Effects of human fibroblasts on invasiveness of oral cancer cells in vitro: isolation of a chemotactic factor from human fibroblasts

Heparin-Binding Protein 17/Fibroblast Growth Factor-Binding Protein-1 Knockout Inhibits Proliferation and Induces Differentiation of Squamous Cell Carcinoma Cells

Simple Summary

Fibroblast growth factor (FGF) plays an important role in tumor growth by inducing angiogenesis in addition to promoting the proliferation of squamous cell carcinoma (SCC) and oral squamous cell carcinoma (OSCC) cells. Heparin-binding protein 17/fibroblast growth factor-binding protein-1 (HBp17/FGFBP-1) purified from A431 cell-conditioned media based on its capacity to bind to FGF-1 and FGF-2 is recognized as a pro-angiogenic molecule as a consequence of its interaction with FGF-2. In this study, we have examined the functional role of HBp17/FGFBP-1 in A431 and HO-1-N-1 cells using the CRISPR/Cas9 technology. Our results showed that HBp17/FGFBP-1 knockout inhibited cell proliferation, colony formation, and cell motility compared to control. The amount of FGF-2 was decreased in culture medium conditioned by HBp17/FGFBP-1 knockout cells compared to control. We performed cDNA/protein expression analysis followed by Gene Ontology and protein–protein interaction analysis. The results demonstrate that both gene and protein expression related to epidermal development, cornification, and keratinization were upregulated in HBp17/FGFBP-1-knockout A431 and HO-1-N-1 cells.

Abstract

Heparin-binding protein 17/fibroblast growth factor-binding protein-1 (HBp17/FGFBP-1) has been observed to induce the tumorigenic potential of epithelial cells and is highly expressed in oral cancer cell lines and tissues. It is also recognized as a pro-angiogenic molecule because of its interaction with fibroblast growth factor (FGF)-2. In this study, we examined the functional role of HBp17/FGFBP-1 in A431 and HO-1-N-1 cells. Originally, HBp17/FGFBP-1 was purified from A431 cell-conditioned media based on its capacity to bind to FGF-1 and FGF-2. We isolated and established HBp17/FGFBP-1-knockout (KO)-A431 and KO-HO-1-N-1 cell lines using the clusters of regularly interspaced short palindromic repeats (CRISPR) and CRISPR-associated protein 9 (Cas9) gene editing technology. The amount of FGF-2 secreted into conditioned medium decreased for A431-HBp17-KO and HO-1-N-1-HBp17-KO cells compared to their WT counterparts. Functional assessment showed that HBp17/FGFBP-1 KO inhibited cell proliferation, colony formation, and cell motility in vitro. It also inhibited tumor growth in vivo compared to controls, which confirmed the significant difference in growth in vitro between HBp17-KO cells and wild-type (WT) cells, indicating that HBp17/FGFBP-1 is a potent therapeutic target in squamous cell carcinomas (SCC) and oral squamous cell carcinomas (OSCC). In addition, complementary DNA/protein expression analysis followed by Gene Ontology and protein–protein interaction (PPI) analysis using the Database for Visualization and Integrated Discovery and Search Tool for the Retrieval of Interacting Genes/Proteins showed that both gene and protein expression related to epidermal development, cornification, and keratinization were upregulated in A431-HBp17-KO and HO-1-N-1-KO cells. This is the first discovery of a novel role of HBp17/FGFBP-1 that regulates SCC and OSCC cell differentiation.

In vitro study on anti-cancer properties of genistein in tongue cancer

Purpose

Tongue cancer is an extremely aggressive disease and is characterized by a poor prognosis. It is a complex disease to treat and current therapies have produced mediocre results with many side effects. Some facts suggest that natural essences can support traditional cancer therapy by carrying out a synergistic function with chemotherapy. Therefore, we evaluated the antitumor effects of genistein on tongue carcinoma cells.

Methods

Genistein 20, 50 and 100 µM were used for 24, 48 and 72 hours on 3 tongue carcinoma cell lines. xCELLigence system was used to evaluate the effects on cell adhesion, proliferation and to calculate IC₅₀ values. Both MTT assay and Trypan blue assay were used to evaluate alterations in cell viability, scratch assay for cell migration and Western blot analysis for expression of some proteins.

