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R Giavazzi

Publications and source records attributed to R Giavazzi.

At least 37 records · Page 2Linked to original sources
PubMed2000

Characterization of novel clonal murine endothelial cell lines with an extended life span.

A murine endothelial cell line was recently established from microvessels that had invaded a subcutaneous sponge implant (Dong, Q. G.; Bernasconi, S.; Lostaglio, S., et al. Arterioscl. Thromb. Vasc. Biol. 17:1599-1604; 1997). From these sponge-induced endothelial (SIE) cells, we have isolated two subpopulations endowed with different phenotypic properties. Clone SIE-F consists of large, highly spread cells that have a relatively slow growth rate, form contact-inhibited monolayers, do not grow under anchorage-independent conditions, express elevated levels of thrombospondin-1 (TSP-1) and are not tumorigenic in vivo. In contrast, clone SIE-S2 consists of small, spindle-shaped cells that have a high proliferation rate, do not show contact-inhibition, grow under anchorage-independent conditions, express very low levels of TSP-1 and are tumorigenic in vivo. Both clones express the endothelial markers vascular endothelial-cadherin and vascular intercellular adhesion molecule-1, but do not express CD31 and E-selectin. In addition, SIE-S2 cells, but not SIE-F cells, express the alpha-smooth muscle actin isoform. SIE-S2 cells, but not SIE-F cells, are able to form branching tubes in fibrin gels. The SIE-F and SIE-S2 clones, which have properties of nontransformed and transformed cells, respectively, should provide useful tools to investigate physiological and pathological processes involving vascular endothelium.

Actins↗
PubMed1999

Human immunodeficiency virus-1 (HIV-1)-Tat protein promotes migration of acquired immunodeficiency syndrome-related lymphoma cells and enhances their adhesion to endothelial cells.

Human immunodeficiency virus-1 (HIV-1)-Tat, the transactivating gene product of HIV-1, has been shown to interact with different cell types, inducing gene expression, altering their growth and migratory behavior. In this study we examined whether Tat might affect functions of acquired immunodeficiency syndrome (AIDS)-related non-Hodgkin's lymphoma (NHL), relevant to the in vivo dissemination. Our results show that Tat significantly augmented the motility of the two AIDS-related Burkitt's lymphoma cell lines (AS283 and PA682PB) and AIDS-primary effusion lymphoma cell line (HBL-6-AIDS-PEL). Mutations in RGD or basic domain of Tat (KGE-MBP and LxI-MBP, respectively) sharply reduced migration compared with wild type, suggesting that both domains are required for migration. In contrast, a Tat protein mutation outside the active domains (NH(2)-TAT-GST) did not reduce lymphoma cell migration. The treatment of lymphoma cells with Tat did not influence their adhesion to matrix proteins or to human vascular endothelial cells, but endothelial cells treated with Tat became more adhesive to lymphoma cells. Flow cytometric analysis showed that treatment of endothelial cells with Tat induced the cell surface expression of the adhesion molecules vascular cell adhesion molecule-1 (VCAM-1) and E-selectin and increased the expression of intercellular adhesion molecule-1 (ICAM-1). Only antibodies against VCAM-1 on endothelial cells or against the VLA-4 integrin expressed on AS283 cells inhibited the increment of adhesion, indicating the relevance of this pathway in the adhesion of lymphoma cells to vascular endothelium. In our work, we show for the first time that Tat can enhance the migration of lymphoma cells and their adhesion to endothelial cells, two processes that may contribute to the malignant behavior of NHL in patients with AIDS.

Cell Adhesion↗
PubMed1999

Mesothelial cells induce the motility of human ovarian carcinoma cells.

The dissemination of ovarian carcinoma cells within the abdominal cavity involves interaction of tumor cells with the peritoneal mesothelium. The aim of our study was to investigate whether mesothelial cells might directly affect the spreading of this tumor by inducing motility and invasiveness of human ovarian carcinoma cells. Serum-free supernatants of cultured human mesothelial cells [conditioned medium (CM)] induced chemotaxis and invasiveness of the human ovarian carcinoma cell lines SK-OV-3, OVCAR-5 and A2780 in a Boyden chamber. Checkerboard analysis indicated that the stimulated motility was prevalently directional. Most of the chemotactic activity was retained by a heparin affinity column, indicating that the motility factor(s) is a heparin-binding protein. Using different monoclonal antibodies (MAbs) directed against chemotactic factors that are secreted by mesothelial cells, we found that chemotaxis was partially prevented (64.8% inhibition) by antibodies against fibronectin (FN). CM also induced haptotactic migration of ovarian carcinoma cells, and anti-FN antibodies significantly inhibited haptotaxis. The presence of FN in the CM was confirmed by Western blot analysis. Our findings suggest that mesothelium plays an active role in inducing the intraperitoneal spread of ovarian carcinoma cells, and point to FN as being one of the main mediators of mesothelium-induced ovarian carcinoma cell motility.

