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PubMed2004

A versatile in vivo chamber angiogenesis assay for measuring anti-angiogenic activity in mice.

We recently described an in vivo angiogenesis assay for rats--an optimized Matrigel plug assay based on subcutaneously implanted chambers with fixed volume and shape. Here we examine the possibility of switching the host animal from rat to mouse, thereby reducing the requirement for test compound an order of magnitude. The chambers consist of a plexiglas ring with a 0.2 ml volume and two nylon net filters. Chambers containing growth factor-reduced Matrigel supplemented with basic fibroblast growth factor (bFGF) were subcutaneously implanted in the right flank of three different strains of mice; BALB/c, C57BL/6J, and NMRI-nu. On day 10 post-implantation: i) each chamber was taken out, ii) a picture of the induced angiogenic response was taken, and iii) the redness of the chamber content was quantified by computer image analysis. The level of bFGF-induced angiogenesis in the mouse assay was lower than in the previously published rat assay. Importantly, the background angiogenesis in mice in chambers containing Matrigel alone was correspondingly decreased. Therefore, a more sensitive threshold for the computer image analysis was used. In all three strains of mice, bFGF-induced angiogenesis was significantly increased compared to Matrigel alone. Furthermore, the positive anti-angiogenic control compound TNP-470 (10 mg/kg/d s.c.) completely inhibited the bFGF-induced angiogenesis. The in vivo chamber angiogenesis assay allows quantitative analysis of angiogenic and anti-angiogenic activity in mice. The model is very robust and only little influenced by the choice of mouse strain.

Angiogenesis Inhibitors↗
PubMed2005

Anti-angiogenic effects of a nutrient mixture on human umbilical vein endothelial cells.

Matrix metalloproteinases (MMPs) have been recognized as key players in the degradation of the extracellular matrix (ECM) by migration and proliferation of endothelial cells and their subsequent invasion of the underlying stroma. The prevention of ECM degradation through the inhibition of MMP activity has been shown to be a promising therapeutic approach to block the invasion that occurs during angiogenesis. In previous studies, we demonstrated the anti-tumor effect of a nutrient mixture (NM) containing ascorbic acid, lysine, proline, green tea extract, arginine, N-acetyl cysteine, selenium, copper and manganese on various tumor cell lines in vivo and in vitro. The aim of the present study was to determine whether this mixture has anti-angiogenic effects on human umbilical vein endothelial cells (HUVECs). At near confluence, the HUVEC cell cultures were tested with NM at 0, 10, 50, 100, 500, and 1000 microg/ml in triplicate at each dose for proliferation, migration, MMP expression, and invasion. Cell proliferation was evaluated by MTT assay, invasion potential by Matrigel invasion, MMP expression by gelatinase zymography, and cell migration by a 2 mm-wide scratch in plates. For tube formation, HUVECs were cultured in previously polymerized Matrigel. NM inhibited HUVEC migration, MMP expression and invasion through Matrigel in a dose-dependent manner. Zymography showed a dose-dependent inhibition of MMP-2 expression with virtual total inhibition at a 500 microg/ml concentration. Invasion through Matrigel was totally inhibited at 500 microg/ml NM. NM reduced cell migration by scratch test in a dose-dependent fashion with total inhibition at a 500 microg/ml concentration. NM also inhibited the tube formation of HUVECs, but did not significantly inhibit cell proliferation. These results together with our earlier findings suggest that NM is a relatively non-toxic formulation with anti-angiogenic effects, such as inhibiting vascular tube formation and endothelial cell invasion and migration.

Acetylcysteine↗
PubMed2006

[Overexpression of tissue inhibitor of metalloprotease-2 promotes proliferation and infiltration of human monocytic leukemia cells].

