Exogenous expression of N-cadherin in breast cancer cells induces cell migration, invasion, and metastasis

E- and N-cadherin are calcium-dependent cell adhesion molecules that mediate cell-cell adhesion and also modulate cell migration and tumor invasiveness. The loss of E-cadherin-mediated adhesion has been shown to play an important role in the transition of epithelial tumors from a benign to an invasive state. However, recent evidence indicates that another member of the cadherin family, N-cadherin, is expressed in highly invasive tumor cell lines that lacked E-cadherin expression. These findings have raised the possibility that N-cadherin contributes to the invasive phenotype. To determine whether N-cadherin promotes invasion and metastasis, we transfected a weakly metastatic and E-cadherin-expressing breast cancer cell line, MCF-7, with N-cadherin and analyzed the effects on cell migration, invasion, and metastasis. Transfected cells expressed both E- and N-cadherin and exhibited homotypic cell adhesion from both molecules. In vitro, N-cadherin-expressing cells migrated more efficiently, showed an increased invasion of Matrigel, and adhered more efficiently to monolayers of endothelial cells. All cells produced low levels of the matrix metalloproteinase MMP-9, which was dramatically upregulated by treatment with FGF-2 only in N-cadherin-expressing cells. Migration and invasion of Matrigel were also greatly enhanced by this treatment. When injected into the mammary fat pad of nude mice, N-cadherin-expressing cells, but not control MCF-7 cells, metastasized widely to the liver, pancreas, salivary gland, omentum, lung, lymph nodes, and lumbar spinal muscle. The expression of both E- and N-cadherin was maintained both in the primary tumors and metastatic lesions. These results demonstrate that N-cadherin promotes motility, invasion, and metastasis even in the presence of the normally suppressive E-cadherin. The increase in MMP-9 production by N-cadherin-expressing cells in response to a growth factor may endow them with a greater ability to penetrate matrix protein barriers, while the increase in their adherence to endothelium may improve their ability to enter and exit the vasculature, two properties that may be responsible for metastasis of N-cadherin-expressing cells.     

Antimetastatic activity of pinosylvin, a natural stilbenoid, is associated with the suppression of matrix metalloproteinases

Metastasis is a major cause of death in cancer patients. Our previous studies showed that pinosylvin, a naturally occurring trans-stilbenoid mainly found in Pinus species, exhibited a potential cancer chemopreventive activity and also inhibited the growth of various human cancer cell lines via the regulation of cell cycle progression. In this study, we further evaluated the potential antimetastatic activity of pinosylvin in in vitro and in vivo models. Pinosylvin suppressed the expression of matrix metalloproteinase (MMP)-2, MMP-9 and membrane type 1-MMP in cultured human fibrosarcoma HT1080 cells. We also found that pinosylvin inhibited the migration of HT1080 cells in colony dispersion and wound healing assay systems. In in vivo spontaneous pulmonary metastasis model employing intravenously injected CT26 mouse colon cancer cells in Balb/c mice, pinosylvin (10 mg/kg body weight, intraperitoneal administration) significantly inhibited the formation of tumor nodules and tumor weight in lung tissues. The analysis of tumor in lung tissues indicated that the antimetastatic effect of pinosylvin coincided with the down-regulation of MMP-9 and cyclooxygenase-2 expression, and phosphorylation of ERK1/2 and Akt. These data suggest that pinosylvin might be an effective inhibitor of tumor cell metastasis via modulation of MMPs.     

