miR-340 inhibition of breast cancer cell migration and invasion through targeting of oncoprotein c-Met

BACKGROUND:

Different microRNAs have been shown to have oncogenic and tumor‐suppressive functions in human cancers. Detection of their expression may lead to identifying novel markers for breast cancer.

METHODS:

The authors detected miR‐340 expression in 4 human breast cell lines and then focused on its role in regulation of tumor cell growth, migration, and invasion and target gene expression. They then analyzed miR‐340 expression in benign and cancerous breast tissue specimens.

RESULTS:

Endogenous miR‐340 expression was down‐regulated in the more aggressive breast cancer cell lines, which was confirmed in breast cancer tissue specimens by using quantitative real‐time polymerase chain reaction. Further studies showed that induction of miR‐340 expression was able to suppress tumor cell migration and invasion, whereas knockdown of miR‐340 expression induced breast cancer cell migration and invasion. At the gene level, the authors identified c‐Met as a direct miR‐340 target to mediate cell migration and invasion through regulation of MMP‐2 and MMP‐9 expression. Ex vivo, loss of miR‐340 expression was associated with lymph node metastasis, high tumor histological grade, clinical stage, and shorter overall survival of breast cancer as well as increased c‐Met expression in breast cancer tissue specimens.

CONCLUSIONS:

miR‐340 may play an important role in breast cancer progression, suggesting that miR‐340 should be further evaluated as a novel biomarker for breast cancer metastasis and prognosis, and potentially a therapeutic target. Cancer 2011. © 2011 American Cancer Society.     

Transient receptor potential melastatin 7 is involved in oestrogen receptor-negative metastatic breast cancer cells migration through its kinase domain

Oestrogen receptor negative (ER^?) invasive ductal carcinoma (IDC) represents a significant clinical challenge and therefore prompts the discovery of novel biomarkers. Transient receptor potential melastatin 7 (TRPM7), a channel protein that also contains a regulatory kinase domain, is overexpressed in IDC and regulates migration. However, the molecular mechanism remains poorly defined. Here, we examined whether TRPM7 regulates migration by its channel function or by its kinase domain. A Magnesium Inhibited Cation current was recorded in two ER^? highly metastatic breast cancer cell lines. Down-regulation of TRPM7 neither affected Ca²⁺-, nor Mg²⁺-homoeostasis but significantly reduced cell migration via a Ca²⁺-independent pathway. Notably, the overexpression of the truncated kinase domain form of TRPM7 decreased cell migration, while the overexpression of the wild-type form strongly increased it. Concomitantly, TRPM7 silencing reduced the myosin IIA heavy chain phosphorylation. Furthermore, we found higher TRPM7 expression in ER^? IDC tissues and lymph nodes than in the non-invasive tumoural samples. In conclusion, TRPM7 plays a critical role in breast cancer cell migration through its kinase domain, and our data support the consideration of using TRPM7 as a novel biomarker and a potential therapeutic target in the treatment of human ER^? IDC.     

Malonyl-coenzyme-A is a potential mediator of cytotoxicity induced by fatty-acid synthase inhibition in human breast cancer cells and xenografts

A biologically aggressive subset of human breast cancers and other malignancies is characterized by elevated fatty-acid synthase (FAS) enzyme expression, elevated fatty acid (FA) synthesis, and selective sensitivity to pharmacological inhibition of FAS activity by cerulenin or the novel compound C75. In this study, inhibition of FA synthesis at the physiologically regulated step of carboxylation of acetyl-CoA to malonyl-CoA by 5-(tetradecyloxy)-2-furoic acid (TOFA) was not cytotoxic to breast cancer cells in clonogenic assays. FAS inhibitors induced a rapid increase in intracellular malonyl-CoA to several fold above control levels, whereas TOFA reduced intracellular malonyl-CoA by 60%. Simultaneous exposure of breast cancer cells to TOFA and an FAS inhibitor resulted in significantly reduced cytotoxicity and apoptosis. Subcutaneous xenografts of MCF7 breast cancer cells in nude mice treated with C75 showed FA synthesis inhibition, apoptosis, and inhibition of tumor growth to less than 1/8 of control volumes, without comparable toxicity in normal tissues. The data suggest that differences in intermediary metabolism render tumor cells susceptible to toxic fluxes in malonyl-CoA, both in vitro and in vivo.     

