Biomedical subjects

G Taraboletti

Publications and source records attributed to G Taraboletti.

51 records · Page 3Linked to original sources

PubMed1990

Induction of haptotactic migration of melanoma cells by neutrophil activating protein/interleukin-8.

Natural or recombinant neutrophil activating cytokine (IL-8) induced migration across polycarbonate filters of human A 2058 melanoma cells. Anti-IL-8 antibodies blocked IL-8 induced melanoma cell migration. Checkerboard experiments revealed a gradient-dependent response of A2058 melanoma cells to IL-8. Filters exposed to IL-8 and washed supported melanoma cell migration, thus implying a haptotactic component in the response. The homologous polypeptide platelet factor 4 was inactive. The observation that IL-8 affects melanoma cells emphasizes the need for a comprehensive analysis of the spectrum of action of platelet factor 4-related peptides. The effect of the inflammatory cytokine IL-8 on melanoma cells may be relevant to augmented secondary localization of tumors at sites of inflammation.

Chemotactic Factors↗

PubMed1990

Platelet thrombospondin modulates endothelial cell adhesion, motility, and growth: a potential angiogenesis regulatory factor.

Components of the extracellular matrix have been shown to modulate the interaction of endothelial cells with their microenvironment. Here we report that thrombospondin (TSP), an extracellular matrix component, induces adhesion and spreading of murine lung capillary (LE-II) and bovine aortic (BAEC) endothelial cells. This TSP-induced spreading was inhibited by heparin and fucoidan, known to bind the amino-terminal globular domain of the molecule. In addition, endothelial cells were induced to migrate by a gradient of soluble TSP (chemotaxis). The chemotactic response was inhibited by heparin and fucoidan, as well as by the mAb A2.5, which also binds to the amino-terminal domain. These data are in agreement with our previous observation that the TSP aminoterminal heparin binding region is responsible for the induction of tumor cell spreading and chemotactic motility. The inhibition of chemotaxis and spreading by antibodies against the beta 3 but not the beta 1 chain of the integrin receptor points to a role for the integrins in the interaction of endothelial cells with TSP. We also found that TSP modulates endothelial cell growth. When added to quiescent LE-II cells, it inhibited the mitogenic effects of serum and the angiogenic factor bFGF, in a dose-dependent manner. The inhibition of DNA synthesis detected in the mitogenic assay resulted in a true inhibition of BAEC and LE-II cell growth, as assessed by proliferation assay. This work indicates that TSP affects endothelial cell adhesion, spreading, motility and growth. TSP, therefore, has the potential to modulate the angiogenic process.

Animals↗

PubMed1989

Membrane fluidity affects tumor-cell motility, invasion and lung-colonizing potential.

Membrane fluidity, determined by steady-state fluorescence polarization measurements, was correlated with metastatic capacity of murine tumor-cell lines. A correlation was observed in cell lines with different metastatic potential, and was confirmed when their lung-colonizing ability was modulated by alteration of either the membrane lipid composition or the culture conditions. Two cellular functions, motility and basement membrane invasion, were affected by the membrane lipid composition, and might explain the role of membrane fluidity observed in cancer metastasis.

Animals↗

PubMed1989

Modulation of laminin receptor expression by estrogen and progestins in human breast cancer cell lines.

The effects of estradiol and two synthetic progestins (ORG2058 and R5020) on the expression of the high-affinity, metastasis-associated laminin receptor in two human breast carcinoma cell lines were examined. The T47D cell line contains estrogen and progesterone receptors, but the MDA-MB 231 cell line lacks both receptors. Treatment of T47D cells with 10(-9) M estradiol alone results in a three-fold increase (P less than or equal to .05) in the steady-state level of laminin receptor mRNA determined by RNA blot analysis as well as in cell-surface, laminin receptor expression that is evaluated by immunofluorescence. No effects of estradiol on the receptor-negative MDA-MB 231 cells were observed. Untreated and steroid-treated MDA-MB 231 cells had higher levels of laminin receptor mRNA than did untreated or estradiol-treated T47D cells. A more dramatic increase (five-fold; P less than or equal to .005) of mRNA and cell-surface expression in T47D cells was observed after treatment with estradiol plus 10(-8) M progestin or with progestin alone. Estradiol treatment also increased chemotaxis and haptotaxis of T47D cells but not of MDA-MB 231 cells to laminin; it had no effect on the attachment of these latter cells to laminin. Interestingly, treatment with estradiol plus progestin or progestin alone significantly increased the attachment of T47D cells to laminin but did not have an effect on either haptotaxis or chemotaxis to laminin. These results suggest that the various cell-laminin interactions are mediated by different mechanisms. The augmentation of laminin receptor mRNA by estrogen and progesterone treatment in hormone receptor-positive cells, but not in cells that lack these receptors, may relate functionally to the difference in the clinical aggressiveness between classes of breast cancers.