Cell Movement↗
PubMed1999

Thrombospondin-1 inhibits Kaposi's sarcoma (KS) cell and HIV-1 Tat-induced angiogenesis and is poorly expressed in KS lesions.

Kaposi's sarcoma (KS), a neoplasm often associated with iatrogenic and acquired immunosuppression, is characterized by prominent angiogenesis. Angiogenic factors released by both KS and host cells, as well as HHV-8 and HIV viral products, have been implicated in the pathogenesis of this lesion. Angiogenesis is the result of imbalance among angiogenesis promoters and inhibitors, which disrupts homeostasis. The aim of this study was to investigate the expression and mechanism of KS control of thrombospondin-1 (TSP), a physiological inhibitor of angiogenesis. Immunohistochemical analysis of four KS lesions showed only spotty reactivity for TSP in the stroma and in less than 10 per cent of lesional blood vessels. In addition, the typical KS spindle cells were not stained. In agreement with these findings, decreased levels of TSP were measured with an ELISA assay in the supernatants of cultured KS cells, compared with endothelial cells. In vitro, TSP inhibited the endothelial cell proliferation and motility induced by KS cell supernatants. TSP also prevented endothelial cell motility induced by Tat, a product of HIV-1 endowed with angiogenic potential and implicated in the pathogenesis of AIDS-KS. In vivo, TSP inhibited the angiogenic activity exerted by Tat in the Matrigel sponge model. These results suggest that TSP down-regulation might be permissive for the development of KS-associated angiogenesis.

Animals↗
PubMed1999

Phenotypic and functional characteristics of tumour-derived microvascular endothelial cells.

We recently developed a method for the isolation and purification of tumour-derived endothelium. In this study the phenotypic and functional properties of human tumour-derived microvascular endothelial cells (TdMEC) were examined. Endothelium obtained from human adrenal gland specimens (HAMEC) was used as a reference microvascular endothelial cell population. TdMEC formed a confluent monolayer with the typical morphological appearance of endothelium and were positive for endothelial markers such as Ulex-1 lectin, CD31 antigen, von Willebrand Factor and VE-cadherin. The addition of acidic Fibroblast Growth Factor (aFGF), basic FGF (bFGF) or Vascular Endothelial Growth Factor (VEGF) substantially improved proliferation of TdMEC; and kidney carcinoma derived endothelial cells were more responsive to FGFs, whereas glioblastoma derived endothelial cells greatly responded to VEGF TdMEC expressed high levels of the VEGF receptors, KDR/flk-1 and Flt-1, as shown by northern blot analysis. TdMEC expressed the adhesion molecules ICAM-1, VCAM-1 and E-selectin that could be further increased by exposing TdMEC culture to interleukin-1. All the TdMEC expressed interleukin-8 mRNA. These findings show that TdMEC in vitro maintain several of the features described for microvasculature. Thus, TdMEC represent a useful tool to study markers for tumor vasculature.

Antigens, CD↗
PubMed1999

High antitumour activity of ET743 against human tumour xenografts from melanoma, non-small-cell lung and ovarian cancer.

BACKGROUND: Ecteinascidin-743 (ET743) is a novel antitumour agent originating from the Caribbean tunicate Ecteinascidia turbinata. It has potent cytotoxic and antitumour activity and a potential new mechanism of action. The aim of the present study was to further explore the antitumour activity of ET743 in human tumour xenografts from melanoma, non-small-cell lung and ovarian cancer. DESIGN: As the antitumour profile of ET743 was largely unknown a chemo-sensitive and a marginal chemo-resistant human tumour xenograft were selected for each tumour type. ET743 was administered intravenously using two administration schedules (days 0, 4, 8 and 0-2, 13-15). RESULTS: ET743 was very active at the maximum tolerated dose (MTD) in the chemo-sensitive xenograft melanoma MEXF 989, non-small-cell lung cancer LXFL 529, and ovarian cancers HOC22 and (marginally resistant to cisplatin) HOC18. Activity was also seen at 1/2 MTD. Apart from HOC18, ET743 caused complete remissions in the responding xenografts. The compound was inactive in the chemo-resistant xenograft melanoma MEXF 514 and non-small-cell lung cancer LXFA 629. In terms of antitumour activity the days 0, 4, 8 schedule had advantages over the days 0-2, 13-15 schedule. CONCLUSIONS: ET743 is a very effective agent in chemo-sensitive and marginal chemo-resistant xenografts, but inactive in chemo-resistant tumour xenografts. The activity of ET743 in the marginally cisplatin-resistant ovarian cancer HOC18 might indicate absence or incomplete cross-resistance against cisplatin. It is recommended to include melanoma, non-small-cell lung cancer, and ovarian cancer in phase II clinical trials and to use an intermittent schedule.

