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Biomedical subjects

V Castronovo

Publications and source records attributed to V Castronovo.

At least 127 records · Page 7Linked to original sources
PubMed1991

Laminin receptor complementary DNA-deduced synthetic peptide inhibits cancer cell attachment to endothelium.

Stable attachment of cancer cells to the endothelium is a key step in the formation of metastasis. In this study, we have investigated the possibility that interaction between laminin and its Mr 67,000 high-affinity receptor (67 LR) could play a major role in this process. Scatchard analysis of laminin-binding studies showed that bovine aortic endothelial cells exhibit 46,000 high-affinity receptors that mediate, at least in part, the attachment of highly invasive melanoma cells. This endothelial cell-melanoma cell interaction was significantly inhibited by soluble laminin and by anti-laminin antibodies. Peptide G, an eicosapeptide derived from the complementary DNA sequence of the 67 LR precursor (IPCNNKGAHSVGLMWWMLAR) that specifically binds to laminin and presumably contains the active ligand-binding site of the receptor, specifically prevented attachment of the melanoma cells to both the bovine aortic endothelial cell monolayer and human umbilical vein endothelium. Thus, peptide G may selectively interfere with the metastatic cascade by inhibiting tumor cell attachment to endothelium via the laminin-67 LR pathway and is a potential new antimetastatic agent.

Amino Acid Sequence↗
PubMed1991

Biosynthesis of the 67 kDa high affinity laminin receptor.

High affinity interactions between cells and laminin are mediated, at least in part, by the 67 kDa laminin receptor (67 LR). A 37 kDa nascent polypeptide (37 LRP), predicted by a full length cDNA clone and obtained by in vitro translation of hybrid-selected laminin receptor mRNA, has been immunologically identified in cancer cell extracts as the putative precursor of the 67 LR. In this study, we used affinity purified antibodies developed against cDNA-deduced 37 LRP synthetic peptides in pulse chase experiments and demonstrated a precursor-product relationship between the 37 LRP and the 67 LR. Immunoblot, pulse chase and immunofluorescence experiments showed that transient transfection of the full length 37 LRP cDNA clone induced a dramatic increase in the synthesis of the 37 LRP but not of the mature 67 LR. We propose that the 67 LR results from the association of two gene products: the 37 LRP and a polypeptide yet to be identified.

Animals↗
PubMed1991

Malignant cell attachment to endothelium of ex vivo perfused human umbilical vein. Modulation by platelets, plasma and fibronectin.

The success of blood-born metastatic spread depends upon a key event: the tumor cell arrest and attachment to the host organ vasculature. In the present study, we have investigated interactions between several normal and cancer cell lines and vascular endothelium in a model of ex vivo perfusion of human umbilical vein. In this system, hydrodynamic parameters are monitored and endothelial cells are kept in their original environment known to modulate their phenotype. Metastatic tumor cell adhesion to the perfused endothelium was found to be significantly higher than that of normal cells tested. Platelets and soluble plasma factors including fibronectin promoted tumor cell arrest and adhesion to endothelium. Altogether our results indicate that the ex vivo perfusion of human umbilical vein allows the study of the interactions between malignant tumor cells, circulating plasma or blood cells and the endothelium during blood-born metastatic spread.

Blood Platelets↗
PubMed1991

The high affinity murine laminin receptor is a member of a multicopy gene family.

The high affinity laminin receptor is differentially expressed in metastasis. We now report that there are multiple copies (6 +/- 1) of the laminin receptor gene in the murine genome of normal diploid cells as well as in cell lines derived from cancer cells. We have analyzed three distinct cDNA clones isolated from an Okayama-Berg cDNA library of transformed mouse fibroblasts that may represent transcripts of three different laminin receptor genes. Polymorphic changes include insertion of bases at the 5' terminus, a base substitution within the coding region resulting in an amino acid change from phenylalanine to leucine, a base substitution obliterating a polyadenylation signal, as well as changes in the length of the 3' untranslated domains. The discovery of multiple transcripts of laminin receptor genes suggests that there is a strong selective pressure to maintain laminin receptor expression in murine cells.

