Stimulation of lung carcinoma cell growth by fibronectin-integrin signalling

Collagen 1 Fiber Volume Predicts for Recurrence of Stage 1 Non-Small Cell Lung Cancer

Background: The standard of care for stage 1 NSCLC is upfront surgery followed by surveillance. However, 20-30% of stage 1 NSCLC recur. There is an unmet need to identify individuals likely to recur who would benefit from frequent monitoring and aggressive cancer treatments. Collagen 1 (Col1) fibers detected by second harmonic generation (SHG) microscopy are a major structural component of the extracellular matrix (ECM) of tumors that play a role in cancer progression. Method: We characterized Col1 fibers with SHG microscopy imaging of surgically resected stage 1 NSCLC. Gene expression from RNA sequencing data was used to validate the SHG microscopy findings. Results: We identified a significant (p ≤ 0.05) increase in the Col1 fiber volume in stage 1 NSCLC that recurred. The increase in Col1 fiber volume was supported by significant increases in the gene expression of Col1 in invasive, compared to noninvasive, lung adenocarcinoma. Significant differences were identified in the gene expression of other ECM proteins, as well as CAFs, immune checkpoint markers, immune cytokines, and T-cell markers. Conclusion: Col1 fiber analysis can provide a companion diagnostic test to evaluate the likelihood of tumor recurrence following stage 1 NSCLC. The studies expand our understanding of the role of the ECM in NSCLC recurrence.

The role of α7-nAChR-mediated PI3K/AKT pathway in lung cancer induced by nicotine

Nicotine enters the environment mainly through human activity, as well as natural sources. This review article examines the increasing evidence implicating nicotine in the initiation and progression of lung cancer. Moreover, it primarily focuses on elucidating the activation mechanism of phosphoinositide 3-kinase (PI3K)/protein kinase B (PKB, also known as AKT) signaling pathway, regulated by α7 subtype nicotinic acetylcholine receptor (α7-nAChR), in relation to the proliferation, invasion, and metastasis of lung cancer cells induced by nicotine, as well as nicotine-mediated anti-apoptotic effects. This process involves PI3K/AKT phosphorylated-B-cell lymphoma-2 (Bcl-2) family proteins, PI3K/AKT/mammalian target of rapamycin (mTOR), PI3K/AKT/nuclear factor-κB (NF-κB), hepatocyte growth factor (HGF)/cellular-mesenchymal epithelial transition factor (c-Met)-induced PI3K/AKT and PI3K/AKT activated-hypoxia-inducible factor-1α (HIF-1α)/vascular endothelial growth factor (VEGF) pathways. In addition, we also deliberated on the related challenges and upcoming prospects within this field. These lay the foundation for further study on nicotine, lung tumorigenesis, and PI3K/AKT related molecular mechanisms. This work has the potential to significantly contribute to the treatment and prognosis of gastric cancer in smokers. Besides, the crucial significance of PI3K/AKT signaling pathway in multiple molecular pathways also suggests that its target antagonists may inhibit the development and progression of lung cancer, providing a possible new perspective for solving the problem of nicotine-promoted lung cancer. The emerging knowledge about the carcinogenic mechanisms of nicotine action should be considered during the environmental assessment of tobacco and other nicotine-containing products.

Lnc-ABCA12-8 confers acquired resistance to gefitinib in non-small cell lung cancer by regulating the alternative splicing of fibronectin 1 in the IIICS region

Acquired resistance to epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs), such as gefitinib, has dramatically impaired the clinical outcomes in non-small cell lung cancer (NSCLC) patients, but the mechanisms are still unclear in substantial cases. In our previous study, we demonstrated that a novel long non-coding RNA (lncRNA), lnc-ABCA12-8, was overexpressed in gefitinib-resistant NSCLC cells, but the exact function is unknown. In this study, we confirmed that lnc-ABCA12-8 was significantly upregulated both in NSCLC cell lines and the plasma samples of NSCLC patients with acquired resistance to gefitinib. Downregulation of lnc-ABCA12-8 could reverse gefitinib resistance both in vitro and in vivo. Mechanistically, lnc-ABCA12-8 interacted with alternative splicing factor/splicing factor 2 (ASF/SF2), promoted the binding of ASF/SF2 to the IIICS exon of fibronectin 1 (FN1) gene and enhanced the IIICS region inclusion during fibronectin 1 (FN1) alternative splicing, resulting in the upregulation of entire IIICS region, and enhanced cell proliferation, migration, invasion, and adhesion. Taken together, our study suggest that lnc-ABCA12-8 is involved in the acquired resistance to gefitinib, and may be a novel biomarker and therapeutic target for monitoring and overcoming gefitinib resistance in NSCLC.

3D matrix promotes cell dedifferentiation into colorectal cancer stem cells via integrin/cytoskeleton/glycolysis signaling

The potential for tumor occurrence triggered by cancer stem cells (CSCs) has emerged as a significant challenge for human colorectal cancer therapy. However, the underlying mechanism of CSC development remains controversial. Our study provided evidence that the bulk of tumor cells could dedifferentiate to CSCs and reacquire CSCs-like phenotypes if cultured in the presence of extracellular matrix reagents, such as Matrigel and fibrin gels. In these 3D gels, CD133^- colorectal cancer cells can regain tumorigenic potential and stem-like phenotypes. Mechanistically, the 3D extracellular matrix could mediate cytoskeletal F-actin bundling through biomechanical force associated receptors integrin β1 (ITGB1), contributing to the release of E3 ligase Tripartite motif protein 11 (TRIM11) from cytoskeleton and degradation of the glycolytic rate-limiting enzyme phosphofructokinase (PFK). Consequently, PFK inhibition resulted in enhanced glycolysis and upregulation of hypoxia-inducible factor 1 (HIF1α), thereby promoting the reprogramming of stem cell transcription factors and facilitating tumor progression in patients. This study provided novel insights into the role of the extracellular matrix in the regulation of CSC dedifferentiation in a cytoskeleton/glycolysis-dependent manner.

Epithelial-Mesenchymal Transition Participates in the Formation of Vestibular Flat Epithelium

The vestibular sensory epithelium of humans and mice may degenerate into a layer of flat cells, known as flat epithelium (FE), after a severe lesion. However, the pathogenesis of vestibular FE remains unclear. To determine whether the epithelial–mesenchymal transition (EMT) participates in the formation of vestibular FE, we used a well-established mouse model in which FE was induced in the utricle by an injection of streptomycin into the inner ear. The mesenchymal and epithelial cell markers and cell proliferation were examined using immunofluorescence staining and quantitative reverse transcription polymerase chain reaction (qRT-PCR). The function of the EMT was assessed through transcriptome microarray analysis. The results demonstrated that mesenchymal cell markers (α-SMA, S100A4, vimentin, and Fn1) were upregulated in vestibular FE compared with the normal utricle. Robust cell proliferation, which was absent in the normal status, was observed in the formation of FE. Microarray analysis identified 1,227 upregulated and 962 downregulated genes in vestibular FE. Gene Ontology (GO) analysis revealed that differentially expressed genes (DEGs) were highly associated with several EMT-related GO terms, such as cell adhesion, cell migration, and extracellular matrix. Pathway enrichment analysis revealed that DEGs were enriched in the EMT-related signaling pathways, including extracellular matrix (ECM)-receptor interaction, focal adhesion, PI3K/Akt signaling pathway and cell adhesion molecule. Protein–protein interaction networks screened 20 hub genes, which were Akt, Casp3, Col1a1, Col1a2, Fn1, Hgf, Igf1,Il1b, Irs1, Itga2, Itga5, Jun, Mapk1, Myc, Nras, Pdgfrb, Tgfb1, Thbs1, Trp53, and Col2a1. Most of these genes are reportedly involved in the EMT process in various tissues. The mRNA expression level of hub genes was validated using qRT-PCR. In conclusion, the present study indicates that EMT plays a significant role in the formation of vestibular FE and provides an overview of transcriptome characteristics in vestibular FE.