Results

Cell adhesion was inhibited especially between 20 and 50 µM of genistein treatment. Proliferation was reduced by 50% for treatments with 20 µM at 24 hours, with 20 or 50 µM at 48 and 50 µM at 72 hours (P<0.0001). Viability tests confirmed a proportional reduction in concentration of genistein and duration of treatments. Even cell migration was reduced significantly (P<0.001). Genistein down-regulates vitronectin, OCT4 and survivin.

Conclusion

This in vitro study clarifies the anti-tumor effect of genistein on tongue carcinoma. In vivo studies are needed to confirm these data and develop a suitable delivery system that is capable of acting directly on tumor.

LDL receptor-related protein 1: unique tissue-specific functions revealed by selective gene knockout studies

The LDL receptor-related protein (originally called LRP, but now referred to as LRP1) is a large endocytic receptor that is widely expressed in several tissues. LRP1 is a member of the LDL receptor family that plays diverse roles in various biological processes including lipoprotein metabolism, degradation of proteases, activation of lysosomal enzymes, and cellular entry of bacterial toxins and viruses. Deletion of the LRP1 gene leads to lethality in mice, revealing a critical, but as of yet, undefined role in development. Tissue-specific gene deletion studies reveal an important contribution of LRP1 in the vasculature, central nervous system, macrophages, and adipocytes. Three important properties of LRP1 dictate its diverse role in physiology: 1) its ability to recognize more than 30 distinct ligands, 2) its ability to bind a large number of cytoplasmic adaptor proteins via determinants located on its cytoplasmic domain in a phosphorylation-specific manner, and 3) its ability to associate with and modulate the activity of other transmembrane receptors such as integrins and receptor tyrosine kinases.

Influences of tumor stroma on the malignant phenotype

BACKGROUND

The microenvironment makes a significant contribution to the progression of oral carcinomas. Many different stromal events, such as vascularization, fibroblast activation, myofibroblast differentiation, and the presence of specific stromal proteins, such as proteolytic enzymes, fibronectin and laminin 5 are all characteristics of the tumor stroma. Less is, however, known of the significance of the biophysical properties of the tumor stroma. The purpose of the present study was to investigate how cellular and mechanical properties of the three-dimensional collagen matrix may influence cell proliferation and invasion of oral carcinoma cell lines.

METHOD

Oral cancer cells were cultured in an organotypic culture system on different collagen concentrations, and invasion was measured. Furthermore, the presence of cancer associated proteins such as glycosylated oncofetal fibronectin and laminin 5 was investigated.

RESULTS

We found that expression of glycosylated oncofetal fibronectin was increased in the invasive phenotype of oral carcinoma cell lines. Furthermore we demonstrated that certain concentrations of collagen in the connective tissue equivalent, appears to stimulate invasiveness of oral carcinoma cells.

A novel function of CD82/KAI-1 on E-cadherin-mediated homophilic cellular adhesion of cancer cells

In this study, we analyzed the effect of the metastasis suppressor CD82/KAI-1, a member of the tetraspanin superfamily, on intercellular adhesion on cancer cells. The newly established invasion assay and the cell aggregation assay revealed that CD82 strengthens E-cadherin-mediated intercellular adhesion. Interestingly, ectopic expression of CD82 stabilized E-cadherin/beta-catenin complex formation. Furthermore, CD82 reduced tyrosine phosphorylation of beta-catenin on HGF stimulation. Taken together, CD82 may stabilize or strengthen E-cadherin-dependent intercellular adhesion by regulating beta-catenin-mediated signal transduction on cancer cells, and consequently, prevent cancer cells from seceding from the primary tumor site.