Animals↗
PubMed1991

Increased expression of the laminin receptor in human colon cancer.

It has been proposed that among the various cell-surface proteins capable of interacting with laminin, the 67-kd high-affinity laminin receptor plays a crucial role during tumor invasion and metastasis. In this study, the expression of laminin-receptor-precursor messenger RNA (mRNA) and 67-kd protein was analyzed in human colon adenocarcinoma. In 22 of 23 patients with colon cancer, we found a 2- to 23-fold increase in levels of laminin-receptor-precursor mRNA in the cancer tissues compared with those in matched normal adjacent colonic mucosa. In 10 of 11 cases studied, the level of 67-kd laminin receptor, detected by affinity-purified anti-laminin-receptor synthetic peptide antibodies on immunoblots of matched tumor and normal tissue extracts, was higher in the colon carcinoma tissue. Immunodetection of laminin receptor in tissue sections using anti-laminin-receptor-peptide antibodies confirmed that the increased expression of laminin receptor was specifically associated with the cancer cells. In a series of 72 paraffin sections of colon lesions, we observed a correlation between the expression of the laminin receptor and the Dukes' classification. Our observations indicate that increased expression of laminin-receptor-precursor mRNA is associated with enhanced levels of the 67-kd laminin receptor as well as with the invasive phenotype of colon carcinoma. Detection of this metastasis-associated gene product may be a valuable adjunct in the evaluation of human colon cancer.

Adenocarcinoma↗
PubMed1991

Absence of laminin deposition in breast cancer and metastases except to the brain.

Laminin, a major glycoprotein of basement membrane has been found to play significant roles during invasion and metastases. In this study, we have examined the distribution of laminin in several human brain carcinoma metastases, human breast cancers, skin and lymph node metastases of breast cancer as well as in an in vitro and an in vivo model of invasion. A laminin accumulation was demonstrated a) at the border between human metastatic carcinoma cells and surrounding neural tissue; b) at the invasive edge between MO4 cells (a highly malignant cell line which synthesizes large amounts of laminin) and host tissues of syngenic mice; c) at the front of invasion between MO4 cells and precultured heart fragments in an in vitro model of invasion. Laminin, but not type IV collagen, promoted attachment of MO4 cells. This attachment was inhibited by preincubation of laminin matrix support with (+)-catechin, a flavonoid which also prevented invasion of the precultured heart fragment in vitro. Our data demonstrate that laminin accumulates between malignant cells and host tissue in human brain metastases and in an in vitro and an in vivo model of invasion. In these later models, accumulation of laminin is the consequence, at least in part, of its biosynthesis by MO4 cells. Since laminin promotes attachment of malignant cells in vitro, increases invasiveness and metastatic activities of murine malignant cells, it is tempting to speculate that laminin synthesized by invasive cells and accumulated at the front of invasion plays a significant role in the first step of invasion.

Adenocarcinoma↗
PubMed1991

Augmentation of type IV collagenase, laminin receptor, and Ki67 proliferation antigen associated with human colon, gastric, and breast carcinoma progression.

The proportion of neoplastic cells immunocytochemically positive for type IV collagenase (IVase), laminin receptor (LR), and Ki67 proliferation-associated antigen increased during the progression of human colon, gastric, and breast carcinomas. Thirty cases of colonic adenoma were compared with 30 cases of Dukes' A or B stage carcinoma and ten cases of Dukes' C stage carcinoma. The percentage of positive cells increased significantly (P less than 0.001) for all three antigens comparing carcinomas with adenomas and Dukes' C stage compared with Dukes' A/B stage. The same pattern of antigen correlation with progression was found with 40 human gastric carcinomas. Gastric carcinomas classified as well-differentiated advanced stage contained a significantly higher proportion of tumor cells positive for IVase (P less than 0.001), LR (P less than 0.001), and Ki67 (P less than 0.001) compared with well-differentiated superficial tumors. Gastric carcinomas classified as poorly differentiated superficial had a significantly higher proportion of cells positive for Ki67 (P less than 0.016), but not IVase (P less than 0.069) or LR (P less than 0.075), compared with poorly differentiated advanced tumors. Metastasis of colon and gastric carcinoma retained the immunostaining pattern of the primary tumors. Thirty cases of breast neoplasia were compared with 30 adjacent samples of normal duct epithelium. A positive correlation (P less than 0.001) was found for the immunoreactivity of all three antigens in the invasive carcinomas compared with the normal epithelium. Invasive ductal carcinoma and invasive lobular carcinoma had a significantly higher percentage of immunoreactivity for the three antigens compared with corresponding in situ lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Breast Neoplasms↗
PubMed1991

