Connective tissue growth factor enhances the migration of gastric cancer through downregulation of E-cadherin via the NF-κB pathway

Local invasion and distant metastasis are difficult problems for surgical intervention and treatment in gastric cancer. Connective tissue growth factor (CTGF/CCN2) was considered to have an important role in this process. In this study, we demonstrated that expression of CTGF was significantly upregulated in clinical tissue samples of gastric carcinoma (GC) samples. Forced expression of CTGF in AGS GC cells promoted their migration in culture and significantly increased tumor metastasis in nude mice, whereas RNA interference-mediated knockdown of CTGF in GC cells significantly inhibited cell migration in vitro. We disclose that CTGF downregulated the expression of E-cadherin through activation of the nuclear factor-κappa B (NF-κB) pathway. The effects of CTGF in GC cells were abolished by dominant negative IκappaB. Collectively, these data reported here demonstrate CTGF could modulate the NF-κappaB pathway and perhaps be a promising therapeutic target for gastric cancer invasion and metastasis.     

Tumor-associated macrophages promote the metastasis and growth of non-small-cell lung cancer cells through NF-κB/PP2Ac-positive feedback loop

Non-small-cell lung cancer (NSCLC), with its aggressive biological behavior, is one of the most diagnosed cancers. Tumor-associated inflammatory cells play important roles in the interaction between chronic inflammation and lung cancer, however the mechanisms involved are far from defined. In the present study, by developing an orthotopic NSCLC mouse model based on chronic inflammation, we proved that an inflammatory microenvironment accelerated the growth of orthotopic xenografts in vivo. Tumor-associated macrophages, the most abundant population of inflammatory cells, were identified. Treatment with macrophage-conditioned medium (MCM) promoted the growth and migration of NSCLC cells. Using bioinformatics analysis, we identified downregulated PP2Ac expression in NSCLC cells upon treatment with MCM. We further confirmed that this downregulation was executed in an NF-κB pathway-dependent manner. As IκB kinase (IKK) has been proved to be a substrate of PP2Ac, inhibition on PP2Ac could result in amplification of NF-κB pathway signaling. Overexpression of PP2Ac, or the dominant-negative forms of IKK or IκB, attenuated the acceleration of growth and metastasis by MCM. Using bioinformatics analysis, we further identified that CXCL1 and COL6A1 could be downstream of NF-κB/PP2Ac pathway. Luciferase assay and ChIP assay further confirmed the location of response elements on the promoter regions of CXCL1 and COL6A1. Elevated CXCL1 facilitated angiogenesis, whereas upregulated COL6A1 promoted proliferation and migration.     

Notch1 promotes glioma cell migration and invasion by stimulating β-catenin and NF-κB signaling via AKT activation

The Notch signaling pathway has been implicated in both developmental processes and tumorigenesis. Aberrant Notch signaling has been repeatedly demonstrated to facilitate the proliferation and survival of glioma cells by regulating downstream effectors or other signaling pathways. In glioblastoma multiforme specimens from 59 patients, Notch1 was highly expressed in tumor tissues compared with normal brain tissues, and this expression was correlated with elevated AKT phosphorylation and Snail expression. Increased nuclear localization of β-catenin and p50 as well as enhanced IKKα/AKT interaction were also observed in glioma tissues. In U87MG cells, the activation of Notch1 by DLL4 stimulation or by the overexpression of Notch intracellular domain (NICD) resulted in AKT activation and thereby promoted β-catenin activity and NF-κB signaling. Inhibition of EGFR partially blocked the β-catenin and NF-κB signaling stimulated by Notch1 activation. Furthermore, NICD overexpression in U87MG cells led to the upregulated expression of several metastasis-associated molecules, which could be abrogated by the knockdown of either β-catenin or p50. In U87MG and U251 cells, DLL4-induced cellular migration and invasion could be inhibited by either β-catenin or a p50 inhibitor. Collectively, these results indicate that Notch activation could stimulate β-catenin and NF-κB signaling through AKT activation in glioma cells. Thus, Notch activation-stimulated β-catenin and NF-κB signaling synergistically promote the migratory and invasive properties of glioma cells.     