Therapeutic potential for phenytoin: targeting Nav1.5 sodium channels to reduce migration and invasion in metastatic breast cancer

Voltage-gated Na(+) channels (VGSCs) are heteromeric membrane protein complexes containing pore-forming α subunits and smaller, non-pore-forming β subunits. VGSCs are classically expressed in excitable cells, including neurons and muscle cells, where they mediate action potential firing, neurite outgrowth, pathfinding, and migration. VGSCs are also expressed in metastatic cells from a number of cancers. The Na(v)1.5 α subunit (encoded by SCN5A) is expressed in breast cancer (BCa) cell lines, where it enhances migration and invasion. We studied the expression of SCN5A in BCa array data, and tested the effect of the VGSC-blocking anticonvulsant phenytoin (5,5-diphenylhydantoin) on Na(+) current, migration, and invasion in BCa cells. SCN5A was up-regulated in BCa samples in several datasets, and was more highly expressed in samples from patients who had a recurrence, metastasis, or died within 5?years. SCN5A was also overexpressed as an outlier in a subset of samples, and associated with increased odds of developing metastasis. Phenytoin inhibited transient and persistent Na(+) current recorded from strongly metastatic MDA-MB-231 cells, and this effect was more potent at depolarized holding voltages. It may thus be an effective VGSC-blocking drug in cancer cells, which typically have depolarized membrane potentials. At a concentration within the therapeutic range used to treat epilepsy, phenytoin significantly inhibited the migration and invasion of MDA-MB-231 cells, but had no effect on weakly metastatic MCF-7 cells, which do not express Na(+) currents. We conclude that phenytoin suppresses Na(+) current in VGSC-expressing metastatic BCa cells, thus inhibiting VGSC-dependent migration and invasion. Together, our data support the hypothesis that SCN5A is up-regulated in BCa, favoring an invasive/metastatic phenotype. We therefore propose that repurposing existing VGSC-blocking therapeutic drugs should be further investigated as a potential new strategy to improve patient outcomes in metastatic BCa.     

Secreted CXCL1 is a potential mediator and marker of the tumor invasion of bladder cancer.

PURPOSE: The purpose of this study was to identify proteins that are potentially involved in the tumor invasion of bladder cancer. EXPERIMENTAL DESIGN: We searched for the candidate proteins by comparing the profiles of secreted proteins among the poorly invasive human bladder carcinoma cell line RT112 and the highly invasive cell line T24. The proteins isolated from cell culture supernatants were identified by shotgun proteomics. We found that CXCL1 is related to the tumor invasion of bladder cancer cells. We also evaluated whether the amount of the chemokine CXCL1 in the urine would be a potential marker for predicting the existence of invasive bladder tumors. RESULTS: Higher amount of CXCL1 was secreted from highly invasive bladder carcinoma cell lines and this chemokine modulated the invasive ability of those cells in vitro. It was revealed that CXCL1 regulated the expression of matrix metalloproteinase-13 in vitro and higher expression of CXCL1 was associated with higher pathologic stages in bladder cancer in vivo. We also showed that urinary CXCL1 levels were significantly higher in patients with invasive bladder cancer (pT1-4) than those with noninvasive pTa tumors (P = 0.0028) and normal control (P < 0.0001). Finally, it was shown that CXCL1 was an independent factor for predicting the bladder cancer with invasive phenotype. CONCLUSIONS: Our results suggest that CXCL1 modulates the invasive abilities of bladder cancer cells and this chemokine may be a potential candidate of urinary biomarker for invasive bladder cancer and a possible therapeutic target for preventing tumor invasion.     

MicroRNA-30a inhibits cell migration and invasion by downregulating vimentin expression and is a potential prognostic marker in breast cancer

