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PubMed2004

The fibroblast growth factor receptor-4 Arg388 allele is associated with prostate cancer initiation and progression.

PURPOSE: Increased expression of fibroblast growth factors that can activate the fibroblast growth factor receptor-4 (FGFR-4) occurs in a substantial fraction of human prostate cancers in vivo. A germline polymorphism of the FGFR-4 gene resulting in expression of arginine at codon 388 (Arg388) is associated with aggressive disease in patients with breast and colon cancer. We therefore sought to determine whether the FGFR-4 Arg388 allele was associated with prostate cancer incidence and/or the occurrence of aggressive disease. EXPERIMENTAL DESIGN: The FGFR-4 genotype of men undergoing radical prostatectomy and controls of the same race was determined and the genotype correlated with clinical and pathologic markers of disease aggressiveness. PNT1A cell lines expressing predominantly the FGFR-4 Arg388 or Gly388 allele were established, and cell migration and invasiveness of these cells were assessed by a wounding assay and by quantitative determination of invasion through Matrigel. Expression of urokinase-type plasminogen activator receptor was determined by quantitative RT-PCR and enzyme-linked immunoabsorption assay. RESULTS: Homozygosity for the FGFR-4 Arg388 allele is strongly associated with the occurrence of prostate cancer in white men. The presence of the FGFR-4 Arg388 allele is also correlated with the occurrence of pelvic lymph node metastasis and biochemical (prostate-specific antigen) recurrence. Expression of FGFR-4 Arg388 in immortalized prostatic epithelial cells results in increased cell motility and invasion through Matrigel and was associated with increased expression of urokinase-type plasminogen activator receptor. CONCLUSION: The FGFR-4 Arg388 allele is associated with both an increased incidence and clinical aggressiveness of prostate cancer and results in changes in cellular motility and invasiveness in immortalized prostate epithelial cells consistent with the promotion of metastasis.

Alleles↗
PubMed2005

The transforming growth factor-beta family members bone morphogenetic protein-2 and macrophage inhibitory cytokine-1 as mediators of the antiangiogenic activity of N-(4-hydroxyphenyl)retinamide.

PURPOSE: Tumor growth appears to be an angiogenesis-dependent process. N-(4-hydroxyphenyl)retinamide (fenretinide; 4HPR) has been found to inhibit and/or prevent tumor growth under diverse conditions. Although 4HPR is antiangiogenic, the molecular mechanisms of this effect remain largely unknown. EXPERIMENTAL DESIGN: Endothelial cells were treated with 4HPR in vitro to study the effects on migration, invasion, and organization, as well as gene expression by microarray and quantitative PCR studies. In vivo angiogenesis was evaluated in the Matrigel model. RESULTS: 4HPR treatment substantially modified the biological activities of endothelial cells, repressing their capacity to migrate, invade, and organize into capillary-like structures. The inhibition of invasion induced by 4HPR was also associated with decreased activities of the metalloproteases matrix metalloproteinase-2 and CD13/APN. Using oligonucleotide microarrays, we observed that bone morphogenetic protein-2 and macrophage inhibitory cytokine-1, two multifunctional cytokines of the transforming growth factor-beta family that regulate the growth, differentiation, apoptosis, and matrix accumulation of a variety of cells, are up-regulated in vitro by 4HPR. Both these molecules specifically inhibited endothelial cell growth, migration, and invasion in vitro and suppressed angiogenesis in the Matrigel plug assay in vivo. Blocking antibodies to bone morphogenetic protein-2 were able to reverse the suppressive effects of 4HPR in vitro and in vivo. CONCLUSIONS: These data support the conclusion that 4HPR inhibits tumor growth by repression of new vessel growth and identify novel points of regulation of angiogenesis in transforming growth factor-beta family proteins.

Angiogenesis Inhibitors↗
PubMed2006

Potentiation of taxol efficacy and by discodermolide in ovarian carcinoma xenograft-bearing mice.