Species-specific fibroblasts required for triggering invasiveness of partially transformed oral keratinocytes

This study tests the hypothesis that invasion of partially transformed keratinocytes is initiated by diffusible, proinvasive signals provided by species-specific fibroblasts. In vitro organotypic cultures of neoplastic human oral mucosa were constructed by growing a partially transformed, nontumorigenic keratinocytic cell line isolated from a dysplastic human oral lesion (DOK-ECACC94122104) on top of various types of connective tissue equivalents. Cultured tissues were analyzed by histomorphometry (depth and area of invasion: Dinv, Ainv) and immunohistochemistry. Presence of human fibroblasts in the matrix induced a local invasion of DOK (Dinv = 95.6 +/- 7.1 microm, Ainv = 45.8 +/- 3.5%). Minimal invasion (P < 0.05) was observed when DOK grew on simple collagen matrix (Dinv = 14.1 +/- 2.1 microm, Ainv = 3.7 +/- 0.8%) or matrices containing fibroblasts from mouse (Dinv = 11.5 +/- 4.0 microm, Ainv = 4.3 +/- 1.0%) or rat (Dinv = 15.6 +/- 1.2 microm, Ainv = 6.1 +/- 0.5%). In these cultures, local invasion could be induced by the presence of human fibroblasts in a bottom layer of the collagen matrix (P < 0.05) or by conditioned medium from organotypic cultures of DOK on human fibroblast-containing matrix (P < 0.05) but not by conditioned medium from human fibroblast monocultures (P > 0.05). Deposition of human collagen IV was observed at epithelial-matrix interface only when DOK behaved invasively. In conclusion, invasion of partially transformed oral keratinocytes was triggered by keratinocyte-induced fibroblast-derived diffusible factor(s) in a species-specific manner and associated with de novo synthesis of collagen IV.

Expression of the urokinase receptor regulates focal adhesion assembly and cell migration in adenoid cystic carcinoma cells

Adenoid cystic carcinoma (AdCC) cell lines (ACCS and ACCT) showed higher migration responses and adhesion to the extracellular matrix (ECM), especially types I and IV collagen, than did the oral squamous cell carcinoma (SCC) lines (NA and TF). The response to collagens was largely and exclusively inhibited by anti-alpha(2) integrin antibody. Moreover, AdCC cell lines expressed higher surface levels of urokinase-type plasminogen activator receptor (uPAR) than did SCC cell lines. When AdCC cells were plated on collagen, the surface level of uPAR was increased, and numerous focal adhesions consisting of uPAR, vinculin, and paxillin were assembled; whereas collagen-stimulated SCC cell counterparts or AdCC cells plated on other types of ECM, such as fibronectin, failed to assemble such definite focal adhesions. In order to elucidate the association of uPAR with collagen-induced events, an ACCS-AS cell line transfected with a vector expressing antisense uPAR RNA was established and shown to have reduced uPAR (about 10% that of parental ACCS at both the protein and mRNA levels). ACCS-AS showed a strong reduction of collagen-stimulated migration and focal adhesion assembly of alpha(2) integrin, vinculin, and paxillin. These findings suggest that AdCC has a proclivity for migrating to types I and IV collagens due to the overexpression of uPAR, which plays a key role in focal adhesion assembly and migration.

Inhibition of epidermal growth factor-induced invasion by dexamethasone and AP-1 decoy in human squamous cell carcinoma cell lines

Invasive squamous cell carcinoma (SCC) cells degrade extracellular matrix (ECM) via an extracellular protease cascade that includes urokinase-type plasminogen activator (uPA), plasmin, and the metalloprotease (MMP) family of collagenases. In this study, treatment of oral SCC cells with epidermal growth factor (EGF) stimulated the cells to invade Matrigel (constructive basement membrane (BM) protein). EGF-induced cell invasion was inhibited by antibodies to uPA and by synthetic uPA inhibitors. EGF also induced increased expression of uPA and uPA receptor (uPAR) proteins and mRNA, as well as transcription factor activator protein-1 (AP-1)-DNA binding. These EGF-induced changes were inhibited by treatment with dexamethasone (DEX). DEX treatment also stimulated the production of plasminogen activator inhibitor type 1. Moreover, transfection of SCC cells with AP-1 decoy oligodeoxynucleotides (ODNs) resulted in the suppression of EGF-induced uPA and uPAR expression and Matrigel invasion. These results suggest that oral SCC cells invade Matrigel mainly through the uPA-plasmin cascade, which is mediated by the transcription factor AP-1. The uPA-uPAR interaction is essential for augmenting proteolytic activity and uPAR-mediated signaling, which ultimately induce motility and invasion. Since DEX inhibits the expression of both uPA and uPAR, it may be a useful treatment for oral SCC.