Tumor recurrence and metastasis result in an unfavorable prognosis for cancer patients. Recent studies have suggested that specific microRNAs (miRNAs) may play important roles in the development of cancer cells. However, prognostic markers and the outcome prediction of the miRNA signature in breast cancer patients have not been comprehensively assessed. The aim of this study was to identify miRNA biomarkers relating to clinicopathological features and outcome of breast cancer. A miRNA microarray analysis was performed on breast tumors of different lymph node metastasis status and with different progression signatures, indicated by overexpression of cyclin D1 and β-catenin genes, to identify miRNAs showing a significant difference in expression. The functional interaction between the candidate miRNA, miR-30a, and the target gene, Vim, which codes for vimentin, a protein involved in epithelial-mesenchymal transition, was examined using the luciferase reporter assay, western blotting, and migration and invasion assays. The association between the decreased miR-30a levels and breast cancer progression was examined in a survival analysis. miR-30a negatively regulated vimentin expression by binding to the 3'-untranslated region of Vim. Overexpression of miR-30a suppressed the migration and invasiveness phenotypes of breast cancer cell lines. Moreover, reduced tumor expression of miR-30a in breast cancer patients was associated with an unfavorable outcome, including late tumor stage, lymph node metastasis, and worse progression (mortality and recurrence) (p < 0.05). In conclusion, these findings suggest a role for miR-30a in inhibiting breast tumor invasiveness and metastasis. The finding that miR-30a downmodulates vimentin expression might provide a therapeutic target for the treatment of breast cancer.     

TRPM7 mediates breast cancer cell migration and invasion through the MAPK pathway

Metastasis is an inherent feature of breast cancer and transient receptor potential (TRP) channels were found to be potentially implicated in this process. Particularly, TRPM7 may regulate cell motility. We therefore examined the expression of TRPM7 mRNA in the Oncomine database and found that TRPM7 is correlated to metastasis and invasive breast cancer. Silencing TRPM7 with RNA interference resulted in a significant decrease in migration and invasion capability of MDA-MB-435 breast cancer cells, and phosphorylation levels of Src and MAPK but not AKT. Our results suggest that TRPM7 regulates migration and invasion of metastatic breast cancer cells via MAPK pathway.     

Notch1 is involved in migration and invasion of human breast cancer cells

The Notch pathway displays several functions related to tumor progression. Breast carcinomas commonly express Notch1, Notch2, Notch3 and Notch4 at variable levels and these are mainly involved in differentiation, proliferation and survival. Notch1 can also induce the invasion of breast cancer cells. However, the precise role and mechanism of Notch1 in tumor invasion remains unclear. In?this report, we used small interference RNA technology to knock down the expression of Notch1, resulting in reduced migration and invasion of breast cancer cells. Meanwhile, F-actin polymerization, which is essential for cellular generation of the forces needed for motility, was also impaired in Notch1 knockdown cells. We further investigated the expression of extracellular matrix metalloproteinase inducer (EMMPRIN), matrix metalloproteases-2 (MMP-2) and MMP-9, and found that the expression of functional EMMPRIN and MMP-2 was significantly decreased in Notch1 knockdown cells, while the expression of MMP-9 was constant. Additionally, the silencing of?Notch1 expression likewise impaired cell-to-matrix and cell-to-cell adhesion. Western blotting results showed that reduction of Notch1 levels impacted the phosphorylation of PAK, phosphorylation of Akt, phosphorylation of FAK, the phosphorylation of integrin β1, ICAM-1 and β-catenin. Collectively, these findings suggest that targeting Notch1 has important therapeutic value in breast cancer.     

Nerve growth factor is a potential therapeutic target in breast cancer

We show here that nerve growth factor (NGF), the prototypic neurotrophin, can be targeted in breast cancer to inhibit tumor cell proliferation, survival, and metastasis. Analysis of a series of biopsies revealed widespread expression of NGF in the majority of human breast tumors, with anti-NGF immunoreactivity concentrated in the epithelial cancer cells. Moreover, immunodeficient mice xenografted with human breast cancer cells and treated with either anti-NGF antibodies or small interfering RNA against NGF displayed inhibited tumor growth and metastasis. Such treatments directed against NGF induced a decrease in cell proliferation with a concomitant increase in apoptosis of breast cancer cells and an inhibition of tumor angiogenesis. Together, these data indicate that targeting NGF in breast cancer may have therapeutic ramifications.     

Expression of a novel factor in human breast cancer cells with metastatic potential.

Clinical and experimental evidence suggests that tumor cells shed into the circulation from solid cancers are ineffective in forming distant metastasis unless the cells are able to respond to growth conditions offered by the secondary organs. To identify the phenotypic properties that are specific for such growth response, we injected carcinoma cells, which had been recovered from bone marrow micrometastases in a breast cancer patient who was clinically devoid of overt metastatic disease and established in culture, into the systemic circulation of immunodeficient rats. The animals developed metastases in the central nervous system, and metastatic tumor cells were isolated with immunomagnetic beads coated with an antibody that was reactive with human cells. The segregated cell population was compared with the injected cells by means of differential display analysis, and two candidate fragments were identified as up-regulated in the fully metastatic cells. The first was an intracellular effector molecule involved in tyrosine kinase signaling, known to mediate nerve growth factor-dependent promotion of cell survival. The second was a novel gene product (termed candidate of metastasis-1), presumably encoding a DNA-binding protein of helix-turn-helix type. Constitutive expression of candidate of metastasis-1 seemed to distinguish breast cancer cells with metastatic potential from cells without metastatic potential. Hence, our experimental approach identified factors that may mediate the growth response of tumor cells upon establishment in a secondary organ and, thereby, contribute to the metastatic phenotype.     