Breast Neoplasms↗

PubMed1987

Role of laminin receptor in tumor cell migration.

Polyclonal antisera were made against biochemically purified laminin receptor protein as well as against synthetic peptides deduced from a complementary DNA clone corresponding to the COOH-terminal end of the laminin receptor (U.M. Wewer et al., Proc. Natl. Acad. Sci. USA, 83: 7137-7141, 1986). These antisera were used to study the potential role of laminin receptor in laminin-mediated attachment and haptotactic migration of human A2058 melanoma cells. The anti-laminin receptor antisera reacted with the surface of suspended, nonpermeabilized melanoma and carcinoma cells. The anti-laminin receptor antisera blocked the surface interaction of A2058 cells with endogenous laminin, resulting in the inhibition of laminin-mediated cell attachment. The A2058 melanoma cells migrated toward a gradient of solid phase laminin or fibronectin (haptotaxis). Anti-laminin antiserum abolished haptotaxis on laminin but not on fibronectin. Synthetic peptide GRGDS corresponding to the fibronectin cell-binding domain inhibited haptotaxis on fibronectin but not on laminin. Both types of anti-laminin receptor antisera inhibited haptotaxis on laminin but not on fibronectin. Using immunohistochemistry, invading human carcinoma cells in vivo exhibited a marked cytoplasmic immunoreactivity for the receptor antigen. Together these findings indicate a specific role for the laminin receptor in laminin-mediated migration and that the ligand binding of the laminin receptor is encompassed in the COOH-terminal end of the protein.

Cell Adhesion↗

PubMed1987

Chemotactic factor and P15E-related chemotaxis inhibitor in human melanoma cell lines with different macrophage content and tumorigenicity in nude mice.

The present study was designed to characterize the production of chemoattractants by human melanoma lines with high (M4Be, M3Da, NTerDa) or low tumorigenic (Doc8, M1Do) potential when heterotransplanted in nude mice. Supernatants from the Doc8 and M1Do cell lines were strongly chemotactic in vitro for mononuclear phagocytes. Chemotactic activity was destroyed by proteolytic enzymes, and upon gel filtration on Sephadex G75, it eluted in the cytochrome c region corresponding to an apparent m.w. of 12,000. Upon chromatofocusing, the Sephadex-separated tumor-derived chemotactic factor (TDCF) showed an isoelectric point of 5.5 to 6. Cell lines with high tumorigenic potential contained low or no detectable chemotactic activity. When culture supernatants of cell lines with modest (M3Da) or no (M4Be) chemotactic activity were exposed to immobilized monoclonal antibodies directed against the retroviral transmembrane protein P15E, appreciable chemotactic activity was detectable (M4Be) or preexisting levels increased (M3Da). The material eluted from Sepharose-bound anti-P15E antibodies inhibited the migration of monocytes in response to chemoattractants. These findings demonstrate the coexistence in some human melanoma cell line supernatants of factors (TDCF and P15E-related inhibitor) with opposite influence on monocyte chemotaxis. That tumor cell products play a pivotal role in regulating the extravasation of monocytes into neoplastic tissues is suggested by the close correlation observed between macrophage levels in melanomas grown in nude mice and levels of chemotactic activity detectable in culture supernatants.

Animals↗

PubMed1987

Antiproliferative properties of flavone acetic acid (NSC 347512) (LM 975), a new anticancer agent.