OBJECTIVE: To investigate the functional role of human tissue inhibitor of metalloprotease (TIMP)-2 gene on the proliferation and infiltrating capability of human monocytic leukemic cells. METHODS: Human monocytic leukemic cells of the line SHI-1 were cultured and the TIMP-2 expression on the cell membrane was detected by flow cytometry (FCM). The SHI-1 cells were transfected with human TIMP-2 gene (SHI-1/TIMP-2 cells) or blank vector (SHI-1/MSCV cells). The TIMP-2 expressed on the surface of the cell membranes of SHI-1/TIMP-2 and SHI-1/MSCV cells was detected by FCM. The SHI-1/TIMP-2 and SHI-1/MSCV cells were inoculated into the 96-well plate, 24, 48, 72, and 96 hours later MMT method and ELISA were used, and the cell growth curve was drawn to detect the proliferation ability of the cells. Matrigel was put into the upper layer of Transwell chamber. Human bone marrow matrix cells (BMMC) of leukemia patient and SHI-1/TIMP-2 cells or SHI-1/MSCV cells were put into the upper layers as experimental groups, and SHI-1/TIMP-2 cells or SHI-1/MSCV cells only, without human BMMC, were put into the upper layers as control groups. 72 hours later blood cell counting plate was used to measure the number of cells migrating through Matrigel. SHI-1/TIMP-2 cells or SHI-1/MSCV cells were injected intravenously into pre-treated BALB/c nu/nu mice. Thirty days later 8 mice from each group were killed to observe the tumorigenesis in the organs, especially the central nervous system leukemia (CNL). The survival of the other mice was observed. RESULTS: The expression level of TIMP-2 on the cell membrane of the SHI-1/TIMP-2 cells was 99.3% +/- 0.1%, significantly higher than that of the SHI-1/MSCV cells (85.9% +/- 2.6%, P < 0.05). The A values 24, 48, 72, and 96 hours later of the SHI-1/TIMP-2 cells were 0.34 +/- 0.05, 0.6 +/- 0.05, 0.97 +/- 0.12, and 1.28 +/- 0.06 respectively, all significantly higher than those of the SHI-1/MSCV cells (0.28 +/- 0.03, 0.36 +/- 0.03, 0.54 +/- 0.09, and 0.99 +/- 0.03 respectively, all P < 0.05). The SHI-1/TIMP-2 cells and SHI-1/MSCV cells only could not migrate through Matrigel basically. 24 - 48 hours after co-cultivation Shi-1 cells began to appear in the lower layer of Transwell chambers, 72 hours later the trans-Matrigel SHI-1/TIMP-2 cells accounted for 24.7% +/- 6.9% of the inoculated SHI-1/TIMP-2 cells, a proportion significantly higher than that in the case of the SHI-1/MSCV cells (12% +/- 1.4%, P < 0.05). 24 days after the inoculation the mean body weight of the mice inoculated with SHI-1/TIMP-2 cells was 21.5 g +/- 0.4 g, significantly higher than that of the mice inoculated with SHI-1/MSCV cells (17.4 g +/- 0.6 g, P < 0.01). The mice inoculated with SHI-1/TIMP-2 cells showed much more tumors in different organs and much more severe infiltration in the CNS in comparison with the mice inoculated with SHI-1/MSCV cells The mean survival time of the mice inoculated with the SHI-1/TIMP-2 cells was 33.7 days, significantly shorter than that of the mice inoculated with SHI-1/MSCV cells (40 days). CONCLUSION: TIMP-2 expressed on the cell membrane is critical to promote the proliferation and infiltration of SHI-1 cells.

Animals↗
PubMed2007

Increased invasive potential and up-regulation of MMP-2 in MDA-MB-231 breast cancer cells expressing the beta3 integrin subunit.

Integrins are a family of transmembrane adhesion receptors that might transduce signals from the extracellular matrix into the inside of cells after ligand binding. In order to investigate whether beta3 integrins expressed in tumor cells might mediate such outside-in signaling, human MDA-MB-231 breast cancer cells that were stably transfected with either beta3 integrin or mock-transfected were investigated in a matrigel degradation assay and a grafting experiment was performed on the developing chicken chorioallantoic membrane (CAM). After cultivation on matrigel for time periods between one and five days, more matrigel was digested in the wells in which beta3 integrin expressing cells were incubated than in wells of mock-transfected cells. Furthermore, extracts of beta3 integrin expressing cells contained higher levels of MMP-2 protein as determined by immunoblotting and more MMP-2 associated gelatinase activity as detected by zymography than extracts of mock-transfected cells. Matrigel degradation and gelatinase activity as well as MMP-2 expression were elevated when beta3 integrin expressing cells were incubated in the presence of the RGD peptide (mimicking an integrin ligand). After grafting on 10 day-old embryonic chicken CAM for three to five days, beta3 integrin expressing cells assembled in spheroids showed higher rates of spreading on the CAM surface and CAM invasion as well as a significant MMP-2 up-regulation compared to mock-transfected cells. The results from the in vivo and in vitro experiments allow the conclusion that the presence of beta3 integrin in MDA-MB-231 breast cancer cells induced an increased MMP-2 expression and activity that might contribute to the enhanced invasive potential observed.

