Search PubMed⌕ Search

Biomedical subjects

V Castronovo

Publications and source records attributed to V Castronovo.

At least 73 records · Page 4Linked to original sources
PubMed1996

Peptide G, containing the binding site of the 67-kDa laminin receptor, increases and stabilizes laminin binding to cancer cells.

We investigated the effect of peptide G, a synthetic peptide derived from the sequence of the 37-kDa laminin receptor precursor, on the interaction of laminin in two tumor cell lines one of which produces laminin and one of which does not. Addition of peptide G to the culture medium induced a significant increase in the amount of endogenous laminin detectable on the cell membrane of both cell lines. Moreover, pretreatment of exogenous laminin with peptide G dramatically increased laminin binding on both cell lines. Kinetics analysis of membrane-bound labeled laminin revealed a 3-fold decrease in the kd of peptide G-treated laminin compared with untreated or unrelated or scrambled peptide-treated laminin. Moreover, the affinity constant of peptide G-treated laminin increased 2-fold, with a doubling of the number of laminin binding sites, as determined by Scatchard analysis. Expression of the VLA6 integrin receptor on the cell membrane increased after incubation with peptide G-treated laminin. However, the lower binding inhibition of peptide G-treated laminin after anti-VLA6 antibody or cation chelation treatment indicates that membrane molecules in addition to integrin receptors are involved in the recognition of peptide G-modified laminin. These "new" laminin-binding proteins also mediated cell adhesion to laminin, the first step in tumor invasion. Together, the data suggest that peptide G increases and stabilizes laminin binding on tumor cells, involving surface receptors that normally do not take part in this interaction. This might explain the abundant clinical and experimental data suggesting a key role for the 67-kDa laminin receptor in the interaction between cancer cells and the basement membrane glycoprotein laminin during tumor invasion and metastasis.

Cell Adhesion↗
PubMed1996

Cloning and expression of a new HOXC6 transcript encoding a repressing protein.

Homeodomain-containing proteins are transcription factors that regulate the co-ordinated expression of multiple genes involved in development, differentiation and malignant transformation. In an attempt to characterize expressed homeobox (HOX) genes in breast cancer cells, we cloned two distinct HOXC6 transcripts from an MCF7 cDNA library, Interestingly, one of them represents a new HOXC6 mRNA encoding a homeodomain-containing protein harbouring a unique N-terminal sequence. Moreover we demonstrate that this HOXC6 transcript is less abundant in human breast cancer cells than in non-tumorigenic cell lines, is detected in breast carcinomas and adjacent tissues and is expressed in a variety of human tumours. In addition, transient co-transfection experiments illustrated that both HOXC6 transcripts encode gene products that repress transcription from a HOX binding sequence in MDA-MB231 cells and co-operate with other HOX gene products such as HOXB7 on their target genes. Taken together, our results suggest that HOXC6 proteins might contribute to the breast cell phenotype through co-operative interactions with other HOX-derived proteins and repression of their target genes.

Amino Acid Sequence↗
PubMed1996

Expression of bone sialoprotein in primary human breast cancer is associated with poor survival.

We have recently demonstrated that bone sialoprotein (BSP), a bone-matrix protein involved in hydroxyapatite crystal formation, is ectopically expressed in human breast cancers. We explored a possible association between expression of BSP in primary breast cancer and patients' survival. We analyzed BSP expression in 454 breast-cancer patients by immunohistochemistry on archival paraffin-embedded material using an anti-BSP polyclonal antibody. BSP expression was correlated to survival, tumor size, axillary lymph-node status and first site of distant metastasis. Of the breast cancers analyzed, 89% expressed detectable amounts of BSP. We found a statistical association between expression of BSP and poor prognosis as indicated by survival curves analyzed using the log rank and the Gehan methods. BSP expression was significantly higher in breast-cancer patients with axillary lymph-node involvement. Interestingly, survival of patients with positive lymph nodes but BSP-negative tumors was significantly higher than that of patients with no lymph-node involvement but BSP-positive cancers. The frequency of bone metastases was higher in the group of patients with BSP-positive tumors (22%) than in the group with BSP-negative cancers (7%). There was a significant increase in the incidence of lung metastases in patients whose tumors were negative for BSP. Our data show that bone sialoprotein expression in breast cancer is associated with poor prognosis. BSP detection also appears to be a valuable marker with which to identify, among the lymph-node-negative patients, those who have high risk of disease progression.