Curcumin inhibits lung cancer cell migration and invasion through Rac1-dependent signaling pathway

Curcumin, a natural and crystalline compound isolated from the plant Curcuma longa with low toxicity in normal cells, has been shown to protect against carcinogenesis and prevent tumor development. However, little is known about antimetastasis effects and mechanism of curcumin in lung cancer. Rac1 is an important small Rho GTPases family protein and has been widely implicated in cytoskeleton rearrangements and cancer cell migration, invasion and metastasis. In this study, we examined the influence of curcumin on in vitro invasiveness of human lung cancer cells and the expressions of Rac1. The results indicate that curcumin at 10 μM slightly reduced the proliferation of 801D lung cancer cells but showed an obvious inhibitory effect on epidermal growth factor or transforming growth factor β1-induced lung cancer cell migration and invasion. Meanwhile, we demonstrated that the suppression of invasiveness correlated with inhibition of Rac1/PAK1 signaling pathways and matrix metalloproteinase (MMP) 2 and 9 protein expression by combining curcumin treatment with the methods of Rac1 gene silence and overexpression in lung cancer cells. Laser confocal microscope also showed that Rac1-regulated actin cytoskeleton rearrangement may be involved in anti-invasion effect of curcumin on lung cancer cell. At last, through xenograft experiments, we confirmed the connection between Rac1 and the growth and metastasis inhibitory effect of curcumin in vivo. In summary, these data demonstrated that low-toxic levels of curcumin could efficiently inhibit migration and invasion of lung cancer cells through inhibition of Rac1/PAK1 signaling pathway and MMP-2 and MMP-9 expression, which provided a novel insight into the molecular mechanism of curcumin against lung cancer.     

Role of PTHrp and PTHrp-engaged pathways in MCF-7 cells migration/invasion.

In this paper the effect of N-terminal parathyroid hormone-related protein (PTHrp) and PTHrp-engaged pathways on MCF-7 breast cancer cell migration/invasivity and matrix metalloproteinases (MMPs) production were investigated. We found that: a) migration is not affected by PTHrp and Forskolin (FK)-activated PKA, while Phorbol Myristate Acetate (PMA)-activated PKC strongly stimulates MCF-7 cells motility. b) MMPs production was unaffected by PTHrp, but FK reduced membrane-type (MT)-1 MMP expression. Conversely, PMA induced a marked increase of MT1-MMP and MMP-9. c) Chemical activation of PKC is not sufficient, by itself, to confer invasive ability to MCF-7 cells, unless they were provided with additional factors, supplied by fibroblasts. d) Matrix invasion likely occurs through an activation cascade, involving at least three components: pro-MMP-9 and MT-1 MMP (supplied by PMA-stimulated MCF-7 cells) and pro MMP-2 (supplied by fibroblasts). e) The selective chemical inhibition of the adenylylciclase (AC)/PKA and phospholipase C (PLC)/PKC pathways confirmed that MCF-7 cells invasivity is not affected by exogenous PTHrp, which can only modulate their growth. However, the PTHrp responsibility in breast cancer invasion cannot be completely excluded. Indeed, fibroblasts are known to respond to PTHrp (which is a normal product of MCF-7 as well as other breast cancer cells) with enhanced release of MMP-2. On the basis of the documented requirement of fibroblast-derived MMP-2 for MCF-7 cell invasivity, a novel humoral fibroblast-breast cancer cell interaction, mediated by PTHrp, can be recognised.     

CXCR4 promotes oral squamous cell carcinoma migration and invasion through inducing expression of MMP-9 and MMP-13 via the ERK signaling pathway

The increased migration and invasion of oral squamous cell carcinoma cells are key events in the development of metastasis to the lymph nodes and distant organs. Although the chemokine receptor CXCR4 and its ligand, stromal cell-derived factor-1α, have been found to play an important role in tumor invasion, its precise role and potential underlying mechanisms remain largely unknown. In this study, we showed that knockdown of CXCR4 significantly decreased Tca8113 cells migration and invasion, accompanied with the reduction of MMP-9 and MMP-13 expression. Inhibition of ligand binding to CXCR4 by a specific antagonist TN14003, also led to reduced cancer cell migration and invasion. Because the degradation of the extracellular matrix and the basement membrane by proteases, such as matrix metalloproteinases (MMP) is critical for migration and invasion of cancer cells, we investigated the expression of several MMPs and found that the expression of functional MMP-9 and MMP-13 was selectively decreased in CXCR4 knockdown cells. More importantly, decreased cell migration and invasion of CXCR4 knockdown cells were completely rescued by exogenous expression of MMP-9 or MMP-13, indicating that the two MMPs are downstream targets of CXCR4-mediated signaling. Furthermore, we found the level of phosphorylated extracellular signal-regulated kinase (ERK) was significantly decreased in CXCR4-silenced cells, suggesting that ERK may be a potential mediator of CXCR4-regulated MMP-9 and MMP-13 expression in Tca8113 cells. Taken together, our results strongly suggest the underlying mechanism of CXCR4 promoting Tca8113 migration and invasion by regulating MMP-9 and MMP-13 expression perhaps via activation of the ERK signaling pathway.     

