Biomedical subjects

S Colucci

Publications and source records attributed to S Colucci.

At least 19 recordsLinked to original sources

PubMed2000

Breast cancer cell line MDA-231 stimulates osteoclastogenesis and bone resorption in human osteoclasts.

Breast cancers commonly cause osteolytic metastases in bone, a process that is dependent upon osteoclast-mediated bone resorption, but the mechanism responsible for tumor-mediated osteoclast activation has not yet been clarified. In the present study we utilized a well-known human breast cancer cell line (MDA-231) in order to assess its capability to influence osteoclastogenesis in human bone marrow cultures and bone resorption in fully differentiated osteoclasts. We demonstrated that conditioned medium (CM) harvested from MDA-231 increased the formation of multinucleated TRAP-positive cells in bone marrow cultures. Bone resorption activity of fully differentiated human osteoclasts and of osteoclast-like cell lines, from giant cell tumors of bone (GCT), was highly increased by the presence of MDA-231 CM. Moreover, while MDA-231 by themselves did not produce IL-6 tumor cell, CM increased the secretion of IL-6 by primary human osteoclasts and GCT cell lines compared to untreated controls. These data suggest that MDA-231 produce osteoclastic activating factor(s) that increase both osteoclast formation in bone marrow culture and bone resorption activity by mature cells. Moreover, breast cancer cells stimulate IL-6 secretion by osteoclasts that is one of the factors known to supports osteoclastogenesis.

Acid Phosphatase↗

PubMed2000

Synthesis, analytical characterization, and osteoblast adhesion properties on RGD-grafted polypyrrole coatings on titanium substrates.

The covalent attachment of an Arg-Gly-Asp (RGD) containing peptide to polypyrrole(PPy)-coated titanium substrates has been investigated in order to develop a bioactive material of potential use in orthopedic fields. Polypyrrole has been employed as the coating polymer because of its suitability to be electrochemically grown directly onto metallic substrates of different shapes, leading to remarkably adherent films. The synthetic peptide Cys-Gly-(Arg-Gly-Asp)-Ser-Pro-Lys, containing the cell-adhesive region of fibronectin (RGD), has been grafted to the polymer substrate via the cysteine residue using a procedure recently developed in the authors laboratory. The effectiveness of grafting was monitored by X-ray photoelectron spectroscopy (XPS), which assessed the presence of the peptide grafted onto the polymer surface exploiting the cysteine sulfur as target element. Neonatal rat calvarial osteoblasts were attached to RGD-modified PPy-coated Ti substrates at levels significantly greater than on unmodified PPy-coated Ti and glass coverslip substrates.

Animals↗

PubMed1999

Radiobiological effects of docetaxel (Taxotere): a potential radiation sensitizer.

PURPOSE: To investigate the ability of docetaxel (Taxotere) to radiosensitize human cell lines of differing malignant status, intrinsic radiosensitivity and p53 status. MATERIALS AND METHODS: Cell survival following treatment with drug and/or radiation was determined by colony-forming assay on two malignant human colon cell lines of widely different radiosensitivity (HT29 and SW48). An immortal human keratinocyte line (HaCaT), which does not form tumours in nude mice, was used to assess the effect on non-malignant human epithelium. RESULTS: The experiments indicate that docetaxel had the greatest cytotoxic and radiosensitizing effect on the SW48 (p53wt) cell line. The degree of radiosensitization was not improved by increasing the drug concentration, although the overall cytotoxicity was increased with increasing concentrations of the two agents. Both p53mut lines were less sensitive to the drug, irrespective of their malignant potential. CONCLUSION: The results support a role for Taxotere as a weak radiosensitizer of the three cell lines tested. The p53 status and intrinsic radiosensitivity may be relevant to the mechanism.

Apoptosis↗

PubMed1999

Course and cost of treatment for depression with fluoxetine, paroxetine, and sertraline.