A Five Collagen-Related Gene Signature to Estimate the Prognosis and Immune Microenvironment in Clear Cell Renal Cell Cancer

Collagen is the main component of the extracellular matrix (ECM) and might play an important role in tumor microenvironments. However, the relationship between collagen and clear cell renal cell cancer (ccRCC) is still not fully clarified. Hence, we aimed to establish a collagen-related signature to predict the prognosis and estimate the tumor immune microenvironment in ccRCC patients. Patients with a high risk score were often correlated with unfavorable overall survival (OS) and an immunosuppressive microenvironment. In addition, the collagen-related genetic signature was highly correlated with clinical pathological features and can be considered as an independent prognostic factor in ccRCC patients. Moreover, GSEA results show that patients with a high risk grade tend to be associated with epithelial–mesenchymal junctions (EMT) and immune responses. In this study, we developed a collagen-related gene signature, which might possess the potential to predict the prognosis and immune microenvironment of ccRCC patients and function as an independent prognostic factor in ccRCC.

Aberrant Methylation and Immune Microenvironment Are Associated With Overexpressed Fibronectin 1: A Diagnostic and Prognostic Target in Head and Neck Squamous Cell Carcinoma

Background: Fibronectin 1 (FN1) is involved in cell adhesion and migration processes such as metastasis, wound healing, embryogenesis, blood coagulation, and host defense. However, the role of FN1 in the diagnosis and prognosis of head and neck squamous cell carcinoma (HNSCC) is far from understood. Methods: FN1 expression profiles and clinical parameters from multiple HNSCC datasets were applied to evaluate the association between FN1 expression and HNSCC survival. We also identified FN1 expression in the mRNA and protein levels in 20 pairs of clinical samples by quantitative polymerase chain reaction (qPCR) and immunohistochemistry. Receiver operator characteristic (ROC) analysis was used to demonstrate the potential diagnostic value of FN1 in HNSCC. Aberrant methylation PPI networks were established using multiple bioinformatic tools based on TCGA database. The immune microenvironment and levels of immune checkpoints were investigated between groups with high and low FN1 expression. Results: FN1 was significantly upregulated in HNSCC compared with para-carcinoma tissues on the basis of TCGA database and our clinical samples. Univariate and multivariate Cox regression analysis revealed that FN1 could be an independent indicator for prognosis of HNSCC. GO enrichment and KEGG pathway analysis demonstrated that cell adhesion, focal adhesion, and the PI3K-Akt signaling pathway might be involved in the potential mechanisms of FN1's prognostic performance in HNSCC. Methylation of FN1 was also higher and closely associated with poorer survival in HNSCC. In addition, FN1 expression was positively correlated with three DNA methyltransferases (DNMT1, DNMT3A, and DNMT3B). Furthermore, FN1 was positively associated with CD4⁺ T cells, endothelial cells, macrophages, and NK cells and negatively correlated with CD8⁺ T cells Conclusion: FN1 might be an independent prognostic biomarker for HNSCC patients. Hypermethylation, the aberrant proportions of immune cells, and the PI3K/Akt signaling pathway might be involved in the mechanism of FN1's oncogene role in HNSCC.

Transcriptomic Profiling of In Vitro Tumor-Stromal Cell Paracrine Crosstalk Identifies Involvement of the Integrin Signaling Pathway in the Pathogenesis of Mesenteric Fibrosis in Human Small Intestinal Neuroendocrine Neoplasms

Aim

Analysis of the pathophysiology of mesenteric fibrosis (MF) in small intestinal neuroendocrine tumors (SI-NETs) in an in vitro paracrine model and in human SI-NET tissue samples.

Methods

An indirect co-culture model of SI-NET cells KRJ-I and P-STS with stromal cells HEK293 was designed to evaluate the paracrine effects on cell metabolic activity, gene expression by RT2 PCR Profilers to analyse cancer and fibrosis related genes, and RNA sequencing. The integrin signaling pathway, a specific Ingenuity enriched pathway, was further explored in a cohort of human SI-NET tissues by performing protein analysis and immunohistochemistry.

Results

RT Profiler array analysis demonstrated several genes to be significantly up- or down-regulated in a cell specific manner as a result of the paracrine effect. This was further confirmed by employing RNA sequencing revealing multiple signaling pathways involved in carcinogenesis and fibrogenesis that were significantly affected in these cell lines. A significant upregulation in the expression of various integrin pathway – related genes was identified in the mesenteric mass of fibrotic SI-NET as confirmed by RT-qPCR and immunohistochemistry. Protein analysis demonstrated downstream activation of the MAPK and mTOR pathways in some patients with fibrotic SI-NETs.

Conclusion

This study has provided the first comprehensive analysis of the crosstalk of SI-NET cells with stromal cells. A novel pathway – the integrin pathway – was identified and further validated and confirmed in a cohort of human SI-NET tissue featured by a dual role in fibrogenesis/carcinogenesis within the neoplastic fibrotic microenvironment.

A PTAL-miR-101-FN1 Axis Promotes EMT and Invasion-Metastasis in Serous Ovarian Cancer

Long non-coding RNAs (lncRNAs) play vital roles in the metastasis and invasion of cancer cells. Systematic analysis of ovarian cancer (OvCa) expression profiles suggests that deregulation of lncRNA AC004988.1, designated promoting transition-associated lncRNA (PTAL), is involved in OvCa progression. However, the underlying mechanism of PTAL in OvCa remains unknown. In this study, we showed that PTAL was significantly upregulated in mesenchymal subtype samples compared with epithelial subtype samples from TCGA serous OvCa datasets. PTAL expression was positively correlated with the expression of fibronectin1 (FN1), whereas PTAL and FN1 were negatively correlated with miR-101 expression in the mesenchymal OvCa samples. In addition, knockdown of PTAL inhibited cell migration and invasion and blunted the progression of metastasis in vitro. Meanwhile, knockdown of PTAL increased the expression of miR-101 and subsequently inhibited the expression of FN1. Importantly, PTAL positively regulated the expression of FN1 through sponging of miR-101 and promoted OvCa cell metastasis by regulating epithelial-mesenchymal transition. Overall, our study demonstrates the role of PTAL as a miRNA sponge in OvCa and suggests that PTAL may be a potential target for preventing OvCa metastasis.

Long noncoding RNA lnc-ABCA12-3 promotes cell migration, invasion, and proliferation by regulating fibronectin 1 in esophageal squamous cell carcinoma

Long noncoding RNAs (lncRNAs) have been shown to play important roles in human cancers, including esophageal squamous cell carcinoma (ESCC). We previously demonstrated that a novel lncRNA, lnc-ABCA12-3, was overexpressed in ESCC tissues. However, the exact function of lnc-ABCA12-3 is unknown. In the current study, we aimed to evaluate the expression of lnc-ABCA12-3 in ESCC and to explore the potential mechanism of lnc-ABCA12-3 in cell migration, invasion, and proliferation. We showed that lnc-ABCA12-3 was upregulated in ESCC tumor tissues and cell lines. The increased expression of lnc-ABCA12-3 was positively associated with advanced tumor-node-metastasis stages and poor prognosis. The knockdown of lnc-ABCA12-3 inhibited the cell migration, invasion, and proliferation abilities of KYSE-510 and Eca-109 cells. We also found that fibronectin 1 (FN1) was upregulated in ESCC tumor tissues. The expression of FN1 messenger RNA was positively correlated with the expression of lnc-ABCA12-3 in ESCC tumor tissues. After lnc-ABCA12-3 knockdown, the expression of FN1 was downregulated. In addition, the overexpression of FN1 restored the abilities of cell migration, invasion and proliferation in Eca-109 cells. Further studies indicated that lnc-ABCA12-3 acted as a competing endogenous RNA for miR-200b-3p to regulate FN1 expression. In conclusion, these results suggest that lnc-ABCA12-3 is a novel oncogene in tumorigenesis and that its high expression is related to a poor prognosis for patients with ESCC. lnc-ABCA12-3 promotes cell migration, invasion, and proliferation via the regulation of FN1 in ESCC. Our data suggest that lnc-ABCA12-3 might serve as a potential prognostic biomarker and therapeutic target for ESCC.

