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V Castronovo

Publications and source records attributed to V Castronovo.

At least 55 records · Page 3Linked to original sources
PubMed1998

The 67-kDa laminin receptor originated from a ribosomal protein that acquired a dual function during evolution.

The 67-kDa laminin receptor (67LR) is a nonintegrin cell surface receptor that mediates high-affinity interactions between cells and laminin. Overexpression of this protein in tumor cells has been related to tumor invasion and metastasis. Thus far, only a full-length gene encoding a 37-kDa precursor protein (37LRP) has been isolated. The finding that the cDNA for the 37LRP is virtually identical to a cDNA encoding the ribosomal protein p40 has suggested that 37LRP is actually a component of the translational machinery, with no laminin-binding activity. On the other hand, a peptide of 20 amino acids deduced from the sequence of 37LR/p40 was shown to exhibit high laminin-binding activity. The evolutionary relationship between 23 sequences of 37LRP/p40 proteins was analyzed. This phylogenetic analysis indicated that all of the protein sequences derive from orthologous genes and that the 37LRP is indeed a ribosomal protein that acquired the novel function of laminin receptor during evolution. The evolutionary analysis of the sequence identified as the laminin-binding site in the human protein suggested that the acquisition of the laminin-binding capability is linked to the palindromic sequence LMWWML, which appeared during evolution concomitantly with laminin.

Amino Acid Sequence↗
PubMed1998

Evidence that breast cancer associated microcalcifications are mineralized malignant cells.

Microcalcifications are often associated with both benign and malignant human breast lesions. Around 40% of mammary carcinoma present such ectopic mineralization and frequently, they are the only mammographic feature that indicate the presence of a tumoral lesion. Microcalcifications associated with breast cancer are usually composed of hydroxyapatite, the bone specific mineral. The mechanisms responsible for the formation of such crystals within breast malignant tissue have not been elucidated. A possible clue could be provided by the recent demonstration that breast cancer cells express several bone matrix proteins including osteonectin, osteopontin and bone sialoprotein (BSP). This latter phospho-protein is involved in the initiation of hydroxyapatite crystallisation and its expression in breast cancer has been associated to the presence of hydroxyapatite microcalcifications. We examined 10 human breast cancer lesions which were characterized by the presence of microcalcifications and high expression of BSP. Histological examination of the lesions suggested, in most of the cases, that the microcalcifications were breast cancer cells which became mineralized. Hydroxyapatite stained in blue by hematoxylin appears concentrated around single of associated cancer cells. Staining of these tissue sections with 4',6 diamidino-2-phenylindole which specifically labels DNA led us to demonstrate that the mineralizated structures contain cells. These data are the first direct demonstration that breast microcalcifications are fossils of cancer cells. The mechanisms for such a phenomenon remain to be demonstrated. We speculate that the high expression of BSP could create an appropriate microenvironment for the crystallisation of calcium and phosphate into hydroxyapatite.

Breast Neoplasms↗
PubMed1998

[Cancer of the cervix uteri: analysis of the cost-benefit and efficacy of opportunistic screening versus organized screening].

Cervical cancer is the fourth cancer in women. It is the first malignancy for which mass population screening has been demonstrated to significantly reduce the mortality due to this disease. In Belgium, the mortality associated to cervical cancer decreased from 6 to 4 per 100,000 women-years from 1955-1959 to 1985-1989. European recommendations regarding cervical cancer screening are to perform a cervical smear each three years in women aged 25 to 65 years. In Belgium, while the Flemish region has decided to organize the cervical cancer screening according to the European recommendations, the screening in the French part of the country is essentially opportunistic. In this short review, the cost/benefit of the organized screening versus the opportunistic screening is discussed.

Adult↗
PubMed1998

Transglutaminase-mediated oligomerization of galectin-3 modulates human melanoma cell interactions with laminin.