Adult↗
PubMed1999

BAY 12-9566, a novel inhibitor of matrix metalloproteinases with antiangiogenic activity.

Matrix metalloproteinases (MMPs) have been implicated in tumor cell invasion, metastasis, and angiogenesis. BAY 12-9566, a novel, non-peptidic biphenyl MMP inhibitor, has shown preclinical activity on a broad range of tumor models and is currently in clinical development. The purpose of this study was to investigate the antiangiogenic activity of BAY 12-9566. In vitro, BAY 12-9566 prevented matrix invasion by endothelial cells in a concentration-dependent manner (IC50 = 8.4x10(-7) M), without affecting cell proliferation. In vivo, oral daily administration of BAY 12-9566 (50-200 mg/kg) inhibited angiogenesis induced by basic fibroblast growth factor in the Matrigel plug assay, reducing the hemoglobin content of the pellets. Histological analysis showed a reduction in the amount of functional vessels within the Matrigel. We conclude that the MMP inhibitor BAY 12-9566 inhibits angiogenesis, a property that further supports its clinical development as an antimetastatic agent.

Angiogenesis Inhibitors↗
PubMed1998

Molecular characterisation of a panel of human ovarian carcinoma xenografts.

In a panel of 16 human ovarian tumours transplanted in nude mice, the expression of genes involved in cell cycle regulation and in response to drug treatment were characterised. In the 16 tumours analysed we could not detect overexpression of Erb-B2 oncogene while expression of MDR1 mRNA was not detected in 11/15 samples and was low in 4/15 tumours. Only three tumours had mutations in the p53 gene exons 5-8 and one of these mutations did not result in any amino acid alteration. The levels of mRNA for cyclins A, D1 and E were heterogeneous with some tumours expressing high levels and others not expressing them at all. The same was found for the cyclin dependent kinases (CDK) CDK2 and CDK4 and for CDK inhibitors p21/WAF1, p27/KIP1 and p16/CDKN2. Two genes belonging to the nucleotide excision repair, ERCC1 and ERCC3 were detectable in all the samples examined, as were the genes MGMT and MAG, also involved in DNA repair. The data indicate a heterogeneity in the expression of genes considered to be involved in the cellular responses to cytotoxic drug treatment and indicate the possibility of using these tumour models to test specifically molecules with a defined mechanism of action.

Animals↗
PubMed1998

Batimastat, a synthetic inhibitor of matrix metalloproteinases, potentiates the antitumor activity of cisplatin in ovarian carcinoma xenografts.

Batimastat (also known as BB-94) is a synthetic matrix metalloproteinase inhibitor that has shown antineoplastic and antiangiogenic activity in various tumor models. In this study, two human ovarian carcinoma (HOC) xenografts (HOC22 and HOC8) were used to investigate the effect of batimastat on the antineoplastic activity of cisplatin. Both xenografts produced ascites and solid lesions in the peritoneal cavity of nude mice. HOC cells were inoculated i.p. in nude mice, and treatment was started at different stages of the disease. Batimastat was administered alone or concurrently with or subsequent to cisplatin therapy. In all of the protocols, the response of HOC xenografts was confirmed by cytological analysis of ascites and histological examination of the organs in the peritoneal cavity. Treatment of nude mice bearing early-stage (3 days after tumor implantation) HOC22 or HOC8 with cisplatin or batimastat alone delayed tumor growth and increased the survival time of the mice, although all animals eventually died. In contrast, treatment with batimastat (60 mg/kg i.p. every other day, for a total of eight injections) concomitantly with cisplatin (4 mg/kg i.v., every 7 days for a total of three injections) completely prevented growth and spread of both xenografts, and all animals were alive and healthy on day 200. The potentiation of cisplatin's activity by batimastat was dose dependent and was observed in the treatment of both advanced (7 days after tumor inoculation) and late-stage (20 days after inoculation) tumor. The administration of batimastat following cisplatin therapy also led to significant improvement in the survival of mice compared to treatment with cisplatin alone. These results suggest a potentiation of the antineoplastic activity of cisplatin by batimastat and support the use of the two agents in combination in the treatment of ovarian cancer patients.