PURPOSE: To evaluate the drug combination of discodermolide and Taxol in human ovarian cancer cells and in an in vivo model of ovarian carcinoma. EXPERIMENTAL DESIGN: The combination index method was used to evaluate the interaction of Taxol and discodermolide in human ovarian SKOV-3 carcinoma cells. Data were correlated with alterations in cell cycle distribution and caspase activation. In addition, SKOV-3 xenograft-bearing mice were treated with either Taxol, discodermolide, or a combination of both drugs given concurrently to evaluate the antitumor efficacy and toxicity of this combination. The Matrigel plug assay and CD31 immunohistochemistry were done to assess antiangiogenic effects. RESULTS: Taxol and discodermolide interact synergistically over a range of concentrations and molar ratios that cause drug-induced aneuploidy in ovarian carcinoma cells. In SKOV-3 xenograft-bearing mice, the combination is significantly superior to either single agent, and induces tumor regressions without notable toxicities. Immunohistochemical analysis of CD31 and Matrigel plug analysis show decreased vessel formation in mice treated with the combination relative to either drug alone. CONCLUSIONS: The synergistic activity of Taxol and discodermolide in cells is most potent at drug concentrations that result in drug-induced aneuploidy rather than mitotic arrest. Moreover, in an animal model of ovarian carcinoma, this is a well-tolerated combination that induces tumor regressions and suppresses angiogenesis. These data confirm the potency of this combination and support the use of concurrent low doses of Taxol and discodermolide for potential use in cancer therapeutics.

Alkanes↗
PubMed2005

Overexpression of stefin A in human esophageal squamous cell carcinoma cells inhibits tumor cell growth, angiogenesis, invasion, and metastasis.

PURPOSE: Evidence is accumulating that an inverse correlation exists between stefin A level and malignant progression. The aim of this study is to investigate the role of stefin A in human esophageal squamous cell carcinoma cells and to evaluate the possibility of stefin A for cancer therapy. EXPERIMENTAL DESIGN: We stably transfected stefin A cDNA into human EC9706 or KYSE150 esophageal squamous cell carcinoma cells. Subsequently, we evaluated the effect of stefin A overexpression on cell growth, cathepsin B activity, cell motility and invasion, tumor growth, and metastasis. Immunoanalysis was done to assess the expression of factor VIII and to support the localization of stefin A and cathepsin B. We also evaluated the effect of CA074Me, a selective membrane-permeant cathepsin B inhibitor. RESULTS: Both transfection of stefin A and treatment with 10 micromol/L CA074Me significantly reduced cathepsin B activity and inhibited the Matrigel invasion. Combination of both further reduced cathepsin B activity and inhibited the Matrigel invasion. Overexpression of stefin A delayed the in vitro and in vivo growth of cells and significantly inhibited lung metastasis compared with 50% of lung metastasis in xenograft mice from EC9706 or empty vector cells. Transfection with stefin A showed a dramatic reduction of factor VIII staining in the tumors of xenograft mice. CONCLUSIONS: Our data strongly indicate that stefin A plays an important role in the growth, angiogenesis, invasion, and metastasis of human esophageal squamous cell carcinoma cells and suggest that stefin A may be useful in cancer therapy.

Animals↗
PubMed2005

Plasmalemmal vesicle associated protein-1 is a novel marker implicated in brain tumor angiogenesis.