Overexpression of response gene to complement 32 (RGC32) promotes cell invasion and induces epithelial–mesenchymal transition in lung cancer cells via the NF-κB signaling pathway

Response gene to complement 32 (RGC32) is a novel cellular protein that has been reported to be expressed aberrantly in multiple types of human tumors. However, the role of RGC32 in cancer is still controversial, and the molecular mechanisms by which RGC32 contributes to the development of cancer remain largely unknown. In the present study, we constructed a recombinant expression vector pCDNA3.1-RGC32 and transfected it into human lung cancer A549 cells. Stable transformanted cells were identified by real-time PCR and Western blot analysis. Functional analysis showed that forced overexpression of RGC32 increased invasive and migration capacities of lung cancer cells in vitro, and induced the acquisition of epithelial–mesenchymal transition (EMT) phenotype, as demonstrated by the spindle-like morphology, downregulation of E-cadherin, and upregulation of Vimentin, Fibronectin, Snail and Slug. Also, overexpression of RGC32 increased expression and activities of matrix metalloproteinase (MMP)-2 and MMP-9 in A549 cells. Furthermore, the downregulation of E-cadherin induced by RGC32 was remarkably attenuated by nuclear factor-κB (NF-κB) inhibitor BAY 11-7028 and small interfering RNA targeting NF-κB p65, suggesting a role of the NF-κB signaling pathway in RGC32-induced EMT. Taken together, our data suggest that RGC32 promotes cell migration and invasion and induces EMT in lung cancer cells via the NF-κB signaling pathway.     

Annexin-1 interacts with NEMO and RIP1 to constitutively activate IKK complex and NF-κB: implication in breast cancer metastasis

The molecular mechanisms underlying constitutive nuclear factor-κB (NF-κB) activation in solid tumors has not been elucidated. We show that Annexin-1 (ANXA1) is involved in this process, and suppression of ANXA1 in highly metastatic breast cancer cells impedes migration and metastasis capabilities in vitro and in vivo. ANXA1 expression correlates with NF-κB activity, suggesting that ANXA1 may be required for the constitutive activity of IκB kinase (IKK) and NF-κB in highly metatstatic breast cancer. Gel-filtration analysis demonstrated that ANXA1 co-elutes with the members of the IKK complex and NF-κB signaling pathway, and immunoprecipitation confirmed that ANXA1 can bind to and interact with IKKγ or NEMO, but not IKKα or IKKβ. Importantly, silencing of ANXA1 prevents the interaction of NEMO and RIP1, which indicates that ANXA1 is required for the recruitment of RIP1 to the IKK complex, which may be important for the activation of NF-κB. Downstream targets of NF-κB include uPA and CXCR4, which can be modulated by ANXA1 silencing. CXCR4-mediated migration of breast cancer cell lines in response to CXCL12 was significantly modulated by ANXA1, indicating its importance in the tissue-specific migration of breast cancer cells. Chromatin immunoprecipitation experiments confirmed that in ANXA1 overexpressed cells, NF-κB was recruited to CXCR4 promoter without external stimulation, indicating that ANXA1 is critical for the constitutive activation of NF-κB in breast cancer to promote metastasis. Finally, we show that ANXA1 overexpression enhances metastasis and reduces survival in an intracardiac metastasis model, while ANXA1-deficient mice crossed with MMTV-PyMT mice display significantly less metastasis than their heterozygous littermates, indicating that ANXA1 is an important gene in breast cancer metastasis. Our data reveal that ANXA1 can constitutively activate NF-κB in breast cancer cells through the interaction with the IKK complex, and suggests that modulating ANXA1 levels has therapeutic potential to suppress breast cancer metastasis.     