Fibronectin promotes cervical cancer tumorigenesis through activating FAK signaling pathway

Cervical cancer is a cancer arising from the cervix, and it is the fourth most common cause of death in women. Overexpression of fibronectin 1 (FN1) was observed in many tumors and associated with the survival and metastasis of cancer cells. However, the mechanism by which FN1 promotes cervical cancer cell viability, migration, adhesion, and invasion, and inhibits cell apoptosis through focal adhesion kinase (FAK) signaling pathway remains to be investigated. Our results demonstrated that FN1 was upregulated in patients with cervical cancer and higher FN1 expression correlated with a poor prognosis for patients with cervical cancer. FN1 knockdown by small interfering RNA (siRNA) inhibited SiHa cell viability, migration, invasion, and adhesion, and promoted cell apoptosis. FN1 overexpression in CaSki cell promoted cell viability, migration, invasion, and adhesion, and inhibited cell apoptosis. Further, phosphorylation of FAK, a main downstream signaling molecule of FN1, and the protein expression of Bcl-2/Bax, matrix metalloproteinase 2 (MMP-2), matrix metalloproteinase 9 (MMP-9), and N-cadherin was upregulated in CaSki cells with FN1 overexpression, but caspase-3 protein expression was downregulated. The FAK phosphorylation inhibitor PF573228 inhibited FN1 overexpression-induced expression of those proteins in CaSki cells with FN1 overexpression. In vivo experiment demonstrated that FN1 knockdown significantly inhibited FN1 expression, phosphorylation of FAK, and tumor growth in xenograft from the nude mice. These results suggest that FN1 regulates the viability, apoptosis, migration, invasion, and adhesion of cervical cancer cells through the FAK signaling pathway and is a potential therapeutic target in the treatment of cervical cancer.

Expression of fibronectin in esophageal squamous cell carcinoma and its role in migration

BACKGROUND

Fibronectin (FN) is a high-molecular-weight glycoprotein component of the extracellular matrix involved in cell adhesion, migration, metastasis, proliferation and differentiation, as well as embryogenesis, wound healing, and blood coagulation. Considerable recent research has established that tumor expression of FN is closely associated with tumor formation and development as well as disease prognosis. However, the mechanisms underlying this relationship have remained unclear. The aim of this study was to investigate FN protein expression in esophageal squamous cell carcinoma (ESCC) and determine its potential prognostic relevance, while also elucidating the source and function of FN.

METHODS

We conducted immunohistochemical analyses of protein expression in primary tumors of ESCC patients and analyzed their association with standard prognostic parameters and clinical outcomes. Expression of FN in two ESCC cell lines (Eca-109 and TE-1) was also examined by RT-PCR, immunofluorescence, and ELISA. ESCC cells were cultured in a microenvironment containing a high FN content, and changes in their morphology and migration ability were assessed by microscopy, wound-healing assays, and Transwell assays.

RESULTS

FN expression in ESCC specimens was mainly detected in the tumor stroma, with very little FN detected in tumor cells. Stromal FN content in ESCC specimens was associated with lymphatic metastasis (P = 0.032) and prognosis. In this latter context, patients with high tumor stromal expression of FN showed worse overall survival (P = 0.002) and progression-free survival (P < 0.001) than those with low expression of FN. Interestingly, FN expression and secretion in ESCC cell lines (Eca-109 and TE-1) was found to be low, but these cells adopted a more migratory phenotype when cultured in vitro in a microenvironment containing high levels of FN.

CONCLUSIONS

High FN expression in the stroma of ESCC tumors is closely associated with poor prognosis of patients. High stromal FN content facilitates tumor cell metastasis by promoting morphological changes and improving the motility and migratory ability of ESCC cells.

In Vivo Cancer Cells Elimination Guided by Aptamer-Functionalized Gold-Coated Magnetic Nanoparticles and Controlled with Low Frequency Alternating Magnetic Field

Biomedical applications of magnetic nanoparticles under the influence of a magnetic field have been proved useful beyond expectations in cancer therapy. Magnetic nanoparticles are effective heat mediators, drug nanocarriers, and contrast agents; various strategies have been suggested to selectively target tumor cancer cells. Our study presents magnetodynamic nanotherapy using DNA aptamer-functionalized 50 nm gold-coated magnetic nanoparticles exposed to a low frequency alternating magnetic field for selective elimination of tumor cells in vivo. The cell specific DNA aptamer AS-14 binds to the fibronectin protein in Ehrlich carcinoma hence helps deliver the gold-coated magnetic nanoparticles to the mouse tumor. Applying an alternating magnetic field of 50 Hz at the tumor site causes the nanoparticles to oscillate and pull the fibronectin proteins and integrins to the surface of the cell membrane. This results in apoptosis followed by necrosis of tumor cells without heating the tumor, adjacent healthy cells and tissues. The aptamer-guided nanoparticles and the low frequency alternating magnetic field demonstrates a unique non-invasive nanoscalpel technology for precise cancer surgery at the single cell level.

MicroRNA-200c binding to FN1 suppresses the proliferation, migration and invasion of gastric cancer cells

We aimed to investigate the effects of miR-200c binding to fibronectin 1 (FN1) on proliferation, migration and invasion of gastric cancer (GC) cells. A total of 52 GC tissues and their corresponding normal adjacent tissue samples were collected. Then, miR-200c and FN1 were tested using quantitative real-time RT-PCR in the clinical specimens and GC cells, while immunohistochemistry and western blotting assay were carried out to detect FN1 expressions. Dual luciferase reporter gene assay was used to assess the effect of miR-200c on the luciferase activity of FN1 3'UTR. BGC-823 cells were transfected with miR-200c mimics, miR-200c inhibitors and FN1 siRNA, respectively. The effects of miR-200c inhibitors and FN1 siRNA on cellular proliferation, migration and invasion were detected through MTT assay and Transwell assay. Compared to normal tissues and cells, miR-200c was significantly down-regulated and FN1 was significantly up-regulated (P<0.01). Dual luciferase reporter gene assay showed that miR-200c could specifically bind to the 3'-UTR of FN1 and significantly repress the luciferase activity (P<0.01). Both mRNA and protein expressions of FN1 were decreased significantly in GC cells when miR-200c was over expressed. The proliferation, migration and invasion of GC cells could be suppressed by over-expression of miR-200c or down-regulation of FN1. In conclusion, miR-200c was significantly down-regulated in both GC tissues and cell lines, while FN1 presented the opposite trends. Besides, miR-200c inhibited the proliferation, migration and invasion of GC cells through binding to FN1.

Advanced Glycation End-Products Enhance Lung Cancer Cell Invasion and Migration

Effects of carboxymethyllysine (CML) and pentosidine, two advanced glycation end-products (AGEs), upon invasion and migration in A549 and Calu-6 cells, two non-small cell lung cancer (NSCLC) cell lines were examined. CML or pentosidine at 1, 2, 4, 8 or 16 μmol/L were added into cells. Proliferation, invasion and migration were measured. CML or pentosidine at 4-16 μmol/L promoted invasion and migration in both cell lines, and increased the production of reactive oxygen species, tumor necrosis factor-α, interleukin-6 and transforming growth factor-β1. CML or pentosidine at 2-16 μmol/L up-regulated the protein expression of AGE receptor, p47(phox), intercellular adhesion molecule-1 and fibronectin in test NSCLC cells. Matrix metalloproteinase-2 protein expression in A549 and Calu-6 cells was increased by CML or pentosidine at 4-16 μmol/L. These two AGEs at 2-16 μmol/L enhanced nuclear factor κ-B (NF-κ B) p65 protein expression and p38 phosphorylation in A549 cells. However, CML or pentosidine at 4-16 μmol/L up-regulated NF-κB p65 and p-p38 protein expression in Calu-6 cells. These findings suggest that CML and pentosidine, by promoting the invasion, migration and production of associated factors, benefit NSCLC metastasis.