Animals↗
PubMed1991

Hepatocellular phenotype in vitro is influenced by biophysical features of the collagenous substratum.

Hepatocytes maintained on different substrata in vitro possess strikingly different morphological and biochemical features. Rounded, multicellular aggregates of hepatocytes are seen if the cells are plated onto Matrigel, a reconstituted basement membrane, whereas a flattened, monolayer of hepatocytes is observed with Vitrogen. Hepatocellular protein synthesis is much greater on the Matrigel, although collagen biosynthesis appears selectively enhanced on Vitrogen-grown hepatocytes. We determined that denatured type I collagen could be substituted for Matrigel as the substratum, with the hepatocytes remaining the same both morphologically and biochemically. This suggested that the cells respond to the biophysical state of the extracellular matrix not only to protein sequences that determine a binding site. Measurement of steady-state messenger RNA levels within cells cultured onto different matrices indicated that the fluid substrate of either Matrigel or denatured type I collagen were facilitative for induction of cytochrome P-450b/e, which was not seen with the rigid type I collagen substrata. In contrast the messenger RNA level for the cytoskeletal protein actin was decreased on the fluid matrices, suggesting that the rounded cells had a lower requirement for this protein. These findings indicate that hepatocytes are responsive to the biophysical state of the extracellular matrix, which can lead to significant changes in gene expression by the cells.

Actins↗
PubMed1990

Invasion of extracellular matrix by cultured colon cancer cells: dependence on urokinase receptor display.

Several urokinase-expressing tumor cells display surface receptors that avidly bind the plasminogen activator. The present study was undertaken to determine the importance of receptor bound urokinase in promoting the invasive phenotype by cultured colon cancer cells. An HCT 116 cell line that elaborates urokinase and displays 11 x 10(4) receptors per cell, 57% of which are tagged with endogenous plasminogen activator, invaded extracellular matrix (Matrigel) in a plasminogen dependent manner. Matrigel invasion was contingent on plasmin production mediated by urokinase, since epsilon-aminocaproic acid diminished the invasive capacity of the HCT 116 cells by 75%. A specific urokinase receptor peptide-antagonist reduced cell invasion in a dose dependent manner with a maximum effect (78% reduction in tumor cell infiltration) being achieved with a 10(-4) M concentration. These results did not reflect a non-specific "shut down" of urokinase expression by the receptor antagonist insofar as steady state urokinase transcript levels were unchanged compared with untreated controls. In addition, LH-RH, a control peptide, failed to suppress Matrigel invasion by HCT 116 cells. The CBS and FET colon cancer cell lines, which secrete amounts of urokinase similar to HCT 116 cells and display one tenth of the receptor number were found to be poorly invasive. Over a three day period, less than 0.8% of these cells invaded the Matrigel in contrast to the 6.9% seen for HCT 116 cells. These data suggest that for cultured colon cancer cells, at least, the display of receptor bound urokinase was a prerequisite for plasminogen dependent invasion.

Cell Line↗
PubMed1995

Macrophage colony-stimulating factor mediates invasion of ovarian cancer cells through urokinase.

