ERK1/2 and p38 MAP kinase control MMP-2, MT1-MMP, and TIMP action and affect cell migration: a comparison between mesothelioma and mesothelial cells

Adult Mesenchymal Stem Cells and Derivatives in Improved Elastin Homeostasis in a Rat Model of Abdominal Aortic Aneurysms

Abdominal aortic aneurysms (AAAs) are localized rupture-prone expansions of the aorta with limited reversibility that develop due to proteolysis of the elastic matrix. Natural regenerative repair of an elastic matrix is difficult due to the intrinsically poor elastogenicity of adult vascular smooth muscle cells (VSMCs). This justifies the need to provide external, pro-elastin regenerative- and anti-proteolytic stimuli to VSMCs in the AAA wall towards reinstating matrix structure in the aorta wall. Introducing alternative phenotypes of highly elastogenic and contractile cells into the AAA wall capable of providing such cues, proffers attractive prospects for AAA treatment. In this regard, we have previously demonstrated the superior elastogenicity of bone marrow mesenchymal stem cell (BM-MSC)-derived SMCs (cBM-SMCs) and their ability to provide pro-elastogenic and anti-proteolytic stimuli to aneurysmal SMCs in vitro. However, the major issues associated with cell therapy, such as their natural ability to home into the AAA tissue, their in vivo biodistribution and retention in the AAA wall, and possible paracrine effects on AAA tissue repair processes in the event of localization in remote tissues remain uncertain. Therefore, in this study we focused on assessing the fate, safety, and AAA reparative effects of BM-MSC-derived cBM-SMCs in vivo. Our results indicate that the cBM-SMCs (a) possess natural homing abilities similar to the undifferentiated BM-MSCs, (b) exhibit higher retention upon localization in the aneurysmal aorta than BM-MSCs, (c) downregulate the expression of several inflammatory and pro-apoptotic cytokines that are upregulated in the AAA wall contributing to accelerated elastic matrix breakdown and suppression of elastic fiber neo-assembly, repair, and crosslinking, and (d) improve elastic matrix content and structure in the AAA wall toward slowing the growth of AAAs. Our study provides initial evidence of the in vivo elastic matrix reparative benefits of cBM-SMCs and their utility in cell therapy to reverse the pathophysiology of AAAs.

Matrix Metalloproteinases as Biomarkers and Treatment Targets in Mesothelioma: A Systematic Review

Metalloproteinases (MMPs) have an important role in tissue remodeling and have been shown to have an effect on tumor progression, invasion, metastasis formation, and apoptosis in several tumors, including mesothelioma. Mesothelioma is a rare tumor arising from pleura and peritoneum and is frequently associated with asbestos exposure. We have performed a systematic search of PubMed.gov and ClinicalTrials.gov databases to retrieve and review three groups of studies: studies of MMPs expression in tumor tissue or body fluids in patients with mesothelioma, studies of MMPs genetic variability, and studies of MMPs as potential novel drug targets in mesothelioma. Several studies of MMPs in mesothelioma tissues reported a link between higher expression levels of commonly studied MMPs and clinical parameters, such as overall survival. Fewer studies have investigated genetic variability of MMP genes. Nevertheless, these studies suggested that certain genetic variants in MMP genes can have either protective or tumor-promoting effects on mesothelioma patients. MMPs have been also reported as novel drug targets, but so far no clinical trials of MMP inhibitors are registered in mesothelioma. In conclusion, MMPs play an important role in mesothelioma, but further studies are needed to elucidate the potentials of MMPs as biomarkers and drug targets in mesothelioma.

Cell and extracellular matrix interaction models in benign mesothelial and malignant pleural mesothelioma cells in 2D and 3D in-vitro

Malignant pleural mesothelioma (MPM) is an aggressive tumour that grows in the pleural cavity. MPM spheroids released in the pleural fluid can form new tumour foci. Cell-cell, cell-extracellular matrix (ECM) interactions in 2D and 3D impact malignant cell behaviour during cell adhesion, migration, proliferation and epithelial-mesenchymal transition (EMT). In this study, epithelioid, biphasic and sarcomatoid MPM cell types as well as benign mesothelial cells were tested with regards to the above phenotypes. Fibronectin (FN) and homologous cell-derived extracellular matrix (hcd-ECM) treated substratum differentially affected the above phenotypes. 3D MPM spheroid invasion was higher in FN-collagen matrices in the epithelioid and biphasic cells, while 3D cell cultures of epithelioid and sarcomatoid MPM cells in FN-collagen showed a higher contractility compared to hcd-ECM-collagen. Cell aggregates demonstrated invasive behaviour in hcd-ECM matrices alone. Our results suggest that ECM and the dimensionality affect malignant cell behaviour during cell culture studies.

Bex1 significantly contributes to the proliferation and invasiveness of malignant tumor cells

Invasion has a significant role in cancer progression, including expansion to surrounding tissue and metastasis. Previously, we assessed the invasive ability of cancer cells using an easy-to-prepare double-layered collagen gel hemisphere (DL-CGH) method by which cancer cell invasion can be easily visualized. The present study examined multiple lung adenocarcinoma and malignant pleural mesothelioma (MPM) cell lines using the DL-CGH method and identified inherently invasive cell lines. Next, by comparing gene expression between invasive and non-invasive cells by cDNA microarray, the potential candidate gene brain-expressed x-linked protein 1 (Bex1) was identified to be involved in cancer invasion, as it was highly expressed in the invasive cell lines. Downregulation of Bex1 suppressed the invasion and proliferation of the invasive tumor cell lines. The findings of the present study suggested that Bex1 may promote metastasis in vivo and could be a potential oncogene and molecular therapeutic target in lung adenocarcinoma and MPM.

Long acting β2-agonist's activation of cyclic AMP cannot halt ongoing mitogenic stimulation in airway smooth muscle cells

Airway smooth muscle cell (ASMC) hyperplasia causes airway wall remodelling, which is resisting to therapy. Long acting β2-agonists (LABA) relax airway muscles, but their effect on remodelling is unclear. This study compared the anti-proliferative effect of LABA in human primary ASMC, in situations where LABA were applied before, together, or after platelet derived growth factor (PDGF-BB). Cells obtained from controls (n = 5), and asthma patients (n = 5) were stimulated by PDGF-BB (10 ng/ml) before or after the application of formoterol or salmeterol. Proliferation was determined by direct cell counts over three days, cell cycle control proteins p21^(Waf1/Cip1), p27^(Kip1), signalling proteins Erk1/2 and p38 mitogen activated protein kinase (MAPK) were detected by immuno-blotting. PDGF-BB induced proliferation was significantly stronger in asthmatic ASMC versus controls. Proliferation was prevented by 30 min pre-incubation with LABA. When LABA were applied together or after PDGF-BB, their anti-proliferative effect was no longer significant. In untreated ASMC, LABA increased the expression of p21^(Waf1/Cip1) and p27^(Kip1) through cAMP, and this mechanism was abolished by the presence of PDGF-BB. The data show that the anti-proliferative effect of cAMP signalling cannot overcome the mitogenic signalling cascade once it was activated. Therefore, remodelling in asthma cannot be reduced by LABA.