Axilla↗
PubMed1996

Isolation from a multigene family of the active human gene of the metastasis-associated multifunctional protein 37LRP/p40 at chromosome 3p21.3.

The 37 kD precursor of the 67 kD laminin receptor (37LRP) is a polypeptide whose expression is consistently upregulated in aggressive carcinoma. Interestingly, the 37LRP appears to be a multifunctional protein involved in the translational machinery and has also been identified as p40 ribosome-associated protein. Although highly conserved cDNAs corresponding to this polypeptide have been isolated from several species including vertebrates, invertebrates, plants and prokaryotes, characterization of any of the corresponding active genes has never been reported. In this study, we have cloned an intron-containing fragment which permitted us to isolate the active 37LRP/p40 human gene. This gene contains seven exons and six introns. Ribonuclease protection experiments suggest multiple transcription start sites. The promoter area does not bear a TATA box but contains four Sp1 sites. The first intron is also GC rich containing five Sp1 sites. Intron 4 contains the full sequence of the small nuclear RNA E2 and two Alu sequences are found in intron 3. Fluorescent in situ hybridization localized the 37LRP/p40 active gene on chromosome 3 in the locus 3p21.3 which, interestingly, is a hot spot for genetic alterations in several cancers and particularly in small cell lung carcinoma.

Amino Acid Sequence↗
PubMed1996

Detection of HOXA1 expression in human breast cancer.

Homeodomain-containing proteins are transcription factors that regulate the coordinated expression of multiple genes involved in development, differentiation and malignant transformation. To better understand the role played by these proteins in breast cancer cells, we demonstrate, using semi-quantitative RT-PCR experiments, that progestin induces HOXA1 mRNAs in MCF7 cells. This is the first evidence of regulation of a HOX gene by steroids. Moreover, we detected HOXA1 expression in a variety of human breast cancer lesions, suggesting that HOXA1 may be required for the establishment of breast cancer cells phenotype. We propose that HOXA1 gene could be one of the orchestrators that regulate breast epithelial cell differentiation and that alteration of HOXA1 expression could play a role in breast cancer progression.

Actins↗
PubMed1996

Seventeen copies of the human 37 kDa laminin receptor precursor/p40 ribosome-associated protein gene are processed pseudogenes arisen from retropositional events.

A cDNA coding for a 37 kDa polypeptide has been identified in several species as both the potential precursor of the 67 kDa laminin receptor (37LRP) and a putative ribosome-associated protein (p40). Interestingly, increased expression of this polypeptide (37LRP/p40) is consistently observed in invasive and metastatic cancer cells and is associated with poor prognosis. Southern-blot analysis of human genomic DNA predicted multiple copies of the 37LRP/p40 gene. In this study, we report that the number of copies of this sequence in the human genome is 26 +/- 2. We have sequenced and analyzed 19 genomic clones corresponding to the 37LRP/p40 gene and found that they were all processed pseudogenes. They all lack intronic sequences and show multiple genetic alterations leading in some cases to the appearance of stop codons. Moreover, they all bear characteristic features of retroposons as the presence of a poly(A)-tail at their 3' end and short direct repeated flanking DNA sequences. None of the pseudogenes analyzed present cis-elements in their 5' flanking region such as TATA or GC boxes. Our date reveal that over 50% of the 37LRP/p40 gene copies are pseudogenes most probably generated by retropositional events. The finding of multiple pseudogenes for the 37LRP/p40 suggests that the accumulation of several copies of this gene might have given a survival advantage to the cell in the course of evolution.

Base Sequence↗
PubMed1996

Decreased expression of galectin-3 is associated with progression of human breast cancer.