Silibinin inhibits triple negative breast cancer cell motility by suppressing TGF-β2 expression

Transforming growth factor-beta (TGF-β) is a multifunctional cytokine that regulates many biological events including cell motility and angiogenesis. Here, we investigated the role of elevated TGF-β2 level in triple negative breast cancer (TNBC) cells and the inhibitory effect of silibinin on TGF-β2 action in TNBC cells. Breast cancer patients with high TGF-β2 expression have a poor prognosis. The levels of TGF-β2 expression increased significantly in TNBC cells compared with those in non-TNBC cells. In addition, cell motility-related genes such as fibronectin (FN) and matrix metalloproteinase-2 (MMP-2) expression also increased in TNBC cells. Basal FN, MMP-2, and MMP-9 expression levels decreased in response to LY2109761, a dual TGF-β receptor I/II inhibitor, in TNBC cells. TNBC cell migration also decreased in response to LY2109761. Furthermore, we observed that TGF-β2 augmented the FN, MMP-2, and MMP-9 expression levels in a time- and dose-dependent manner. In contrast, TGF-β2-induced FN, MMP-2, and MMP-9 expression levels decreased significantly in response to LY2109761. Interestingly, we found that silibinin decreased TGF-β2 mRNA expression level but not that of TGF-β1 in TNBC cells. Cell migration as well as basal FN and MMP-2 expression levels decreased in response to silibinin. Furthermore, silibinin significantly decreased TGF-β2-induced FN, MMP-2, and MMP-9 expression levels and suppressed the lung metastasis of TNBC cells. Taken together, these results suggest that silibinin suppresses metastatic potential of TNBC cells by inhibiting TGF-β2 expression in TNBC cells. Thus, silibinin may be a promising therapeutic drug to treat TNBC.

The Extracellular Matrix in Epithelial Ovarian Cancer - A Piece of a Puzzle

Epithelial ovarian cancer is the fifth leading cause of cancer-related deaths in women and the most lethal gynecological malignancy. Extracellular matrix (ECM) is an integral component of both the normal and tumor microenvironment. ECM composition varies between tissues and is crucial for maintaining normal function and homeostasis. Dysregulation and aberrant deposition or loss of ECM components is implicated in ovarian cancer progression. The mechanisms by which tumor cells induce ECM remodeling to promote a malignant phenotype are yet to be elucidated. A thorough understanding of the role of the ECM in ovarian cancer is needed for the development of effective biomarkers and new therapies.

Cellular fibronectin 1 promotes VEGF-C expression, lymphangiogenesis and lymph node metastasis associated with human oral squamous cell carcinoma

Lymph node metastasis (LNM) is associated with poor survival in patients with oral squamous cell carcinoma (OSCC). Vascular endothelial growth factor-C (VEGF-C) is thought to be responsible for increased lymphangiogenesis and LNM. Understanding of the mechanism by which VEGF-C expression is regulated in OSCC is thus important to design logic therapeutic interventions. We showed that inoculation of the SAS human OSCC cells expressing the venus GFP (V-SAS cells) into the tongue in nude mice developed LNM. V-SAS cells in LNM were isolated by FACS and re-inoculated into the tongue. This procedure was repeated eight times, establishing V-SAS-LM8 cells. Differential metastasis PCR array between the parental V-SAS and V-SAS-LM8 was performed to identify a molecule responsible for lymphangiogenesis and LNM. Fibronectin 1 (FN1) expression was elevated in V-SAS-LM8 cells compared to V-SAS-cells. V-SAS-LM8 tongue tumor showed increased expression of FN1 and VEGF-C, and promoted lymphangiogenesis and LNM compared with V-SAS tumor. Further, phosphorylation of focal adhesion kinase (FAK), a main downstream signaling molecule of FN1, was up-regulated, and epithelial-mesenchymal transition (EMT) was promoted in V-SAS-LM8 cells. Silencing of FN1 by shRNA in V-SAS-LM8 cells decreased FAK phosphorylation, VEGF-C expression and inhibited lymphangiogenesis and LNM. EMT was also reversed. The FAK phosphorylation inhibitor PF573228 also decreased VEGF-C expression and reversed EMT in V-SAS-LM8 cells. Finally, we detected intense FN1 expression in some clinical specimens obtained from OSCC patients with LNM. These results demonstrate that elevated expression of cellular FN1 and following activation of FAK lead to increased VEGF-C expression, lymphangiogenesis and LNM and promoted EMT in SAS human OSCC cells and suggest that FN1-phosphorylated FAK signaling cascade is a potential therapeutic target in the treatment of LNM in OSCC.

Gene Signatures Stratify Computed Tomography Screening Detected Lung Cancer in High-Risk Populations

BACKGROUND

Although screening programmes of smokers have detected resectable early lung cancers more frequently than expected, their efficacy in reducing mortality remains debatable. To elucidate the biological features of computed tomography (CT) screening detected lung cancer, we examined the mRNA signatures on tumours according to the year of detection, stage and survival.

METHODS

Gene expression profiles were analysed on 28 patients (INT-IEO training cohort) and 24 patients of Multicentre Italian Lung Detection (MILD validation cohort). The gene signatures generated from the training set were validated on the MILD set and a public deposited DNA microarray data set (GSE11969). Expression of selected genes and proteins was validated by real-time RT-PCR and immunohistochemistry. Enriched core pathway and pathway networks were explored by GeneSpring GX10.

FINDINGS

A 239-gene signature was identified according to the year of tumour detection in the training INT-IEO set and correlated with the patients' outcomes. These signatures divided the MILD patients into two distinct survival groups independently of tumour stage, size, histopathological type and screening year. The signatures can also predict survival in the clinically detected cancers (GSE11969). Pathway analyses revealed tumours detected in later years enrichment of the PI3K/PTEN/AKT pathway, with up-regulation of PDPK1, ITGB1 and down-regulation of FOXO1A. Analysis of normal lung tissue from INT-IEO cohort produced signatures distinguishing patients with early from late detected tumours.

INTERPRETATION

The distinct pattern of "indolent" and "aggressive" tumour exists in CT-screening detected lung cancer according to the gene expression profiles. The early development of an aggressive phenotype may account for the lack of mortality reduction by screening observed in some cohorts.

Induction of fibronectin by HER2 overexpression triggers adhesion and invasion of breast cancer cells

Fibronectin (FN), an extracellular matrix ligand, plays a pivotal role in cell adhesion, migration, and oncogenic transformation. Aberrant FN expression is associated with poor prognoses in various types of cancer, including breast cancer. In the current study, we investigated the relationship between FN induction and HER2 expression in breast cancer cells. Our results showed that the level of FN expression increased in response to HER family ligands, EGF and TGF-α in a time- and dose-dependent manner. On the other hand, EGF-induced FN expression decreased in response to trastuzumab, which is a HER2-targeted monoclonal antibody. However, EGF-induced FN expression was not affected by trastuzumab in JIMT-1 breast cancer cells, which are trastuzumab insensitive cells. Next, we introduced the HER2 gene into MDA-MB231 cells to verify the relationship between FN and HER2. The level of FN expression significantly increased in HER2-overexpressed MDA-MB231 cells. In contrast, the induction of FN by HER2 was significantly decreased in response to trastuzumab treatment. In addition, the induction of FN by HER2 was down-regulated by the MEK 1/2 specific inhibitor, U0126. Using conditioned culture media of vec- and HER2-overexpressed MDA-MB231 cells, we observed the cell morphology, adhesion, and invasion of MDA-MB231 cells. Interestingly, in conditioned culture media of HER2-overexpressed MDA-MB231 cells, the cell morphology was altered, and adhesion and invasion of MDA-MB231 cells significantly increased. In addition, our results showed that recombinant human FN augmented cell adhesion and invasion of MDA-MB231 cells while these inductions decreased in response to an FN inhibitor. Therefore, we demonstrated that the induction of FN by HER2 triggers cell adhesion and invasion capacities.

