the apical cell border. However, in the esophagus, which has a stratified squamous epithelium, no occludin expression could be detected, but ZO-1 was expressed in the spinous layer. As for cancers, both occludin and ZO-1 showed the same expression in differentiated adenocarcinoma cells as in normal epithelium, but in poorly differentiated adenocarcinomas, the expression of these two proteins was reduced. There was significant correlation between tumor differentiation and expression of these proteins. These results suggest that occludin, together with ZO-1, is involved in the formation of gland-like structures. In addition, occludin expression can serve as a histopathological indicator for differentiation in gastrointestinal adenocarcinomas.     

MicroRNA-940在乳腺癌中的表达变化及作用机制

目的 探讨microRNA-940(miR-940)在乳腺癌组织和细胞中的表达以及对乳腺癌细胞增殖、侵袭、迁移能力的影响及其相关分子机制。 方法 实时定量聚合酶链反应（Real-time PCR）检测2016年1月~2017年1月我院手术切除的78例患者的乳腺癌组织、癌旁组织和人乳腺癌细胞系MCF-7、SK-BR-3、MDA-MB-231、BT-549及人正常乳腺细胞系MCF-10 A中miR-940的表达情况。在乳腺癌细胞系MDA-MB-231中利用脂质体LipofectaminsTM 2000转染miR-940模拟物上调miR-940的表达,CCK-8实验检测细胞增殖活性的改变,小室侵袭及迁移实验（transwell）检测细胞侵袭、迁移能力的改变。生物学信息法预测miR-940的可能作用靶基因,双荧光素酶报告实验检测miR-940与CXC趋化因子受体2 (CXCR2)的3’UTR区结合情况,Western blotting检测miR-940对CXCR2 蛋白表达的影响。 结果 miR-940在乳腺癌组织和细胞中表达明显降低（P<0.01）,并且miR-940的表达与TNM分期和淋巴结转移密切相关（P<0.01）。上调MDA-MB-231细胞miR-940表达后,细胞的增殖活性明显下降（P<0.01）,侵袭及迁移能力明显下降（P<0.01）。双荧光素酶报告显示,miR-940可与CXCR2 的3’UTR区特定序列结合显著抑制荧光素酶活性(P<0.01),上调miR-940后细胞中CXCR2 蛋白的表达均明显下降(P<0.01)。 结论 miR-940在乳腺癌中的表达降低,miR-940可以通过靶向CXCR2抑制乳腺癌细胞的增殖、侵袭及迁移能力。     

DAAM1-mediated migration and invasion of ovarian cancer cells are suppressed by miR-208a-5p

Ovarian cancer (OvCa) has the highest morbidity among all gynecologic cancers worldwide, and its distant metastasis is one of main causes for the poor prognosis of OvCa patients. Our previous studies have reported that DAAM1-involved signaling pathways play vital roles in metastasis of breast cancer. However, whether DAAM1 participates in OvCa migration and/or invasion is still unknown. The impact of DAAM1 on cell migration and invasion in OvCa was evaluated by wound healing assay and Boyden chamber assay. The specific miRNA targeting DAAM1 was predicted by bioinformatics methods and verified by dual-luciferase activity assay. The miR-208a-5p expression levels in OvCa tissues and the impacts of miR-208a-5p on cell migration and invasion were also assessed, respectively. High expression of DAAM1 was associated with distant metastasis in OvCa. Silence of DAAM1 by siRNA blocked the migration and invasion of OVCAR-3 cells. MiR-208a-5p directly targeted DAAM1 and was shown a decreased expression in metastatic OvCa tissues. Elevated expression of miR-208a-5p inhibited the migration and invasion of OVCAR-3 cell which can be rescued by DAAM1 overexpression. Our data suggest that miR-208-5p/DAAM1 axis participates in OvCa migration and invasion and may be a novel clinical target to limit OvCa metastasis.     

Secretory leukocyte protease inhibitor is associated with MMP-2 and MMP-9 to promote migration and invasion in SNU638 gastric cancer cells