microRNA-140通过下调HDAC4抑制胃癌细胞迁移和侵袭能力

目的 探讨microRNA-140(miR-140)对胃癌细胞SGC-7901迁移及侵袭能力的影响及其调控机制.方法 将miR-140 mimics (miR-140)、miR-140特异性抑制剂(Anti-miR-140)和针对HDAC4的siRNA (HDAC4siRNA)分别通过脂质体转染至细胞,应用实时荧光定量(qRT-PCR)检测细胞中miR-140和HDAC4 mRNA表达情况,并采用蛋白质印迹法(WB)分析HDAC4蛋白水平.采用Transwell小室模型分析miR-140上调和下调以及HDAC4调低对SGC-7901细胞迁移和侵袭能力的影响.结果 miR-140转染可使HDAC4蛋白表达降低,HDAC4 mRNA水平则无明显变化.miR-140上调与HDAC4调低均可显著抑制SGC-7901细胞的迁移和侵袭能力,而在转染了Anti-miR-140的SGC-7901细胞中HDAC4蛋白表达增高,细胞迁移和侵袭能力增强.结论 miR-140在转录后水平调控HDAC4表达.miR-140抑制胃癌细胞迁移和侵袭能力,部分是通过下调HDAC4而实现.miR-140可能作为肿瘤转移诊断及治疗的新靶点.     

Protease-activated receptor-2 is essential for factor VIIa and Xa-induced signaling, migration, and invasion of breast cancer cells

Protease-activated receptors (PAR) are G protein-coupled receptors that function as cell-surface sensors for coagulant proteases, as well as other proteases associated with the tumor microenvironment. PAR1 is activated by thrombin whereas the upstream coagulant protease VIIa bound to tissue factor and Xa can activate both PAR1 and PAR2. PAR1 has been implicated in tumor cell growth, migration, and invasion whereas the function of PAR2 in these processes is largely unknown. Towards defining the functional importance of PAR2 in cancer cells, we used small interfering RNAs to deplete highly invasive breast cancer cells of endogenous PAR proteins. Our findings strongly suggest that PAR2 is critical for MDA-MB-231 and BT549 breast cancer cell migration and invasion towards NIH 3T3 fibroblast conditioned medium. To define the relative importance of PAR1 versus PAR2 in mediating factor VIIa and Xa responses, we assessed signaling in cancer cells lacking either endogenous PAR1 or PAR2 proteins. Strikingly, in MDA-MB-231 cells depleted of PAR2, we observed a marked inhibition of VIIa and Xa signaling to phosphoinositide hydrolysis and extracellular signal-regulated kinase 1/2 activation whereas signaling by VIIa and Xa remained intact in PAR1-deficient cells. Factor VIIa and Xa-induced cellular migration was also impaired in MDA-MB-231 cells deficient in PAR2 but not in cells lacking PAR1. Together, these studies reveal the novel findings that PAR2, a second protease-activated G protein-coupled receptor, has a critical role in breast cancer cell migration and invasion and functions as the endogenous receptor for coagulant proteases VIIa and Xa in these cells.     

MiR-339-5p inhibits breast cancer cell migration and invasion in vitro and may be a potential biomarker for breast cancer prognosis

Background  

MicroRNAs (miRNAs) play an important role in the regulation of cell growth, differentiation, apoptosis, and carcinogenesis. Detection of their expression may lead to identifying novel markers for breast cancer.     