OBJECTIVE: To compare depression-related treatment costs and total healthcare costs for patients diagnosed with depression and treated with either sertraline, paroxetine, or fluoxetine. PATIENTS AND METHODS: Claims records from a national database of patients diagnosed with depression who began treatment with an SSRI in 1995, following an antidepressant medication-free period of at least 6 months, were included. Treatment course and associated depression-related treatment and total healthcare costs during the subsequent 12-month treatment period were examined using univariate and multivariate methods. RESULTS: Nine-hundred five (905) patients taking sertraline, 492 on paroxetine, and 945 on fluoxetine met inclusion criteria. The groups were similar and representative with respect to gender and age. Mean dose over the 12-month treatment period increased 24%, indicating significant titration in all cohorts. Patients treated with paroxetine had shorter treatment duration (157.0 days) than did patients treated with fluoxetine (192.6 days) or sertraline (166.9 days, P < 0.001). Patients receiving index treatment with paroxetine were most likely to switch to another SSRI (21.3%); those taking sertraline were second most likely to switch (16.1%); and those on fluoxetine were least likely (12.4%, P = 0.001). Mean costs for depression-related outpatient visits and hospitalizations were similar. Mean antidepressant prescription costs differed, being $586, $419, and $446 for fluoxetine, paroxetine and sertraline cohorts, respectively (P < 0.001). In this sample, the fluoxetine cohort did not have lower nonpharmaceutical healthcare costs to offset higher pharmaceutical acquisition costs. Conclusions from median and multivariate analyses were robust to these findings. CONCLUSIONS: During this study period when fluoxetine, paroxetine, and sertraline were all well-established agents, similar depression-related treatment courses and cost characteristics among all 3 drugs were observed.

Adolescent↗

PubMed1998

Activation of alphav beta3 integrin on human osteoclast-like cells stimulates adhesion and migration in response to osteopontin.

Integrins mediate cell adhesion and can induce different cellular responses, including changes in intracellular pH, changes and oscillation in intracellular free calcium, and protein phosphorylation on tyrosine. During bone resorption, the integrin alphav beta3 regulates adhesion of osteoclasts to bone extracellular matrix proteins, such us osteopontin (Opn). Adhesion via alphav beta3 is followed by osteoclast polarization onto the bone surface and by the onset of bone resorption. To characterize these events at the molecular level, we investigated the state of activation of alphav beta3 on the human osteoclast-like cell line GCT23 using the monoclonal antibody AP5 which binds to and can induce, under low calcium conditions, activated alphav beta3. By flow cytometry, approximately 50% of alphav beta3 on the surface of the osteoclast-like cell line GCT23 was reactive with AP5 and was therefore in the activated state. Incubation with AP5 in the presence of low calcium concentrations increased activated alphav beta3 to 90-100%. Activation of alphav beta3 increased the efficiency of GCT23 adhesion to Opn by 2-fold. Furthermore, haptotactic migration on Opn was also enhanced about 40% compared to control. We propose that changes in the activation state of alphav beta3 may be a regulation point for osteoclasts during bone resorption.

Antibodies, Monoclonal↗

PubMed1998

Response of human osteoblasts to polymethylmetacrylate In vitro.

The effects of a polymethylmetacrylate (PMMA) powder with a diameter between 0.5 and 25 mu m have been studied in vitro on several human osteoblast populations obtained from different sources. Parameters of cell activity such as cell growth, collagen synthesis, osteocalcin, and interleukin-6 (IL-6) production have been evaluated. Cell proliferation and collagen synthesis were inhibited after exposure to bone cement, whereas osteocalcin and IL-6 production were stimulated. These results suggest that PMMA particles could affect osteoblast activity in a way that could contribute, together with other factors, to periprosthetic osteolysis through two different pathways: a reduced periprosthetic bone formation due to the reduced osteoblast proliferation and collagen synthesis, and an osteoblast-mediated activation of osteoclastic bone resorption as suggested by the increased osteocalcin and IL-6 synthesis. In fact, osteocalcin has been demonstrated to have a role in osteoclast recruitment to bone surfaces, and IL-6 is known to induce osteoclastogenesis and to directly stimulate bone resorption.

Bone Cements↗

PubMed1998

Alendronate reduces adhesion of human osteoclast-like cells to bone and bone protein-coated surfaces.

Bisphosphonates (BPs) are potent inhibitors of bone resorption and are therapeutically effective in disease of increased bone turnover, but their mechanism(s) of action remain to be elucidated. Using as experimental model human osteoclast-like cell lines derived from giant cell tumors of bone, extensively characterized for their osteoclast features, we investigated the adhesive properties of osteoclasts on bone slices and on different proteins of the extracellular matrix in the presence of BPs. Adhesion assays using bone slices pretreated with ALN, at the established active concentration, showed that, although the morphology of osteoclasts plated onto pretreated bone slices was not modified, the number of adherent cells was reduced by the treatment of about 50% vs. controls. The effect of ALN on the adhesion of osteoclast-like cells onto specific extracellular matrix proteins, such as bone sialoprotein-derived peptide, containing the RGD sequence, conjugated to BSA (BSP-BSA) and fibronectin (FN), was also tested. In the case of FN the treatment with ALN of protein-coated wells did not modify the percentage of cell adhesion compared with the control, whereas onto BSP-BSA the presence of ALN significantly reduced adhesion of about 40-45%, suggesting that the inhibitory effect of ALN on cell adhesion could probably be due to the interference with receptors specifically recognizing bone matrix proteins as alphaVbeta3 integrins. Furthermore, ALN induced Ca-mediated intracellular signals in osteoclasts, triggering a 2-fold increase in intracellular calcium concentration.