Cortex Dictamni extracts inhibit over-proliferation and migration of rat airway smooth muscle cells via FAK/p38/Bcl-2 signaling pathway

Airway smooth muscle (ASM) is a prominent effecter in maintaining bronchial muscle contraction and responsible for airway hyper-responsiveness (AHR); the phenotype change and over-proliferation of airway smooth muscle cells (ASMCs) play key roles in the pathogenesis of asthma. The aim of this study was to investigate the anti-proliferation effects of Cortex Dictamni aqueous extract (CDAE) and ethanol extract (CDE) on ASMCs and the possible underline mechanisms. Cell proliferation rates were determined by MTT assay; matrix metalloproteinases-2 (MMP-2) activity was examined by gelatin zymography; cell proliferation and migration were appraised by in-vitro cell-gap closure assessment; protein expressions of p38, Bcl-2 and FAK of ASMCs were evaluated by western blotting and Ca²⁺ influx of cells was measured by confocal laser microscope. Our data demonstrated that the proliferation, migration and MMP-2 expressions of ASMCs were inhibited by CDAE or CDE; the protein expressions of p38, Bcl-2 and FAK in ASMCs were substantially reduced by CDAE and CDE detected by western blotting or immunocytochemistry; also the increased calcium influx has been observed instantaneously after ASMCs were stimulated by CDAE or CDE. These findings suggested that Cortex Dictamni extracts might have inhibitory effects on ASMCs over-proliferation which could be one of the underline mechanisms for the therapy of asthma.

Open-angle glaucoma: therapeutically targeting the extracellular matrix of the conventional outflow pathway

INTRODUCTION

Ocular hypertension in open-angle glaucoma is caused by a reduced rate of removal of aqueous humour (AH) from the eye, with the majority of AH draining from the anterior chamber through the conventional outflow pathway, comprising the trabecular meshwork (TM) and Schlemm's Canal. Resistance to outflow is generated, in part, by the extracellular matrix (ECM) of the outflow tissues. Current pressure-lowering topical medications largely suppress AH production, or enhance its clearance through the unconventional pathway. However, therapies targeting the ECM of the conventional pathway in order to decrease intraocular pressure have become a recent focus of attention. Areas covered: We discuss the role of ECM of the TM in outflow homeostasis and its relevance as a target for glaucoma therapy, including progress in development of topical eye formulations, together with gene therapy approaches based on inducible, virally-mediated expression of matrix metalloproteinases to enhance aqueous outflow. Expert opinion: There remains a need for improved glaucoma medications that more specifically act upon sites causative to glaucoma pathogenesis. Emerging strategies targeting the ECM of the conventional outflow pathway, or associated components of the cytoskeleton of TM cells, involving new pharmacological formulations or genetically-based therapies, are promising avenues of future glaucoma treatment.

Transforming growth factor-β, matrix metalloproteinases, and urokinase-type plasminogen activator interaction in the cancer epithelial to mesenchymal transition

Transforming growth factor-β (TGF-β) is a pleiotropic factor that acts as a tumor suppressor in the early stages, while it exerts tumor promoting activities in advanced stages of cancer development. One of the hallmarks of cancer progression is the capacity of cancer cells to migrate and invade surrounding tissues with subsequent metastasis to different organs. Matrix metalloproteinases (MMPs) together with urokinase-type plasminogen activator (uPA) and its receptor (uPAR), whose main original function described is the proteolytic degradation of the extracellular matrix, play key cellular roles in the enhancement of cell malignancy during cancer progression. TGF-β tightly regulates the expression of several MMPs and uPA/uPAR in cancer cells, which in return can participate in TGF-β activation, thus contributing to tumor malignancy. TGF-β is one of the master factors in the induction of cancer-associated epithelial to mesenchymal transition (EMT), and recently both MMPs and uPA/uPAR have also been shown to be implicated in the cancer-associated EMT process. In this review, we analyze the main molecular mechanisms underlying MMPs and uPA/uPAR regulation by TGF-β, as well as their mutual implication in the development of EMT in cancer cells. Developmental Dynamics 247:382-395, 2018. © 2017 Wiley Periodicals, Inc.

Baicalein inhibits pancreatic cancer cell proliferation and invasion via suppression of NEDD9 expression and its downstream Akt and ERK signaling pathways

Baicalein, a flavone ingredient of Scutellaria baicalensis Georgi, is a promising anti-cancer agent. However, its potential anti-pancreatic cancer effects and the underlying mechanisms are still unclear. In this study, we showed that Baicalein not only induced apoptosis, but also suppressed proliferation, migration and invasion of two pancreatic cancer cell lines BxPC-3 and PANC-1 in a dose- and time-dependent manner. Notably, Baicalein exhibited low toxicity to normal human liver or kidney cells. We further discovered that Baicalein suppressed BxPC-3 and PANC-1 cell proliferation and invasion through targeting the expression of NEDD9, a Cas scaffolding protein, to decrease Akt and ERK activities. Especially, Baicalein decreased Akt phosphorylation at T-308 via lowering NEDD9-dependent PDK1 expression. Overexpression of NEDD9 effectively rescued proliferation and invasion of BxPC-3 and PANC-1 cells dampened by Baicalein. Taken together, our findings suggest that Baicalein is a potent remedy applied to pancreatic cancer treatment in the future.

Polarized Secretion of Matrix Metalloproteinases and Their Inhibitors by Retinal Pigment Epithelium Derived from Induced Pluripotent Stem Cells During Wound Healing

PURPOSE

To characterize the secretion of matrix metalloproteinases (MMPs) and tissue inhibitors of matrix metalloproteinases (TIMPs) by induced pluripotent stem cell-derived retinal pigment epithelium (iPS-RPE) during wound healing. We hypothesize that iPS-RPE secretes mediators of tissue remodeling such as MMPs and TIMPs to promote migration and proliferation of cells during wound healing.

METHODS

iPS-RPE was grown on transwells until fully confluent and pigmented. The monolayers were scratched to induce a wound. Conditioned media were collected from the apical and basolateral sides of the transwells every 72 h for 12 days. The media were analyzed by multiplex ELISA assays to detect secreted MMPs and TIMPs. Activity assays were performed to detect the active form of MMP-2 in conditioned media.

RESULTS

MMP-2 and TIMP-1, -2, -3, and -4 were detected in conditioned media from iPS-RPE. The proteins were found to be secreted in a polarized manner. The apical secretion and activation of MMP-2 was elevated from days 3 to 12 after wounding. TIMP-1, -2, -3, and -4 were detected in conditioned media from both the apical and basolateral sides of wounded cells. Apical secretion of all 4 TIMPs increased within 3 days after wounding.

CONCLUSIONS

These results indicate that iPS-RPE secretes MMP-2 and all 4 TIMPs in a polarized manner. After wounding, apical secretion of MMP-2 was higher compared to control. Apical secretion of all 4 TIMPs increased compared to control, while only TIMP-1 showed increased basolateral secretion compared to control.

Inhibition of HeLa cells metastasis by bioactive compounds in crocodile (Crocodylus siamensis) white blood cells extract

Matrix metalloproteinases (MMPs) play a key role in cancer progression, including cell invasion, metastasis, cell growth, apoptosis, angiogenesis, and cell adhesion. Thus, suppression of the MMPs activities is crucial for inhibiting cancer cells metastasis. Herein, bioactive agents from crocodile (Crocodylus siamensis) leukocyte extracts (WBCex) showed the anticancer activity with HeLa cells and inhibited the migration and invasion process by reducing gelatinases (MMP-2, MMP-9) activity and their protein levels. This mechanism is regulated via interfering Ras and p38 signal transduction. Moreover, disrupting VEGF and integrin-signaling cascade by bioactive agents are the predictable mechanisms that cause the decreasing of MMP-2 and MMP-9 activity. Hence, bioactive substances in WBCex may play the mode of action similar with MMPs inhibitor due to HeLa cell metastasis being suppressed in vitro. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1329-1336, 2016.