Lymphotoxin-α promotes tumor angiogenesis in HNSCC by modulating glycolysis in a PFKFB3-dependent manner

Tumor angiogenesis is critical for tumor progression as the new blood vessels supply nutrients and facilitate metastasis. Previous studies indicate tumor associated lymphocytes, including B cells and T cells, contribute to tumor angiogenesis and tumor progression. The present study aims to identify the function of Lymphotoxin-α (LT-α), which is secreted by the activated lymphocytes, in the tumor angiogenesis of head and neck squamous cell carcinoma (HNSCC). The coculture system between HNSCC cell line Cal27 and primary lymphocytes revealed that tumor cells promoted the LT-α secretion in the cocultured lymphocytes. In vitro data further demonstrated that LT-α promoted the proliferation, migration and tube formation of human umbilical vein endothelial cells (HUVECs) by enhancing the PFKFB3-mediated glycolytic flux. Genetic and pharmacological inhibition of PFKFB3 suppressed the enhanced proliferation and migration of HUVECs. We further identified that LT-α induced PFKFB3 expression was dependent on the TNFR/NF-κB signaling pathway. In addition, we proved that PFKFB3 blockade decreased the density of CD31 positive blood vessels in HNSCC xenografts. Finally, the results from the human HNSCC tissue array revealed that the expression of LT-α in HNSCC samples positively correlated with microvessel density, lymphocytes infiltration and endothelial PFKFB3 expression. In conclusion, infiltrated lymphocyte secreted LT-α enhances the glycolysis of ECs in a PFKFB3-dependent manner through the classical NF-κB pathway and promotes the proliferation and migration of ECs, which may contribute to the aberrant angiogenesis in HNSCCs. Our study suggests that PFKFB3 blockade is a promising therapeutic approach for HNSCCs by targeting tumor angiogenesis.     

Exosomes Derived from Irradiated Esophageal Carcinoma-Infiltrating T Cells Promote Metastasis by Inducing the Epithelial–Mesenchymal Transition in Esophageal Cancer Cells

Exosomes are nanovesicles derived from tumor and normal cells that are detectable in human biological fluids, such as plasma, and cell culture supernatants. The function of exosome secretion from “normal” cells is unclear. Although numerous studies have investigated exosomes derived from hematopoietic cells, little is known regarding exosomes fromT cells, even though these cells play significant roles in innate and acquired immunity. A CCK-8 assay was used to examine the ability of exosomes to inhibit TE13 cell proliferation. In vitro invasion and wound healing assays were conducted to explore the effects of exosomes on TE13 cell migration and invasion. A Western blottinganalys is was performed to investigate the effects of exosomes on the expression of the EMT-related moleculesβ-catenin, NF-κB and snail. This study aimed to investigate the effects of exosomes from irradiated T cells on the human esophageal squamous cell carcinoma (ESCC) cell line TE13 and revealed that exosomes inhibit the proliferation but promote the metastasis of TE13 cells in a dose-and time-dependent manner. Furthermore, exosomes significantly increased the expression of β-catenin, NF-κB and snail in TE13 cells. The results of this study suggest an important role for T cell-derived exosomes in the progression of esophageal carcinoma: T cell-derived exosomes promote esophageal cancer metastasis, likely by promoting the EMT through the upregulation of β-catenin and the NF-κB/snail pathway. Moreover, this study supports the use of exosomes as a nearly perfect example of biomimetic nanovesicles that could be utilized in future therapeutic strategies against various diseases, including cancer.     

RANK induces epithelial-mesenchymal transition and stemness in human mammary epithelial cells and promotes tumorigenesis and metastasis

Paracrine signaling through receptor activator of NF-κB (RANK) pathway mediates the expansion of mammary epithelia that occurs during pregnancy, and activation of RANK pathway promotes mammary tumorigenesis in mice. In this study we extend these previous data to human cells and show that the RANK pathway promotes the development of mammary stem cells and breast cancer. Overexpression of RANK (FL-RANK) in a panel of tumoral and normal human mammary cells induces the expression of breast cancer stem and basal/stem cell markers. High levels of RANK in untransformed MCF10A cells induce changes associated with both stemness and transformation, including mammary gland reconstitution, epithelial-mesenchymal transition (EMT), increased migration, and anchorage-independent growth. In addition, spheroids of RANK overexpressing MCF10A cells display disrupted acinar formation, impair growth arrest and polarization, and luminal filling. RANK overexpression in tumor cells with nonfunctional BRCA1 enhances invasiveness in acinar cultures and increases tumorigenesis and metastasis in immunodeficient mice. High levels of RANK were found in human primary breast adenocarcinomas that lack expression of the hormone receptors, estrogen and progesterone, and in tumors with high pathologic grade and proliferation index; high RANK/RANKL expression was significantly associated with metastatic tumors. Together, our findings show that RANK promotes tumor initiation, progression, and metastasis in human mammary epithelial cells by increasing the population of CD44(+)CD24(-) cells, inducing stemness and EMT. These results suggest that RANK expression in primary breast cancer associates with poor prognosis.     