Tumor cell adhesion and migration to laminin are important events during invasion and metastatic spread. Galectin-3, a multifunctional member of the galectin family, binds specifically the poly-N-acetyllactosamine residues of laminin and has been implicated in tumor invasion and metastasis. Galectin-3 is multimerized by transglutaminase, an enzyme that catalyzes cross-linking between glutamine and other aminoacid residues. In this study, we examined the consequences of transglutaminase-mediated galectin-3 oligomerization on the interactions between cancer cells and laminin. We first demonstrated that human galectin-3 is cross-linked by guinea pig liver transglutaminase, forms oligomers, and incorporates the marker 5-(biotinamido) pentylamine. Expression of transglutaminase activity in the A375 and A2058 human melanoma cell extracts was revealed by its ability to induce galectin-3 oligomerization and 5-(biotinamido) pentylamine incorporation. Transglutaminase-treated galectin-3 did not affect adhesion or migration of the melanoma cells to laminin but consistently induced a significant increase of the percentage of cell spreading compared to the control (23.5 +/- 2.3%, vs. 10.6 +/- 1.9% at 180 min, p < 0.05), or to untreated galectin-3 or transglutaminase alone. Our study is the first demonstration that human galectin-3 is oligomerized by transglutaminase with, as a consequence, a specific effect of melanoma cell spreading on laminin. This phenomenon could be of significance in the modulation of cancer cell interactions with laminin during tumor invasion and metastasis.

Amines↗
PubMed1998

Expression and modulation of homeobox genes from cluster B in endothelial cells.

Angiogenesis is a complex phenomenon likely to be under the strict control of a group of transcription factor(s). Homeobox (HOX)-containing proteins have been identified as regulators controlling the coordinated expression of genes involved in organ development and tissue differentiation. In this study, we have demonstrated that human umbilical vein endothelial cells (HUVEC) express 8 of the 10 HOX genes contained in cluster B. Treatment of HUVEC with tissue plasminogen activator (TPA), an agent known to induce morphologic changes in endothelial cells, or vascular endothelium growth factor (VEGF), a proliferative and angiogenesis inducer, results in a specific time-dependent modulation of the eight HOX genes identified. Interestingly, neither basic fibroblast growth factor, an endothelial proliferative agent, nor TNP-470, a fumagillin derivative with potent antiendothelial cell proliferation properties, affected expression of these HOX genes. Specific modulation of HOX genes by differentiating agents but not by proliferative or antiproliferative molecules suggests that they could be involved in the control of the genetic program that coordinates the construction of new blood vessels.

Base Sequence↗
PubMed1997

New insights into the metastasis-associated 67 kD laminin receptor.

The interactions between tumor cells and laminin or other components of the extracellular matrix have been shown to play an important role in tumor invasion and metastasis. These interactions are mediated by different cell surface molecules, including the monomeric 67 kD laminin receptor. This molecule appears to be very peculiar since so, far only a full-length gene encoding a 37 kD precursor protein has been isolated and the mechanism by which the precursor reaches the mature form is not understood. Based on clinical data, which clearly demonstrate the importance of the receptor in tumor progression, studies were conducted to define the structure, expression, and function of this laminin receptor as a step toward developing therapeutic strategies that target this molecule. The data suggest that acylation of the precursor is the key mechanism in maturation of the 67 kD form. The function of the membrane receptor is to stabilize the binding of laminin to cell surface integrins, acting as an integrin-accessory molecule, although homology of the gene encoding the receptor precursor with other genes suggests additional functions. Downregulation of the receptor expression on tumor cells might open new therapeutic approaches to decrease tumor aggressiveness.

Animals↗
PubMed1997

Co-regulation and physical association of the 67-kDa monomeric laminin receptor and the alpha6beta4 integrin.

The interactions between tumor cells and laminin or other components of the extracellular matrix have been shown to play an important role in tumor invasion and metastasis. However, the role of the monomeric 67-kDa laminin receptor (67LR) remains unclear. We analyzed the regulation of 67LR expression under different culture conditions with respect to the expression of other well characterized laminin receptors. In A431 cells treated with laminin for different time periods, the regulation of 67LR expression correlated with expression of the alpha6 integrin subunit but not with the expression of other laminin receptors. Moreover, cytokine treatment resulted in down-modulated expression of the alpha6 integrin subunit and the 67LR. Co-regulation of the expression of the two receptors was further suggested by the observation that specific down-modulation of the alpha6-chain by antisense oligonucleotides was accompanied by a proportional decrease in the cell surface expression of 67LR. Biochemical analyses indicated co-immunoprecipitation of 67LR and the alpha6 subunit with an anti-alpha6 but not an anti-beta1 monoclonal antibody. Co-regulation of 67LR and alpha6 subunit expression, together with the physical association between the two receptors, supports the hypothesis that 67LR is an auxiliary molecule involved in regulating or stabilizing the interaction of laminin with the alpha6beta4 integrin.