Alendronate↗

PubMed1998

Long-term results of excimer laser photorefractive keratectomy in high myopia: a preliminary report.

BACKGROUND AND OBJECTIVE: To evaluate the results of 193-nm excimer laser photorefractive keratectomy (PRK) performed on highly myopic eyes with a follow-up of at least 2 years. PATIENTS AND METHODS: Fifty-three eyes of 41 patients were treated with a myopic PRK for an attempted correction ranging between -8 and -17 D (mean -10.9 +/- 2.8 SD). RESULTS: The follow-up ranged from 24 to 60 months (mean 34.1 months +/- 10 SD). Fifty-three percent of the eyes achieved a refraction within +/- 2 D of the planned correction, with a refractive error greater than 4 D in 21% of the treated eyes. The uncorrected visual acuity was 20/40 or better in 45% of the eyes. There were no significant opacities in 85% of the eyes examined. A second treatment was performed on 5 eyes. CONCLUSION: The results suggest that excimer laser PRK is a safe and relatively effective alternative for treating highly myopic eyes, and its effects are stable over a long period of time.

Adult↗

PubMed1997

p53 mutations and protein expression in primary cultures of normal oral mucosa in smokers and non-smokers.

The normal oral mucosa from 77 individuals of known smoking and alcohol-intake history was cultured. After 14-21 days in culture, epithelial cells were stained for p53 expression using immunohistochemistry. PCR-SSCP analysis of the p53 gene was also performed on a random sub-set of these samples (20 non-smokers and 21 smokers). Expression of the stable, non-functional form of p53 protein as detected by the p53-240 antibody was found to be significantly elevated in the cultured oral mucosa of smokers. (P < 0.01). PCR-SSCP analyses indicated a higher level of base changes in smokers than in non-smokers. These observations are consistent with other findings of significantly increased p53 protein expression in the oral mucosa and other tissues of smokers and suggests that p53 mutations may be an early event in smoking-induced oral cancers.

Adolescent↗

PubMed1997

Induction of multiple PCR-SSCPE mobility shifts in p53 exons in cultures of normal human urothelium exposed to low-dose gamma-radiation.

We have previously shown that primary explant cultures of human urothelium exposed to low doses of gamma-radiation subsequently accumulate a high level of stable p53 but it was not clear from those studies whether this protein stabilization occurred through an event in another gene involved in p53 protein control or possibly an epigenetic event. In these experiments, primary urothelial cultures from five different patients were exposed to either 0.5 or 5 Gy gamma-radiation from a 60 Cobalt source and allowed to grow for 7-10 division cycles to allow development of any radiation-induced, non-lethal changes in the cells. C-myc, Bcl-2 and stable p53 proteins were found to be elevated in cultures following both radiation doses. PCR-SSCPE analysis of the p53 gene was performed on cultures in order to determine whether genetic mutations could be the underlying basis for persistent increased stable p53 expression. Following 0.5 Gy exposure, the cultures also developed multiple distinct 'foci' of rapidly dividing cells which strongly overexpressed p53. These grew on a background of morphologically normal cells. When such foci were selectively analysed for their p53 mutation status by PCR-SSCPE, there was evidence that they contained cells which had developed changes to the p53 gene post-irradiation. These changes appeared to occur more frequently in focal cells than in cells of normal morphological appearance in the same culture. These results may have mechanistic importance given the controversy regarding low-dose radiation effects and p53-related genomic instability.

Culture Techniques↗

PubMed1997

p53 protein expression and increased SSCP mobility shifts in the p53 gene in normal urothelium cultured from smokers.

This study provides evidence of a significantly (P = 0.018) increased level of expression of the stable conformation of p53 in normal urothelial cells, cultured in vitro from bladder biopsies obtained from normal smokers without malignant disease of any site. With two significant exceptions, non-smokers showed low or no expression of this protein. Past smokers appeared to segregate into high or low p53 expressers, but the expression was not correlated with years since quitting smoking or with pack years smoked. The mean data in this group were not quite significantly different (P = 0.08) from the non-smoker group, due to the wide inter-patient variation. For most of the smoker group, pack years correlated with p53 expression with a mean unit of 1.7 +/- 0.37% p53 per pack year but there was a small group of very heavy smokers who showed lower than expected expression (approximately 0.3-0.8% p53 per pack year). These were statistical outliers (Grubbs test). No explanation could be found for this. Over-expression of p53 protein, often correlates with mutations in the gene, but may also indicate that breakdown of wild-type p53 has slowed. SSCP analysis of the biopsy material was not possible on all patients due to ethical constraints on the amounts of tissue which could be taken but in the cases where it was possible the association between loss of p53 protein function and mobility shifts in p53 exons 5-8 was confirmed with smokers having 3.5 times the number of mobility shifts detected in non-smoker DNA. Thus the results may point to a role for the early abrogation of p53 protein function in bladder carcinogenesis induced by cigarette smoking.