Molecular inhibition of cancer cell invasion and metastasis.

A group of coordinated cellular processes, not just one gene product, is responsible for invasion and metastasis, the most life-threatening aspect of cancer. It is now recognized that negative factors may be just as important as positive elements. Genetic changes causing an imbalance of growth regulation lead to uncontrolled proliferation necessary for both primary tumor and metastasis expansion. However, unrestrained growth does not, by itself, cause invasion and metastasis. This phenotype may require additional genetic changes. Thus, tumorigenicity and metastatic potential have both overlapping and separate features. Invasion and metastasis can be facilitated by proteins which stimulate tumor cell attachment to host cellular or extracellular matrix determinants, tumor cell proteolysis of host barriers, such as the basement membrane, tumor cell locomotion, and tumor cell colony formation in the target organ for metastasis. Facilitory proteins may act at many levels both intracellularly and extracellularly, but are counterbalanced by factors which can block their production, regulation or action. A common theme has emerged: in addition to loss of growth control, an imbalanced regulation of adhesion, proteolysis, and motility appears to be required for invasion and metastasis. Re-equilibrating the expression of the genes involved in these tumor invasion related events could potentially constitute the basis for new anti-cancer therapeutic strategies.

Amino Acid Sequence↗
PubMed1990

Laminin and fibronectin increase the steady state level of the 67 kD high affinity metastasis-associated laminin receptor mRNA in human cancer cells.

Among the various known laminin binding proteins, the 67 kD high affinity laminin receptor (LR) is intimately involved during tumor invasion and metastasis. In this study, we report that laminin and fibronectin, two attachment glycoproteins, significantly increased the total cellular level of 67 kD LR mRNA in two human cancer cell lines, T47D breast carcinoma cells and A2058 melanoma cells. Neither GRGDS nor YIGSR synthetic peptides induced such a stimulatory effect. Since the steady state level of LR mRNA has been shown to control the number of receptors expressed at the cell surface, these results suggest that contact of the cancer cells with laminin and fibronectin in the host matrix may be an important regulatory mechanism by which cancer cells maintain a high number of LR at their cell surface as they progress through the several steps of tumoral invasion and metastasis.

Amino Acid Sequence↗
PubMed1990

Spatiotemporal segregation of endothelial cell integrin and nonintegrin extracellular matrix-binding proteins during adhesion events.

Bovine aortic endothelial cell (BAEC) attachments to laminin, fibronectin, and fibrinogen are inhibited by soluble arginine-glycine-aspartate (RGD)-containing peptides, and YGRGDSP activity is responsive to titration of either soluble peptide or matrix protein. To assess the presence of RGD-dependent receptors, immunoprecipitation and immunoblotting studies were conducted and demonstrated integrin beta 1, beta 3, and associated alpha subunits as well as a beta 1 precursor. Immunofluorescence of BAECs plated on laminin, fibronectin, and fibrinogen reveals different matrix-binding specificities of each of these integrin subclasses. By 1 h after plating, organization of beta 1 integrin into fibrillar streaks is influenced by laminin and fibronectin, whereas beta 3 integrin punctate organization is influenced by fibrinogen and the integrin spatial distribution changes with time in culture. In contrast, the nonintegrin laminin-binding protein LB69 only organizes after cell-substrate contact is well established several hours after plating. Migration of BAECs is also mediated by both integrin and nonintegrin matrix-binding proteins. Specifically, BAEC migration on laminin is remarkably sensitive to RGD peptide inhibition, and, in its presence, beta 1 integrin organization dissipates and reorganizes into perinuclear vesicles. However, RGD peptides do not alter LB69 linear organization during migration. Similarly, agents that block LB69--e.g., antibodies to LB69 as well as YIGSR-NH2 peptide--do not inhibit attachment of nonmotile BAECs to laminin. However, both anti-LB69 and YIGSR-NH2 inhibit late adhesive events such as spreading. Accordingly, we propose that integrin and nonintegrin extracellular matrix-binding protein organizations in BAECs are both temporally and spatially segregated during attachment processes. High affinity nonintegrin interaction with matrix may create necessary stable contacts for longterm attachment, while lower affinity integrins may be important for initial cell adhesion as well as for transient contacts of motile BAECs.