Galectin-3, a member of the beta-galactoside-binding lectin family, is involved in several biological events including binding to the basement membrane glycoprotein laminin. Although the exact role of galectin-3 during the interactions between cells and laminin is not yet known, it has recently been observed that its expression is down-regulated at both the protein and the mRNA level in colon cancer tissues in correlation with progression of the disease. This study investigated the possibility that breast cancer cells might also exhibit decreased galectin-3 expression in association with their aggressiveness. The expression of galectin-3 was examined by immunoperoxidase staining, using a polyclonal antibody raised against recombinant galectin-3, in a collection of 98 human breast lesions including 12 fibroadenomas, 15 fibrocystic disease lesions, 22 in situ carcinomas, and 49 infiltrating ductal carcinomas, 19 of which had positive axillary lymph nodes. Normal breast tissue adjacent to the lesions was present in 59 biopsies. Normal breast tissue expressed high levels (3+) of galectin-3. High expression (2+ to 3+) was also found in most benign lesions examined. The expression of galectin-3 was significantly decreased in in situ carcinoma and this down-regulation was more pronounced in invasive ductal carcinoma, particularly when associated with infiltration of axillary lymph nodes. These data constitute the first observation that galectin-3 is down-regulated in breast cancer and suggest the decreased expression of this galactoside-binding lectin is associated with the acquisition of the invasive and metastatic phenotype.

Antibody Specificity↗
PubMed1996

Overexpression of the 67-kD laminin receptor correlates with tumour progression in human colorectal carcinoma.

The high affinity 67-kD laminin receptor (67LR) is a cell surface protein whose expression is increased in a number of human carcinoma models. To date, 67LR expression in colorectal carcinomas has been examined in a small number of cases. 67LR expression has been immunohistochemically analysed in a large series of human colorectal neoplasms, using the MLuC5 monoclonal antibody. The study included 59 samples of non-neoplastic mucosa, 45 polyps (11 hyperplastic, 34 adenomas), 196 carcinomas, and lymph node metastases of 87 carcinomas. Epithelial cells of normal mucosa and hyperplastic polyps were negative or showed weak positivity in the paranuclear and apical areas of the cytoplasm. In adenomas and carcinomas, the staining was stronger, with a membranous or cytoplasmic pattern. The expression of 67LR correlated significantly with the progression from normal mucosa (22 per cent) to adenoma (44 per cent), carcinoma (61 per cent), and lymph node metastasis (75 per cent) (P < 0.0001). Expression of the laminin receptor showed a tendency to be more frequently positive in advanced stage (III+IV; 67 (III+IV; 67 per cent) when compared with early stage (I+II) carcinomas (54 per cent). The difference, however, was not statistically significant (P = 0.058). In addition, 14 out of 28 (50 per cent) primary carcinomas without 67LR expression became positive in lymph node metastases, while most (86 per cent) of the MLuC5-positive primary carcinomas were also immunoreactive in metastases. In conclusion, these results indicate that 67LR is up-regulated in the progression of human colorectal carcinomas and may play a role in the local and metastatic progression of these tumours.

Adenocarcinoma↗
PubMed1996

Shedding of the 67-kD laminin receptor by human cancer cells.

The 67-kD laminin receptor (67LR) is a cell membrane-associated molecule exhibiting high affinity for the basement membrane glycoprotein, laminin. While export of the 67LR toward the extracellular matrix has been recently suggested by electron microscopy studies, there is to date no evidence of shedding of the 67LR from cells. Using two monoclonal antibodies directed against the 67LR, we developed a double-determinant radioimmunoassay that demonstrates that the 67LR is released from cancer cells into the culture medium. The shed molecule exhibited the same apparent molecular weight as that of the membrane-associated 67LR, suggesting that no proteolytic cleavage is involved in the process. Furthermore, we demonstrate that the 67LR is not anchored to the membrane through a glycolsyl-phosphatidylinositol bridge. However, the observation that lactose increased the release of 67LR suggests that a lectin-type interaction is involved in the cell membrane association of this laminin binding protein and the cell surface. Interestingly, the released 67LR recovered after HPLC gel filtration was found free as well as associated to high molecular weight complexes. The free 67LR retained its ability to bind to the cell surface. Our study is the first demonstration that the 67LR is effectively shed by cancer cells. The released free 67LR could play an important role in modulating interactions between cancer cells and laminin during tumor invasion and metastasis.