Adult↗

PubMed1996

Retinoic acid induces cell proliferation and modulates gelatinases activity in human osteoclast-like cell lines.

The effect of Retinoic Acid (RA) on human osteoclast-like cell lines, obtained from Giant Cell tumors (GCT) of bone, has been investigated evaluating its action on bone resorption, cell proliferation, microtubular organization and gelatinases expression and activity. Increasing concentrations of RA significantly dose-dependently decreased GCTs bone resorption, while 10(-7) M RA promoted an increase of cell proliferation. By immunofluorescence we demonstrated that GCTs express A and B gelatinases and, by zymography, that their activity was enhanced in medium collected from GCTs cultured in the presence of 10(-7) M RA. These data indicate that RA increases cell proliferation and modulates metalloproteinases (MMPs) activity, crucial events during the migration of osteoclast precursors toward bone surfaces.

Bone Resorption↗

PubMed1996

Hepatocyte growth factor is a coupling factor for osteoclasts and osteoblasts in vitro.

Hepatocyte growth factor (HGF), also known as scatter factor, is a powerful motogen, mitogen, and morphogen produced by cells of mesodermal origin, acting on epithelial and endothelial cells. Its receptor is the tyrosine kinase encoded by the c-MET protooncogene. We show that the HGF receptor is expressed by human primary osteoclasts, by osteoclast-like cell lines, and by osteoblasts. In both cell lineages, HGF stimulation triggers the receptor kinase activity and autophosphorylation. In osteoclasts, HGF receptor activation is followed by increase in intracellular Ca2+ concentration and by activation of the pp60c-Src kinase. HGF induces changes in osteoclast shape and stimulates chemotactic migration and DNA replication. Osteoblasts respond to HGF by entering the cell cycle, as indicated by stimulation of DNA synthesis. Interestingly, osteoclasts were found to synthesize and secrete biologically active HGF. These data strongly suggest the possibility of an autocrine regulation of the osteoclast by HGF and a paracrine regulation of the osteoblast by the HGF produced by the osteoclast.

Bone Neoplasms↗

PubMed1996

Human osteoclast-like cells selectively recognize laminin isoforms, an event that induces migration and activates Ca2+ mediated signals.

Osteoclast precursors are chemotactically attracted to sites of bone resorption via migration pathways that include transendothelial crossing in blood capillaries. Transendothelial migration involves poorly understood interactions with basal lamina molecules, including laminins. To investigate osteoclast-laminin interactions, we used human osteoclast-like cell lines obtained from giant cell tumors of bone (GCT 23 and GCT 24). These cell lines are a well-characterized model for osteoclast functions, such as bone resorption and the behaviour of osteoclast precursors. Both GCT cell lines adhered to laminin-2 (merosin) coated wells in standard adhesion assays, but failed to adhere to laminin-1 (EHS-laminin). By light microscopy, GCT cells on laminin-2 were partially spread, with a motile morphology. None of the anti-integrin antibodies tested inhibited GCT cells adhesion to laminin-2. Peptides containing the integrin adhesion site RGD or the laminin adhesion sequence IKVAV did not inhibit GCT cell adhesion to laminin-2. By immunofluorescence, beta 1 integrins were organized in focal adhesions. However, in the presence of monensin this reorganization of beta 1 integrins was abolished, indicating that it was probably due to secretion of fibronectin by GCT cells subsequent to adhesion to laminin-2. GCT cells transmigrated through membranes coated with laminin-2, much more efficiently than through membranes coated with collagen. Migration was induced by osteocalcin, as a chemoattractant, in a dose-dependent manner. At low osteocalcin concentrations, transmigration was detectable on laminin-2 but not collagen. In cells loaded with fura-2, a sharp increase in intracellular Ca2+ was detected upon addition of soluble laminin-2, but not laminin-1, due to release from thapsigargin-dependent intracellular stores. In summary, osteoclasts may recognize laminin isoforms differentially. Initial adhesion to laminin-2 appears to be due to integrin-independent mechanisms. Such adhesion, though, may trigger secretion of fibronectin that could then support spreading and efficient chemotactic migration. These mechanisms may play an important role in facilitating chemotactic migration of osteoclast precursors toward the bone surface.