The role of FGF-2/HGF and fibronectin matrix on pleomorphic adenoma myoepithelial cell morphology and immunophenotype: an in vitro study

Myoepithelial cells play a central role in glandular tumors, regulating the progression of in situ to invasive neoplasias, with the tumor microenvironment being shown to be involved in both initiation and progression. This study aimed to analyze the in vitro effects of fibroblast growth factor-2 (FGF-2) and hepatocyte growth factor (HGF) in myoepithelial cells under the influence of the fibronectin matrix extracellular protein. Benign myoepithelial cells were obtained from pleomorphic adenoma and cultured on a fibronectin substratum. FGF-2 and HGF were supplemented at different concentrations and time intervals, in order to evaluate cell proliferation, morphology and immunophenotype. Individually, FGF-2 and HGF supplementation did not alter myoepithelial cell proliferation, morphology or immunophenotype. The fibronectin substratum provoked an increase in cell proliferation and immunopositivity for α-smooth muscle actin and FGF-2. The myoepithelial cell morphology changed when the fibronectin substratum and FGF-2 acted together, highlighting the importance of the fibronectin extracellular matrix protein on the behavior of these cells.

Protocatechuic acid inhibits lung cancer cells by modulating FAK, MAPK, and NF-κB pathways

Cytotoxic effects of protocatechuic acid (PCA) upon 3 nonsmall cell lung cancer (NSCLC) cell lines, A549, H3255, and Calu-6 cell lines, were examined. PCA at 1, 2, 4, and 8 μM was used to treat these cells. Results showed that PCA dose-dependently reduced cell growth; and at 2-8 μM enhanced protein expression of Bax and cleaved caspase-3; as well as diminished Bcl-2 expression. This compound destabilized mitochondrial membrane via increasing caspase-3 activity, decreasing mitochondrial membrane potential and Na(+)-K(+)-ATPase activity in these cells. PCA treatments dose-dependently decreased protein expression of vascular endothelial growth factor and fibronectin, as well as lowered interleukin (IL)-6 and IL-8 release; and at 2-8 μM suppressed protein expression of basic fibroblast growth factor, matrix metalloproteinase (MMP)-2 and MMP-9. Furthermore, PCA treatments dose-dependently downregulated nuclear factor kappa (NF-κ)B p50 and NF-κB p65 protein expression, and at 2-8 μM suppressed protein expression of p-p38, p-JNK, and p-focal adhesion kinase (FAK). Our data revealed that PCA declined FAK, mitogen-activated protein kinase, and NF-κB activation, which subsequently decreased the production of cytokines and growth factors, and consequently inhibited proliferation of 3 test NSCLC cells. These findings suggest that PCA could provide wide-ranging anti-NSCLC potency.

A portable microfluidic device for the rapid diagnosis of cancer metastatic potential which is programmable for temperature and CO2

If metastasis of lung cancer can be found and treated early, a victim might have an improved chance to prevail over it, but routine examinations such as chest radiography, computed tomography and biopsy cannot characterize the metastatic potential of lung cancer cells; critical diagnoses to define optimal therapeutic strategies are thus lost. We designed a portable microfluidic device for the rapid diagnosis of cancer metastatic potential. Featuring a micro system to control temperature and a bicarbonate buffered environment, our device discriminates a rate of surface detachment as an index of the migratory ability of cells cultured on pH-responsive chitosan. We labeled metastatic subpopulations of lung cancer cell lines, and verified that our device is capable of separating cells according to their metastatic ability. As only few cells are needed, a patient's specimen from biopsies, e.g. from fine-needle aspiration, can be processed on site to offer immediate information to physicians. We expect that our design will provide valuable information in pre-operative evaluations to assist the definition of therapeutic plans for lung cancer, as well as for metastatic tumors of other types.

Decreased expression of the long non-coding RNA FENDRR is associated with poor prognosis in gastric cancer and FENDRR regulates gastric cancer cell metastasis by affecting fibronectin1 expression

BACKGROUND

FENDRR is a long non-coding RNAs (lncRNA) that binds to polycomb repressive complexe 2 (PRC2) to epigenetically regulate the expression of its target gene. The clinical role of FENDRR in carcinomas remains yet to be found.

METHOD

Real-time polymerase chain reaction (PCR) was used to examine FENDRR expression in gastric cancer cell lines/tissues compared with normal epithelial cells/adjacent non-tumorous tissues. Cell proliferation assays, Wound healing assays, and in vitro and in vivo invasion and migration assays were performed to detect the biological effects of FENDRR in gastric cancer cells. Real-time PCR, western-blot and immunohistochemistry were used to evaluate the mRNA and protein expression of fibronectin1 (FN1). Secreted matrix metalloproteinase (MMP) activities were detected and characterized using gelatin zymography assay.

RESULTS

FENDRR was downregulated in gastric cancer cell lines and cancerous tissues, as compared with normal gastric epithelial cells and adjacent noncancerous tissue samples. Low FENDRR expression was correlated with deeper tumor invasion (p < 0.001), higher tumor stage (p = 0.001), and lymphatic metastasis (p = 0.007). Univariate and multivariate analyses indicated that low FENDRR expression predicted poor prognosis. Histone deacetylation was involved in the downregulation of FENDRR in gastric cancer cells. FENDER overexpression suppressed invasion and migration by gastric cancer cells in vitro, by downregulating FN1 and MMP2/MMP9 expression.

CONCLUSION

Low expression of the lncRNA FENDRR occurs in gastric cancer and is associated with poor prognosis. Thus, FENDRR plays an important role in the progression and metastasis of gastric cancer.

Chronic exposure of lung alveolar epithelial type II cells to tobacco-specific carcinogen NNK results in malignant transformation: a new in vitro lung carcinogenesis model

Lung cancer is the leading cause of cancer-related mortality in both men and women throughout the world. This disease is strongly associated with tobacco smoking. The aim of this manuscript was to establish an in vitro model that mimics the chronic exposures of alveolar epithelial type II cells to the tobacco-specific nitrosamine carcinogen, NNK. Immortalized non-neoplastic alveolar epithelial cells type II, (E10 cells), from BALB/c mice were exposed to low concentration of NNK (100 pM) during 5, 10, 15, and 20 cycles of 48 h. NNK-transformed cells showed an increase of proliferation rate and motility. Moreover, these cells underwent epithelial-to-mesenchymal transition (EMT). Increased migratory capacity and EMT were correlated to the time of exposure to NNK. NNK-transformed cells were tested for their growth and metastatic capacity in vivo. Subcutaneous injection of cells exposed to NNK for 20 cycles (E10-NNK20 clone) into BALB/c mice led to the formation of subcutaneous tumors that arose after 40 ± 17 d in all animals, which died 95 ± 18 d after cell inoculation, with lymph nodes and lung metastasis. The morphological characteristics of tumors were compatible with metastatic undifferentiated carcinoma. Cells exposed to NNK for 5-10 cycles did not display metastatic capacity, while those exposed for 15 cycles displayed low capacity. Our results show that prolonged exposures to NNK led the cells to increasingly acquire malignant properties. The cellular model presented in this study is suitable for studying the molecular events involved in the different stages of malignant transformation.

Expression and prognostic significance of fibronectin and matrix metalloproteases in breast cancer metastasis

AIMS

Fibronectin (FN) has attracted interest in cancer research, owing to its role in tumour progression. The aims of this study were to investigate the expression and clinical relevance of FN in breast cancer, and to explore its relationship with the expression of matrix metalloproteases (MMPs) and their inhibitors (TIMPs).

METHODS AND RESULTS

An immunohistochemical study was performed using tumours from 110 breast cancer patients, with tissue arrays and specific antibodies against FN, MMP-7, MMP-9, MMP-11, TIMP-1, and TIMP-2. The results indicated that FN expression was related to tumour size, histological grade, and MMP-9 expression. Tumours with high FN expression by tumour cells were significantly associated with a higher probability of metastasis, poorer overall survival, and expression of MMP-7, MMP-9, MMP-11, TIMP-1 and TIMP-2 by mononuclear inflammatory cells (MICs). In addition, the combination of FN expression by tumour cells and MMP-11 by MICs was strongly associated with distant metastasis development.