PURPOSE: Plasmalemmal vesicle associated protein-1 (PV-1) is up-regulated in the endothelium of human glioblastoma. We sought to further characterize the expression pattern of PV-1 in human brain tumors and interrogate its role in brain tumor angiogenesis. EXPERIMENTAL DESIGN: Quantitative reverse transcription-PCR and in situ hybridization were used to measure PV-1 expression in a panel of 46 human brain tumors and related pathologic states. Matrigel tubulogenesis assays and cell migration assays were used to show function of PV-1 in primary human endothelial cells (HMVEC) under gene knockdown conditions. RESULTS: PV-1 is selectively up-regulated in a variety of high-grade human brain tumors, including glioblastoma and metastatic carcinoma, as well as other cerebral disorders associated with blood-brain barrier disruption, such as acute ischemia. Expression levels were reduced in low-grade neoplasia; however, tumors associated with the ependyma and choroid plexus, known sites of PV-1 expression, also exhibited robust expression. Cerebral expression of PV-1 mRNA was confined to endothelial cells in all cases. PV-1 expression was induced in HMVEC cells in vitro by exposure to medium conditioned by U87MG and U251MG human brain tumor cell lines and by medium supplemented with exogenous vascular endothelial growth factor or scatter factor/hepatocyte growth factor. RNA interference-mediated inhibition of PV-1 induction in HMVEC cells blocked Matrigel-induced tubulogenesis and inhibited cell migration induced by conditioned medium or angiogenic growth factors. CONCLUSIONS: Our results confirm that PV-1 is preferentially induced in the endothelium of high-grade human brain tumors. Inhibition of PV-1 expression is associated with failure of endothelial differentiation in vitro. PV-1 represents a novel marker of brain tumor angiogenesis and integrity of the blood-brain barrier and is a potential therapeutic target.

Biomarkers, Tumor↗
PubMed2006

Targeting tumor angiogenesis with histone deacetylase inhibitors: the hydroxamic acid derivative LBH589.

PURPOSE: Angiogenesis is required for tumor progression and represents a rational target for therapeutic intervention. Histone deacetylase (HDAC) inhibitors have been shown to have activity against various tumor cell types by inhibiting proliferation and inducing apoptosis both in vitro and in vivo. HDAC inhibitors have also been reported to inhibit angiogenesis. The goal of this study was to characterize the antiangiogenic and antitumor activity of a recently developed HDAC inhibitor, the hydroxamic derivative LBH589. MATERIALS AND METHODS: To evaluate the antiangiogenesis activity of LBH589, we did cell cycle analysis, cell proliferation, tube formation, invasion assays in vitro, and Matrigel plug assay in vivo. To determine the antitumor activity of LBH589, we established human prostate carcinoma cell PC-3 xenografts in vivo. To evaluate the effect of LBH589 on endothelial signaling pathways, gene expression, and protein acetylation, we did Western blots and reverse transcription-PCR in human umbilical vein endothelial cells (HUVEC). Immunohistochemical analysis was done to evaluate new blood vessel formation in vivo. RESULTS: LBH589 induced acetylation of histone H3 and alpha-tubulin protein in HUVECs. Histone and nonhistone protein acetylation correlated with induction of G(2)-M cell cycle arrest, inhibition of HUVEC proliferation, and viability. Noncytotoxic concentrations of LBH589 inhibited endothelial tube formation, Matrigel invasion, AKT, extracellular signal-regulated kinase 1/2 phosphorylation, and chemokine receptor CXCR4 expression. In vivo dosing of mice with LBH589 (10 mg/kg/d) reduced angiogenesis and PC-3 tumor growth. CONCLUSION: This study provides evidence that LBH589 induces a wide range of effects on endothelial cells that lead to inhibition of tumor angiogenesis. These results support the role of HDAC inhibitors as a therapeutic strategy to target both the tumor and endothelial compartment and warrant the clinical development of these agents in combination with angiogenesis inhibitors.

Acetylation↗
PubMed2006

The vascular targeting property of paclitaxel is enhanced by SU6668, a receptor tyrosine kinase inhibitor, causing apoptosis of endothelial cells and inhibition of angiogenesis.