The antiproliferative activity of flavone acetic acid (LM 975) was investigated on human adenocarcinoma cell lines (HCC-P2998, HCC-M1544, HCC-M1410, HT 29, LoVo), on a murine colon adenocarcinoma cell line (Colon 26), on murine pancreatic adenocarcinoma cells growing in primary culture (Pan 03) and on human normal fibroblasts (N1). No cytotoxic effects were found against human normal fibroblasts. LM 975 was active against murine adenocarcinoma Pan 03 and Colon 26, known to be sensitive in vivo too and, to variable extents, on human adenocarcinoma cell lines. LM 975 in vitro cytotoxic potency was relatively low. The high concentrations (1.0-1.4 mM) required to obtain a cytotoxic effect are, however, pharmacologically reasonable since they are comparable with drug plasma levels in mice or in patients treated with tolerable doses. After a relatively short LM 975 treatment (2 h) DNA, RNA and protein synthesis were inhibited in different proportions. In more sensitive cells LM 975 appeared to inhibit RNA synthesis more than DNA and protein synthesis. Inhibition of macromolecule synthesis after 2 h exposure was completely reversed in 24 h recovery. After 2 h treatment no detectable DNA breakage was found by the alkaline elution method, thus corroborating the idea that this compound does not act by causing DNA damage.

Adenocarcinoma↗

PubMed1987

Thrombospondin-induced tumor cell migration: haptotaxis and chemotaxis are mediated by different molecular domains.

Thrombospondin induces the migration of human melanoma and carcinoma cells. Using a modified Boyden chamber assay, tumor cells migrated to a gradient of soluble thrombospondin (chemotaxis). Checkerboard analysis indicated that directional migration was induced 27-fold greater than stimulation of random motility. Tumor cells also migrated in a dose-dependent manner to a gradient of substratum-bound thrombospondin (haptotaxis). A series of human melanoma and carcinoma cells were compared for their relative motility stimulation by thrombospondin haptotaxis vs. chemotaxis. Some cell lines exhibited a stronger haptotactic response compared to their chemotactic response while other lines exhibited little or no migration response to thrombospondin. Human A2058 melanoma cells which exhibit a strong haptotactic and chemotactic response to thrombospondin were used to study the structural domains of thrombospondin required for the response. Monoclonal antibody C6.7, which binds to the COOH-terminal region of thrombospondin, inhibited haptotaxis in a dose-dependent optimal manner. C6.7 had no significant effect on thrombospondin chemotaxis. In contrast, monoclonal antibody A2.5, heparin, and fucoidan, which bind to the NH2-terminal heparin-binding domain of thrombospondin, inhibited thrombospondin chemotaxis but not haptotaxis. Monoclonal antibody A6.1 directed against the internal core region of thrombospondin had no significant effect on haptotaxis or chemotaxis. Synthetic peptides GRGDS (50 micrograms/ml), but not GRGES, blocked tumor cell haptotaxis on fibronectin, but had minimal effect on thrombospondin or laminin haptotaxis. The 140-kD fragment of thrombospondin lacking the heparin-binding amino-terminal region retained the property to fully mediate haptotaxis but not chemotaxis. When the COOH region of the 140-kD fragment, containing the C6.7-binding site, was cleaved off, the resulting 120-kD fragment (which retains the RGDA sequence) failed to induce haptotaxis. Separate structural domains of thrombospondin are therefore required for tumor cell haptotaxis vs. chemotaxis. This may have implications during hematogenous cancer metastases formation.

Blood Platelets↗

PubMed1986

The macrophage content of tumors is unrelated to levels of NK cell-mediated resistance.

Three malignant tumors (3LL carcinoma, mFS6 sarcoma, and B16 F1 melanoma) were transplanted in mice with congenital (beige) or acquired (anti-asialo GM1-treated) defects of natural killer cell (NK) activity. The macrophage content of the neoplastic tissues was not influenced by host NK activity levels. These data suggest that NK cell-mediated resistance does not play an appreciable role in the regulation of the levels of tumor-associated macrophages in established malignancy.

Animals↗

PubMed1986

Ia antigen expression and IL-1 activity in murine tumour-associated macrophages.