Thrombospondin stimulates focal adhesion disassembly through Gi- and phosphoinositide 3-kinase-dependent ERK activation

The matricellular protein thrombospondin (TSP) stimulates stress fiber and focal adhesion disassembly through a sequence (hep I) in its heparin-binding domain. TSP/hep I signals focal adhesion disassembly by binding cell surface calreticulin (CRT) and activating phosphoinositide 3-kinase (PI3K). However, other components of this signaling pathway have not been identified. We now show that TSP induces focal adhesion disassembly through activation of pertussis toxin (PTX)-sensitive G proteins and ERK phosphorylation. PTX pretreatment inhibits TSP/hep I-mediated focal adhesion disassembly as well as PI3K activation. In addition, membrane-permeable Galpha(i2)- and Gbetagamma-blocking peptides inhibit hep I-mediated focal adhesion disassembly. Hep I stimulates a transient increase in ERK activation, which is abrogated by both PTX and PI3K inhibitors. Inhibiting ERK activation with MEK inhibitors blocks hep I-mediated focal adhesion disassembly, indicating that ERK activation is required for cytoskeletal reorganization. G protein signals and ERK phosphorylation are induced by TSP binding to cell surface CRT, because CRT null mouse embryonic fibroblasts (MEF) fail to stimulate ERK phosphorylation in response to TSP/hep I treatment. These data show that G(i) protein and ERK, in concert with PI3K, are stimulated by TSP.CRT interactions at the cell surface to induce de-adhesive changes in the cytoskeleton.

Role of HGF/c-met system in invasion and metastasis of oral squamous cell carcinoma cells in vitro and its clinical significance

We examined the role of the hepatocyte growth factor (HGF)/c-met system on invasion and metastasis of oral squamous cell carcinoma (SCC) cells. In monolayer culture, exogenous HGF marginally affected the growth of oral SCC cells (BHY, HN, IH) and human gingival epithelial cells (GE). In type I collagen matrix, however, HGF significantly enhanced the invasive growth of the cancer cells (p < 0.05). We detected the expression of c-met (HGF receptor) mRNA in all of the cancer cells, but not in human gingival fibroblasts (GF). Oral SCC cells did not secret HGF protein into the medium, but GF secreted a large amount of HGF protein (15 ng/ml). Furthermore, HGF markedly enhanced the migration of cancer cells in a Transwell invasion chamber. Then, we examined the serum levels of HGF in oral SCC patients, or HGF concentrations in oral cancer tissues. Serum levels of HGF in the patients were significantly higher than those in healthy volunteers (p < 0.05). After initial treatment, all of the tumor-free survivors showed a marked decline in the serum HGF levels. Furthermore, HGF concentrations in metastatic cancer tissues were significantly higher than those of non-metastatic cancer tissues and normal gingiva (p < 0.01). These results suggest that HGF plays an important role in invasion and metastasis of oral SCC cells as a paracrine factor, and an elevated HGF level in the cancer tissue can be a predictive marker for metastasis formation in patients with oral SCC.

Production of bioengineered cancer tissue constructs in vitro: epithelium-mesenchyme heterotypic interactions

A few models have been established to study cancer cells in vitro. However, the cellular interactions have rarely been studied specifically using bioengineered cancer constructs combining human carcinoma cells and tumor-associated fibroblasts. We developed an in vitro model of tridimensional bioengineered cancer tissue constructs (bCTC) by seeding mammary epithelial cancer cells or normal keratinocytes over a mesenchymal layer containing tumor-derived fibroblastic cells or normal skin fibroblasts. After the introduction of epithelial cells, each construct was cultured for another 10 d. Histologic analyses showed that carcinoma cell lines could invade the subjacent mesenchymal layer and that the capacity to migrate was related to the invasive potential of cancer cells and the type of fibroblasts used, while noninvasive populations did not. Of the tested epithelial cells, MDA-MB-231 and, to a lesser degree, HDQ-P1 cell lines were invasive, and the invasion was deeper into the mesenchymal component containing tumor-derived fibroblasts. However, with normal skin fibroblasts, the mesenchymal layer was degraded twice faster than with tumor-derived fibroblastic cells. MDA-MB-231 cells and normal keratinocytes induced the highest level of gelatinase B, and the level was lowest with the MCF-7 cell line. The activated form of gelatinase B was, however, induced to the highest levels in the keratinocyte-seeded bCTC containing tumor-derived but not normal fibroblasts. MDA-MB-231 was the only epithelial cancer cell line whose activity of gelatinase A was reduced when cocultured with tumor-derived fibroblasts but not under normal fibroblast stimulation. Finally, a 50/48-kDa gelatinase band has been observed in bCTCs with noninvasive epithelial cells only. Our study demonstrates the selective secretion of gelatinases according to the phenotype of the cells seeded in the various bCTCs.