Animals↗
PubMed1998

Impact of fibroblast growth factor-2 on tumor microvascular architecture. A tridimensional morphometric study.

Three cell clones originated by transfection of human endometrial adenocarcinoma HEC-1-B cells with fibroblast growth factor-2 (FGF-2) cDNA and characterized by a different capacity to produce and secrete the growth factor were transplanted subcutaneously in nude mice. Corrosion casting of the tumor microvasculature of xenografts produced by injection of 2 x 10(6) or 10 x 10(6) FGF-2-B9 cells (which produce and secrete significant amounts of FGF-2), 10 x 10(6) FGF-2-A8 cells (which produce comparable amounts of FGF-2 but do not secrete it), or 10 x 10(6) control FGF-2-B8 cells (which produce only trace amounts of FGF-2) was performed after 14 days of growth. Interbranching distances, intervascular distances, branching angles, and vessel diameters were then determined using tridimensional stereo pairs of the casted tumor vascularity. When transplanted at the same concentration, FGF-2-B9 cells grew faster in nude mice compared with FGF-2-A8 and FGF-2-B8 clones. The total amount of new vessel formation was far higher in FGF-2-B9 tumors than in FGF-2-B8 or FGF-2-A8 tumors. Also, vessel courses were more irregular and blind-ending vessels and evasates were more frequent in FGF-2-B9 tumors. Moreover, FGF-2-B9 tumor microvasculature was characterized by a wider average vascular diameter and by an extreme variability of the diameter of each individual vessel along its course between two ramifications. No statistical differences were observed when the distribution curves of the values of intervascular distances, interbranching distances, and branching angles of the microvessel network were compared among the different experimental groups. The distinctive features of the microvasculature of FGF-2-B9 tumors were retained, at least in part, in the smaller lesions produced by injection of a limited number of cells. The data indicate that FGF-2 production and release confer to FGF-2-B9 cells the ability to stimulate the formation of new blood vessels with distinctive architectural features. Neovascularization of FGF-2-B9 lesions parallels the faster rate of growth of the neoplastic parenchyma. This does not affect the overall architecture of the microvessel network that appears to be primed by characteristics of the HEC-1-B tumor cell line and/or by the microenvironment of the host. To our knowledge, this work represents the first attempt to define the influence of a single, defined growth factor on the tridimensional tumor vascular pattern.

Adenocarcinoma↗
PubMed1998

Ecteinascidin-743, a new marine natural product with potent antitumor activity on human ovarian carcinoma xenografts.

The antitumor activity of ecteinascidin (ET)-743, a novel marine natural product, was evaluated against a panel of human ovarian carcinoma xenografts characterized by different malignant behaviors and drug responsiveness in nude mice. These tumor models included three xenografts transplanted s.c. (HOC18, HOC22-S, and MNB-PTX-1) into nude mice, representing different levels of sensitivity to cisplatinum (DDP), which was used as reference drug for ovarian carcinoma, and two other xenografts (HOC22 and HOC8), which are highly malignant in the peritoneal cavity of nude mice, representing the growth pattern of this neoplasm. At the maximum tolerated dose of 0.2 mg/kg using an intermittent schedule of one i.v. injection every 4 days, ET-743 was highly active against HOC22-S (sensitive to DDP), inducing long-lasting, complete regressions, and against HOC18 (marginally sensitive to DDP), inducing partial tumor regressions. Moreover, significant growth delay was observed in mice bearing late-stage HOC18 tumor (400-mg tumor weight; nonresponsive to DDP). ET-743, however, was not active against MNB-PTX-1, a tumor that is highly resistant to chemotherapy, including DDP. In the i.p. ovarian carcinoma xenograft model, ET-743 at the maximum tolerated dose induced complete tumor remissions in all mice bearing HOC22 tumor, with 25% histopathologically confirmed cures, and produced marginal tumor growth delay against HOC8. These results indicate that ET-743 is a potent drug against ovarian carcinoma xenografts, being equally as active or more efficacious than DDP in the same tumor line. Our findings with human ovarian carcinoma xenografts justify clinical assessment of this drug with this tumor target.