Tumour-associated macrophages (TAM) isolated from five murine sarcomas had a relatively high frequency of I-A+ cells, with mean values of 27% (mFS6), 52% (MN/MCA1), 68% (N3), 62% (N4) and 98% (J3) for TAM compared to 12% for resident peritoneal macrophages. Expression of I-E in TAM was also high (29%) in the only sarcoma (N4) examined in this respect. Expression of I-A by TAM declined in culture but exposure to lymphokine supernatants maintained and increased the frequency of I-A+ cells in TAM. Transplantation of tumours into nude mice caused a marked decrease in the percentage of I-A+ TAM in the case of the N4 sarcoma (8% compared to 48%), whereas for the MN/MCA1 sarcoma the diminution was only marginal (from 53 to 41%), TAM from murine sarcomas did not constitutively release appreciable levels of interleukin-1 (IL-1) activity. Upon stimulation with bacterial lipopolysaccharides or silica, TAM showed a limited capacity to produce and release IL-1 activity compared to peritoneal macrophages. Thus the expression of I-A antigens and the IL-1-producing capacity are uncoupled in TAM from murine sarcomas. These properties of TAM could play an important role in the generation of anti-tumour immunity and/or of suppressive T-cell circuits.

Animals↗

PubMed1986

Characterization of spontaneous metastases from autochthonous 3-methylcholanthrene-induced tumors.

In mice bearing autochthonous 3-methylcholanthrene-induced tumors metastasis was rare, with only 2 out of 47 (4%) animals showing lung secondaries and 1 showing kidney lesions. Surgical excision of autochthonous growing tumors brought only a slight increase in incidence of metastasis (5 out of 42 mice, 12%). Cell lines were established by in vivo and/or in vitro passage from two kidney metastasis found in the same host (0.13-K1 and 0.13-K3) and from a spontaneous lung metastasis found in 2 mice (mR80/43 and mR80/17) and compared to lines from the respective primary tumors (0.13; R80/17; R80/43). Cell lines from metastases and primary tumors were heterogeneous in tumorigenicity, growth rate, metastatic potential (spontaneous), and colonizing capacity (i.v. inoculation). In particular, the mR80-43 line was more metastatic to lungs upon intravenous injection than the parent R80-43 primary tumor. Similarly the 013-K1 line from a kidney secondary caused more lung nodules when inoculated intravenously than the parent 0.13 line, but this was not the case with the 013-K3 line derived from another kidney secondary in the same host. The R80-17 and mR80-17 lines had similar lung-colonizing capacity. Lung colonizing ability was not strictly correlated to the capacity to form spontaneous metastases. Changes in lung-colonizing capacity occurred in part of the lines (013, 013-K1, R80-17, mR80-17) upon in vitro or in vivo passage. These findings with lines from spontaneous metastases from three autochthonous sarcomas extend previous observations on the heterogenous behavior of transplanted metastatic neoplasms.

Animals↗

PubMed1985

Tumor-derived chemotactic factor(s) from human ovarian carcinoma: evidence for a role in the regulation of macrophage content of neoplastic tissues.

Supernatants from freshly disaggregated human ovarian carcinomas maintained in vitro for 24 hr, from primary ovarian carcinoma cultures (4-6 days in culture) and from established ovarian cancer cell lines were examined for chemotactic activity on blood monocytes in blind-well chemotaxis chambers. Tumor-cell culture supernatants induced migration of peripheral blood monocytes across polycarbonate filters with considerable heterogeneity among different tumors. Induction of migration occurred only in the presence of a gradient between the lower and upper compartments of the chamber. Chemotactic activity was characterized by means of supernatants from primary ovarian carcinoma cultures. Chemotactic factor(s) was (were) produced in serum-free conditions and the production was inhibited by emetine but not by mitomycin C. The activity was destroyed by exposure to proteolytic enzymes and by heating at 100 degrees C but was unaffected by RNase, DNase, lipase and exposure to extreme pH values or heating at 56 degrees C. Upon fractionation on Sephadex G 75, the activity eluted as a single peak in the cytochrome C region, corresponding to an apparent molecular weight of about 12 kd. The percentage of macrophages was assessed in 25 freshly disaggregated tumor specimens. Ovarian carcinomas were heterogeneous in their macrophage content with values ranging from 4 to 36%. A significant (r = 0.62; p = 0.00097), though far from absolute, correlation was found between chemotactic activity of culture supernatants and percentage of tumor-associated macrophages. Tumor-derived chemotactic factor(s) could be one of the mechanisms involved in the regulation of the macrophage content of human ovarian carcinomas.

Carcinoma↗

PubMedDate not supplied

Cytokine-induced pseudopodial protrusion is coupled to tumour cell migration.