LOX1在胃癌中的表达及其促肿瘤生长的机制探讨

目的:探讨血凝素样氧化型低密度脂蛋白受体1（lectin-like oxidized low density lipoprotein receptor-1,LOX1）在胃癌中的表达及与预后相关性,同时明确其促胃癌生长作用及潜在机制。方法:利用人类癌症基因组图谱(TCGA)、基因表达汇编(GEO)和癌症细胞系百科全书(CCLE)数据库分析LOX1在胃癌组织和细胞中的表达水平;利用多种统计方法分析LOX1表达水平与胃癌患者预后及临床特征的相关性;通过质粒转染敲低LOX1,进一步应用细胞功能实验（CCK-8、克隆形成、EdU实验）探究LOX1对胃癌细胞增殖能力的调控作用;通过Western blot、qPCR、免疫荧光分析LOX1对NF-κB信号通路激活的调控作用。结果:LOX1在胃癌组织和细胞中显著高表达;高水平LOX1提示胃癌患者预后较差且肿瘤较易发生转移;敲低LOX1显著抑制肿瘤细胞增殖;敲低LOX1显著抑制胃癌细胞中NF-κB信号通路的激活。结论:LOX1通过激活NF-κB信号通路对胃癌细胞增殖能力具有调控作用;LOX1可作为生物标记物提示患者预后;靶向LOX1可作为潜在胃癌治疗新方案。     

核转录因子-κ B在胰腺癌中的表达及其与上皮细胞间质转化的关系

目的 研究核转录因子-κ B(NF-κ B)在人类胰腺癌组织中的表达及与上皮细胞间质转化(EMT)标志物上皮性钙黏附蛋白(E-cad)和波形蛋白(Vimentin)的关系,探讨其与胰腺癌恶性生物学行为的关系.方法 应用免疫组织化学法检测62例人类胰腺癌组织中NF-κ B、上皮源性标志物E-cad蛋白、间质源性标志物Vimentin蛋白的表达,并分析它们相互间及其与临床病理因素间的关系.结果 胰腺癌组织中NF-κ B和Vimentin蛋白阳性表达率分别为81%(50/62)和61%(38/62),E-cad蛋白的表达缺失率为55%(34/62).在胰腺癌组织中NF-κ B的表达和Vimentin蛋白的阳性表达、E-cad蛋白的缺失表达均呈正相关(r值分别为0.343、0.352,均P＜0.05),并且NF-κ B的阳性表达与胰腺癌的淋巴结转移(x2=11.761,P＜0.05)、远处转移(x2=9.225,P＜0.05)相关,而与患者性别、年龄、肿瘤部位、肿瘤类型及分化程度无关(P＞0.05).E-cad蛋白的表达缺失、Vimentin蛋白的阳性表达与胰腺癌的淋巴结转移、远处转移均有相关性(x2值分别为6.914、4.984;7.753、5.144,均P＜0.05).结论 NF-κ B在胰腺癌中表达增高,同时可能通过诱导胰腺癌组织的EMT而促进胰腺癌的浸润和转移.