The macrophage colony-stimulating factor (CSF-1) is best known as a hematopoietic cytokine important to macrophage activation. Recently, the importance of CSF-1 and its receptor (encoded by the c-fms proto-oncogene) in epithelial ovarian cancer has also been recognized, with overexpression of CSF-1 denoting poor prognosis in ovarian cancer patients. During macrophage activation, CSF-1 promotes urokinase-type plasminogen activator (uPA) activity; in macrophages and in malignant cells of lung, breast, colon, and prostatic origin, uPA activity is strongly correlated with the ability to invade and, in the malignant cells, to metastasize. While there is clear evidence of CSF-1 and uPA expression in primary and metastatic ovarian cancer, the significance of their expression to invasion of these cells has not been explored. We find that all of our ovarian cancer cell lines which we have studied co-express CSF-1 and uPA transcripts and protein. Urokinase expression in these ovarian cancer cell lines correlates with the degree of tumorigenicity in nude mice, with the most virulent tumor resulting from Hey cells, a strong expressor of uPA. We studied the invasion of these primary and established ovarian cancer cells through a Matrigel (reconstituted basement membrane matrix) barrier. The ability of ovarian cancer cells to invade is strongly correlated with endogenous CSF-1 expression (Pearson's correlation, r = 0.91; P = 0.01). A total of 0.90 +/- 0.16% of Bix3 cells (very weak expressor of CSF-1) invaded through the barrier, in contrast to 6.95 +/- 0.75% of Hey cells (strong CSF-1 expressor) and 10.44 +/- 2.33% of Bixler cells (the strongest CSF-1 expressor). We studied the ability of two of the cell lines to invade human laminin and type IV collagen (Bix3, a weak invader of Matrigel, and Hey, a strong invader), to determine (a) whether our results on a Matrigel matrix may represent a relevant model for invasion in humans and (b) whether there is a potential confounding effect from the cytokines and proteases in Matrigel. On this human simple matrix, we confirm that Bix3 is a weakly invasive cell line (0.33 +/- 0.04% invasion) which contrasted to the strongly invasive Hey cell line (8.51 +/- 0.47%). Treatment of Bix3 cells with exogenous CSF-1 stimulates percentage of invasion by 2-fold and results in a similar increase in the level of uPA transcripts and cellular associated uPA antigen. Furthermore, cell surface-bound uPA increased from 74% in the absence of CSF-1 to 100% (fully saturated) in the presence of CSF-1.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1994

[Antitumor effect of intratumoral administration of a Coriolus preparation, PSK: inhibition of tumor invasion in vitro].

The antitumor effects of biological response modifiers (BRM) in an experimental mouse model, the "double grafted tumor system," were analysed. Intratumoral administration of PSK (polysaccharide Kureha), a Coriolus preparation into primary tumor induced a cure of not only the primary solid tumor but also the metastatic, distant tumor. The effect of PSK on in vitro invasion by murine RL male-1 leukemia cells was studied using Biocoat Matrigel Invasion Chamber (Becton Dickinson Labware). We determined the ability of tumor cells to penetrate matrigel-coated filters in the presence or absence of PSK. PSK (100 micrograms/ml) reduced to half the number of invasive tumor cells for 3 hr incubation. PSK inhibited tumor cell invasion of matrigel-coated filters in a dose-dependent manner. Matrigel includes laminin, collagen, fibronectin and heparan sulfate proteoglycan. It is possible, therefore, that PSK may inhibit enzymes which digest the components of basement membranes, extra cellular matrices (ECM). This phenomenon suggests that PSK also inhibits metastatic activity of tumor cells in vivo.

Animals↗
PubMed1995

Critical role of extracellular matrix on induction by phenobarbital of cytochrome P450 2B1/2 in primary cultures of adult rat hepatocytes.