Biomass Smoke Exposure Enhances Rhinovirus-Induced Inflammation in Primary Lung Fibroblasts

Biomass smoke is one of the major air pollutants and contributors of household air pollution worldwide. More than 3 billion people use biomass fuels for cooking and heating, while other sources of exposure are from the occurrence of bushfires and occupational conditions. Persistent biomass smoke exposure has been associated with acute lower respiratory infection (ALRI) as a major environmental risk factor. Children under the age of five years are the most susceptible in developing severe ALRI, which accounts for 940,000 deaths globally. Around 90% of cases are attributed to viral infections, such as influenza, adenovirus, and rhinovirus. Although several epidemiological studies have generated substantial evidence of the association of biomass smoke and respiratory infections, the underlying mechanism is still unknown. Using an in vitro model, primary human lung fibroblasts were stimulated with biomass smoke extract (BME), specifically investigating hardwood and softwood types, and human rhinovirus-16 for 24 h. Production of pro-inflammatory mediators, such as IL-6 and IL-8, were measured via ELISA. Firstly, we found that hardwood and softwood smoke extract (1%) up-regulate IL-6 and IL-8 release (p ≤ 0.05). In addition, human rhinovirus-16 further increased biomass smoke-induced IL-8 in fibroblasts, in comparison to the two stimulatory agents alone. We also investigated the effect of biomass smoke on viral susceptibility by measuring viral load, and found no significant changes between BME exposed and non-exposed infected fibroblasts. Activated signaling pathways for IL-6 and IL-8 production by BME stimulation were examined using signaling pathway inhibitors. p38 MAPK inhibitor SB239063 significantly attenuated IL-6 and IL-8 release the most (p ≤ 0.05). This study demonstrated that biomass smoke can modulate rhinovirus-induced inflammation during infection, which can alter the severity of the disease. The mechanism by which biomass smoke exposure increases inflammation in the lungs can be targeted and inhibited via p38 MAP kinase pathway.

Inhibition of Macrophage Migration Inhibitory Factor Protects against Inflammation and Matrix Deposition in Kidney Tissues after Injury

Background. Macrophage migration inhibitory factor (MIF) is an important immunoregulatory cytokine involved in inflammation, which may be one important reason resulting in matrix deposition in renal tissues after injury. However, the underlying mechanisms have not yet been elucidated. Methods and Results. We uncovered a crucial role of MIF in inflammation and collagen deposition in vivo and in vitro. In rats, ureteral obstruction induced tubular injury, matrix accumulation, and inflammatory cell infiltration. Additionally, enhanced MIF levels in the obstructed kidneys were closely related to the increasing numbers of CD68-positive macrophages. These obstruction-induced injuries can be relieved by recanalization, consequently resulting in downregulated expression of MIF and its receptor CD74. Similarly, ischemia reperfusion induced renal injury, and it was accompanied by elevated MIF levels and macrophages infiltration. In cultured tubular epithelial cells (TECs), aristolochic acid (AA) promoted matrix production and increased MIF expression, as well as the release of macrophage-related factors. Inhibition of MIF with an antagonist ISO-1 resulted in the abolishment of these genotypes in AA-treated TECs. Conclusion. MIF plays an important role in macrophage-related inflammation and matrix deposition in kidney tissues following injury. MIF as a specific inhibitor may have therapeutic potential for patients with inflammatory and fibrotic kidney diseases.

Epigenetic down-regulation of integrin α7 increases migratory potential and confers poor prognosis in malignant pleural mesothelioma

Malignant pleural mesothelioma (MPM) is a devastating malignancy characterized by invasive growth and rapid recurrence. The identification and inhibition of molecular components leading to this migratory and invasive phenotype are thus essential. Accordingly, a genome-wide expression array analysis was performed on MPM cell lines and a set of 139 genes was identified as differentially expressed in cells with high versus low migratory activity. Reduced expression of the novel tumour suppressor integrin α7 (ITGA7) was found in highly motile cells. A significant negative correlation was observed between ITGA7 transcript levels and average displacement of cells. Forced overexpression of ITGA7 in MPM cells with low endogenous ITGA7 expression inhibited cell motility, providing direct evidence for the regulatory role of ITGA7 in MPM cell migration. MPM cells showed decreased ITGA7 expressions at both transcription and protein levels when compared to non-malignant mesothelial cells. The majority of MPM cell cultures displayed hypermethylation of the ITGA7 promoter when compared to mesothelial cultures. A statistically significant negative correlation between ITGA7 methylation and ITGA7 expression was also observed in MPM cells. While normal human pleura samples unambiguously expressed ITGA7, a varying level of expression was found in a panel of 200 human MPM samples. In multivariate analysis, ITGA7 expression was found to be an independent prognostic factor. Although there was no correlation between histological subtypes and ITGA7 expression, importantly, patients with high tumour cell ITGA7 expression had an increased median overall survival compared to the low- or no-expression groups (463 versus 278 days). In conclusion, our data suggest that ITGA7 is an epigenetically regulated tumour suppressor gene and a prognostic factor in human MPM.

Protective effects of intestinal trefoil factor (ITF) on gastric mucosal epithelium through activation of extracellular signal-regulated kinase 1/2 (ERK1/2)

The rapid repair of gastric mucosa is critical upon exposure to injurious agents. Intestinal trefoil factor (ITF) is a member of the trefoil factor family domain peptides, which play an important role in the cytoprotection of gastric epithelium. However, the underlying molecular mechanisms that are responsible for ITF-induced gastric epithelial repair remain unclear. In the present study, we demonstrate that ITF enhances the proliferation and migration of GES-1 gastric endothelial cells in a dose- and time-dependent manner through the activation of extracellular signal-regulated kinase 1/2 (ERK1/2). Furthermore, the ITF-mediated protection of GES-1 cells from a NS398 (nonsteroidal anti-inflammatory drug) was dependent on the ERK1/2 signaling pathway. Taken together, the results provide a mechanistic explanation for ITF-mediated protection of gastric epithelial mucosa cells, suggesting that activation of the ERK1/2 signaling pathway may provide a new therapeutic strategy for repairing gastric injury.

CIAPIN1 targets Na⁺/H⁺ exchanger 1 to mediate MDA-MB-231 cells' metastasis through regulation of MMPs via ERK1/2 signaling pathway

Cytokine-induced antiapoptotic inhibitor 1 (CIAPIN1) was recently identified as an essential downstream effector of the Ras signaling pathway and has been confirmed to be closely associated with various malignant tumors. However, its potential role in regulating breast cancer metastasis remains unclear. Matrix metalloproteinases (MMPs) are a broad family of zinc-biding endopeptidases that participate in the extracellular matrix (ECM) degradation that accompanies cancer cell invasion, metastasis and angiogenesis. In this study, we found up-regulation of CIAPIN1 by lentiviral expression vector inhibited the migration, invasion and MMPs expression of MDA-MB-231 cells. Further, CIAPIN1 over-expression decreased NHE1 (Na(+)/H(+) exchanger 1) expression and ERK1/2 phosphorylation. Importantly, treating CIAPIN1 over-expressed MDA-MB-231 cells with the NHE1 specific inhibitor, Cariporide, further inhibited the metastatic capacity, MMPs expression and phosphorylated ERK1/2. Treatment with the MEK1 specific inhibitor, PD98059, induced nearly the same suppression of CIAPIN1 over-expression-dependent migration, invasion and MMPs expression as was observed with Cariporide. Further, Cariporide and PD98059 synergistically suppressed migration, invasion and MMPs expression of CIAPIN1 over-expressed MDA-MB-231 cells. Thus, our results revealed the mechanism by which CIAPIN1 targeted NHE1 to mediate migration and invasion of MDA-MB-231 cells through regulation of MMPs via ERK1/2 signaling pathway.