Glucose regulated protein 78 promotes cell invasion via regulation of uPA production and secretion in colon cancer cells

Glucose regulated protein 78 (GRP78) is frequently highly expressed in tumor cells, contributing to the acquisition of several phenotypic cancer hallmarks. GRP78 expression is also positively correlated with tumor metastasis, and promotes hepatocellular carcinoma cell invasion via increasing cell motility, however, other mechanisms involving the prometastatic roles of GRP78 remain to be elucidated. Here we report that forced GRP78 expression promotes colon cancer cell migration and invasion through upregulating MMP-2, MMP-9 and especially uPA production. These effects of GRP78 are mediated by enhancing the activation of β-catenin signaling. Interestingly, we identify that GRP78 interacts with uPA both in the cells and in the culture medium, suggesting that GRP78 protein is likely to directly facilitate uPA secretion via protein-protein interaction. Taken together, our findings demonstrate for the first time that besides stimulation of cell motility, GRP78 can act by increasing proteases production to promote tumor cell invasion. [BMB Reports 2014; 47(8): 445-450]     

The novel estrogen receptor GPER regulates the migration and invasion of ovarian cancer cells

G protein-coupled estrogen receptor (GPER) was identified as a new member of the estrogen receptor family in recent years. It has become apparent that GPER mediates the non-genomic signaling of 17β-estradiol (E₂) in a variety of estrogen-related cancers. Our previous study has found that GPER was overexpressed in human epithelial ovarian cancer and was positively correlated with the expression of matrix metalloproteinase 9 (MMP-9), which suggested GPER might promote the metastasis of ovarian cancer. However, the mechanisms underlying GPER-dependent metastasis of ovarian cancer are still not clear. In the present study, estrogen receptor α (ERα)-negative/GPER-positive OVCAR5 ovarian cancer cell line was used to investigate the role of GPER in the migration and invasion of ovarian cancer. Wound healing assay and transwell matrigel invasion assay were performed to determine the potentials of cell migration and invasion, respectively. The production and activity of MMP-9 in OVCAR5 cells were examined by Western blot and gelatin zymography analysis. The results showed that E₂ and selective GPER agonist G-1 increased cell motility and invasiveness, and upregulated the production and proteolytic activity of MMP-9 in OVCAR5 cells. Small interfering RNA (siRNA) targeting GPER and G protein inhibitor pertussin toxin (PTX) inhibited the migration and invasion of OVCAR5 cells, and also reduced the expression and activity of MMP-9. Our data suggested that GPER promoted the migration and invasion of ovarian cancer cells by increasing the expression and activity of MMP-9. GPER might play an important role in the progression of ovarian cancer.     