PURPOSE: Different antiangiogenic approaches have been proposed in cancer treatment where therapeutic efficacy has been shown with the addition of cytotoxic agents. Here, we used SU6668, a small-molecule receptor tyrosine kinase inhibitor, to investigate the combinatorial effect with paclitaxel on the cellular populations of the developing vasculature. EXPERIMENTAL DESIGN: The effect of this combination was evaluated in vitro in a 72-hour proliferation assay on human umbilical vein endothelial cells (HUVEC) and human microvascular endothelial cells derived from lungs, endothelial cells, aortic smooth muscle cells, and human ovarian carcinoma cells sensitive (1A9) and resistant (1A9-PTX22) to paclitaxel. Combination data were assessed by isobologram analysis. Cell survival was determined by terminal deoxyribonucleotide transferase-mediated nick-end labeling and Annexin V staining. The activity of the combination in vivo was evaluated in fibroblast growth factor-2-induced angiogenesis in Matrigel plugs s.c. implanted in mice. The 1A9-PTX22, paclitaxel-resistant xenograft model was used to evaluate tumor response. RESULTS: Combination index values and isobologram analysis showed synergy in inhibition of proliferation of HUVEC, human microvascular endothelial cells derived from lungs, and aortic smooth muscle cells. The combination induced greater apoptosis in HUVEC than the single agents. The addition of paclitaxel to the treatment with SU6668 significantly decreased the hemoglobin content and the number of CD31-positive vessels in Matrigel plugs in vivo. The combination of the drugs was more active than either single agent against 1A9-PTX22 xenografts; the tumor growth delay was accompanied by a significant reduction of vascular density. CONCLUSIONS: These findings show that the activity of angiogenesis inhibitors on vascular cells could be potentiated when administered in combination with chemotherapeutic agents that themselves have vascular targeting properties.

Animals↗
PubMed2006

TC1(C8orf4) correlates with Wnt/beta-catenin target genes and aggressive biological behavior in gastric cancer.

PURPOSE: We have recently reported that TC1(C8orf4), a small protein present in vertebrates, functions as a novel regulator of the Wnt/beta-catenin pathway. TC1 up-regulates beta-catenin target genes that are implicated in the aggressive behavior of cancers. Our aim was to investigate the clinical and pathobiological relevance of TC1 in gastric cancer. EXPERIMENTAL DESIGN: The expression of TC1 was analyzed using tissue microarray in correlation with clinicopathologic variables and beta-catenin target genes in 299 gastric cancers. The biological effects of TC1 on Matrigel invasiveness and the proliferation of cancer cells were analyzed. TC1 expression was analyzed in gastric cancer cells after serial peritoneal implantation in nude mice. RESULTS: TC1 expression was present in 111 carcinomas (37.1%), correlating with tumor stage (P < 0.002), poor differentiation (P < 0.001), lymphatic infiltration (P < 0.005), and lymph node metastasis (P < 0.006). TC1 also correlated with poor survival in diffuse type carcinomas (P < 0.0001), and even in patients with lymph node metastasis (P < 0.0014). TC1 also correlated with the expression of beta-catenin target genes including laminin gamma2, metalloproteinase-7 and metalloproteinase-14, cyclin D1, c-Met, and CD44. TC1 enhanced Matrigel invasiveness and proliferation, supporting its role in the aggressive biological behavior of cancers. The expression of TC1 increased in MKN45 cells after serial peritoneal seeding in nude mice. CONCLUSIONS: Our data suggests that TC1 coordinates the up-regulation of Wnt/beta-catenin target genes that are implicated in the aggressive biological behavior of cancers. The strong clinical relevance, even in patients with lymph node metastasis, suggested that TC1 could be a potential therapeutic target of advanced gastric cancers.

Animals↗
PubMed2005

Suppression of tumor cell invasion by cyclooxygenase inhibitors is mediated by thrombospondin-1 via the early growth response gene Egr-1.