Rac1/Pak1/p38/MMP-2 Axis Regulates Angiogenesis in Ovarian Cancer

PURPOSE

Zoledronic acid is being increasingly recognized for its antitumor properties, but the underlying functions are not well understood. In this study, we hypothesized that zoledronic acid inhibits ovarian cancer angiogenesis preventing Rac1 activation.

EXPERIMENTAL DESIGN

The biologic effects of zoledronic acid were examined using a series of in vitro [cell invasion, cytokine production, Rac1 activation, reverse-phase protein array, and in vivo (orthotopic mouse models)] experiments.

RESULTS

There was significant inhibition of ovarian cancer (HeyA8-MDR and OVCAR-5) cell invasion as well as reduced production of proangiogenic cytokines in response to zoledronic acid treatment. Furthermore, zoledronic acid inactivated Rac1 and decreased the levels of Pak1/p38/matrix metalloproteinase-2 in ovarian cancer cells. In vivo, zoledronic acid reduced tumor growth, angiogenesis, and cell proliferation and inactivated Rac1 in both HeyA8-MDR and OVCAR-5 models. These in vivo antitumor effects were enhanced in both models when zoledronic acid was combined with nab-paclitaxel.

CONCLUSIONS

Zoledronic acid has robust antitumor and antiangiogenic activity and merits further clinical development as ovarian cancer treatment.

Anti-fibrotic effects of nintedanib in lung fibroblasts derived from patients with idiopathic pulmonary fibrosis

BACKGROUND

Idiopathic pulmonary fibrosis (IPF) is a progressive lung disease with poor prognosis. The kinase inhibitor nintedanib specific for vascular endothelial growth factor receptor (VEGFR), platelet-derived growth factor receptor (PDGFR) and fibroblast growth factor receptor (FGFR) significantly reduced the rate of decline of forced vital capacity versus placebo.

AIM

To determine the in vitro effect of nintedanib on primary human lung fibroblasts.

METHODS

Fibroblasts were isolated from lungs of IPF patients and from non-fibrotic controls. We assessed the effect of VEGF, PDGF-BB and basic FGF (bFGF) ± nintedanib on: (i) expression/activation of VEGFR, PDGFR, and FGFR, (ii) cell proliferation, secretion of (iii) matrix metalloproteinases (MMP), (iv) tissue inhibitor of metalloproteinase (TIMP), and (v) collagen.

RESULTS

IPF fibroblasts expressed higher levels of PDGFR and FGFR than controls. PDGF-BB, bFGF, and VEGF caused a pro-proliferative effect which was prevented by nintedanib. Nintedanib enhanced the expression of pro-MMP-2, and inhibited the expression of TIMP-2. Transforming growth factor-beta-induced secretion of collagens was inhibited by nintedanib.

CONCLUSION

Our data demonstrate a significant anti-fibrotic effect of nintedanib in IPF fibroblasts. This effect consists of the drug's anti-proliferative capacity, and on its effect on the extracellular matrix, the degradation of which seems to be enhanced.

Platelets and cancer: a casual or causal relationship: revisited

Human platelets arise as subcellular fragments of megakaryocytes in bone marrow. The physiologic demand, presence of disease such as cancer, or drug effects can regulate the production circulating platelets. Platelet biology is essential to hemostasis, vascular integrity, angiogenesis, inflammation, innate immunity, wound healing, and cancer biology. The most critical biological platelet response is serving as "First Responders" during the wounding process. The exposure of extracellular matrix proteins and intracellular components occurs after wounding. Numerous platelet receptors recognize matrix proteins that trigger platelet activation, adhesion, aggregation, and stabilization. Once activated, platelets change shape and degranulate to release growth factors and bioactive lipids into the blood stream. This cyclic process recruits and aggregates platelets along with thrombogenesis. This process facilitates wound closure or can recognize circulating pathologic bodies. Cancer cell entry into the blood stream triggers platelet-mediated recognition and is amplified by cell surface receptors, cellular products, extracellular factors, and immune cells. In some cases, these interactions suppress immune recognition and elimination of cancer cells or promote arrest at the endothelium, or entrapment in the microvasculature, and survival. This supports survival and spread of cancer cells and the establishment of secondary lesions to serve as important targets for prevention and therapy.

Membrane localization of membrane type 1 matrix metalloproteinase by CD44 regulates the activation of pro-matrix metalloproteinase 9 in osteoclasts

CD44, MT1-MMP, and MMP9 are implicated in the migration of osteoclast and bone resorption. This study was designed to determine the functional relationship between CD44 and MT1-MMP in the activation of pro-MMP9. We used osteoclasts isolated from wild-type and CD44-null mice. Results showed that MT1-MMP is present in multiple forms with a molecular mass ~63, 55, and 45 kDa in the membrane of wild-type osteoclasts. CD44-null osteoclasts demonstrated a 55 kDa active MT1-MMP form in the membrane and conditioned medium. It failed to activate pro-MMP9 because TIMP2 binds and inhibits this MT1-MMP (~55 kDa) in CD44-null osteoclasts. The role of MT1-MMP in the activation of pro-MMP9, CD44 expression, and migration was confirmed by knockdown of MT1-MMP in wild-type osteoclasts. Although knockdown of MMP9 suppressed osteoclast migration, it had no effects on MT1-MMP activity or CD44 expression. These results suggest that CD44 and MT1-MMP are directly or indirectly involved in the regulation of pro-MMP9 activation. Surface expression of CD44, membrane localization of MT1-MMP, and activation of pro-MMP9 are the necessary sequence of events in osteoclast migration.

RNA interference-mediated silencing of VEGF and bFGF suppresses endostatin secretion in pancreatic carcinoma cells

Pro-angiogenic factors [vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF)] and anti-angiogenic factors (endostatin) play important roles in the progression of pancreatic cancer. The purpose of the present study was to investigate the knockdown effect by either VEGF or bFGF siRNA on the expression and secretion of endostatin in pancreatic carcinoma cells. Pancreatic carcinoma cell lines (sw1990, Panc-1 and PCT-3) were treated with VEGF and bFGF siRNA. The expression of VEGF, bFGF and endostatin in pancreatic carcinoma cell lines was determined by reverse transcription-polymerase chain reaction (RT-PCR) and western blot analysis. Secretion of endostatin was measured by enzyme-linked immunosorbent assay (ELISA). bFGF and VEGF siRNA significantly reduced the expression of bFGF and VEGF mRNA, respectively, but did not affect mRNA and protein expression of endostatin in pancreatic carcinoma cell lines. However, secretion of endostatin in PCT-3, Panc-1 and sw1990 cells was significantly inhibited by bFGF and VEGF siRNA. This study demonstrated that pro-angiogenic factors (VEGF and bFGF) differentially modulate expression and secretion of anti-angiogenic factors (endostatin). This result may have important implications in the anti-angiogenesis therapy in pancreatic cancer.

Caffeic Acid phenethyl ester inhibits oral cancer cell metastasis by regulating matrix metalloproteinase-2 and the mitogen-activated protein kinase pathway

Caffeic acid phenethyl ester (CAPE), an active component extracted from honeybee hives, exhibits anti-inflammatory and anticancer activities. However, the molecular mechanism by which CAPE affects oral cancer cell metastasis has yet to be elucidated. In this study, we investigated the potential mechanisms underlying the effects of CAPE on the invasive ability of SCC-9 oral cancer cells. Results showed that CAPE attenuated SCC-9 cell migration and invasion at noncytotoxic concentrations (0 μM to 40 μM). Western blot and gelatin zymography analysis findings further indicated that CAPE downregulated matrix metalloproteinase-2 (MMP-2) protein expression and inhibited its enzymatic activity. CAPE exerted its inhibitory effects on MMP-2 expression and activity by upregulating tissue inhibitor of metalloproteinase-2 (TIMP-2) and potently decreased migration by reducing focal adhesion kinase (FAK) phosphorylation and the activation of its downstream signaling molecules p38/MAPK and JNK. These data indicate that CAPE could potentially be used as a chemoagent to prevent oral cancer metastasis.