Pseudopodia protrusion is a prominent feature of actively motile cells in vitro and invading tumour cells in vivo; however, the function and regulation of pseudopodia are poorly understood. Tumour autocrine motility factor (AMF) represents a new class of cytokines which are secreted by tumour cells and embryonic cells and induce random motility in the producer cells or in heterologous cells with appropriate receptors. Here we report that a major effect of this factor is to induce the extension of cell pseudopodia before cell translocation. Using a new method to quantify and isolate pseudopodia, we find that human breast carcinoma cell AMF (at concentrations of 1 nM or below) stimulates random pseudopodia formation in a dose-dependent and time-dependent manner. Anti-AMF antibodies inhibit pseudopodia protrusion and cell motility, showing the importance of pseudopodia formation during locomotion. AMF-stimulated motility and pseudopodia formation occur on a wide variety of adhesive substrata which suggests that certain intrinsic motility events are independent of the attachment mechanism. Induced pseudopodia show a prominent axial actin network in the electron microscope. The number of laminin receptor and fibronectin RGD recognition sites is increased by a factor of 20 in the induced pseudopodia when compared to the average distribution in unstimulated cells. Exploratory pseudopodia regulated by cell-derived motility factors contain receptors for matrix proteins and could serve as 'senseorgans' essential to the process of cell locomotion.

Actins↗

PubMedDate not supplied

Increased tumorigenicity and invasiveness of C6 rat glioma cells transfected with the human alpha-2,8 sialyltransferase cDNA.

Gangliosides are thought to be involved in tumor cell proliferation, migration and invasiveness as so far demonstrated by the addition of exogenous gangliosides to the culture medium. To better understand the direct influence that alterations in ganglioside synthesis can exert on these functional aspects of cell biology, in the present study, we investigated the behaviour of C6 rat glioma cells after stable transfection with the human CMP-NeuAc:NeuAcalpha2-3Galbeta1-4GlcCer alpha2,8-sialyltransferase (SAT-II, EC 2.4.99.8) gene. The enzyme synthesizes ganglioside GD(3) by adding a sialic acid residue to ganglioside GM(3). Stable transfection of the constructs into C6 cells and expression of the human SAT-II gene were evaluated using PCR and RT-PCR amplification, respectively. Qualitative and quantitative analysis of the ganglioside profile was performed by conventional HP-TLC and identity of de novo synthesized species was assessed by TLC immunostaining. Results show that whereas C6 parental cells and C6 cells transfected with the empty expression vector synthesize, almost exclusively, ganglioside GM(3), de novo synthesis of GD(3) is clearly observed in clones expressing the alpha2,8-sialyltransferase. Subcutaneous grafting in athymic nude mice of cells expressing high levels of GD(3) induces tumors growing faster and more aggressively than controls. In in vitro assays, the same cells demonstrate increased proliferation rate, motility and invasiveness. Chemotaxis and chemoinvasion were assayed using the modified Boyden chamber. Data obtained suggest that endogenously neosynthesized GD(3) is able to modify proliferation rate, motility and invasion of C6 rat glioma cells, enhancing the features of malignancy of this tumor cell line.

Animals↗

PubMedDate not supplied

Angiogenesis and angiogenesis inhibitors in cancer.

Angiogenesis, the development of a new blood supply, is an essential process of tumour growth and metastasis. Over the past few years, this has led to the consideration of the tumour vasculature as an optimal target for anti-cancer strategies. The process of angiogenesis consists of a series of interactive events: quiescent endothelial cells are stimulated by angiogenic factors to degrade the underlying basement membrane, to migrate within the interstitial matrix, to proliferate and to organise themselves into tubular structures which become mature blood vessels. During angiogenesis, the endothelial cells undergo functional changes and show molecular features which are different from normal, quiescent endothelium. These differences can be exploited in order to selectively target tumour endothelium and to prevent neo-vessel formation. Two main approaches have been followed: i. the inhibition of the angiogenic process and vessel formation (anti-angiogenesis), and ii. direct targeting and destruction of tumour vasculature (vascular targeting). Compounds of different origin and mechanism of action have the potential to inhibit angiogenesis and hence tumour growth. This review takes into consideration some angiogenesis antagonists that are in development and the leader compounds that are under clinical trial for the treatment of cancer.

Angiogenesis Inhibitors↗