CONCLUSIONS

Breast carcinomas with distant metastasis frequently have tumour cells expressing intracellular FN. There is a strong association between FN expression by tumour cells and MMP or TIMP expression by stromal MICs, and this may represent crosstalk that is of prognostic relevance in breast cancer.

EDA-containing fibronectin increases proliferation of embryonic stem cells

Embryonic stem cells (ESC) need a set of specific factors to be propagated. They can also grow in conditioned medium (CM) derived from a bovine granulosa cell line BGC (BGC-CM), a medium that not only preserves their main features but also increases ESC´s proliferation rate. The mitogenic properties of this medium were previously reported, ascribing this effect to an alternative spliced generated fibronectin isoform that contains the extra domain A (FN EDA⁺). Here, we investigated if the FN EDA⁺ isoform increased proliferation of mouse and human ES cells. We analyzed cell proliferation using conditioned media produced by different mouse embryonic fibroblast (MEF) lines genetically engineered to express FN constitutively including or excluding the EDA domain (FN EDA^-), and in media supplemented with recombinant peptides containing or not the EDA. We found that the presence of EDA in the medium increased mouse and human ESC’s proliferation rate. Here we showed for the first time that this FN isoform enhances ESC’s proliferation. These findings suggest a possible conserved behavior for regulation of ES cells proliferation by this FN isoform and could contribute to improve their culturing conditions both for research and cell therapy.

Fibronectin promotes migration and invasion of ovarian cancer cells through up-regulation of FAK-PI3K/Akt pathway

Ovarian cancer is the leading cause of death from gynecological malignancy, and the fourth most common cause of cancer death among American women. This study investigates the mechanism of fibronectin (FN) in stimulating ovarian cancer cell migration and invasion through up-regulation of focal adhesion kinase (FAK) pathway. Human ovarian cancer cells (OVCAR-3, A2780/CP70) were cultured and treated with fibronectin (10 µg/mL). Trans-well plates were used to conduct the migration assay, real-time RT-PCR for FAK mRNA expression, and FAK siRNA for blocking FAK expression. Western blots were used for P-FAK, P-PI3K, and P-Akt analysis. Fibronectin-treated OVCAR-3, A2780/CP70 cells have increased ability to migrate and invade. It significantly promoted this behavior through the phosphorylation of FAK. The cell displayed significantly increased signaling regulation of the FAK pathway (p-PI3K/P-Akt). Furthermore, siRNA FAK-treated cells had reduced the levels of p-PI3K/P-Akt after induced by fibronectin. Our results indicate that FAK inhibition can suppress ovarian cancer cells migration and invasion through inhibiting downstream signaling (PI3K/AKT), which might be a therapeutic target or biomarker for ovarian cancer.

The EDA-containing cellular fibronectin induces epithelial-mesenchymal transition in lung cancer cells through integrin α9β1-mediated activation of PI3-K/AKT and Erk1/2

Cellular fibronectin (cFN) is one of the main components of tissue extracellular matrices and is involved in multiple physiologic and pathologic processes such as embryogenesis, wound healing, inflammation and tumor progression. The function of fibronectin in regulating normal cell adhesion and migration is well documented, but its function in cancer progression is only partially unraveled. We have reported previously that fibronectin stimulates the proliferation and survival of non-small lung carcinoma cells through upregulation of pro-oncogenic signals related to cyclooxygenase-2/phosphatidylinositol-3-kinase/protein kinase B (COX-2/PI3-K/AKT)/mammalian target of rapamycin triggered by activation of the integrin α5β1. Here, we extend these studies by showing that fibronectin promotes epithelial-mesenchymal transition (EMT) in lung cancer cells. We found that cFN, but not plasma fibronectin or type 1 collagen, induces lung carcinoma cell scattering in vitro, promotes cell migration and invasion of Matrigel and stimulates the expression of the mesenchymal marker α-smooth muscle actin while decreasing the expression of the epithelial marker E-cadherin through PI3-K and Erk pathways. Interestingly, the extra domain A (EDA) within cFN was found to be crucial for this process, as confirmed by testing cells overexpressing EDA or cells exposed to EDA-containing matrices. We found that the integrin α9, but not α5, mediated cFN-induced EMT as silencing integrin α9 neutralized cFN-induced EMT. Overall, our findings show that the EDA domain within cFN induces EMT in lung carcinoma cells through integrin α9-mediated activation of PI3-K and Erk.

N-glycoprotein SRMAtlas: a resource of mass spectrometric assays for N-glycosites enabling consistent and multiplexed protein quantification for clinical applications

Protein biomarkers have the potential to transform medicine as they are clinically used to diagnose diseases, stratify patients, and follow disease states. Even though a large number of potential biomarkers have been proposed over the past few years, almost none of them have been implemented so far in the clinic. One of the reasons for this limited success is the lack of technologies to validate proposed biomarker candidates in larger patient cohorts. This limitation could be alleviated by the use of antibody-independent validation methods such as selected reaction monitoring (SRM). Similar to measurements based on affinity reagents, SRM-based targeted mass spectrometry also requires the generation of definitive assays for each targeted analyte. Here, we present a library of SRM assays for 5568 N-glycosites enabling the multiplexed evaluation of clinically relevant N-glycoproteins as biomarker candidates. We demonstrate that this resource can be utilized to select SRM assay sets for cancer-associated N-glycoproteins for their subsequent multiplexed and consistent quantification in 120 human plasma samples. We show that N-glycoproteins spanning 5 orders of magnitude in abundance can be quantified and that previously reported abundance differences in various cancer types can be recapitulated. Together, the established N-glycoprotein SRMAtlas resource facilitates parallel, efficient, consistent, and sensitive evaluation of proposed biomarker candidates in large clinical sample cohorts.

Cytomegalovirus-induced salivary gland pathology: resistance to kinase inhibitors of the upregulated host cell EGFR/ERK pathway is associated with CMV-dependent stromal overexpression of IL-6 and fibronectin

Background

Recently we identified a relationship between human cytomegalovirus (hCMV) and human salivary gland (SG) mucoepidermoid carcinoma (MEC) in over 90% of cases; tumorigenesis in these cases uniformly correlated with active hCMV protein expression and an upregulation of the EGFR → ERK pathway. Our previously characterized, novel mouse organ culture model of mouse CMV (mCMV)-induced tumorigenesis displays a number of histologic and molecular characteristics similar to human MEC.

Methods

Newborn mouse submandibular glands (SMGs) were incubated with 1 × 10⁵ PFU/ml of lacZ-tagged mCMV RM427+ on day 0 for 24 hours and then cultured in virus-free media for a total of 6 or 12 days with or without EGFR/ERK inhibitors and/or aciclovir. SMGs were collected for histology, immunolocalization (pERK, FN, IL-6), viral distribution, or Western blot analysis (pERK).

Results

Here we report: (1) mouse SMG tumors soon exhibit an acquired resistance to EGFR/ERK pathway kinase inhibitors, alone or in combination; (2) long term tumor regression can only be sustained by concurrent inhibitor and antiviral treatment; (3) CMV-dependent, kinase inhibitor resistance is associated with overexpression of fibronectin and IL-6 proteins in abnormal stromal cells.

Conclusions

Acquired resistance to kinase inhibitors is dependent upon CMV dysregulation of alternative pathways with downstream effectors common with the targeted pathway, a phenomenon with important therapeutic implications for human MEC of salivary glands.