Antigens, Neoplasm↗
PubMed1997

Galectin-3 and laminin expression in neoplastic and non-neoplastic thyroid tissue.

Galectin-3 is a 31 kD beta-galactoside-binding lectin which is expressed by several types of non-neoplastic and neoplastic cells and which may be involved in cell-extracellular matrix interactions. An immunohistochemical study has been made of the expression of galectin-3, as well as its ligand, laminin, in a spectrum of benign and malignant thyroid neoplasms and in some non-neoplastic conditions. Immunohistochemistry with anti-human recombinant galectin-3 antibody showed consistent, intense positivity in the neoplastic cells of 18 cases of papillary carcinoma and less intense staining in the five anaplastic carcinomas studied. In addition, two out of three poorly differentiated carcinomas, three out of six medullary carcinomas, and four out of eight follicular carcinomas had less intense or focal positivity. One case of Hürthle cell carcinoma showed scattered strongly positive cells. Eight follicular adenomas, three hyperplastic nodules, five nodular goitres, and normal thyroid tissue were negative. Galectin-3 mRNA expression was also evaluated in three of the papillary carcinomas, two follicular adenomas, and one hyperplastic nodule with matched normal tissue. Northern blot analysis demonstrated mRNA overexpression in the three cases of papillary carcinomas, whereas normal and benign tissues were negative. Laminin distribution in neoplastic and non-neoplastic tissue varied with architectural patterns but did not correlate with galectin-3 immunohistochemical expression. We conclude that expression of galectin-3 is limited to inflammatory foci in normal and benign thyroid tissue and is a phenotypic feature of malignant thyroid neoplasms, especially papillary carcinomas.

Antigens, Differentiation↗
PubMed1997

Expression of the 67 KD laminin receptor in human cervical preneoplastic and neoplastic squamous epithelial lesions: an immunohistochemical study.

Interactions of cancer cells with laminin play a critical role during the progression of solid malignant tumours. Increased expression of the 67 kD laminin receptor (67LR), one of the several laminin binding proteins, is associated with the invasive and metastatic capacity of various types of cancer, including breast, colon, ovary, lung, and endometrial carcinoma. In this study, 67LR expression was analysed in a series of cervical biopsy specimens including 16 normal cervical tissues, 36 low-grade squamous intraepithelial lesions (SILs), 24 high-grade SILs, and 11 invasive carcinomas. Detection of the 67LR was performed using immunoperoxidase staining and the monoclonal antibody MLuC5 which specifically recognizes the 67LR. Immunostaining of the 67LR was correlated with human papillomavirus (HPV) type detected by in situ hybridization and with proliferative activity of the lesion determined by immunohistochemistry with the MIB-1 monoclonal antibody, specific for the Ki67 antigen. Increased expression of the 67LR was correlated with the histological severity of the lesions, with the strongest immunoreactivity being found in invasive carcinomas. Significant differences in 67LR expression were found between normal cervical epithelium and high-grade SILs (P < 0.05, non-parametric Mann-Whitney test) or invasive carcinomas (P < 0.001), as well as between low- or high-grade SILs and invasive carcinoma (P < 0.01 and P < 0.05, respectively). Ki67 antigen expression also increased with the severity of the lesions. There was a positive correlation for each type of lesion between expression of the 67LR and of the Ki67 antigen. No specific relationship was found between 67LR or Ki67 antigen immunostaining and HPV type detected in SILs, segregated into low-grade and high-grade lesions. These data add weight to the evidence that increased expression of the 67LR is a consistent, but not sufficient feature of the invasive and metastatic phenotype and suggest that high expression of the 67LR might be associated with both more proliferative and more aggressive cervical (pre)neoplastic lesions.