Aquaporin 3 expression is up-regulated by TGF-β1 in rat peritoneal mesothelial cells and plays a role in wound healing

Aquaporin 3 (AQP3) is expressed in many tissues including the peritoneum and kidney. In cultured mesothelial cells, glucose up-regulates AQP3, which may be important for water transport through the peritoneal membrane. However, there has been no research into the role of AQP3 in human peritoneal mesothelial cell (HPMC) migration or peritoneal fibrosis. We investigated the effects of transforming growth factor-β1 (TGF-β1) on AQP3 expression in HPMCs. We also investigated the role of AQP3 in the peritoneal wound healing process in rats. Chronic exposure to glucose-containing solution increased peritoneal myofibroblasts, with TGF-β1 and AQP3 expression in a model of long-term peritoneal dialysis. In vitro, TGF-β1 induced AQP3 expression in HPMCs. AQP3 knockdown by small-interfering RNA inhibited TGF-β1-induced AQP3 and α-smooth muscle actin expression and also slowed HPMC migration. AQP3 overexpression induced faster migration of HPMCs. Treatment with an extracellular signal-regulated kinase inhibitor and p38 kinase inhibitor attenuated TGF-β1-induced AQP3 expression in HPMCs. These data suggest that TGF-β1 induces AQP3 and that AQP3 has a critical role in TGF-β-induced HPMC migration. These findings provide evidence of a novel role for AQP3 in peritoneal fibrosis and wound healing. The effect of TGF-β1 on AQP3 expression in HPMCs is mediated, at least in part, by ERK and p38 signaling.

p38α MAPK mediates 17β-estradiol inhibition of MMP-2 and -9 expression and cell migration in human lovo colon cancer cells

Epidemiological studies demonstrate that the incidence and mortality rates of colorectal cancer in women are lower than in men. However, it is unknown if 17β-estradiol (E(2)) treatment is sufficient to inhibit cell proliferation and cell migration in human colon cancer cells. Up-regulation of urokinase plasminogen activator (uPA), tissue plasminogen activator (tPA), and matrix metallopeptidases (MMPs) is reported to associate with the development of cancer cell mobility, metastasis, and subsequent malignant tumor. In the present study, we treated human LoVo colon cancer cells with E(2) to explore whether E(2) down-regulates cell proliferation and migration, and to identify the precise molecular and cellular mechanisms behind the down-regulatory responses. Here, we found that E(2) treatment decreased cell proliferation and cell cycle-regulating factors such as cyclin A, cyclin D1 and cyclin E. At the same time, E(2) significantly inhibited cell migration and migration-related factors such as uPA, tPA, MMP-2, and MMP-9. However, E(2) treatment showed no effects on upregulating expression of plasminogen activator inhibitor-1 (PAI-1), tissue inhibitor of metalloproteinase-1, -2, -3, and -4 (TIMP-1, -2, -3, and -4). After administration of inhibitors including QNZ (NFκB inhibitor), LY294002 (Akt activation inhibitor), U0126 (ERK1/2 inhibitor), SB203580 (p38 MAPK inhibitor) or SP600125 (JNK1/2 inhibitor), E(2) -downregulated cell migration and expression of MMP-2 and MMP-9 in LoVo cells is markedly inhibited only by p38 MAPK inhibitors, SB203580. Application of specific target gene siRNA (ERα, ERβ, p38α, and p38β) to LoVo cells further confirmed that p38 MAPK mediates E(2) /ERs inhibition of MMP-2 and -9 expression and cell motility in LoVo cells. Collectively, these results suggest that E(2) treatment down-regulates cell proliferation by modulating the expression of cyclin A, cyclin D1 and cyclin E. E(2) treatment simultaneously impaired cell migration by inhibiting the expression of uPA, tPA, MMP-2, and MMP-9 through E(2) /ERs - p38α MAPK signaling pathway in human LoVo colon cancer cells.

Changes in global gene expression associated with 3D structure of tumors: an ex vivo matrix-free mesothelioma spheroid model

Tumor microenvironments present significant barriers to anti-tumor agents. Molecules involved in multicellular tumor microenvironments, however, are difficult to study ex vivo. Here, we generated a matrix-free tumor spheroid model using the NCI-H226 mesothelioma cell line and compared the gene expression profiles of spheroids and monolayers using microarray analysis. Microarray analysis revealed that 142 probe sets were differentially expressed between tumor spheroids and monolayers. Gene ontology analysis revealed that upregulated genes were primarily related to immune response, wound response, lymphocyte stimulation and response to cytokine stimulation, whereas downregulated genes were primarily associated with apoptosis. Among the 142 genes, 27 are located in the membrane and related to biologic processes of cellular movement, cell-to-cell signaling, cellular growth and proliferation and morphology. Western blot analysis validated elevation of MMP2, BAFF/BLyS/TNFSF13B, RANTES/CCL5 and TNFAIP6/TSG-6 protein expression in spheroids as compared to monolayers. Thus, we have reported the first large scale comparison of the transcriptional profiles using an ex vivo matrix-free spheroid model to identify genes specific to the three-dimensional biological structure of tumors. The method described here can be used for gene expression profiling of tumors other than mesothelioma.

Ardipusilloside inhibits survival, invasion and metastasis of human hepatocellular carcinoma cells

ETHNOPHARMACOLOGICAL RELEVANCE

Ardipusilloside I is a triterpene-saponin isolated from the Traditional Chinese Medicine Ardisia pusilla A. DC. Its effects and mechanism on invasion and metastasis of liver cancer cells are unclear.

MATERIALS AND METHODS

The human hepatocellular carcinoma cell line HepG2 and SMMC-7721 cells were treated with different doses of Ardipusilloside I. Cellular survival, in vitro migration and invasion were evaluated. In vivo metastatic abilities of the HCC cells were detected. We further investigated expression and phosphorylation of Mek, Erk and Akt by using Western blot. MMP2 and MMP9 activities were evaluated by gelatin zymography. E-cadherin expression, Rac1 and Cdc42 activities were examined by Western blot and pull-down assay.

RESULTS

Ardipusilloside I inhibited invasion and metastasis of HCC cells both in vitro and in vivo by reducing the protein expressions of metalloproteinase (MMP)-9 and MMP2 proteins. Ardipusilloside I activated Rac1 that enhanced E-cadherin activity and resulted in significantly less metastasis.

CONCLUSION

Our findings indicate that Ardipusilloside I has the potential of inhibition of liver cancer survival, invasion and metastasis both in vitro and in vivo.

Molecular changes in mesothelioma with an impact on prognosis and treatment

CONTEXT

In recent decades, research on malignant pleural mesothelioma (MPM) has been developed to improve patients' outcomes by increasing the level of confidence in MPM diagnosis and prognosis.

OBJECTIVE

To summarize data on genetic and epigenetic abnormalities in MPM that may be of interest for a better management of patients with MPM.

DATA SOURCES

Data were obtained from scientific publications on genetic and epigenetic abnormalities in MPM by studying gene mutations, DNA methylation, and gene and microRNA expression profiling.

CONCLUSIONS

Molecular changes in MPM consist in altered expression and in activation or inactivation of critical genes in oncogenesis, especially tumor suppressor genes at the INK4 and NF2 loci. Activation of membrane receptor tyrosine kinases and deregulation of signaling pathways related to differentiation, survival, proliferation, apoptosis, cell cycle control, metabolism, migration, and invasion have been demonstrated. Alterations that could be targeted at a global level (methylation) have been recently reported. Experimental research has succeeded especially in abolishing proliferation and triggering apoptosis in MPM cells. So far, targeted clinical approaches focusing on receptor tyrosine kinases have had limited success. Molecular analyses of series of MPM cases have shown that defined alterations are present in MPM subsets, consistent with interindividual variations of molecular alterations, and suggesting that identification of patient subgroups will be essential to develop more specific therapies.