Homophilic interactions of Tetraspanin CD151 up-regulate motility and matrix metalloproteinase-9 expression of human melanoma cells through adhesion-dependent c-Jun activation signaling pathways

The tetraspanin membrane protein CD151 has been suggested to regulate cancer invasion and metastasis by initiating signaling events. The CD151-mediated signaling pathways involved in this regulation remain to be revealed. In this study, we found that stable transfection of CD151 into MelJuSo human melanoma cells lacking CD151 expression significantly increased cell motility, matrix metalloproteinase-9 (MMP-9) expression, and invasiveness. The enhancement of cell motility and MMP-9 expression by CD151 overexpression was abrogated by inhibitors and small interfering RNAs targeted to focal adhesion kinase (FAK), Src, p38 MAPK, and JNK, suggesting an essential role of these signaling components in CD151 signaling pathways. Also, CD151-induced MMP-9 expression was shown to be mediated by c-Jun binding to AP-1 sites in the MMP-9 gene promoter, indicating AP-1 activation by CD151 signaling pathways. Meanwhile, CD151 was found to be associated with alpha(3)beta(1) and alpha(6)beta(1) integrins in MelJuSo cells, and activation of associated integrins was a prerequisite for CD151-stimulated MMP-9 expression and activation of FAK, Src, p38 MAPK, JNK, and c-Jun. Furthermore, CD151 on one cell was shown to bind to neighboring cells expressing CD151, suggesting that CD151 is a homophilic interacting protein. The homophilic interactions of CD151 increased motility and MMP-9 expression of CD151-transfected MelJuSo cells, along with FAK-, Src-, p38 MAPK-, and JNK-mediated activation of c-Jun in an adhesion-dependent manner. Furthermore, C8161 melanoma cells with endogenous CD151 were also shown to respond to homophilic CD151 interactions for the induction of adhesion-dependent activation of FAK, Src, and c-Jun. These results suggest that homophilic interactions of CD151 stimulate integrin-dependent signaling to c-Jun through FAK-Src-MAPKs pathways in human melanoma cells, leading to enhanced cell motility and MMP-9 expression.     

Dioscin suppresses TGF-β1-induced epithelial-mesenchymal transition and suppresses A549 lung cancer migration and invasion

Epithelial-to-mesenchymal transition (EMT), an important cellular process, occurs during cancer development and progression, has a crucial role in metastasis by enhancing the motility of tumor cells. Dioscin is a polyphenolic component isolated from Phyllanthus amarus, which exhibits a wide range of pharmacological and physiological activities, such as anti-tumor, anti-inflammatory, anti-obesity, anti-fungal, and anti-viral activities. However, the possible role of dioscin in the EMT is unclear. We investigated the suppressive effect of dioscin on the EMT. Transforming growth factor-beta 1 (TGF-β1) is known to induce EMT in a number of cancer cell types and promote lung adenocarcinoma migration and invasion. To verify the inhibitory role of dioscin in lung cancer migration and invasion, we investigated the use of dioscin as inhibitors of TGF-β1-induced EMT in A549 lung cancer cells in vitro. Here, we found that dioscin prominently increased expression of the epithelial marker E-cadherin and expression of the mesenchymal marker N-cadherin and Snail during the TGF-β1-induced EMT. In addition, dioscin inhibited the TGF-β1-induced increase in cell migration and invasion of A549 lung cancer cells. Also, dioscin remarkably inhibited TGF-β1-regulated activation of MMP-2/9, Smad2, and p38. Taken together, our findings provide new evidence that dioscin suppresses lung cancer migration, and invasion in vitro by inhibiting the TGF-β1-induced EMT.     

Matrix metalloproteinases and tissue inhibitor of metalloproteinase-2 in fetal rabbit lung

Cell-extracellular matrix interaction and extracellular matrix remodeling are known to be important in fetal lung development. We investigated the localization of matrix metalloproteinases (MMPs) in fetal rabbit lungs. Immunohistochemistry for type IV collagen, MMP-1, MMP-2, MMP-9, membrane type (MT) 1 MMP, and tissue inhibitor of metalloproteinase (TIMP)-2 and in situ hybridization for MMP-9 mRNA were performed. Gelatin zymography and Western blotting for MT1-MMP in lung tissue homogenates were also studied. MMP-1 and MT1-MMP were detected in epithelial cells, and MMP-2 and TIMP-2 were detected in epithelial cells and some mesenchymal cells in each stage. MMP-9 was found in epithelial cells mainly in the late stage. Gelatin zymography revealed that the ratio of active MMP-2 to latent MMP-2 increased dramatically during the course of development. MT1-MMP was detected in tissue homogenates, especially predominant in the late stage. These findings suggest that MMPs and their inhibitors may contribute to the formation of airways and alveoli in fetal lung development and that activated MMP-2 of alveolar epithelial cells may function to provide an extremely wide alveolar surface.     