BACKGROUND: Although it has been known for more than three decades that administration of lipophilic chemicals, including phenobarbital, produces liver hypertrophy, proliferation of smooth endoplasmic reticulum, and induction of liver microsomal enzymes such as cytochromes P450 (CYP) 2B1 and 2B2, the mechanism of this adaptive response remains largely unknown. An important advance was the recognition that, unlike cultures of continuously proliferating liver cell lines or cultures of primary non-proliferating adult rat hepatocytes maintained on either plastic or collagen-coated dishes, hepatocytes cultured on a basement membrane gel, Matrigel, formed rounded clusters and permitted phenobarbital-mediated induction in vitro of CYP 2B1/2 mRNAs and immunoreactive proteins (1). EXPERIMENTAL DESIGN AND RESULTS: We cultured adult rat hepatocytes on Type 1 collagen (Vitrogen) and allowed the cells to spread, flatten, and firmly attach to the substratum. Subsequent incubation in medium containing Matrigel as a soluble component, fully restored, in a dose-dependent manner, the ability to respond to phenobarbital with induction of CYP 2B1/2 mRNAs. Repeating this experiment with medium containing equivalent amounts of purified laminin, a major component of Matrigel, or with YIGSR or SIKVAV, two peptides known to mimic various activities of laminin, similarly restored phenobarbital responsiveness to hepatocytes cultured on Vitrogen. In contrast, use of equal amounts of SHA-23, a scrambled peptide relevant to SIKVAV, produced no such effect. None of these treatments caused a rounding or any other observable change in the flattened, cellular morphology, making it unlikely that cell-spreading or alterations in cell shape account for loss of such differentiated liver functions as phenobarbital induction of CYP 2B1/2 mRNAs in cultured hepatocytes on Vitrogen. Hepatocytes cultured on Matrigel in the presence of either colchicine, cytochalasins B and D, nocodazole, or taxol did not show induction of 2B1/2 mRNAs by phenobarbital specifically, while the amounts of both albumin and glucose-6-phosphate dehydrogenase (G6PD) mRNAs were unaffected. CONCLUSIONS: We conclude that the process by which phenobarbital induced 2B1/2 mRNAs in hepatocytes appears to require highly concerted effects of specific extracellular components prominently involving laminin. This likely occurs through a signal transduction process requiring probably both microfilament and microtubular integrity.

Amino Acid Sequence↗
PubMed1996

Stimulus specificity of matrix metalloproteinase dependence of human T cell migration through a model basement membrane.

Chemotaxis of human T lymphoblastoma cells of the Tsup-1 line, which migrate similarly to blood T cells, through a layer of basement membrane-like Matrigel on a polycarbonate micropore filter was evoked by vasoactive intestinal peptide (VIP; concentration for a maximal response, 10(-7)M), IL-2 (10(-9)M), and the chemokines RANTES (10(-10)M) and macrophage inflammatory protein-1 alpha (10(-10)M). Chemotactic concentrations of each factor increased Tsup-1 cell secretion of matrix metalloproteinase-9 (MMP-9), with significant responses by 4 h for VIP, IL-2, and IL-4, but only after 24 h for macrophage inflammatory protein-1 alpha and RANTES, as quantified by Western blots and zymography. 3H-Labeled type IV human collagen incorporated in the Matrigel layer was degraded by migrating Tsup-1 cells, as assessed by release of radioactive fragments of the collagen. The in situ degradation of type IV collagen in Matrigel by migrating Tsup-1 cells was enhanced most significantly by VIP, IL-2, and IL-4 after 4 h at concentrations that increased the secretion of MMP-9 optimally, but only after 24 h by macrophage inflammatory protein-1 alpha and RANTES. The specific MMP inhibitor GM6001 suppressed Tsup-1 cell MMP activity evoked by all stimuli, as determined by zymography and in situ degradation of 3H-Labeled type IV human collagen. The chemotactic migration of Tsup-1 cells through Matrigel, but not through a filter alone, in response to optimal concentrations of VIP, IL-2, and IL-4, but not the chemokines, was inhibited by GM6001, with a concentration dependence similar to that for suppression of MMP activity. Thus elicitation of T cell chemotactic migration through a model basement membrane by stimuli that increase MMP activity early in the response depends on degradation of matrix proteins by MMP, whereas stimuli that recruit MMP late may rely on early activation of other proteases.

Basement Membrane↗
PubMed1996

Transduction of specific inhibition of HuT 78 human T cell chemotaxis by type I vasoactive intestinal peptide receptors.