Antibodies, Monoclonal↗
PubMed1996

Bone sialoprotein expression in primary human breast cancer is associated with bone metastases development.

Breast cancer metastasizes to bone more frequently than to any other organ, and over 80% of advanced breast cancer patients develop bone metastases. Our recent demonstration that human breast cancer cells express bone sialoprotein (BSP), a bone matrix protein, provides a possible clue for the selective affinity of breast cancer cells for bone. We tested the hypothesis that detection of BSP in primary human breast cancer could be a potential indicator of the ability of breast cancer cells to metastasize to bone. BSP expression was evaluated in the primary breast cancers of 39 patients using immunoperoxidase and two specific anti-BSP antibodies. None of these patients presented clinically or scintigraphically detectable bone metastases at the time of surgery. In the course of their disease, 22 patients developed clinically diagnosed bone metastases. Expression of BSP in breast cancer cells from patients who developed bone metastases was significantly higher (p = 0.008, according to the Mann-Whitney test) than in patients with no bone involvement. No association was found between BSP expression in the primary breast lesions and axillary lymph node metastases. BSP expression was significantly increased in infiltrating ductal carcinoma compared with infiltrating lobular carcinoma (p = 0.0023). No correlation was found between immunoreactivity to BSP antibodies and estrogen receptor (ER) status, progesterone receptor (PR) status, or age. Our data suggest that BSP could help to identity which women will develop bone metastases and provide new bases for the understanding of the molecular mechanism(s) responsible for breast cancer cells osteotropism.

Adult↗
PubMed1996

Expression of the 67 kD laminin receptor in human ovarian carcinomas as defined by a monoclonal antibody, MLuC5.

Previous immunohistochemical data from our laboratory have demonstrated that expression of the 67 kD laminin receptor (67LR), a cancer-associated, high-affinity laminin-binding protein, is upregulated in ovarian carcinoma cells compared with normal serosal cells, and that this increased expression in cancer cells could be related to patient outcome. The aim of this study was to validate MLuC5, a monoclonal antibody that recognises the 67LR, as a tool to perform future immunohistochemical studies on larger populations of ovarian carcinoma patients. Expression of the 67LR was determined in 51 primary human ovarian carcinoma samples using immunohistochemistry and MLuC5. The 67LR was detected in ovarian carcinoma cell clusters of variable extent. Analysis of the data determined that 67LR expression was significantly increased in the samples from patients with disease progression, compared with those with no evidence of disease after completion of primary therapy, and in pooled grade 2 and 3 tumours compared to borderline and grade 1 tumours (P < 0.05, chi-squared test). No other significant correlation between 67LR expression and other clinicopathological parameters could be established. These data suggest that the 67LR is correlated to ovarian tumour progression. Detection of the 67LR using this monoclonal antibody could constitute an interesting parameter in prognosis determination of ovarian cancer.

Adenocarcinoma↗
PubMed1996

Sleep and upper airway obstruction in children with achondroplasia.

OBJECTIVE: The features of achondroplasia, the most common form of dwarfism, includes short cranial base and midface hypoplasia; both abnormalities increased the risk of upper airway obstruction during sleep. The aim of our study was to evaluate sleep and respiratory function of children with achondroplasia and to differentiate central from obstructive apnea. We also wanted to correlate apneic events with foramen magnum stenosis. STUDY DESIGN: Sixteen children with achondroplasia (mean age, 4.7 years) were studied by noctumal polysomnography and brain computed tomography or magnetic resonance imaging. A comparison of sleep and respiratory findings was made between the study group and 25 children with adenotonsillar hypertrophy. RESULTS: The study revealed no significant difference between groups with respect to sleep architecture. We also found no relationship between apnea type and foramen magnum stenosis. Twelve children (75%) with achondroplasia had significant upper airway obstruction during sleep, with symptoms of continuous snoring and periods of brief obstructive apnea, hypopnea, or both. The mean apneahypopnea index (per hour of sleep) did not differ significantly between the two groups. However, the breathing rate during sleep was increased in children with achondroplasia. These findings indicate that the most important breathing disorder during sleep in children with achondroplasia is upper airway obstruction. CONCLUSION: We conclude that polysomnography with detailed scoring of breathing abnormalities is a useful tool in evaluating sleep-disordered breathing in children with achondroplasia.