Biomarkers, Tumor↗
PubMed1997

The spectrum of 67-kD laminin receptor expression in breast carcinoma progression.

Laminin is a glycoprotein of the basement membrane (BM), involved in a variety of normal and pathological cellular events including tumour invasion and metastasis. Cells bind laminin through different types of receptor. The 67-kD laminin receptor (67LR) is a cell-surface protein which binds laminin with high affinity. 67LR expression has been shown to increase in neoplastic cells, compared with normal tissues, and 67LR seems to play an important role during the first steps of neoplastic progression. In this study, 67LR expression was analysed during the morphological phases of breast cancer progression from normal tissue to invasive carcinoma. A total of 506 formalin-fixed, paraffin-embedded normal breast structures and lesions were stained by immunohistochemistry usign the MLuC5 monoclonal antibody, which is specific for 67LR. The results show that in normal breast and in any kind of breast lesion, myoepithelial and endothelial cells express 67LR. While 67LR is not seen in the epithelium of normal breast, cysts, adenosis, and benign tumours, it is expressed in the epithelial cells of several hyperplasias and carcinomas in situ, both ductal and lobular, as well as in all invasive carcinomas. The 67LR-positive cell subpopulation expands from hyperplastic lesions to invasive carcinoma, suggesting that 67LR could be related to the induction and progression of breast cancer.

Breast↗
PubMed1997

Differential expression of galectin-1 and galectin-3 during first trimester human embryogenesis.

Development of complex organisms requires specific temporospatial differentiation and expression of the correct phenotype through activation of a variety of genes. Galectins are mammalian lectins able to interact with various extracellular matrix glycoconjugates and have been implicated in several biological events including cell attachment, differentiation, apoptosis, embryogenesis, and cancer invasion and metastasis. In this study, we have examined the expression of galectin-1 and galectin-3 during human first trimester embryogenesis using immunohistochemistry and Western blotting. Variable amounts of galectin-1 and galectin-3 were detected in all tissue protein extracts. Galectin-1 expression was demonstrated in the connective tissue and derived tissues such as smooth and striated muscle cells, and in some epithelia, such as in the basal layers of the skin after 14 weeks and in the epithelial cells of the gonads. Galectin-3 was detected mainly in epithelia, such as the skin, epithelial lining of the digestive and respiratory tract, and urothelium and excretory tubes of the kidney, but also in the myocardial cells, in the peripheral and preossifying hypertrophic chondrocytes, and in the notochord and in the liver. Our study constitutes the first demonstration of galectin-1 and galectin-3 during human embryogenesis. The differential expression of these two lectins suggests that they could participate in the complex processes of tissue differentiation.

Antigens, Differentiation↗
PubMed1997

Expression of bone sialoprotein in human lung cancer.

Lung cancer belongs to the group of malignant lesions that specifically select bone as secondary implantation site. The molecular bases for this property, defined as osteotropism, is still largely unknown. The recent demonstration that human breast cancer cells express and attach to bone sialoprotein (BSP), a sulfated phosphoprotein rich in bone and other mineralized tissues, could provide a clue to elucidating bone metastases formation. BSP contains the integrin binding peptide Arg-Gly-Asp (RGD), as well as non-RGD cell attachment domain. Using an immunoperoxidase technique and a specific polyclonal antibody directed against a BSP synthetic peptide, we examined the expression of BSP in 48 lung lesions including 25 squamous carcinoma, 21 adenocarcinoma, and 2 bronchioloalveolar cancers, as well as 38 human ovarian carcinoma that constitute a group of generally nonosteotropic cancers. BSP was not specifically detected in normal lung tissue with the exception of cartilage associated with bronchi. Most of the adenocarcinoma (74%) and all squamous carcinoma of the lung examined exhibited detectable levels of BSP. Staining was mainly cytoplasmic and membrane associated. The two bronchioloalveolar lung cancers examined did not show detectable amounts of BSP. When microcalcifications were observed in pulmonary malignant lesions, they were usually associated with cancer cells expressing BSP. Only 21% of the ovarian cancers examined contained malignant cells with 2+ or 3+ positivity for BSP. We further demonstrated that in 8 of 10 additional lung cancers, BSP was detected at the mRNA level. Our observation is the first demonstration that BSP is expressed in non-small cell lung carcinoma. Lung cancer cells are now the second type of osteotropic malignant cells described to express BSP. Added to the observation that BSP expression is not frequent in ovarian carcinoma, a low osteotropic cancer, our study supports our hypothesis that BSP could play a role in determining the affinity of cancer cells to bone.