Secretory leukocyte protease inhibitor (SLPI) protects tissue from proteases, and promotes cell proliferation and healing during inflammatory response. SLPI is also overexpressed in gastric, lung and ovarian cancers, which accelerates the metastasis of cancer cells. Matrix metalloproteinases-2, -9 (MMP-2 and MMP-9) are overexpressed in high metastatic cancers, and promote the migration of cancer cells through collagen degradation. SLPI and MMP-2, -9 are critical factors in stimulating the metastatic processes but there are no reports of a direct correlation between these molecules. Therefore, this study examined the role of SLPI related to MMP-2 and MMP-9 using two gastric cancer cell lines, such as characterized non-metastatic SNU484 and highly metastatic SNU638 cells. SLPI, MMP-2 and MMP-9 mRNA and protein expression were higher in SNU638 cells than in SNU484 cells. In addition, the rate of cell migration and invasion was higher in the SNU638 cells than in SNU484 cells. Interestingly, after treatment with SLPI, the rate of migration and invasion was higher in the SNU484 cells than in the positive control (PC) SNU484 cells. The rate of migration was also higher in the SNU638 cells after SLPI treatment than in the SNU638 cells (PC) but the invasion rate was not changed. The expression and secretion of MMP-2 and MMP-9 as well the rate of cell migration and invasion were significantly lower in SLPI-siRNA transfected SNU638 cells (si-SLPI/SNU638) but higher in SLPI-treated SNU484 cells (SNU484 + SLPI). Strong Elk-1 phosphorylation was detected in SNU484 + SLPI and SNU638 cells but was barely detectable in SNU484 and si-SLPI/SNU638 cells. These results show that SLPI promotes the metastasis of SNU638 gastric cancer cells by increasing MMP-2 and MMP-9 expression through Elk-1 signaling, indicating its role as a signaling molecule not a protease inhibitor.     

紧密连接蛋白1 mRNA和蛋白表达与胃癌侵袭转移及预后的相关性

目的 探讨紧密连接蛋白1(ZO-1)mRNA及蛋白表达在胃癌侵袭转移及预后中的意义.方法 Real-time qPCR法检测52例胃腺癌细胞ZO-1 mRNA表达,组织芯片SP免疫组织化学法检测228例胃腺癌细胞ZO-1蛋白表达定位变化情况.结果 81.1%的胃癌组织出现不同程度的ZO-1胞膜表达异位至胞质迷离表达的现...     

E3 ubiquitin-protein ligase 2 inhibits cell proliferation,migration, and invasion of non-small cell lung cancer through ubiquitination of Notch1

This study aimed to explore the role of MIB2 in non-small cell lung cancer (NSCLC) and the underlying mechanism. Quantitative real-time PCR (QRT-PCR) and western blot were first performed to detect MIB2 expression in tumor tissues obtained from NSCLC patients (n = 30) and NSCLC cells, respectively. 3-(4, 5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide (MTT) and transwell assays were then used to examine the effect of MIB2 on the proliferation, migration and invasion of NSCLC cells. Western blot was further performed to examine the effect of Mind bomb 2 (MIB2), an E3 ligase on Notch1 protein and its ubiquitination. MIB2 was significantly down-regulated in NSCLC tissues and cells, both in mRNA and protein level. MIB2 also note worthily inhibited the proliferation, migration, and invasion of NSCLC cells. Furthermore, MIB2 only down-regulated Notch1 protein level, while facilitated the ubiquitination of Notch1. Additionally, Notch1 significantly relieved the repressed proliferation, migration and invasion of NSCLC cells induced by MIB2. Conclusively, MIB2 inhibited cell proliferation, migration and invasion via inducing Notch1 ubiquitination and degradation in NSCLC.     

Vertebrate Claudin/PMP22/EMP22/MP20 family protein TMEM47 regulates epithelial cell junction maturation and morphogenesis

Background: TMEM47 is the vertebrate orthologue of C. elegans VAB‐9, a tetraspan adherens junction protein in the PMP22/EMP/Claudin family of proteins. VAB‐9 regulates cell morphology and adhesion in C. elegans and TMEM47 is expressed during kidney development and regulates the activity of Fyn. The conserved functions of VAB‐9 and TMEM47 are not well understood. Results: expression of TMEM47 in C. elegans functionally rescues vab‐9 mutations. Unlike Claudins, expression of TMEM47 in L fibroblasts does not generate tight junction strands; instead, membrane localization requires E‐cadherin expression. Temporally, TMEM47 localizes at cell junctions first with E‐cadherin before ZO‐1 colocalization and in polarized epithelia, TMEM47 colocalizes with adherens junction proteins. By immunoprecipitation, TMEM47 associates with classical adherens junction proteins, but also with tight junction proteins Par6B and aPKCλ. Over‐expression of TMEM47 in MDCK cells decreases apical surface area, increases activated myosin light chain at cell–cell contacts, disrupts cell polarity and morphology, delays cell junction reassembly following calcium switch, and selectively interferes with tight junction assembly. Reduced TMEM47 expression results in opposite phenotypes. Conclusions: TMEM47 regulates the localization of a subset of tight junction proteins, associated actomyosin structures, cell morphology, and participates in developmental transitions from adherens to tight junctions. Developmental Dynamics 245:653–666, 2016. © 2016 Wiley Periodicals, Inc.