Prostate stromal cell-derived hepatocyte growth factor induces invasion of prostate cancer cell line DU145 through tumor-stromal interaction

BACKGROUND

In prostate cancer, several growth factors derived from stromal cells regulate tumor cell growth. Hepatocyte growth factor (HGF) possesses biological activities that promote cancer proliferation and invasion through tumor-stromal interaction. We examined how prostate stromal cell-derived HGF affects invasion of prostate cancer cells through this interaction.

METHODS

The effects of HGF, various growth factors (transforming growth factor (TGF)-alpha, TGF-beta1, basic fibroblast growth factor, keratinocyte growth factor, and platelet-derived growth factor), and conditioned medium (CM) from prostate stromal cells (PrSC) on prostate cancer cells (LNCaP, PC-3, and DU145) were determined by collagen gel invasion assay. DU145 cells and PrSC were cocultured for Matrigel invasion chamber assay. Induction activity of CM from cancer cells to stimulate HGF production by PrSC was studied by the ELISA method and Western blotting.

RESULTS

LNCaP and PC-3 cells did not respond to any of the factors examined. Invasion of DU145 cells into the collagen gel matrix was induced by HGF and TGF-beta1, but not by any of the other factors tested. When DU145 cells were cultured in CM from PrSC or cocultured with PrSC, the cells acquired invasive potential, and this invasion was inhibited by an antibody against HGF, but not against TGF-beta1. Native-type HGF production in PrSC was enhanced by some unknown inducer(s) produced by cancer cells.

CONCLUSIONS

PrSC-derived HGF enhanced invasive activity of the prostate cancer cell line DU145 through tumor-stromal interaction, wherein DU145 cells secreted some HGF-inducer(s) for PrSC.

Involvement of proteasomes in migration and matrix metalloproteinase-9 production of oral squamous cell carcinoma

We investigated whether proteasomes were involved in the invasiveness of oral squamous cell carcinoma (SCC) cells. The migration of SCC cells through a gelatin-coated membrane was enhanced with tumor necrosis factor alpha (TNF alpha), which was strongly inhibited by a peptide aldehyde, N-acetyl-Leu-Leu-norleucinal (ALLN), but not by its structurally related compound, N-acetyl-Leu-Leu-methioninal (ALLM). Since ALLN is a more potent inhibitor against proteasomal proteolysis than ALLM, cell migration inhibited by ALLN may thus likely depend on proteasomes. The TNF alpha-induced migration through gelatin appeared to be associated with the gelatinolytic activity from the cells, since TNF alpha strongly enhanced the production of matrix metalloproteinase (MMP)-9/gelatinase B in the SCC cells, as detected by gelatin zymography. The production of MMP-9 was also inhibited by pretreatment with ALLN, but not ALLM, in a dose-dependent manner. Moreover, ALLN could block the activation and nuclear translocation of a transcription-activating factor, NF-kappaB, which is known to regulate MMP-9 expression in TNF alpha-stimulated SCC cells. The TNF alpha-induced degradation of IkappaB alpha was also suppressed by ALLN treatment, thus implying that the molecule linking proteasome to MMP-9 production should be IkappaB alpha. We finally reconfirmed the involvement of proteasomes in the invasive behavior of oral SCC using lactacystin, a specific proteasome inhibitor, which could prevent TNF alpha from enhancing MMP-9 production, NF-kappaB activation, induction of MMP-9 mRNA and cell migration.