The major immunoregulatory effects of vasoactive intestinal peptide (VIP) are mediated by structurally distinct types I (VIPR1) and II (VIPR2) G protein-associated receptors on some T cells, B cells, and macrophages. Identification of the separate immunologic activities of each type of VIPR has been complicated by the usual expression of only VIPR2 or of VIPR1 and VIPR2 together by most human T cells obtainable in sufficient number for functional analyses. The results of reverse-transcription PCR, Western blot, and [125I]VIP-binding studies have established that HuT 78 cultured human lymphoma T cells bear a mean of 75,000 VIPR1s per cell with a mean Kd of 3.3 nM, which transduce mean maximal increases in intracellular concentration of cAMP of 2.1-fold (ED50 = 72 nM), but no VIPR2s. HuT 78 T cells, in contrast to T cells that express VIPR2, did not respond to VIP by chemotaxis through micropore filters without or with a top layer of basement membrane-like Matrigel. Matrix metalloproteinase (MMP)-dependent in situ cleavage of [3H]type IV human collagen in the layer of Matrigel by HuT 78 T cells also was not stimulated by VIP. In contrast, IL-4 and TNF-alpha both stimulated HuT 78 T cell chemotaxis and in situ MMP activity at respective optimal concentrations ranging from 3 x 10(-10) M to 3 x 10(-9) M and 10(-10) M to 3 x 10(-10) M. VIP inhibited significantly HuT 78 T cell chemotaxis through Matrigel in response to both IL-4 and TNF-alpha, as a result of suppression of both chemotactic mobility, assessed by migration through micropore filters without Matrigel, and in situ MMP activity. The transduction of opposite effects of VIP on T cell migration through a model basement membrane by VIPR1 and VIPR2 suggests that the net chemotactic response of most T cells to VIP is determined by the VIPR2/VIPR1 ratio and that the predominant expression of VIPR1 would stabilize T cell populations in lymphoid follicles and tissue infiltrates.

Base Sequence↗
PubMed1998

Inhibition of angiogenic differentiation of human umbilical vein endothelial cells by curcumin.

Angiogenesis is a crucial step in the growth and metastasis of cancers. Curcumin inhibits tumor initiation and growth. We analyzed the effect of curcumin on endothelial cell migration, attachment, and tube formation on Matrigel. Curcumin had no effect on endothelial cell migration or attachment to either plastic or Matrigel. Curcumin treatment resulted in a dose-dependent inhibition of tube formation when the cells were treated before plating or at the time of plating on Matrigel. Curcumin treatment also caused the preformed tubes to break down. Curcumin inhibited angiogenesis in a s.c. Matrigel plug model in mice. The role of metalloproteinases has been shown to be important in angiogenesis; therefore, zymography was performed to determine whether curcumin affected protease activity. Zymographs of curcumin-treated culture supernatants showed a decrease in the gelatinolytic activities of secreted 53- and 72-kDa metalloproteinases. Western and Northern analysis showed a dose-dependent decrease in the protein expression and transcript of 72 kDa, indicating that curcumin may be exerting its inhibitory effect at both the transcriptional and posttranscriptional level. These findings suggest that curcumin acts as an angiogenesis inhibitor by modulating protease activity during endothelial morphogenesis. Curcumin could be developed as an antiangiogenic drug.

Animals↗
PubMed1998

Refinement of an in vitro cell model for cytochrome P450 induction.

Induction of cytochromes P450 (P450s) by drugs can lead to drug-drug interactions. Primary hepatocytes have been reported to retain inducible P450s. To optimize the use of primary hepatocytes for predicting induction of P450 (CYP 3A and 2B) expression in vivo, both culture conditions and expression of induction potentials were investigated. In rat hepatocytes, basal CYP 3A1/2 expression was better maintained in cells cultured on Matrigel compared with collagen when low concentrations of dexamethasone were used. However, CYP 3A1/2 induction was not affected by either matrix. In contrast, induction of CYP 2B1/2 by phenobarbital was markedly stronger in hepatocytes cultured on Matrigel. To further validate the in vitro model, Sprague-Dawley rats and isolated hepatocytes cultured on Matrigel were exposed to a series of compounds. In an attempt to minimize large variability between experiments, a novel approach for calculating induction potential was applied. In vitro results for CYP 3A1/2 and 2B1/2 induction correlated well with those observed in vivo. In contrast with rat hepatocytes, basal CYP 3A4 expression in human hepatocytes decreased rapidly in cells cultured on either Matrigel or collagen. However, CYP 3A4 inducibility was retained in cells cultured on either matrix. Interestingly, induction of CYP 3A4 in human hepatocytes by several model compounds did not correlate with the induction of CYP 3A1/2 in rat hepatocytes. This in vitro assay should facilitate the demand for a fast and reproducible method for addressing P450 induction by numerous compounds at the drug discovery stage.