Helicobacter pylori induces gastric epithelial cell invasion in a c-Met and type IV secretion system-dependent manner

Helicobacter pylori interacts with gastric epithelial cells, activating signaling pathways important for carcinogenesis. In this study we examined the role of H. pylori on cell invasion and the molecular mechanisms underlying this process. The relevance of H. pylori cag pathogenicity island-encoded type IV secretion system (T4SS), CagA, and VacA for cell invasion was also investigated. We found that H. pylori induces AGS cell invasion in collagen type I and in Matrigel invasion assays. H. pylori-induced cell invasion requires the direct contact between bacteria and cancer cells. H. pylori-mediated cell invasion was dependent on the activation of the c-Met receptor and on increased MMP-2 and MMP-9 activity. The abrogation of the c-Met receptor using the specific NK4 inhibitor or the silencing of c-Met expression with small interference RNA suppressed both cell invasion and MMP activity. Studies with different H. pylori strains revealed that cell invasion, c-Met tyrosine phosphorylation, and increased MMP-2 and MMP-9 activity were all dependent on the presence of a functional bacterial T4SS, but not on VacA cytotoxicity. Our findings demonstrate that H. pylori strains with a functional T4SS stimulate gastric epithelial cell invasion through a c-Met-dependent signaling pathway that comprises an increase in MMP-2 and MMP-9 activity.     

Sodium hydrogen exchanger and phospholipase D are required for alpha1-adrenergic receptor stimulation of metalloproteinase-9 and cellular invasion in CCL39 fibroblasts

Matrix metalloproteinase 9 (MMP-9) plays a critical role in digesting the extracellular matrix and has a vital function in tumor metastasis and invasion; this protease activity is significantly increased in non-small cell lung cancers. The sodium hydrogen exchanger isoform 1 (NHE1) functions as a focal point for signal coordination and cytoskeletal reorganization. NHE1 is thought to play a central role in establishing signaling components at the leading edge of a migrating cell. Therefore, we studied the relationship between NHE1 and MMP-9 activity in Chinese hamster lung fibroblasts (CCL39) stimulated with phenylephrine (PE). We show that PE increases MMP-9 gelatinolytic activity in CCL39 cells. The inhibition of phospholipase D (PLD) signaling abrogated PE-induced MMP-9 activity. The role of PLD as an essential signaling intermediate was confirmed when the addition of permeable phosphatidic acid increased MMP-9 activity in the same cells. PE-induced invasion was increased 1.9-fold over controls and the PE response was lost when 1-butanol was used to block PLD signaling. Cells pre-treated with the NHE1 inhibitor, 5-(N-ethyl-N-isopropyl) amiloride (EIPA) prior to PE addition resulted in a notable decrease in MMP-9 activation and cell invasion as compared to untreated PE-stimulated cells. CCL39 NHE1 null cells demonstrated no increase in MMP-9 protease activity or cell invasion in response to PE treatment. Reconstitution of NHE1 expression recovered the PE-induced activation of protease activity and cell invasion. MMP-9 processing was altered in cells expressing a proton transport defective NHE1 but retained the ability to respond to PE. Conversely, cells expressing an ezrin, radixin, moesin (ERM)-binding deficient NHE1 had a lower MMP-9 activity and the protease did not respond to PE addition. Parallel studies on NCI-H358 non-small cell lung cancer (NSCL) cells showed that PE stimulated both MMP-9 activity and cell invasion in an NHE1 dependent manner. This work describes for the first time a PE-induced relationship between NHE1 and MMP-9 and a new potential mechanism by which NHE1 could promote tumor formation and metastasis.