Integrin α5β1, the Fibronectin Receptor, as a Pertinent Therapeutic Target in Solid Tumors

Integrins are transmembrane heterodimeric proteins sensing the cell microenvironment and modulating numerous signalling pathways. Changes in integrin expression between normal and tumoral cells support involvement of specific integrins in tumor progression and aggressiveness. This review highlights the current knowledge about α5β1 integrin, also called the fibronectin receptor, in solid tumors. We summarize data showing that α5β1 integrin is a pertinent therapeutic target expressed by tumoral neovessels and tumoral cells. Although mainly evaluated in preclinical models, α5β1 integrin merits interest in particular in colon, breast, ovarian, lung and brain tumors where its overexpression is associated with a poor prognosis for patients. Specific α5β1 integrin antagonists will be listed that may represent new potential therapeutic agents to fight defined subpopulations of particularly aggressive tumors.

Fibronectin stimulates migration through lipid raft dependent NHE-1 activation in mouse embryonic stem cells: involvement of RhoA, Ca(2+)/CaM, and ERK

BACKGROUND

Extracellular matrix (ECM) components and intracellular pH (pH(i)) may serve as regulators of cell migration in various cell types.

METHODS

The Oris migration assay was used to assess the effect of fibronectin (FN) on cell motility. The Na(+)/H(+) exchanger (NHE)-1 activity was evaluated by measuring pH(i) and [(22)Na(+)] uptake. To examine activated signaling molecules, western blot analysis and immunoprecipitation was performed.

RESULTS

ECM components (FN, laminin, fibrinogen, and collagen type I) increased [(22)Na(+)] uptake, pH(i), and cell migration. In addition, FN-induced increase of cell migration was inhibited by NHE-1 inhibitor amiloride or NHE-1-specific siRNA. FN selectively increased the mRNA and protein expression of NHE-1, but not that of NHE-2 or NHE-3. FN binds integrin β1 and subsequently stimulates caveolin-1 phosphorylation and Ca(2+) influx. Then, NHE-1 is phosphorylated by RhoA and Rho kinases, and Ca(2+)/calmodulin (CaM) signaling elicits complex formation with NHE-1, which is enriched in lipid raft/caveolae microdomains of the plasma membrane. Activation of NHE-1 continuously induces an increase of [(22)Na(+)] uptake and pH(i). Finally, NHE-1-dependent extracellular signal-regulated kinase (ERK) 1/2 phosphorylation enhanced matrix metalloproteinase-2 (MMP-2) and filamentous-actin (F-actin) expression, partially contributing to the regulation of embryonic stem cells (ESCs) migration.

CONCLUSIONS

FN stimulated mESCs migration and proliferation through NHE-1 activation, which were mediated by lipid raft-associated caveolin-1, RhoA/ROCK, and Ca(2+)/CaM signaling pathways.

GENERAL SIGNIFICANCE

The precise role of NHE in the modulation of ECM-related physiological functions such as proliferation and migration remains poorly understood. Thus, this study analyzed the relationship between FN and NHE in regulating the migration of mouse ESCs and their related signaling pathways.

The transcription factor ETS-1 regulates angiotensin II-stimulated fibronectin production in mesangial cells

Angiotensin II (ANG II) produced as result of activation of the renin-angiotensin system (RAS) plays a critical role in the pathogenesis of chronic kidney disease via its hemodynamic effects on the renal microcirculation as well as by its nonhemodynamic actions including the production of extracellular matrix proteins such as fibronectin, a multifunctional extracellular matrix protein that plays a major role in cell adhesion and migration as well as in the development of glomerulosclerosis. ETS-1 is an important transcription factor essential for normal kidney development and glomerular integrity. We previously showed that ANG II increases ETS-1 expression and is required for fibronectin production in mesangial cells. In these studies, we determined that ANG II induces phosphorylation of ETS-1 via activation of the type 1 ANG II receptor and that Erk1/2 and Akt/PKB phosphorylation are required for these effects. In addition, we characterized the role of ETS-1 on the transcriptional activation of fibronectin production in mesangial cells. We determined that ETS-1 directly activates the fibronectin promoter and by utilizing gel shift assays and chromatin immunoprecipitation assays identified two different ETS-1 binding sites that promote the transcriptional activation of fibronectin in response to ANG II. In addition, we identified the essential role of CREB and its coactivator p300 on the transcriptional activation of fibronectin by ETS-1. These studies unveil novel mechanisms involved in RAS-induced production of the extracellular matrix protein fibronectin in mesangial cells and establish the role of the transcription factor ETS-1 as a direct mediator of these effects.

Reduction by strontium of the bone marrow adiposity in mice and repression of the adipogenic commitment of multipotent C3H10T1/2 cells

Multipotent mesenchymal cells (MMCs) differentiate into osteoblasts or adipocytes through RUNX2 and PPARγ2, respectively. Strontium ranelate has been shown to promote osteoblastogenesis and prevent adipogenesis in long-term experiments using MMCs. The present study involved in-vitro and in-vivo investigations of whether Sr might first be an inhibitor of adipogenesis, thus explaining late osteoblastogenesis. It was established in vivo that Sr reduces adipogenesis in mice treated only for 3 weeks with a 6 mmol/kg/day dose of Sr while the trabecular bone volume is increased. In order to decipher molecular mechanisms during inhibition of adipogenesis, we used murine MMCs C3H10T1/2 cultured under adipogenic conditions (AD) and treated Sr of a concentration up to 3 mM. It was shown that early on (day 1), Sr dose-dependently reduced PPARγ2 and CEBPα mRNA without affecting the RUNX2 gene expression whereas it repressed ALP mRNA. Later (day 5), PPARγ2 and CEBPα mRNA remained inhibited by Sr, preventing adipocyte lipid accumulation, while Runx2 and ALP mRNA were increased. Moreover, under the mentioned conditions, Sr was able to quickly induce the Cyclin D1 gene expression, proliferation and fibronectin fibrillogenesis, both involved in the inhibition of adipogenesis. The inhibition of the ERK pathway by U0126 blunted the Sr-induced PPARγ2 repression while restoring the lipid accumulation. These results demonstrated that Sr was capable of rapidly reducing adipogenesis by a selective PPARγ2 repression that can be explained by its ability to promote MMC proliferation.

Insulin action on H292 bronchial carcinoma cells as compared to normal bronchial epithelial cells

Inhaled insulin may contribute to bronchial carcinoma due to IGF-I receptor activation by high local concentrations. Therefore, effects of insulin and IGF-I on human bronchial carcinoma cells (H292) and normal bronchial epithelium cells (HBE) were studied. TGF-β was included since it also influences carcinoma progression. H292 and HBE cells expressed both the insulin receptor and the IGF-I receptor; in H292 cells an additional, shorter, splicing variant (IR-A) of the insulin receptor was present. Insulin receptor expression was around four to five times higher in H292 than in HBE cells at mRNA and protein levels. Insulin and TGF-β exerted contrary actions on proliferation and gene expression in H292 cells. Genes regulated by insulin, IGF-I, and TGF-β were linked to inflammation, cell adhesion, muscle contraction and differentiation. Insulin and IGF-I also suppressed DNA repair genes. EC(50) for insulin-induced proliferation was around 5 nM in H292 and around 30 nM HBE cells. The EC(50) values for gene expression ranged from 9 to 90 nM in both cell types, dependent on the gene studied. In H292 cells, the proliferative response was much stronger if TGF-β was present. In HBE cells this interaction of insulin and TGF-β was not observed, and changes in gene expression were mostly lower by at least 10-fold as compared to H292. All in all, the insulin effects in H292 were generally much stronger than in HBE cells and - with regard to proliferation - occurred at lower concentrations. Thus, insulin will hardly induce cancer from normal bronchial cells but may favour progression of pre-existing tumours.