Achondroplasia↗
PubMed1996

Expression of the 67-kD laminin receptor, galectin-1, and galectin-3 in advanced human uterine adenocarcinoma.

Alterations of tumor cell interactions with laminin, a basement membrane glycoprotein, are consistent features of the invasive and metastatic phenotype. Qualitative and quantitative changes in the expression of cell surface laminin-binding proteins have been correlated with the ability of cancer cells to cross basement membranes during the metastatic cascade. Such phenotypic modifications are usually associated with poor prognosis. In this study, the authors examined the possibility that expression of three laminin-binding proteins, the 67-kD laminin receptor (67LR), galectin-1, and galectin-3, is altered in human endometrial cancer in a fashion similar to that reported in other carcinomas, such as breast, colon, and ovarian cancer. Twenty advanced uterine adenocarcinomas were analyzed for expression of these three molecules using immunoperoxidase staining and specific antibodies. The authors found a significant increase in the expression of the 67LR and galectin-1 in cancer cells compared with normal adjacent endometrium (P = .0004 and .0022, respectively). As observed in other carcinomas, a significant down-regulation of galectin-3 expression was found in endometrial cancer cells compared with normal mucosa (P = .02). In the galectin-3 positive tumors, galectin-3 was detected in the cytoplasm and/or nucleus of cancer cells. Interestingly, tumors in which galectin-3 was detected only in the cytoplasm were characterized by deeper invasion of the myometrium than lesions where galectin-3 was found both in nucleus and cytoplasm (P = .02). This study shows an alteration of nonintegrin laminin-binding protein expression in advanced human endometrial cancer. Further studies on larger populations should determine the prognostic value of the detection of these laminin-binding proteins in endometrial carcinoma. Inverse modulation of the 67LR and galectin-3 appears to be a phenotypical feature of invasive carcinoma.

Adenocarcinoma↗
PubMed1996

Sleep-related painful erections: clinical and polysomnographic features.

The aim of this study was to describe the clinical characteristics and the polysomnographic findings of a sample of patients affected by sleep-related painful erections (SRPE). In a 6-y period 18 patients were diagnosed as having SRPE. The mean age at the onset of the disease was 39.8 +/- 11.6 y and the mean duration of SRPE was 5.4 +/- 3.5 y. According to ICSD criteria, about 60% of patients had a severe form of the disease. None of the patients met any DSM IV Axis-I and Axis-II diagnoses. Twelve patients complained of excessive daytime sleepiness. SRPE patients, compared to age-matched controls, showed a reduced sleep efficiency, an increased wake after sleep onset and a reduced percentage of REM sleep. This study confirms that in SRPE there are no clear predisposing factors, no familial pattern, but REM sleep fragmentation. Concerning the pharmacological treatment, in the history of patients, propranolol and paroxetine, but not amitriptiline and lorazepam, showed a temporary efficacy in some patients.

Adrenergic beta-Antagonists↗
PubMed1996

Identification of the active gene coding for the metastasis-associated 37LRP/p40 multifunctional protein.