PDGF-D/PDGF-ββ receptor-regulated chemotaxis of malignant mesothelioma cells

BACKGROUND/AIMS

Our earlier study suggested that platelet-derived growth factor (PDGF)- ββ receptor regulates chemotaxis of human malignant mesothelioma cells such as MSTO-211H, NCIH-2052, NCIH-2452, and NCIH-28 cells, but not non-malignant Met5A cells. The present study was designed to gain further insight into the PDGF-ββ receptor signals underlying the chemotaxis.

METHODS

PDGF-D secreted from cells, activation of Akt and ERK, and cell migration were monitored for cells with and without knocking-down PDGF-ββ receptor.

RESULTS

FBS significantly stimulated PDGF-D secretion from malignant mesothelioma cells, but not Met5A cells. PDGF-D activated Akt and ERK in both the non-malignant and malignant cells. PDGF-D significantly facilitated migration of malignant mesothelioma cells, but not Met5A cells, with the extent varying among the cell types. The facilitatory action of PDGF-D was clearly prevented by knocking-down PDGF-ββ receptor or inhibitors of PI3 kinase, PDK1, Akt, Rac1, ROCK, and MEK.

CONCLUSION

The results of the present study indicate that PDGF-D promotes malignant mesothelioma cell chemotaxis through PDGF-ββ receptor signaling pathways along a PI3 kinase/PDK1/Akt/Rac1/ROCK axis and relevant to ERK activation.

TGF-β1 modulates the homeostasis between MMPs and MMP inhibitors through p38 MAPK and ERK1/2 in highly invasive breast cancer cells

Background

Metastasis is the main factor responsible for death in breast cancer patients. Matrix metalloproteinases (MMPs) and their inhibitors, known as tissue inhibitors of MMPs (TIMPs), and the membrane-associated MMP inhibitor (RECK), are essential for the metastatic process. We have previously shown a positive correlation between MMPs and their inhibitors expression during breast cancer progression; however, the molecular mechanisms underlying this coordinate regulation remain unknown. In this report, we investigated whether TGF-β1 could be a common regulator for MMPs, TIMPs and RECK in human breast cancer cell models.

Methods

The mRNA expression levels of TGF-β isoforms and their receptors were analyzed by qRT-PCR in a panel of five human breast cancer cell lines displaying different degrees of invasiveness and metastatic potential. The highly invasive MDA-MB-231 cell line was treated with different concentrations of recombinant TGF-β1 and also with pharmacological inhibitors of p38 MAPK and ERK1/2. The migratory and invasive potential of these treated cells were examined in vitro by transwell assays.

Results

In general, TGF-β2, TβRI and TβRII are over-expressed in more aggressive cells, except for TβRI, which was also highly expressed in ZR-75-1 cells. In addition, TGF-β1-treated MDA-MB-231 cells presented significantly increased mRNA expression of MMP-2, MMP-9, MMP-14, TIMP-2 and RECK. TGF-β1 also increased TIMP-2, MMP-2 and MMP-9 protein levels but downregulated RECK expression. Furthermore, we analyzed the involvement of p38 MAPK and ERK1/2, representing two well established Smad-independent pathways, in the proposed mechanism. Inhibition of p38MAPK blocked TGF-β1-increased mRNA expression of all MMPs and MMP inhibitors analyzed, and prevented TGF-β1 upregulation of TIMP-2 and MMP-2 proteins. Moreover, ERK1/2 inhibition increased RECK and prevented the TGF-β1 induction of pro-MMP-9 and TIMP-2 proteins. TGF-β1-enhanced migration and invasion capacities were blocked by p38MAPK, ERK1/2 and MMP inhibitors.

Conclusion

Altogether, our results support that TGF-β1 modulates the mRNA and protein levels of MMPs (MMP-2 and MMP-9) as much as their inhibitors (TIMP-2 and RECK). Therefore, this cytokine plays a crucial role in breast cancer progression by modulating key elements of ECM homeostasis control. Thus, although the complexity of this signaling network, TGF-β1 still remains a promising target for breast cancer treatment.

NHE1 mediates MDA-MB-231 cells invasion through the regulation of MT1-MMP

Na⁺/H⁺ exchanger 1 (NHE1), an important regulator of intracellular pH (pH(i)) and extracellular pH (pH(e)), has been shown to play a key role in breast cancer metastasis. However, the exact mechanism by which NHE1 mediates breast cancer metastasis is not yet well known. We showed here that inhibition of NHE1 activity, with specific inhibitor Cariporide, could suppress MDA-MB-231 cells invasion as well as the activity and expression of MT1-MMP. Overexpression of MT1-MMP resulted in a distinguished increase in MDA-MB-231 cells invasiveness, but treatment with Cariporide reversed the MT1-MMP-mediated enhanced invasiveness. To explore the role of MAPK signaling pathways in NHE1-mediated breast cancer metastasis, we compared the difference of constitutively phosphorylated ERK1/2, p38 MAPK and JNK in non-invasive MCF-7 cells and invasive MDA-MB-231 cells. Interestingly, we found that the phosphorylation levels of ERK1/2 and p38 MAPK in MDA-MB-231 cells were higher than in MCF-7 cells, but both MCF-7 cells and MDA-MB-231 cells expressed similar constitutively phosphorylated JNK. Treating MDA-MB-231 cells with Cariporide led to decreased phosphorylation level of both p38 MAPK and ERK1/2 in a time-dependent manner, but JNK activity was not influenced. Supplementation with MAPK inhibitor (MEK inhibitor PD98059, p38 MAPK inhibitor SB203580 and JNK inhibitor SP600125) or Cariporide all exhibited significant depression of MDA-MB-231 cells invasion and MT1-MMP expression. Furthermore, we co-treated MDA-MB-231 cells with MAPK inhibitor and Cariporide. The result showed that Cariporide synergistically suppressed invasion and MT1-MMP expression with MEK inhibitor and p38 MAPK inhibitor, but not be synergistic with the JNK inhibitor. These findings suggest that NHE1 mediates MDA-MB-231 cells invasion partly through regulating MT1-MMP in ERK1/2 and p38 MAPK signaling pathways dependent manner.

Artemisinin inhibits in vitro and in vivo invasion and metastasis of human hepatocellular carcinoma cells

Artemisinin (ART) is isolated from the medicinal plant Artemisia annua L. To determine its effects on the invasion and metastasis of tumors, the human hepatocellular carcinoma (HCC) cell lines HepG2 and SMMC-7721 were treated with different concentrations of ART. Starting at 12.5μM, ART had inhibitory effects in migration and invasion assays that increased at higher concentrations. The inhibitory effect also became stronger with time, from 24 to 72h. ART significantly inhibited the in vivo metastatic abilities of the HepG2 HCC cell line. ART inhibited the invasion and metastasis of HCC cells both in vitro and in vivo by reducing the level of the MMP2 metalloproteinase, and by inducing the TIMP2 protein. ART activated Cdc42, which enhanced E-cadherin activity, resulting in greater cell-cell adhesion, and significantly reduced metastasis.