Establishment of a highly migratory subclone reveals that CD133 contributes to migration and invasion through epithelial-mesenchymal transition in pancreatic cancer

Pancreatic cancer is a lethal disease because of invasion and early metastasis. Although CD133, a marker of cancer stem cells (CSCs) in a variety of solid tumors, has been studied in recent decades, its function remains obscure. Recent reports suggest that epithelial-mesenchymal transition (EMT) may be related to the properties of CSCs. In this study, we investigated whether CSC markers are associated with EMT. For Capan1M9, a highly migratory cell subclone established from human pancreatic cancer cell line Capan-1, CD133 expression, migration, and invasion were greater than for the parent cells. In Capan1M9 cells, the EMT-related transcription factors Slug and Snail were up-regulated, and N-cadherin and fibronectin were also substantially increased. In contrast, occludin and desmoplakin were suppressed. Knockdown of endogenous CD133 in the Capan1M9 cells led to Slug suppression and reduction of migration and invasion. Taken together, CD133 has an important role in migration and invasion by facilitating EMT in pancreatic cancer cells.

Inhibition of cell proliferation, invasion and migration by ursolic acid in human lung cancer cell lines

Ursolic acid (UA) is a pentacyclic triterpene naturally occurring in many plant foods. Apoptotic, anti-invasive and anti-migratory effects of UA at 2, 4, 8, or 16 μmol/L in human non-small cell lung cancer A549, H3255 and Calu-6 cell lines were examined. The impact of this compound upon associated biomarkers such as vascular endothelial growth factor (VEGF), intercellular adhesion molecule-1 (ICAM-1) and matrix metalloproteinase (MMP) was also evaluated. UA treatments concentration-dependently decreased cell viability, and lowered Na(+)-K(+)-ATPase activity (P<0.05). This compound at 4-16 μmol/L concentration-dependently increased DNA fragmentation, and reduced VEGF and transforming growth factor beta1 levels in test cancer cells (P<0.05). UA concentration-dependently suppressed ICAM-1 expression (P<0.05). This compound significantly declined fibronectin expression (P<0.05), but concentration-dependent effect was shown in H3255 cells only (P<0.05). UA treatments significantly suppressed the expression of MMP-9 and MMP-2 (P<0.05), and inhibited protein kinase C activity in test cell lines (P<0.05). UA treatments also concentration-dependently reduced cell invasion (P<0.05); however, this compound at 4-16 μmol/L significantly decreased cell migration (P<0.05), and concentration-dependent effect was shown in A549 and Calu-6 cells (P<0.05). These findings suggested that this triterpene was a potent anti-lung cancer agent, and it might be able to retard invasion and metastasis of lung cancer cells.

miRNA-1 targets fibronectin1 and suppresses the migration and invasion of the HEp2 laryngeal squamous carcinoma cell line

MicroRNAs (miRNAs) are an evolutionarily conserved class of endogenous, non-coding RNAs that modulate gene expression at the post-transcriptional level and are involved in tumorigenesis. In this study, we demonstrate that miR-1 suppresses the potential for growth, migration and invasion in the HEp2 cell line. Furthermore, we validate that FN1 is a direct target gene for miR-1 via fluorescent reporter assay and is negatively regulated by miR-1. Moreover, the knockdown of FN1 has the same phenotypic effects as the overexpression of miR-1. Taken together, our results provide evidence that miR-1 may play a role as a tumor suppressor gene in laryngeal carcinoma.

Leptin increases motility and integrin up-regulation in human prostate cancer cells

Prostate cancer is the most commonly diagnosed malignancy in men and shows a predilection for metastasis to distant organs. Leptin, an adipocyte-derived cytokine that is closely associated with obesity, has recently been shown to be involved in carcinogenesis and cancer progression. The aim of this study was to investigate whether leptin is associated with the motility of prostate cancer cells. We found that leptin increased the migration of human prostate cancer cells and expression of αvβ3 integrin on these cells. Leptin-mediated migration and increased integrin expression were attenuated by OBRl receptor antisense oligonucleotide (ODN). Activation of insulin receptor substrate (IRS-1), phosphatidylinositol 3-kinase (PI3K), Akt, and NF-κB pathways after leptin treatment was demonstrated. Furthermore, leptin-induced integrin expression and migration activity were inhibited by specific inhibitors; small interfering RNAs (siRNAs); and mutants of the IRS-1, PI3K, Akt, and NF-κB cascades. Therefore, this study shows that leptin stimulates the migration of human prostate cancer cells, one of the mechanisms underlying leptin-directed migration was transcriptional up-regulation of αvβ3 integrin expression through the OBR1/IRS-1/PI3K/Akt/NF-κB signal transduction pathway.

Involvement of caveolin-1 in fibronectin-induced mouse embryonic stem cell proliferation: role of FAK, RhoA, PI3K/Akt, and ERK 1/2 pathways

Fibronectin (FN) is the foremost proliferation-associated extracellular matrix component promoting cell adhesion, migration, and survival. We examined the effect of FN on cell proliferation and the related signaling pathways in mouse embryonic stem (ES) cells. FN increased integrin β1, Src, focal adhesion kinase (FAK), and caveolin-1 phosphorylation levels in a time-dependent manner. Phosphorylation of Src, FAK, and caveolin-1 was attenuated by integrin β1 neutralizing antibody. Integrin β1, Src, and FAK coimmunoprecipitated with caveolin-1 in the presence of FN. In addition, FN increased RhoA and Rho kinase activation, which were completely blocked by PP2, FAK small interfering RNA (siRNA), caveolin-1 siRNA, or the caveolar disruptor methyl-β-cyclodextrin (MβCD). FN also increased phosphorylation of Akt and ERK 1/2, which were significantly blocked by either FAK siRNA, caveolin-1 siRNA, MβCD, GGTI-286 (RhoA inhibitor), or Y-27632 (Rho kinase inhibitor). FN-induced increase of protooncogenes (c-fos, c-myc, and c-Jun) and cell-cycle regulatory proteins (cyclin D1/CDK4 and cyclin E/CDK2) expression levels were attenuated by FAK siRNA or caveolin-1 siRNA. Furthermore, inhibition of each pathway such as integrin β1, Src, FAK, caveolin-1, RhoA, Akt, and ERK 1/2 blocked FN-induced [(3)H]-thymidine incorporation. We conclude that FN stimulates mouse ES cell proliferation via RhoA-PI3K/Akt-ERK 1/2 pathway through caveolin-1 phosphorylation.

Development of a highly metastatic model that reveals a crucial role of fibronectin in lung cancer cell migration and invasion

Background

The formation of metastasis is the most common cause of death in patients with lung cancer. A major implement to understand the molecular mechanisms involved in lung cancer metastasis has been the lack of suitable models to address it. In this study, we aimed at establishing a highly metastatic model of human lung cancer and characterizing its metastatic properties and underlying mechanisms.

Methods

The human lung adeno-carcinoma SPC-A-1 cell line was used as parental cells for developing of highly metastatic cells by in vivo selection in NOD/SCID mice. After three rounds of selection, a new SPC-A-1sci cell line was established from pulmonary metastatic lesions. Subsequently, the metastatic properties of this cell line were analyzed, including optical imaging of in vivo metastasis, immunofluorescence and immunohistochemical analysis of several epithelial mesenchymal transition (EMT) makers and trans-well migration and invasion assays. Finally, the functional roles of fibronectin in the invasive and metastatic potentials of SPC-A-1sci cells were determined by shRNA analysis.

Results

A spontaneously pulmonary metastatic model of human lung adeno-carcinoma was established in NOD/SCID mice, from which a new lung cancer cell line, designated SPC-A-1sci, was isolated. Initially, the highly metastatic behavior of this cell line was validated by optical imaging in mice models. Further analyses showed that this cell line exhibit phenotypic and molecular alterations consistent with EMT. Compared with its parent cell line SPC-A-1, SPC-A-1sci was more aggressive in vitro, including increased potentials for cell spreading, migration and invasion. Importantly, fibronectin, a mesenchymal maker of EMT, was found to be highly expressed in SPC-A-1sci cells and down-regulation of it can decrease the in vitro and in vivo metastatic abilities of this cell line.

Conclusions

We have successfully established a new human lung cancer cell line with highly metastatic potentials, which is subject to EMT and possibly mediated by increased fibronectin expression. This cell line and its reproducible s.c. mouse model can further be used to identify underlying mechanisms of lung cancer metastasis.