Animals↗
PubMed1997

Inhibitory effect of lead on tube formation by cultured human vascular endothelial cells.

The effect of lead acetate (Pb) on the formation of capillary-like structures (tube formation) by cultured human umbilical vascular endothelial cells (HUVECs) was examined. HUVECs were seeded on a gelled basement membrane matrix (Matrigel). Treatment of HUVECs with 0.3-30.0 microM Pb for 24 hours inhibited the tube formation dose-dependently. The length of tube formation decreased time-dependently with 3.0-10.0 microM Pb. To elucidate the main target factor of Pb for this inhibition, the effects of Pb on the activity of protein kinase C (PKC) and Matrigel were examined. The addition of beta-phorbol 12-myristate 13-acetate (PMA, 50 nM), an activator of PKC, and isoquinolinesulfonamide derivative (H-7, 30 microM), an inhibitor of PKC, showed an increase and decrease in the tube formation, respectively. However, the results of simultaneous addition of Pb and either PMA or H-7 to HUVECs indicated that PMA and H-7 acted not synergistically but additively. When PKC activities in HUVECs were measured by a colorimetric assay after treatments with 3.0-10.0 microM Pb for 24 hours, there was no significant change in PKC activity in the cells. The Pb-inhibition of tube formation was suggested to be independent of PKC activity. Pretreatment of Matrigel with 3.0-10.0 microM Pb for different periods decreased the tube formation dose- and time-dependently. These findings suggest that Pb can inhibit the tube formation by HUVECs dose- and time-dependently and that the inhibitory effect of Pb could be dependent on the degeneration of Matrigel, not on PKC activity.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1998

Matrix-mesangial cell interaction modulates migration of macrophages.

BACKGROUND: Macrophages (Møs) have been demonstrated to play an important role in immune-mediated renal injury. Accumulation of macrophages in the mesangium has been reported to be a key event in the development of focal glomerulosclerosis. We hypothesized that mesangial cells (MCs) and matrix interaction may be a determinant for the migration of Møs into the mesangium. Therefore, we studied the effect of the interaction between matrix and MCs on the migration of Møs. METHODS: Mouse MCs were plated on Petri dishes coated either with buffer, collagen type I, III, IV, or Matrigel in media containing 1% fetal calf serum for 48 hours. Subsequently, supernatants were collected and stored. The effect of these supernatants (conditioned media) was evaluated on the migration of Møs across a filter in a modified Boyden chamber. RESULTS: Conditioned media from MCs grown on Matrigel (MC-Matrigel interaction products, MC-MGP) enhanced the migration of macrophages across a filter in a modified Boyden chamber when compared with conditioned media from MCs grown on plastic, collagen type I, type III, or type IV (MC-PP, MC-CI, MC-CIII, and MC-CIV). MC-MGP enhanced the migration of Møs in a dose dependent manner. Anti-MCP-1 antibodies attenuated (P < 0.05) the MC-MGP-induced Mø migration (MC-MGP, 16.8 +/- 2.5 vs MC-MGP + anti-MCP-1 antibody, 6.5 +/- 1.2 migrated macrophages/field, n = 12). Anti-TGF-beta antibodies did not attenuate MC-MGP-induced Mø migration. MCs grown on Matrigel showed a 5-fold increase of MCP-1 mRNA when compared with cells grown on plastic or collagen type IV. CONCLUSIONS: The present study suggests that matrix components may modulate the migration of Møs. This effect of MC-matrix interaction on macrophage migration may be mediated through the generation of MCP-1.