Cyclooxygenase (COX) inhibitors have antitumorigenic activity and increase the expression of the early growth response gene Egr-1, a tumor suppressor gene and transcription factor. In this study, we have investigated the gene regulatory and anti-invasive activity of two traditional nonsteroidal anti-inflammatory drugs (NSAID), sulindac sulfide and indomethacin. These compounds inhibited tumor cell invasion and induced Egr-1 expression in lung adenocarcinoma A549 cells. Overexpression of Egr-1 reduced cellular invasion in the Matrigel system, whereas suppression of Egr-1 by small interference RNA (siRNA) attenuated the inhibition of Matrigel invasion by these compounds, indicating that Egr-1 is responsible for the decrease in invasion reported following treatment with NSAIDs. Egr-1-overexpressing cells were analyzed for genes involved in invasion and metastasis. Thrombospondin-1 (TSP-1) an antiangiogenic and anti-invasion protein was up-regulated by Egr-1 overexpression, which was confirmed following treatment with sulindac sulfide. Furthermore, the induction of TSP-1 by sulindac sulfide was blocked by Egr-1 siRNA. When TSP-1 was sequestered by the addition of anti-TSP-1 antibody, the inhibition of invasion by sulindac sulfide was attenuated, indicating that TSP-1 is involved in the inhibition of invasion by NSAIDs. We used the Min mouse model to determine if sulindac sulfide would increase Egr-1 and TSP-1 in vivo, because this model is widely used to study the effects of NSAIDs on tumor formation. Treatment of Min mice with concentrations of sulindac sulfide that inhibit tumor formation increased the expression of Egr-1 and TSP-1 in colonic tissues and in the polyps of these mice. This is the first report suggesting that COX inhibitors suppress tumor cell invasion via TSP-1, which occurs downstream of Egr-1.

Adenocarcinoma↗
PubMed2005

Crk-associated substrate tyrosine phosphorylation sites are critical for invasion and metastasis of SRC-transformed cells.

Crk-associated substrate (CAS, p130Cas) is a major tyrosine phosphorylated protein in cells transformed by v-crk and v-src oncogenes. We recently reported that reexpression of CAS in CAS-deficient mouse embryo fibroblasts transformed by oncogenic Src promoted an invasive phenotype associated with enhanced cell migration through Matrigel, organization of actin into large podosome ring and belt structures, activation of matrix metalloproteinase-2, and elevated tyrosine phosphorylation of the focal adhesion proteins FAK and paxillin. We have now extended these studies to examine the mechanism by which CAS achieves these changes and to evaluate the potential role for CAS in promoting in vivo tumor growth and metastasis. Whereas the presence or absence of CAS did not alter the primary growth of subcutaneous-injected Src-transformed mouse embryo fibroblasts, CAS expression was required to promote lung metastasis following removal of the primary tumor. The substrate domain YxxP tyrosines, the major sites of CAS phosphorylation by Src that mediate interactions with Crk, were found to be critical for promoting both invasive and metastatic properties of the cells. The ability of CAS to promote Matrigel invasion, formation of large podosome structures, and tyrosine phosphorylation of Src substrates, including FAK, paxillin, and cortactin, was also strictly dependent on the YxxP tyrosines. In contrast, matrix metalloproteinase-2 activation was most dependent on the CAS SH3 domain, whereas the substrate domain YxxP sites also contributed to this property. Thus multiple CAS-mediated signaling events are implicated in promoting invasive and metastatic properties of Src-transformed cells.

Animals↗
PubMed2005

Nicotine induces cyclooxygenase-2 and vascular endothelial growth factor receptor-2 in association with tumor-associated invasion and angiogenesis in gastric cancer.