Acid Phosphatase↗
PubMed1990

Immunodetection of the metastasis-associated laminin receptor in human breast cancer cells obtained by fine-needle aspiration biopsy.

Fine-needle aspiration biopsy of the breast is a very useful technique for the evaluation of a suspect lesion before surgical removal. Increased expression of the 67-kd laminin receptor has been associated with the metastatic phenotype of cancer cells, particularly in colon and breast cancers. In this study, the expression of laminin receptor was evaluated using the immunoperoxidase technique in 81 breast aspirates (26 benign and 55 neoplastic lesions). Cells obtained from benign samples exhibited a low level of laminin receptor antigen detected by affinity-purified antibody raised against a cDNA-derived laminin receptor peptide. In contrast, 71% of smears obtained from malignant breast lesions contained cells that were strongly stained by the antibody. Heterogeneous expression of the laminin receptor was noted in both breast aspirates and fixed tissue specimens. These data suggest that the immunodetection of laminin receptor in cells obtained by fine-needle aspiration of breast lesions could be a valuable adjunct in the prognostic evaluation of breast lesions.

Antibodies↗
PubMed1989

Anti-laminin receptor antibody targeting of liposomes with encapsulated doxorubicin to human breast cancer cells in vitro.

The tumor cell laminin receptor is a cell-surface protein that binds laminin with high affinity (Kd = 1.0 nM). The putative ligand-binding domain of the laminin receptor has been molecularly cloned and sequenced. In the present study, we used the predicted amino acid sequence of the laminin receptor to generate synthetic peptide antigens and produced immunoglobulin M (IgM) anti-laminin receptor monoclonal antibodies. The disulfide bond group of the IgM molecule was used to couple the antibodies to the surface of liposomes encapsulating doxorubicin. The anti-laminin receptor monoclonal antibodies coupled to the liposomes bound avidly to the surface of MDA-MB-435S (MDA-435) human breast carcinoma cells, which have high numbers of laminin receptors. These antibody-coupled liposomes exhibited a low degree of binding to Hs 578Bst (Hs 578) normal human breast epithelial cells, which express a low number of laminin receptors. Excess liposomes competed for the binding of unbound laminin to the tumor cell surface, and excess laminin competed for binding with the liposomes. Antibody-coupled liposomes encapsulating doxorubicin were specifically more efficient in inhibiting colony formation by MDA-435 cells in vitro than unbound doxorubicin or liposomes without anti-laminin receptor monoclonal antibodies. Unbound doxorubicin inhibited thymidine uptake by 10%-20% in both Hs 578 and MDA-435 cells, whereas the antibody-coupled liposomes encapsulating doxorubicin inhibited thymidine uptake by 90% in MDA-435 cells but only 15% in Hs 578 cells. Thus, use of anti-laminin receptor monoclonal antibodies coupled with liposomes encapsulating doxorubicin represents a new strategy for selective targeting of doxorubicin to carcinoma cells with exposed laminin receptors.

Antibodies, Monoclonal↗
PubMed1989

Evidence for a precursor of the high-affinity metastasis-associated murine laminin receptor.