Rat mesothelioma cell proliferation requires p38δ mitogen activated protein kinase and C/EBP-α

Pleural malignant mesothelioma is a rare but deadly tumour mainly induced by asbestos inhalation. Despite the ban of asbestos in 1990 in 52 countries, mesothelioma cases still increase worldwide. In pleural mesothelioma, p38 mitogen activated protein kinases (MAPK) have been suggested to play a major role in carcinogenesis and aggressiveness of tumours. The aim of this study was to determine the role of the different four p38 MAPK isoforms and their effect on proliferation together with the underlying signalling pathways in a rat pleural mesothelioma cell line. Rat pleural mesothelioma cells were stimulated with platelet-derived growth factor (PDGF)-BB and/or transforming growth factor beta (TGF)-β. MAPK and transcription factor expression and activation was monitored in the cytosol and nucleus by immuno-blotting. Proliferation was determined by manual cell count and siRNAs were used to control MAPK and transcription factor expression and action. Only PDGF-BB, but not TGF-β1 induced proliferation via activated Erk1/2 and p38 MAPK. The p38α and δ isoforms were expressed in the cytosol, and upon activation p38δ translocated into the nucleus, while p38α remained in the cytosol. No other p38 isoform was expressed by rat mesothelioma cells. C/EBP-α was found in both the cytosol and the nucleus, while C/EBP-β was not expressed at all. PDGF-BB induced proliferation was suppressed by down-regulation of either Erk1/2, or p38δ MAPK, or C/EBP-α. Furthermore, TGF-β inhibited PDGF-BB induced proliferation by interruption of p38 MAPK signalling. From this rat model, we conclude that in pleural mesothelioma, p38δ in C/EBP-α mediate proliferation and thus may represent new targets in mesothelioma therapy.

ERK2 is essential for the growth of human epithelioid malignant mesotheliomas

Members of the extracellular signal-regulated kinase (ERK) family may have distinct roles in the development of cell injury and repair, differentiation and carcinogenesis. Here, we show, using a synthetic small-molecule MEK1/2 inhibitor (U0126) and RNA silencing of ERK1 and 2, comparatively, that ERK2 is critical to transformation and homeostasis of human epithelioid malignant mesotheliomas (MMs), asbestos-induced tumors with a poor prognosis. Although MM cell (HMESO) lines stably transfected with shERK1 or shERK2 both exhibited significant decreases in cell proliferation in vitro, injection of shERK2 cells, and not shERK1 cells, into immunocompromised severe combined immunodeficiency (SCID) mice showed significant attenuated tumor growth in comparison to shControl (shCon) cells. Inhibition of migration, invasion and colony formation occurred in shERK2 MM cells in vitro, suggesting multiple roles of ERK2 in neoplasia. Microarray and quantitative real-time PCR analyses revealed gene expression that was significantly increased (CASP1, TRAF1 and FAS) or decreased (SEMA3E, RPS6KA2, EGF and BCL2L1) in shERK2-transfected MM cells in contrast to shCon-transfected MM cells. Most striking decreases were observed in mRNA levels of Semaphorin 3 (SEMA3E), a candidate tumor suppressor gene linked to inhibition of angiogenesis. These studies demonstrate a key role of ERK2 in novel gene expression critical to the development of epithelioid MMs. After injection of sarcomatoid human MM (PPMMill) cells into SCID mice, both shERK1 and shERK2 lines showed significant decreased tumor growth, suggesting heterogeneous effects of ERKs in individual MMs.

MT1-MMP plays an important role in an invasive activity of malignant pleural mesothelioma cell

Malignant pleural mesothelioma (MPM) has a poor prognosis and is a treatment resistant tumor, which is increasing in frequency throughout the world. The poor prognosis is due to the aggressive local invasiveness rather than distant metastasis. In this study, we established a cell line of malignant mesothelioma from a clinical specimen and assessed the relationship between the expression of MT1-MMP and the invasion ability of that line, as well as the cultured cells of several other lines, using the simple method that we created previously. We established a cell line from a clinical specimen from a patient with malignant mesothelioma. We assessed the invasive activities of MPM cells in an easy-to-prepare double-layered collagen gel hemisphere (DL-CGH) system that enabled us to visualize cell movements during invasion. To assess the role of MT1-MMP in the invasive activity of MPM cells, we knocked down its expression by RNA interference (RNAi). The invasion assay with DL-CGH revealed that a high expression of MT1-MMP in MPM cells was associated with aggressive invasive activity. The RNAi of MT1-MMP indicated that the expression of MT1-MMP might have a crucial role in the invasiveness of MPM cells. The MT1-MMP expression in MPM cells is related to their capacity for locally aggressive spreading into the pleura and the surrounding tissues, and MT1-MMP should be a suitable molecular target for the suppression of the invasiveness of MPM.

TGFβ1 induces IL-6 and inhibits IL-8 release in human bronchial epithelial cells: the role of Smad2/3

Human bronchial epithelial (HBE) cells contribute to asthmatic airway inflammation by secreting cytokines, chemokines, and growth factors, including interleukin (IL)-6, IL-8 and transforming growth factor (TGF) β1, all of which are elevated in asthmatic airways. This study examines the signaling pathways leading to TGFβ1 induced IL-6 and IL-8 in primary HBE cells from asthmatic and non-asthmatic volunteers. HBE cells were stimulated with TGFβ1 in the presence or absence of signaling inhibitors. IL-6 and IL-8 protein and mRNA were measured by ELISA and real-time PCR respectively, and cell signaling kinases by Western blot. TGFβ1 increased IL-6, but inhibited IL-8 production in both asthmatic and non-asthmatic cells; however, TGF induced significantly more IL-6 in asthmatic cells. Inhibition of JNK MAP kinase partially reduced TGFβ1 induced IL-6 in both cell groups. TGFβ1 induced Smad2 phosphorylation, and blockade of Smad2/3 prevented both the TGFβ1 modulated IL-6 increase and the decrease in IL-8 production in asthmatic and non-asthmatic cells. Inhibition of Smad2/3 also increased basal IL-8 release in asthmatic cells but not in non-asthmatic cells. Using CHIP assays we demonstrated that activated Smad2 bound to the IL-6, but not the IL-8 promoter region. We conclude that the Smad2/3 pathway is the predominant TGFβ1 signaling pathway in HBE cells, and this is altered in asthmatic bronchial epithelial cells. Understanding the mechanism of aberrant pro-inflammatory cytokine production in asthmatic airways will allow the development of alternative ways to control airway inflammation.

Hypoxia-induced phenotypic switch of fibroblasts to myofibroblasts through a matrix metalloproteinase 2/tissue inhibitor of metalloproteinase-mediated pathway: implications for venous neointimal hyperplasia in hemodialysis access

PURPOSE

Hemodialysis grafts fail because of venous neointimal hyperplasia formation caused by adventitial fibroblasts that have become myofibroblasts (ie, alpha-smooth muscle actin [SMA]-positive cells) and migrate to the neointima. There is increased expression of hypoxia-inducible factor (HIF)-1alpha in venous neointimal hyperplasia formation in experimental animal models and clinical samples. It was hypothesized that, under hypoxic stimulus (ie, HIF-1alpha), fibroblasts will convert to myofibroblasts through a matrix metalloproteinase (MMP)-2-mediated pathway.

MATERIALS AND METHODS

Murine AKR-2B fibroblasts were made hypoxic or normoxic for 24, 48, and 72 hours. Protein expression for HIF-1alpha, alpha-SMA, MMP-2, MMP-9, tissue inhibitor of metalloproteinase (TIMP)-1, and TIMP-2 was performed to determine the kinetic changes of these proteins. Immunostaining for alpha-SMA, collagen, and fibronectin was performed.