Calcium↗

PubMed1995

[Aneurysm of the popliteal artery in a patient over 80 years of age].

The authors report an aneurysm in the popliteal artery surgically treated with success. The operation consisted on the installation of one tubular prosthesis femoro-poplitea with a termino-terminal anastomosis. The follow-up to 3 and 6 months from the operation showed good functional recovery.

Age Factors↗

PubMed1994

New model for bone resorption study in vitro: human osteoclast-like cells from giant cell tumors of bone.

Cells harvested from 12 human giant cell tumors of bone and kept in culture for several passages were characterized for bone-resorbing capability, total and tartrate-resistant acid phosphatase activity, response to the calciotropic hormone calcitonin, cell proliferation, multinucleation after passages, and presence of calcium sensing. Cells obtained from three tumors presented a complete panel of osteoclast characteristics and maintained their multinuclearity after several passages. Cells from four other tumors increased their cAMP levels after treatment with calcitonin, and the other five apparently consisted of cells of stromal origin. These human cell populations with osteoclast characteristics may provide valid in vitro models for the investigation of osteoclastic differentiation and activity.

Acid Phosphatase↗

PubMed1994

Adhesion properties and integrin expression of cultured human osteoclast-like cells.

Osteoclast interaction with extracellular matrix drives the sequential events that end with bone resorption. However, the role of matrix proteins is not yet fully understood. We studied this problem on human osteoclast-like cells derived from giant cell tumors of bone (GCT cells). On GCT cells we considered cytoskeletal organization, adhesion properties, and integrin expression upon plating in serum-free medium onto fibronectin (FN), collagen (COL), thrombospondin (TSP), bone sialoprotein (BSPII), and osteopontin (OPN). GCT cells promptly adhered and spread on FN, BSPII, and OPN, while only 50% adhered on COL and none on TSP. The integrin beta 1 chain was always associated to focal adhesions, while the alpha v beta 3 heterodimer was detected in focal contacts only upon plating on BSPII, OPN, and FN. The focal clustering of beta 1 was impaired by monensin treatment, indicating that endogenous FN secretion was required to drive beta 1 into focal contacts. Conversely, alpha v beta 3 clustering was also not affected by monensin when cells were plated onto plasma FN. Immunoprecipitation of metabolically labeled GCT cell lysates showed that three different heterodimers (alpha v beta 3, alpha 3 beta 1, and alpha 5 beta 1) were assembled. Adhesion to FN was completely inhibited by beta 1 antibodies at dilutions up to 1:400, while beta 3 antibodies, at similar dilutions, impaired spreading but not adhesion. We conclude that alpha v beta 3 is the main integrin used by GCT cells in bone recognition. We also suggest that selected substrata may induce the release and the organization of endogenous FN that eventually drives the recruitment of a beta 1 integrin receptor into focal contacts.

Amino Acid Sequence↗

PubMed1994

Osteocalcin induces chemotaxis, secretion of matrix proteins, and calcium-mediated intracellular signaling in human osteoclast-like cells.

Osteocalcin, also called Bone Gla Protein (BGP), is the most abundant of the non-collagenous proteins of bone produced by osteoblasts. It consists of a single chain of 46-50 amino acids, according to the species, and contains three vitamin K-dependent gamma-carboxyglutamic acid residues (GLA), involved in its binding to calcium and hydroxylapatite. Accumulating evidences suggest its involvement in bone remodeling, its physiological role, however, is still unclear. In this study the adhesion properties and the biological effects of osteocalcin on osteoclasts have been analyzed using as an experimental model, human osteoclast-like cells derived from giant cell tumors of bone (GCT). Osteocalcin promoted adhesion and spreading of these cells, triggering the release of bone sialoprotein (BSP), osteopontin (OPN) and fibronectin (FN), that in turn induced the clustering in focal adhesions of beta 1 and beta 3 integrin chains. Spreading was dependent upon the synthesis of these proteins. In fact, when the cells were incubated in the presence of monensin during the adhesion assay, they still adhered but spreading did not occur, focal adhesions disappeared and BSP, OPN, and FN were accumulated in intracellular granules. Furthermore osteocalcin induced chemotaxis in a dose-dependent manner. The action of BGP on osteoclasts was mediated by an intracellular calcium increase due to release from thapsigargin-sensitive stores. These results provide evidences that BGP exerts a role in the resorption process, inducing intracellular signaling, migration and adhesion, followed by synthesis and secretion of endogenous proteins.

Bone Neoplasms↗