Blockade of angiogenesis is a promising strategy to suppress tumor growth, invasion, and metastasis. Vascular endothelial growth factor (VEGF), which binds to tyrosine kinase receptors [VEGF receptors (VEGFR) 1 and 2], is the mediator of angiogenesis and mitogen for endothelial cells. Cyclooxygenase-2 (COX-2) plays an important role in the promoting action of nicotine on gastric cancer growth. However, the action of nicotine and the relationship between COX-2 and VEGF/VEGFR system in tumorigenesis remain undefined. In this study, the effects of nicotine in tumor angiogenesis, invasiveness, and metastasis were studied with sponge implantation and Matrigel membrane models. Nicotine (200 microg/mL) stimulated gastric cancer cell proliferation, which was blocked by SC-236 (a highly selective COX-2 inhibitor) and CBO-P11 (a VEGFR inhibitor). This was associated with decreased VEGF levels as well as VEGFR-2 but not VEGFR-1 expression. Topical injection of nicotine enhanced tumor-associated vascularization, with a concomitant increase in VEGF levels in sponge implants. Again, application of SC-236 (2 mg/kg) and CBO-P11 (0.4 mg/kg) partially attenuated vascularization by approximately 30%. Furthermore, nicotine enhanced tumor cell invasion through the Matrigel membrane by 4-fold and promoted migration of human umbilical vein endothelial cells in a cocultured system with gastric cancer cells. The activity of matrix metalloproteinases 2 and 9 and protein expressions of plasminogen activators (urokinase-type plasminogen activator and its receptor), which are the indicators of invasion and migration processes, were increased by nicotine but blocked by COX-2 and VEGFR inhibitors. Taken together, our results reveal that the promoting action of nicotine on angiogenesis, tumor invasion, and metastasis is COX-2/VEGF/VEGFR dependent.

Adenocarcinoma↗
PubMed2006

Transforming growth factor-beta1 induces tissue inhibitor of metalloproteinase-1 expression via activation of extracellular signal-regulated kinase and Sp1 in human fibrosarcoma cells.

The net balance of matrix metalloproteinases (MMP) and tissue inhibitor of metalloproteinases (TIMP) system has been known to be a key factor in tumor cell invasion. In the present study, we investigated the molecular mechanisms of anti-invasive and antimigrative activity of transforming growth factor (TGF)-beta1 on HT1080 human fibrosarcoma cells. In in vitro Matrigel invasion and Transwell migration assays, TGF-beta1 dose-dependently inhibited the invasion and migration of HT1080 cells, respectively. Gelatin zymography, Western blot, and real-time PCR analysis showed that TGF-beta1 enhanced the expression and secretion of MMP-2, TIMP-1, and, to a lesser degree, MMP-9 but not membrane type 1-MMP and TIMP-2. The addition of recombinant TIMP-1 protein reduced the Matrigel invasion and Transwell migration of HT1080 cells, similar to TGF-beta1. Because augmentation of TIMP-1 might be the major factor for the anti-invasive and antimigrative activity of TGF-beta1, we investigated possible molecular mechanisms responsible for the expression of TIMP-1 induced by TGF-beta1. Treatment of HT1080 cells with TGF-beta1 rapidly phosphorylated three mitogen-activated protein kinases [MAPK; extracellular signal-regulated kinase 1/2 (ERK1/2), p38, and c-Jun NH2-terminal kinase] and Akt. Among these kinases, the inhibition of only ERK1/2 pathway by PD98059, a specific inhibitor of MAPK/ERK kinase(MEK)-1, and transfection of dominant-negative MEK 1 effectively blocked the TIMP-1 induction by TGF-beta1. Mithramycin, a specific inhibitor of Sp1 transcription factor, but not curcumin, an inhibitor of activator protein-1, and transfection of Sp1 small interfering RNA significantly inhibited the TGF-beta1-induced expression of TIMP-1. In addition, electrophoretic mobility shift assay showed that TGF-beta1 up-regulated Sp1 DNA-binding activity, and PD98059 and mithramycin effectively inhibited these events. Finally, pretreatment of HT1080 cells with PD98059 and mithramycin, but not curcumin, restored the invasive activity of these cells. Taken together, these data suggest that TGF-beta1 modulates the net balance of the MMPs/TIMPs the systems in HT1080 cells for anti-invasion and antimigration by augmenting TIMP-1 through ERK1/2 pathway and Sp1 transcription factor.

Cell Movement↗
PubMedDate not supplied

Invasive potential and substrate dependence of attachment in the dunning R-3327 rat prostate adenocarcinoma model.