Adenocarcinoma↗
PubMed1997

Differential expression of galectin 3 and galectin 1 in colorectal cancer progression.

BACKGROUND & AIMS: Galectins are beta-galactoside-binding proteins possibly involved in tumor progression. The aim of this study was to determine the pattern of galectin 3 and galectin 1 expression and involvement in colorectal cancer progression. METHODS: Galectin 3 expression was examined immunohistochemically in 39 samples of normal mucosae, 25 adenomas, 87 carcinomas, and 39 lymph node metastases. Galectin 1 was analyzed in 25 samples of mucosae, 15 adenomas, 25 carcinomas, and 11 metastases. Western blot analysis was also performed. RESULTS: All normal mucosae showed strong nuclear galectin 3 expression, which was down-regulated in the neoplastic progression, because only 60% of adenomas, 48% of carcinomas, and 44% of metastases were strongly positive (P < 0.0001). Cytoplasmic expression was down-regulated in adenomas (16%) but increased again in carcinomas (64%) (P < 0.0001). Galectin 1 expression was mainly detected in stromal cells and correlated with tumor progression from normal mucosae to adenomas and carcinomas (P < 0.0001). CONCLUSIONS: Galectin 3 expression is down-regulated in the initial stages of neoplastic progression, whereas a dissociated cytoplasmic expression increases in later phases of tumor progression. Galectin 1 in colorectal mucosa is predominantly a stromal product whose overexpression is associated with the neoplastic progression of colorectal cancer.

Adenoma↗
PubMed1997

Expression of bone matrix proteins in human breast cancer: potential roles in microcalcification formation and in the genesis of bone metastases.

The skeleton is the privileged target of metastatic human breast cancer cells. Bone metastases are indeed found in virtually all advanced breast cancer patients and generate major morbidity. The high osteotropism of breast cancer cells suggests that they exhibit a selective affinity for mineralized tissues. The observation that mammary malignant cells are able to induce hydroxyapatite crystals deposition within the primary tumour suggests that they can generate a microenvironment that favors the crystallization of calcium and phosphate ions into the bone specific hydroxyapatite. Osteonectin (OSN), osteopontin (OPN) and bone sialoprotein (BSP), 3 bone matrix proteins involved in bone matrix mineralization, are expressed in human breast cancers. BSP, an RGD (Arg-Gly-Asp) containing phosphoprotein, initiates hydroxyapatite deposition and mediates attachment of osteoclast to the same crystals prior to their resorption. Detection of BSP at both the protein and the mRNA levels in human breast cancer and in human breast cancer cell lines (MCF-7, T47-D and MDA-MB 231) indicates that mammary malignant cells synthesize directly BSP rather than uptaking it from the serum. Interestingly, the level of BSP expression correlates with the development of bone metastases and with poor survival. These data suggest that the ectopic expression of bone matrix proteins could be involved in conferring osteotropic properties to circulating metastatic breast cancer cells. These observations open new alleys of investigation for the identification of the molecular mechanisms responsible for the genesis of bone metastases.

Biomarkers, Tumor↗
PubMed1997

Loss of type IV collagen alpha 5 and alpha 6 chains in human invasive prostate carcinomas.