Abstract：

Objective To investigate the expression of NF-κB and epithelial-mesenchymal transition (EMT) related markers E-cadherin and Vimentin proteins in human pancreatic cancer tissues and its relation with the malignant features. Methods The expression of NF-κB、E-cadherin and Vimentin proteins in 62 cases of pancreatic cancer tissues were detected by using immunohistochemistry and compared with the clinicopathological data of pancreatic cancer. Results The positive expression rate of NF-κB was 81% (50/62), Vimentin protein increased of expression was 61% (38/62), and E-cadherin protein loss of expression was 55 % (34/62) in pancreatic cancer. The positive expression rate of NF-κB was significantly related with the lymph node metastasis (x2=11.761, P＜0.05), distant metastasis (x2=9.225, P＜0.05), the absent expression of epithelial marker E-cadherin protein (r =0.352, P ＜0.05) and the positive expression of mesenchymal marker Vimentin protein (r=0.343, P ＜0.05), but there was no relation with the patients gender,age, tumor location, tumor type and tumor differentiation (P ＞0.05). In addition, the significant correlation of E-cadherin expression loss and Vimentin expression with tumor lymph node metastasis and distant metastasis was found (x 2= 6.914, 4.984, 7.753, 5.144, P ＜0.05). Conclusion The overexpression of NF-κB in pancreatic cancer may accelerate invasion and metastasis of pancreatic cancer through inducing EMT.     

Involvement of PKCα activation in TF/VIIa/PAR2-induced proliferation, migration, and survival of colon cancer cell SW620

Our previous study has demonstrated that protease-activated receptor 2 (PAR2) activation mediated by tissue factor (TF)/VIIa complex triggers the ERK1/2/NF-κB signaling pathway, which further contributes to the proliferation and migration of colon cancer cell line SW620. However, the detailed mechanisms remain unclear. This study was to investigate whether protein kinase Cα (PKCα) is involved in these events and the possible mechanism. The results revealed that PAR2-activating peptide or VIIa could induce time-dependent upregulation of PKCα phosphorylation in SW620 cells and PKCα translocation from the cytoplasm to the perinuclear region and nucleus. The activation of PKCα was sufficient to induce ERK1/2 and NF-κB phosphorylation. The VIIa effect was obviously blocked by both anti-TF and anti-PAR2 antibodies. The PKCα inhibitor, safingol, inhibited ERK1/2 phosphorylation and NF-κB activation that is induced by VIIa and abrogated the enhanced proliferation, migration, and survival of SW620 cells by VIIa treatment. Both safingol and PDTC (NF-κB inhibitor) could apparently rescue the effects of VIIa on expression of MMP-9, caspase-3, TF, and Bcl-2/bax in SW620 cells. Collectively, the data in this study suggest that TF/VIIa/PAR2-induced SW620 cell proliferation, migration, and survival are ascribed to the activation of PKCα, and these effects are achieved through PKCα downstream signaling pathways, ERK1/2 and NF-κB.     

Rab11通过NF-κB信号通路调控膀胱癌细胞的增殖和侵袭

目的:探讨Rab11调控膀胱癌细胞增殖和侵袭的分子机制。方法:用Western blot方法检测膀胱癌BIU-87、T24、RT4、5637细胞系中Rab11的内源表达量。在BIU-87（Rab11低表达）和T24（Rab11高表达）细胞系中分别转染Rab11过表达质粒和Rab11 siRNA。用荧光素酶报告实验检测转染后细胞内的NF-κB信号通路的活性,通过Western blot技术分析与NF-κB信号通路相关蛋白p-IκB的变化情况。用NF-κB抑制剂Bay 11-7082处理转染Rab11过表达质粒的BIU-87细胞系,通过Western blot检测细胞系中细胞周期相关因子cyclin D1和侵袭相关因子MMP9蛋白的变化。结果:转染Rab11过表达质粒的BIU-87细胞系中NF-κB活性水平提高,p-IκB表达量显著提高;而敲除Rab11后NF-κB活性受到抑制,p-IκB的表达受到抑制,而p-IκB与NF-κB信号通路的活性呈正相关。NF-κB抑制剂Bay 11-7082阻遏了Rab11诱导cyclin D1和MMP9表达上调的过程。结论:Rab11通过NF-κB信号通路调控膀胱癌细胞的增殖和侵袭。