Cancer cell attachment to and invasion of the extracellular matrix has been associated with the metastatic potential of cell lines of the Dunning R-3327 rat prostatic adenocarcinoma model. We investigated the cell-matrix interactions of prostate tumor cells by comparing the invasive ability through reconstructed extracellular matrix and attachment upon EHS NATRIX (natural extracellular matrix), fibronectin, laminin, and collagen Type IV. We observed a correlation between metastatic potential and substrate dependence of attachment in prostate cancer cells. Nonmetastatic AT-1 cells possessed a higher adhesive potential to extracellular matrix components than the highly metastatic cells (ML, MLL and AT-3). It was also found that the invasive potential of the three highly metastatic cell lines was significantly higher than that of the nonmetastatic cell line. Here, it is reported that the ability to traverse a matrigel matrix correlates with their metastatic potential. These observations suggest that the extracellular matrix components are highly involved in influencing prostate cancer cell activities. In addition, we investigated the effects of two differentiation agents, retinoic acid (RA) and difluoromethylornithine (DFMO), on the adhesive and invasive profiles of the tumor cells. After treatment with both agents, adhesion was increased to levels not different from nonmetastatic cells. Furthermore, the ability of highly metastatic cells to traverse a matrigel barrier was significantly reduced after treatment with both differentiation agents. These results suggest that RA and DFMO are capable in reversing the metastatic potential of prostate cancer cells in vitro and may give a possible insight into their role as potential therapeutic agents in vivo.

Adenocarcinoma↗
PubMedDate not supplied

A new bioassay using transient transfection for invasion-related gene analysis.

To understand the mechanisms of tumor invasion and metastasis, model systems are required that isolate the individual steps of these complicated, multifaceted processes. We propose a new procedure to identify genes involved in cell invasion and/or motility that features the combined advantages of transient gene transfection and Matrigel invasion assays. Cancer cells were transiently cotransfected with two vectors expressing the gene of interest and luciferase, as a marker of transfected cells, and then assayed for Matrigel invasion. Luciferase cotransfection appeared to be a sensitive semiquantitative assay for transfected cells and was maximal throughout the invasion assay. The proposed transfection procedure, using calcium phosphate precipitation, did not affect cell invasiveness and allowed cellular coexpression of both genes. When applying this method, we found that transient expression of the unliganded and liganded human estrogen receptor alpha prevented invasiveness of MDA-MB-231 breast cancer cells. In conclusion, we propose rapid and versatile in vitro procedure for studying the effects of individual cloned genes on cellular processes, such as invasion and motility.

Basement Membrane↗
PubMedDate not supplied

Effects of all-trans-retinoic acid incorporated into low-density lipoprotein on invasive properties of multidrug-resistant MCF-7 spheroids.

Cultured cells grown as spheroids provide an in vitro model that is closer to an in vivo tumour than conventional monolayer techniques. Previous work from our laboratory has demonstrated that spheroids formed from multidrug-resistant MCF-7 cells exhibit invasive characteristics which were not present in their sensitive counterparts. The treatment of these spheroids by all-trans-retinoic acid (ATRA), a potent inducer of in vitro and in vivo differentiation, decreases their proteolytic activity and ability to invade Matrigel-coated filters. The efficiency of ATRA is enhanced by its incorporation into low-density lipoprotein (LDL) (LDL-ATRA). Indeed, invasion through a reconstituted basement membrane was reduced by 73% with 10(-6) M ATRA and 3 x 10(-8) M LDL-ATRA. Furthermore, inhibition of invasion was correlated with a decrease in several factors: (1) secreted matrix metalloproteinase-9 and enzymes degrading type IV collagen and Matrigel films, and (2) tissue plasminogen activator. The results observed were found with a concentration of LDL-ATRA 30 times lower than that of ATRA. This could be due to the protective effect of LDL and to a better targeting of cancer cells through their LDL receptors. LDL-ATRA may therefore represent a new and potent inhibitor of invasion that could be developed for clinical trials.