Animals↗
PubMed1997

Effect of all trans-retinoic acid (ATRA) on the adhesive and motility properties of acute promyelocytic leukemia cells.

All trans-retinoic acid (ATRA) induces complete remission in acute-promyelocytic-leukemia (APL) patients. This study investigated the adhesive properties of APL cells for the endothelium and the extracellular matrix, their motility and the effect of ATRA on these functions. Blasts from 7 APL patients adhered to resting and IL-1-activated endothelium, to the same degree as normal PMN. Adhesion was partially mediated by ICAM-1 and, for IL-1-activated endothelium, by VCAM-1 and E-selectin. These cells showed less adhesiveness for the matrix than PMN, although they maintained the same substrate preference: they adhered to fibronectin and thrombospondin, but not to laminin and type-IV collagen. Exposure to ATRA in vitro (1 microM for 48 to 96 hr) increased the adhesiveness of APL cells; this effect was particularly evident in the case of sub-endothelial matrix and fibronectin. A similar increment in adhesiveness was observed when comparing cells from 2 patients before and after treatment with ATRA. APL cells migrated in response to fMLP and motility was increased by ATRA. In conclusion, APL cells were less adhesive to the matrix than PMN, but treatment with ATRA considerably enhanced their adhesive properties. This could be important in determining the efflux of leukemic cells from the bone marrow and their tissue infiltration during ATRA therapy.

Adolescent↗
PubMed1997

Outbreaks of hyperkeratotic dermatitis of athymic nude mice in northern Italy.

Hyperkeratotic dermatitis of athymic nude mice is an infectious disease caused by a coryneform bacterium. During the spring of 1995, outbreaks of hyperkeratotic dermatitis were observed in several nude mice facilities in northern Italy. In this report we describe the clinical, histopathological and microbiological features of the disease in two different animal facilities. Affected animals showed a typical 'scaly' appearance with small white flakes of material adherent to the skin. In one of the outbreaks (facility 2) the lesions were less severe and involved only limited areas of the body. The infection spread very quickly and the morbidity reached more than 80% in a few days, while the mortality was about 1%. The lesions resolved spontaneously within 7-10 days. Histological examination of affected skin revealed orthokeratotic hyperkeratosis, acanthosis and dermal inflammatory infiltration which were more severe in mice from facility 1. In Gram-stained sections groups of rods consistent with coryneform bacteria were detectable in the keratin layers covering the epidermal surface. A coryneform bacterium, biochemically typed as Corynebacterium bovis, was isolated from 11 out of 11 mice from facility 1 and from 8 out of 11 mice from facility 2.

Animals↗
PubMed1997

The 140-kilodalton antiangiogenic fragment of thrombospondin-1 binds to basic fibroblast growth factor.

Thrombospondin-1 (TSP) inhibits the angiogenic activity of basic fibroblast growth factor (bFGF). Here we address the hypothesis of a direct interaction between TSP and bFGF. Gel permeation chromatography and cross-linking experiments demonstrated that bFGF binds to TSP in solution. bFGF also bound to immobilized TSP in a solid-phase assay. Binding was dose-dependent, with a Kd in the nanomolar range, and was inhibited by anti-TSP antibodies. The 140-kDa carboxyl-terminal fragment of TSP, but not the 25-kDa heparin-binding fragment, fully retained the bFGF binding capacity. Accordingly, binding was inhibited by monoclonal antibodies directed against this fragment. Heparin completely blocked bFGF binding to TSP and to the 140-kDa fragment. TSP and its 140-kDa fragment inhibited the binding of bFGF to endothelial cells at concentrations (> or = 100 nM) that inhibited endothelial cell proliferation but not motility. Low-affinity binding was inhibited more than high-affinity binding (up to 76 and 41% inhibition, respectively), and the inhibition was reversed by anti-TSP antibodies. Vitronectin and transforming growth factor beta, potentially associated with TSP, did not affect bFGF binding to endothelial cells. Although TSP did not affect the activation of the high-affinity receptors, it reduced the long-term internalization of bFGF. We conclude that TSP binds to bFGF through a domain within its 140-kDa fragment, a mechanism that might affect bFGF interaction with endothelial cells, activity, and association with the extracellular matrix.

Animals↗