Attenuation of junctional adhesion molecule-A is a contributing factor for breast cancer cell invasion

The metastatic potential of cancer cells is directly attributed to their ability to invade through the extracellular matrix. The mechanisms regulating this cellular invasiveness are poorly understood. Here, we show that junctional adhesion molecule A (JAM-A), a tight junction protein, is a key negative regulator of cell migration and invasion. JAM-A is robustly expressed in normal human mammary epithelium, and its expression is down-regulated in metastatic breast cancer tumors. In breast cancer cell lines, an inverse relationship between JAM-A expression and the ability of these cells to migrate on a collagen matrix was observed, which correlates with the known ability of these cells to metastasize. The T47D and MCF-7 cells, which migrate least, are found to express high levels of JAM-A, whereas the more migratory MDA-MB-468 cells have lower levels of JAM-A on the cell surface. MDA-MB-231 cells, which are highly migratory, express the least amount of JAM-A. Overexpression of JAM-A in MDA-MB-231 cells inhibited both migration and invasion through collagen gels. Furthermore, knockdown of JAM-A using short interfering RNAs enhanced the invasiveness of MDA-MB-231 cells as well as T47D cells. The ability of JAM-A to attenuate cell invasion correlated with the formation of increased numbers of focal adhesions and the formation of functional tight junctions. These results show for the first time that an immunoglobulin superfamily cell adhesion protein expressed at tight junctions could serve as a key negative regulator of breast cancer cell invasion and possibly metastasis. Furthermore, loss of JAM-A could be used as a biomarker for aggressive breast cancer.     

Autocrine/paracrine erythropoietin regulates migration and invasion potential and the stemness of human breast cancer cells

Recent studies suggest that erythropoietin (EPO) has pleiotropic effects in several cell types in addition to hematopoietic cells; however, the role of EPO-mediated cell signaling in nonhematopoietic cells, including in cancer cells, remains controversial. Here, we report our findings of autocrine/paracrine production of EPO by breast cancer cells and its functional significance. We detected a significant level of autocrine/paracrine EPO in the conditioned medium from the culture of SKBR3 breast cancer cells, particularly when the cells were cultured in hypoxia. Through knockdown of EPO and EPO receptor expression and experimental elevation of EPO receptor expression in SKBR3 breast cancer cells, we demonstrated novel roles of autocrine/paracrine EPO-mediated cell signaling in regulating migration and invasion potential and stemness-like properties of breast cancer cells.     

三阴性乳腺癌细胞源性外泌体活化的巨噬细胞促进乳腺癌细胞的迁移和侵袭

目的:研究三阴性乳腺癌（triple-negative breast cancer,TNBC）细胞来源的外泌体对巨噬细胞极化作用以及经外泌体活化的巨噬细胞对TNBC细胞迁移和侵袭能力的影响及作用机制。方法:提取TNBC细胞BT-549和MDA-MB-231外泌体,透射电镜、纳米颗粒跟踪分析（nanoparticle tracking analysis,NTA）、蛋白质印记(Western blot)鉴定外泌体;流式细胞术检测经外泌体处理后巨噬细胞分子标志物CD206、CD80的表达;实时荧光定量PCR检测单核细胞THP-1、巨噬细胞M0及外泌体处理后巨噬细胞中CD163、转化生长因子β(transforming growth factor β,TGF-β)、一氧化氮合酶(nitric oxide synthase,iNOS)、肿瘤坏死因子α(tumor necrosis factor α,TNF-α)的mRNA水平;Transwell实验分析外泌体活化的巨噬细胞对TNBC细胞迁移和侵袭的影响,Western blot方法检测MMP-2、MMP-9、N-cadherin、E-cadherin的蛋白水平。结果:透射电镜下BT-549和MDA-MB-231细胞的外泌体具有膜结构囊状小泡并表达外泌体的分子标记物CD81、CD63;BT-549细胞来源的外泌体直径分布为80~150 nm,MDA-MB-231细胞来源的外泌体直径分布为100~200 nm;经BT-549和MDA-MB-231细胞源性外泌体处理的巨噬细胞与M0相比,CD206均有稳定表达（P＜0.05),而CD80表达未见明显差异;外泌体处理后巨噬细胞的CD163、TGF-β mRNA表达水平均增加（P＜0.01),iNOS mRNA表达水平降低（P＜0.05),TNF-α mRNA表达水平未见明显变化;外泌体处理后的巨噬细胞使得TNBC细胞的迁移、侵袭穿膜数目增加(P＜0.01),N-cadherin、MMP-2和MMP-9蛋白表达增加（P＜0.05),E-cadherin 蛋白表达降低（P＜0.05)。结论:TNBC细胞分泌的外泌体可以诱导巨噬细胞向M2极化,进而促进TNBC细胞间质转化,增强TNBC细胞的迁移和侵袭能力。