RESULTS

At all time points, there was significantly increased expression of HIF-1alpha in the hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was significantly increased expression of alpha-SMA at all time points, which peaked by 48 hours in hypoxic fibroblasts compared with normoxic fibroblasts (P < .05). There was a significant increase in the expression of active MMP-2 by 48-72 hours and a significant increase in TIMP-1 by 48-72 hours by hypoxic fibroblasts (P < .05). By 72 hours, there was significant increase in TIMP-2 expression (P < .05). Immunohistochemical analysis demonstrated increased expression of alpha-SMA, collagen, and fibronectin as the duration of hypoxia increased.

CONCLUSIONS

Under hypoxic conditions, fibroblasts will convert to myofibroblasts through an MMP-2-mediated pathway, which may provide insight into the mechanism of venous neointimal hyperplasia.

Benzyl isothiocyanate (BITC) inhibits migration and invasion of human gastric cancer AGS cells via suppressing ERK signal pathways

Metastasis suppressors and associated other regulators of cell motility play a critical initial role in tumor invasion and metastases. Benzyl isothiocyanate (BITC) is a hydrolysis compound of glucotropaeolin in dietary cruciferous vegetables. BITC has been found to exhibit prevention of cancers in laboratory animals and might also be chemoprotective in humans. Here, the purpose of this study was to investigate the effects of BITC on cell proliferation, migration, invasion and mitogen-activated protein kinase (MAPK) pathways of AGS human gastric cancer cells. Wound healing and Boyden chamber (migration and invasion) assays demonstrated that BITC exhibited an inhibitory effect on the abilities of migration and invasion in AGS cancer cells. BITC suppressed cell migration and invasion of AGS cells in a dose-dependent manner. Results from Western blotting indicated that BITC exerted an inhibitory effect on the ERK1/2, Ras, GRB2, Rho A, iNOS, COX-2 for causing the inhibitions of MMP-2, -7 and -9 then followed by the inhibitions of invasion and migration of AGS cells in vitro. BITC also promoted MKK7, MEKK3, c-jun, JNK1/2, VEGF, Sos1, phosphoinositide 3-kinase (PI3K), PKC, nuclear factor-kappaB (NF-κB) p65 in AGS cells. Results from real-time polymerized chain reaction (PCR) showed that BITC inhibited the gene expressions of MMP-2,-7 -9, FAK, ROCK1 and RhoA after BITC treatment for 24 and 48 hours in AGS cells. Taken together, the finding may provide new mechanisms and functions of BITC, which inhibit migration and invasion of human gastric cancer AGS cells.

Spreading of mesothelioma cells is rapamycin-sensitive and requires continuing translation

The interaction of cancer cells with extracellular matrix (ECM) is important in metastasization. Here we identified the molecules of the ECM expressed by sarcomatous malignant mesothelioma, and their effect on adhesion and spreading. In addition, by analyzing the relationship between translation and attachment to matrix, we found that mesothelioma cells rely on continuing translation to efficiently attach to matrix, and rapamycin inhibition affects spreading and migration of cancer cells. Specifically, we found that sarcomatous cells produce high amounts of fibronectin, able to support the spreading of mesothelioma cells. Spreading of cancer cells on fibronectin does not require de novo transcription but is sensitive to cycloheximide, an inhibitor of protein synthesis. Next, we analyzed the involvement of the mammalian target of rapamycin (mTOR) pathway, a major pathway controlling translation. Cancer cells have a constitutively active mTOR pathway; surprisingly, inhibition of mTOR complex 1 (mTORC1) by rapamycin barely affects the global rate of translation and of initiation of translation, but deeply inhibits mesothelioma spreading on ECM. The effects of rapamycin and cycloheximide on spreading were observed in several mesothelioma cell lines, although with different magnitude. Overall, data suggest that adhesion and spreading of mesothelioma cells on ECM require the translation of pre-synthesized mRNAs, and mTORC1 activity. We speculate that mTORC1 activity is required either for the translation of specific mRNAs or for the direct modulation of cytoskeletal remodeling.

MMP-7 mediates cleavage of N-cadherin and promotes smooth muscle cell apoptosis

Aims

Vascular smooth muscle cell (VSMC) apoptosis can lead to thinning of the fibrous cap and plaque instability. We previously showed that cell–cell contacts mediated by N-cadherin reduce VSMC apoptosis. This study aimed to determine whether matrix-degrading metalloproteinase (MMP)-dependent N-cadherin cleavage causes VSMC apoptosis.

Methods and results

Induction of human VSMC apoptosis using different approaches, including 200 ng/mL Fas ligand (Fas-L) and culture in suspension, caused N-cadherin cleavage and resulted in the appearance of a C-terminal fragment of N-cadherin (∼35 kDa). Appearance of this fragment during apoptosis was inhibited by 47% with the broad-spectrum MMP inhibitor BB-94. We observed retarded cleavage of N-cadherin after treatment with Fas-L in aortic mouse VSMCs lacking MMP-7. Furthermore, VSMC apoptosis, measured by quantification of cleaved caspase-3, was 43% lower in MMP-7 knockout mouse VSMCs compared with wild-type VSMCs following treatment with Fas-L. Addition of recombinant active MMP-7 increased the amount of N-cadherin fragment by 82% and augmented apoptosis by 53%. The involvement of MMP-7 was corroborated using human cells, where a MMP-7 selective inhibitor reduced the amount of fragment formed by 51%. Importantly, we observed that treatment with Fas-L increased levels of active MMP-7 by 80%. Finally, we observed significantly increased cleavage of N-cadherin, MMP-7 activity, and apoptosis in human atherosclerotic plaques compared with control arteries, and a significant reduction in apoptosis in atherosclerotic plaques from MMP-7 knockout mice.

Conclusion

This study demonstrates that MMP-7 is involved in the cleavage of N-cadherin and modulates VSMC apoptosis, and may therefore contribute to plaque development and rupture.

Mesothelioma cells escape heat stress by upregulating Hsp40/Hsp70 expression via mitogen-activated protein kinases

Therapy with hyperthermal chemotherapy in pleural diffuse malignant mesothelioma had limited benefits for patients. Here we investigated the effect of heat stress on heat shock proteins (HSP), which rescue tumour cells from apoptosis. In human mesothelioma and mesothelial cells heat stress (39-42 degrees C) induced the phosphorylation of two mitogen activated kinases (MAPK) Erk1/2 and p38, and increased Hsp40, and Hsp70 expression. Mesothelioma cells expressed more Hsp40 and were less sensitive to heat stress compared to mesothelial cells. Inhibition of Erk1/2 MAPK by PD98059 or by Erk1 siRNA down-regulated heat stress-induced Hsp40 and Hsp70 expression and reduced mesothelioma cell survival. Inhibition of p38MAPK by SB203580 or siRNA reduced Hsp40, but not Hsp70, expression and also increased mesothelioma cell death. Thus hyperthermia combined with suppression of p38 MAPK or Hsp40 may represent a novel approach to improve mesothelioma therapy.

Regulators affecting the metastasis suppressor activity of Nm23-H1

Nm23-H1 encodes nucleoside diphosphate kinase A (NDPK-A) and is known to have a metastasis suppressive activity in many tumor cells. However, it has many other functions as well. Recent studies have shown that the interacting proteins with Nm23-H1 which mediate the cell proliferation, may act as modulators of the metastasis suppressor activity. The interacting proteins with Nm23-H1 can be classified into 3 groups. The first group of proteins can be classified as upstream kinases of Nm23-H1 such as CKI and Aurora-A/STK15. The second group of proteins acts as downstream effectors for the regulation of specific gene transcriptions, GTP-binding protein functions, and signal transduction in Erk signal cascade. The third group of proteins can be classified as bi-directionally influencing binding partners of Nm23-H1. As a result, the interactions with Nm23-H1 and binding partners have implications in the biochemical characterization involved in metastasis and tumorigenesis.