Animals↗
PubMed1998

Development and characterization of a mouse prostate adenocarcinoma cell line: ductal formation determined by extracellular matrix.

BACKGROUND: Tumor vaccines show promise as a new approach for treating cancer. We have developed a murine prostate cancer cell line which can be used to study growth factor and extracellular matrix regulation of prostate differentiation and will be useful for generating tumor vaccines using the C3(1)/TAG transgenic model of prostate cancer. METHODS: Pr-14 cells were established in defined growth media (GM) and grown in GM, GM + 2% fetal bovine serum (FBS) or DMEM + 10% FBS on plastic, collagen, or Matrigel. Immunofluorescence and Western blot analyses were performed using antibodies to cytokeratin, vimentin, SV40 large T-antigen, and androgen receptor (AR). RESULTS: Pr-14 cells are cytokeratin-positive, vimentin-negative, and express SV40 large T-antigen. These cells are tumorigenic when injected into athymic nude mice and appear to be androgen-independent. Pr-14 cell lines are nontumorigenic when injected into syngeneic FVB/N mice, but form tumors in transgenic TAG-expressing FVB/N mice. Cell growth and morphology are dependent on media composition which determines whether ductal or acinar structures form when grown on Matrigel. CONCLUSIONS: The mouse prostate adenocarcinoma cell line, Pr-14, undergoes alterations in the state of differentiation dependent upon serum concentration when grown on Matrigel. The Pr-14 cell line is a useful reagent to study prostate cell/extracellular matrix interactions, and for immunotherapy and cancer vaccine studies in C3(1)/TAG transgenic mice.

3T3 Cells↗
PubMed1996

Characterization of tumorigenic sub-lines from a poorly tumorigenic human colon-adenocarcinoma cell line.

The interaction of tumor cells with extracellular-matrix components is suspected to play an important role in tumorigenesis induction. The tumorigenicity of a poorly tumorigenic human colon-adenocarcinoma cell line (BCS-TC2) was induced by co-injection with Matrigel. A new cell sub-line, BCS-TC2.1, was isolated and established from these tumors. Implantation of these cells in nude mice in the absence of Matrigel-generated tumors which allowed the establishment of another tumorigenic cell sub-line, BCS-TC2.2. Matrigel and laminin, but not collagens, promote the tumorigenicity of BCS-TC2 cells, probably due to specific interactions of a pre-existing minor cell sub-population with laminin, which facilitate the initial growth of these cells in vivo. Cytogenetic analysis reveals that both sub-lines originate from the parental one, but a new marker in chromosome 9 is observed. These sub-lines present a lower degree of differentiation, as deduced from the lower CEA content, 5'-nucleotidase and alkaline-phosphatase activities. No variation is observed in the mRNA and protein expression of the 67-kDa laminin-binding protein. However, an increase in beta1 integrins and a parallel decrease in beta4 integrin were detected. Thus, the new sub-lines, compared to the parental cells, present karyotypic and phenotypic differences such as the expression of a distinctive integrin pattern. This system represents a useful model for understanding the development and progression of tumorigenicity in cancer cells.

5'-Nucleotidase↗
PubMed1997

Inverse relationship between invasiveness and differentiative capacity in different human neuroblastoma cell lines.

In order to clarify the relationship between invasiveness and loss of cellular differentiation in tumor cells, we studied the invasive properties on Matrigel of (a) a series of clones we isolated from human neuroblastoma LaN1 and Platt cell lines inducible to differentiation by adhesion on fibronectin, and (b) SY5Y human neuroblastoma cells inducible to differentiation by retinoic acid. We found that, regardless of the parental line, the more differentiated clones were scarcely invasive, while the less differentiated clones showed a higher degree of invasiveness. Differences in invasiveness between differentiated and non-differentiated neuroblastoma clones did not reflect differences in adhesiveness to laminin, the major component of Matrigel. The retinoic acid-sensitive SY5Y human neuroblastoma cells also reduced their invasiveness on Matrigel after differentiation induced by growth in media supplemented with retinoic acid. These results point to an inverse relationship between differentiative properties and invasiveness in human neuroblastoma cell lines.

Cell Adhesion↗