Type IV collagen, a major component of basement membranes, is organized in a network responsible for the mechanical resistance of the basement membranes. It also plays a key role in epithelial cell adhesion to basement membranes. This study was designed to investigate the distribution of type IV collagen alpha-chains in normal, preneoplastic, and malignant prostate basement membranes. For this purpose, immunohistochemistry using specific antibodies raised against the different alpha-chains of type IV collagen was performed in eight normal samples, six prostatic intraepithelial neoplasia, and 20 malignant lesions of the prostate. Our results demonstrate the presence of the "novel" alpha 5 (IV) and alpha 6 (IV) chains along with the "classical" alpha 1 (IV)/alpha 2 (IV) chains in the basement membrane of the normal prostate gland. The alpha 3 (IV) chain was never detected in any prostate specimen. Prostatic intraepithelial neoplasia showed a similar immunostaining pattern to that found in normal glands. In cancer gland basement membranes, we demonstrate for the first time a specific loss of the alpha 5 (IV) and alpha 6 (IV) chains, whereas the classical alpha 1 (IV) and alpha 2 (IV) chains were consistently exhibited. Additionally, type VII collagen colocalized with alpha 5 (IV) collagen chain, and these two proteins, which were always observed in normal and prostatic intraepithelial neoplasia gland basement membranes, were lost in invasive carcinoma basement membranes. This observation raises questions about the possible association or cooperation between alpha 5 (IV)/alpha 6 (IV) chains and anchoring fibrils in prostate glands basement membrane.

Adenocarcinoma↗
PubMed1997

67-Kilodalton laminin receptor expression correlates with worse prognostic indicators in non-small cell lung carcinomas.

Tumor samples obtained from 72 patients resected for non-small cell lung cancer were stained immunohistochemically using an immunoperoxidase method and the MLuC5 monoclonal antibody specific for the 67-kDa laminin receptor. Sixty-one of 72 patients (84.7%) displayed a MLuC5-positive reaction, which was usually localized in both the inner surface of the plasmatic membranes and the cytoplasm of neoplastic cells. When we compared the laminin receptor expression with clinicopathological and biological parameters such as histotype, grading, T status, N status, ploidy, proliferative activity, vessel invasion, and p53 protein accumulation, the following results were observed: (a) the mean expression of the receptor was higher in the group of patients with metastatic nodal involvement than in those with uninvolved lymph nodes (P = 0.02); (b) a high Ki-67 score (>13% of positive cells) was observed in tumors with a higher mean value of laminin receptor (P = 0.004); (c) the tumors harboring neoplastic emboli in their vessels showed a higher laminin receptor immunoreactivity (P = 0.02); and (d) a borderline association was found between the high mean value of laminin receptor immunopositivity and p53 accumulation in neoplastic cell nuclei (P = 0.05). Our observations indicate that detection of high tissue levels of 67-kDa laminin receptor is associated with an invasive phenotype in non-small cell lung cancer and may provide further information in the biological characterization of this type of cancer.

Aged↗
PubMed1996

Enhancement of tamoxifen-induced E-cadherin function by Ca2+ channel antagonists in human breast cancer MCF7/6 cells.

Despite its intensive use in adjuvant breast cancer therapy for more than 30 years, the exact mechanisms of action of tamoxifen have not yet been fully characterized. Tamoxifen was recently shown to restore the E-cadherin function of human breast cancer MCF7/6 cells and to suppress their invasive phenotype. Because tamoxifen interacts with targets implicated in Ca2+ homeostasis, we explored the possibility that the restoration of E-cadherin function in MCF7/6 cells induced by this drug could be affected by Ca2+ modulators. Two different Ca2+ channel antagonists (verapamil and nifedipine) potentiated the effect of tamoxifen on E-cadherin function, as evaluated with a fast cell aggregation assay. These molecules decreased the tamoxifen concentration needed to restore the E-cadherin function from 10(-6) M to 10(-7) M. When incubated with a Ca2+ channel agonist, Bay K8644 (methyl-1,4-dihydro-2,6-dimethyl-3-nitro-4-(2-trifluoro-methylphenyl)- pyridine-5-carboxylate), the effect of tamoxifen on E-cadherin function was completely abolished. These results demonstrate that the restoration of the E-cadherin function induced by tamoxifen depends, at least in part, on a Ca2+ pathway, and support the evidence of an effect of tamoxifen on Ca(2+)-dependent mechanisms. Our data also suggest that Ca2+ channel modulators could make it possible to decrease the dose of tamoxifen administered to patients without reducing the therapeutic effects.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