Antineoplastic Agents↗
PubMedDate not supplied

N-Glycans influence the in vitro adhesive and invasive behaviour of three metastatic cell lines.

Alterations in cellular glycosylation may play a key role in metastatic behaviour of tumour cells. We studied three metastatic cell lines, LOX (malignant melanoma), FEMX (malignant melanoma) and MA-11 (mammary carcinoma). These cell lines have a very different metastatic behaviour in vivo, and different glycans have been postulated to be partly responsible for these differences. To further investigate the functional role of carbohydrates, these three cell lines have been treated with tunicamycin, an inhibitor of the biosynthesis of N-glycans and benzyl- alpha-N-acetylgalactosamine (benzyl-alpha-GalNAc; BnGalNAc), an inhibitor of mature O-linked glycans. Various in vitro adhesion and invasion assays were undertaken for functional studies. Tunicamycin significantly inhibited adhesion to laminin, but only slightly affected cell adhesion to collagen IV. The same compound significantly decreased cellular invasiveness through a Matrigel invasion chamber. Moreover, tunicamycin reduced homotypic aggregation of cells. BnGalNAc had generally little effect on cell behaviour in in vitro assay. The effects of the inhibitors were, however, to some extent cell line-specific. We conclude that N-glycans, but probably not mature O-glycans have important in vitro functions in cell adhesion to laminin, cell invasion through Matrigel and cellular aggregation in the studied cell lines. These results support the view that carbohydrates are functionally involved in several steps of the metastatic process.

Acetylgalactosamine↗
PubMed2001

Effect of IL-2 and IL-6 on parameters related to metastatic activity in a murine melanoma.

Previous results have shown that the metastatic colonization with B16F10 melanoma in vivo increased after in vitro treatment of the cells with IL-2 or IL-6. To further investigate the mechanisms underlying this effect, we have studied adhesion, invasion, and proliferation properties of B16 melanoma, using two sublines with different metastatic ability. Adhesion of tumor cells to Matrigel coats increased using IL-6, which also induced upregulation of VLA-4 expression in both sublines. Unexpectedly, invasion through Matrigel filters was almost completely inhibited by IL-6 and decreased in the presence of IL-2. Cell growth was not affected by these interleukins; however, IL-6 could partially overcome the proliferation blockade induced by stress conditions. Taken together, these results suggest that upregulation of adhesion properties and/or the protective effect induced by IL-6 could account for the enhancement of metastasis exerted by this interleukin.

Animals↗
PubMed2004

Human PRMT5 expression is enhanced during in vitro tubule formation and after in vivo ischemic injury in renal epithelial cells.

BACKGROUND: The interactions between cells and the extracellular matrix (ECM) are important in the regulation of cell growth and differentiation. Cells cultured in ECM differentiate and develop tubular structures. The kidney has the ability to partially recover function after an ischemic insult through repairing its tubular epithelium. The factors that contribute to tubule formation in vitro may mediate tubule regeneration in the recovery stage of acute tubular necrosis. METHODS: RNA purified from cells grown on plastic, on Matrigel and in Matrigel matrix were subjected to differential display analysis to identify the transcripts that are differentially expressed during in vitro tubulogenesis. RESULTS: Protein arginine methyltransferase 5 (PRMT5) expression increased in renal epithelial cells undergoing tubule formation. PRMT5 expression is developmentally regulated and ubiquitously expressed in a variety of adult tissues. We also demonstrated that expression of PRMT5 is enhanced in the renal tubular epithelium of animals subjected to ischemic reperfusion injury (IRI). CONCLUSION: The role of PRMT5 in the regulation of mitosis, its induction in renal epithelial cells undergoing tubule formation in vitro and its expression in the tubules of the kidneys subjected to IRI suggest that it functions in the regulation of cell growth and differentiation during tubule formation and regeneration.

Cells, Cultured↗