The high-affinity cellular receptor for the basement membrane component laminin is differentially expressed during tumor invasion and metastasis. A cDNA clone encoding the murine laminin receptor was isolated and identified on the basis of sequence homology to the human laminin receptor [Wewer et al. (1986) Proc. Natl. Acad. Sci. U.S.A. 83, 7137-7141]. Primer extension experiments demonstrated that the clone contained the complete 5' sequence of the murine laminin receptor mRNA. RNA blot data demonstrated a single-sized laminin receptor mRNA, approximately 1400 bases long, in human, mouse, and rat. The nascent laminin receptor predicted from the cDNA sequence is 295 amino acids long, with a molecular weight of 33,000, and contains one intradisulfide bridge, a short putative transmembrane domain, and an extracellular carboxy-terminal region which has abundant glutamic acid residues and multiple repeat sequences. The precursor of the laminin receptor is apparently smaller than the 67-kilodalton protein isolated from tissue. The apparent molecular weight on SDS-polyacrylamide gels of the rabbit reticulocyte cell-free translation product of selectively hybridized laminin receptor mRNA is 37,000. Antisera to three different domains of the cDNA-predicted receptor were used to study the relationship between the 37- and 67-kilodalton polypeptides. Antisera to cDNA-deduced synthetic peptides of the receptor immunoprecipitated a 37-kilodalton band both from cell-free translation products and from pulse-labeled cell extracts. On immunoblots of cell extracts, one antisynthetic peptide antiserum recognized only the 67-kilodalton receptor, while another antiserum identified both 37- and 67-kilodalton polypeptides, suggesting a precursor-product relationship between the two polypeptides.

Amino Acid Sequence↗
PubMed1989

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

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

Breast Neoplasms↗
PubMed1989

Possible role of human natural anti-Gal antibodies in the natural antitumor defense system.

Expression of Gal alpha 1-3Gal cell surface residues has been correlated with the metastatic potential of murine tumor cells. We report that Gal alpha 1-3Gal residues are expressed at the cell surface of malignant human cancer cells, including four cell lines and 50% of the malignant breast specimens obtained by aspiration biopsy. In contrast, all benign breast biopsies and normal cells were Gal alpha 1-3Gal negative. Affinity-purified anti-alpha-galactosyl IgG (anti-Gal) antibody, which specifically recognizes Gal alpha 1-3Gal residues, significantly inhibited cell attachment in two in vitro assays thought to indicate tumor cell extravasation of the circulatory system during the metastatic process: attachment to perfused human umbilical vein endothelium, and attachment to isolated laminin. Since anti-Gal antibody is a natural component of all human sera, we propose that it may be part of the natural antitumor defense system in humans.

Antigens, Surface↗
PubMed1989

Reactivity of human anti-alpha-galactosyl IgG antibody with alpha(1-->3)-linked galactosyl epitopes exposed on basement membranes and on glomerular epithelial cells: an in vitro and in vivo study in the mouse.

Anti-alpha-galactosyl antibody (a-Gal Ab) is a human natural antibody belonging to the IgG class, found in high titres in all normal sera regardless of blood group, and specifically recognizing alpha (1-->3)-linked galactosyl residues. We have observed by radioimmunoassay, ELISA, passive haemagglutination and immunofluorescence blocking studies that affinity-purified a-Gal Ab reacted with mouse laminin, but not with the other mouse basement membrane proteins tested; it was able to fix complement in vitro. When injected intravenously into mice, the a-Gal Ab was found to mainly accumulate in kidneys, liver, spleen and lungs. No acute respiratory distress syndrome was observed shortly after the i.v. injection of 100 or 200 microg of antibodies. These doses of a-Gal Ab were also unable to induce acute glomerular injury. However, in primary cultures, the a-Gal Ab (100 or 200 microg per ml of medium) was shown to impair the attachment of mouse glomerular epithelial cells to mouse laminin and to elicit complement-dependent cell damage. The data indicate that the a-Gal Ab can interact in vitro and/or in vivo with alpha (1-->3)-linked galactosyl residues exposed on murine laminin or on murine cultured glomerular epithelial cells. Although this antibody fails to be pathogenic when administered at low doses in the intact animal, similar doses can alter some metabolic properties of these cells in vitro.

Animals↗