A 37LRP/p40 polypeptide is of major interest because it is consistently up-regulated in cancer cells in correlation with their invasive and metastatic phenotype. Furthermore, this polypeptide presents intriguing multifunctional properties because it has been characterized as the precursor of the metastasis-associated 67-kD laminin receptor (67LR) and as a cytoplasmic ribosomal-associated protein. The isolation of the 37LRP/p40 gene is a prerequisite for identifying the molecular mechanisms responsible for the constant up-regulation of the 67LR expression in cancer cells. To date, the active 37LRP/p40 gene has never been identified in any species due to the existence of multiple pseudogenes in most vertebrates genomes. In this study, we report for the first time the gene structure and potential regulatory sequences of the 37 LRP/p40 gene. The chicken genome was selected to undergo this characterization because it is the only known vertebrate that bears a single 37 LRP/p40 gene copy. The 37 LRP/p40 active gene is composed of 7 exons and 6 introns and bears features characteristic of a ribosomal protein gene. It does not bear a classical TATA box and it exhibits several transcription initiation sites as demonstrated by RNase protection assay and primer extension. Analysis of potential regulatory regions suggests that gene expression is driven not only by the 5' genomic region but also by the 5' untranslated and intron 1 sequences. On the basis of gene structure and extensive protein evolutionary study, we found that the carboxyterminal domain of the protein is a conserved lock-and-key structure/function domain that could be involved in the biosynthesis of the higher-molecular-weight 67-kD laminin receptor in vertebrates, whereas the central core of the protein would be responsible for the ribosome associated function. The first identification of the active 37LRP/p40 gene presented in this study is a critical step toward the isolation of the corresponding human gene and the understanding of the molecular mechanisms involved in the up-regulation of its expression during tumor invasion and metastasis.

Amino Acid Sequence↗
PubMed1996

An unattended device for sleep-related breathing disorders: validation study in suspected obstructive sleep apnoea syndrome.

Portable devices for the diagnosis of obstructive sleep apnoea (OSA) are considered to be an acceptable alternative to polysomnography (PSG), but their validation is essential. The aim of our study was to validate a device specifically designed for OSA diagnosis. Twenty nine suspected OSA patients were studied with simultaneous nocturnal PSG and an unattended recording device (MicroDigitrapper-S) (M-S). The device measured body position, snoring sound, oronasal flow, thoracic and abdominal effort, heart rate and percentage arterial oxygen saturation (Sa,O2%). We compared the apnoea plus hypopnoea index (AHI) and Sa,O2% results of PSG with that of the system's automatic analysis (M-SA). We also performed a semiautomatic analysis (M-SS) with visual editing of the raw data. Results at different AHI cut-off levels were analysed to obtain an indication of accuracy in diagnosis and severity. Both M-SA and M-SS showed a sensitivity and specificity of 100% at the cut-off level of AHI > 10. When increasing the cut-off levels, M-SA sensitivity decreased (55% for AHI > 40), while specificity remained high (95%). This was improved to a clinically acceptable level of agreement by M-SS analysis (sensitivity 91% and specificity 94%). In conclusion, the MicroDigitrapper-S device showed a good sensitivity and specificity for the diagnosis of OSA. However, the device could not predict the severity of OSA precisely enough. In severe cases (apnoea plus hypopnoea index > 40), semi-automatic scoring was necessary to obtain a more accurate detection of the severity of the disease.

Adult↗
PubMed1996

In vitro and in vivo stimulation of the murine immune system by AGM-1470, a potent angiogenesis inhibitor.

AGM-1470, a potent angiogenesis inhibitor, is already engaged in phase I clinical trials because of its effectiveness to restrain tumor growth and its lack of major side effects. Recently, we showed that AGM-1470 stimulates in vitro human B lymphocyte proliferation through T lymphocytes. These data prompted us to explore the in vivo effects of AGM-1470 on the immune system in a mouse model. In this study, we showed that AGM-1470, in synergy with phytohemagglutinin, stimulates the proliferation of murine lymphocytes isolated from lymph nodes. This effect was similar to the one observed with human lymphocytes. When injected subcutaneously or intraperitoneally into mice at pharmacological doses, AGM-1470 induced a significant increase of axillary and mesenteric lymph nodes, respectively. Histological and morphological analyses showed that this phenomenon is mostly due to a hyperplasia of the germinal centers. On average, the area of the germinal center of lymph nodes from AGM-1470-treated mice were three times larger than in lymph nodes from control mice. Interestingly, no effect was observed when AGM-1470 was injected subcutaneously into T-deficient nude mice. Our data demonstrate that AGM-1470 stimulates B cell proliferation in vivo as suggested by the in vitro experiments. This effect should be taken into account in the follow-up of patients treated with this molecule and calls for additional studies to determine the biological consequences of such a stimulation on the host immune system.

Animals↗