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S Ménard

Publications and source records attributed to S Ménard.

At least 91 records · Page 5Linked 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

Oral administration of anti-doxorubicin monoclonal antibody prevents chemotherapy-induced gastrointestinal toxicity in mice.

Gastrointestinal mucositis is a common and painful condition that afflicts a proportion of cancer patients receiving chemotherapeutic drugs including anthracyclines, and it has become the dose-limiting toxicity for a number of chemotherapeutic regimens. The murine monoclonal antibody MAD11 recognizes the anthracycline doxorubicin, and systemic administration of this antibody in mice treated with doxorubicin was found previously to prevent the toxic effects of the drug. The purpose of this study was to determine whether gastrointestinal toxicity associated with doxorubicin can be reduced by oral administration of anti-doxorubicin MAD11 in mice. Our experiments show that orally administered MAD11 antibodies: (a) are essentially not absorbed in the blood circulation since less than 0.5% of protein-associated radioactivity was recovered from blood samples; (b) reduce the extent of doxorubicin-induced apoptosis in murine intestinal crypts, as determined by labeling strand breaks with modified nucleotides in an enzymatic reaction; and (c) reduce the body weight loss in mice treated with 12 mg/kg body weight of doxorubicin and decrease the early mortality in mice treated with 16 mg/kg body weight. This type of treatment may be useful in preventing anthracycline-induced gastrointestinal mucositis in cancer patients.

Administration, Oral↗
PubMed1996

A comparative study of p53 gene mutations, protein accumulation, and response to cisplatin-based chemotherapy in advanced ovarian carcinoma.

The p53 protein is a multifunctional transcriptional regulator involved in cellular response to DNA damage and has been implicated as a putative determinant of sensitivity of tumor cells to cytotoxic agents. Since the p53 gene becomes inactivated in over one-half of advanced ovarian carcinoma, in this study we have examined the relationships between p53 gene alterations, p53 immunoreactivity, and response to cisplatin-based chemotherapy in ovarian cancer patients. All patients had advanced (FIGO stage III or IV) ovarian carcinoma and, with one exception, were untreated at the time of collection of tumor specimens. After initial debulking surgery, patients received high-dose cisplatin therapy. Tumor samples were analyzed for p53 gene mutations and for p53 protein accumulation, and the findings were correlated with tumor responsiveness. Of the 33 tumors examined, p53 gene mutations were found in 20 cases, including 15 missense mutations, 2 deletions, 2 nonsense mutations, and a base substitution at splice site. Twenty tumors showed positive immunostaining for p53. Only missense mutations were associated with positive immunostaining. In addition, p53 overexpression was detected in five tumors in the absence of mutations. Most (12 of 14) of the missense mutations associated with p53 protein stabilization were found refractory to therapy, as well as tumors overexpressing wild-type p53 (4 of 5). A significant correlation has been found between p53 accumulation, type of mutation (i.e., missense mutations), and pathological response to cisplatin-based therapy. In conclusion, the present results are consistent with a role of p53 as a determinant of chemosensitivity of ovarian carcinoma.

Alleles↗
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

Detection and localization of the EaeA protein of attaching and effacing Escherichia coli O45 from pigs using a monoclonal antibody.

The eaeA-positive, attaching and effacing (A/E) O45 E. coli isolates from pigs express an EaeA protein with an estimated molecular weight of 97 kDa. In the present study, a monoclonal antibody was raised against the EaeA protein of an A/E O45 isolate. Cross reaction of the monoclonal antibody with the EaeA protein of A/E strain of the rabbit (RDEC-1), but not with those of A/E strains of the human (E2348/69) and dog (89-4221), was observed. Reactions of the monoclonal antibody to A/E isolates in the O45 serogroup on the ELISA varied among isolates and appeared to be correlated with in vivo A/E capacity of these isolates. The EaeA protein of A/E O45 E. coli has an apparent isoelectric point of 8.4 and is exposed on the bacterial surface. The monoclonal antibody provides a useful tool for characterization of the EaeA protein of E. coli isolates from pigs.

Adhesins, Bacterial↗
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

Laminin activates the p185HER2 oncoprotein and mediates growth inhibition of breast carcinoma cells.

The interaction between laminin and the oncoprotein encoded by the c-erbB-2 oncogene was studied in vitro and in vivo in human breast carcinomas. In vitro analysis of breast carcinoma cell lines overexpressing p185HER2 revealed that laminin, but not fibronectin, induced tyrosine phosphorylation and down-modulation of oncoprotein membrane expression. Laminin also specifically inhibited growth of p185HER2-positive cell lines. No direct binding between the recombinant extracellular domain of p185HER2 and laminin was found. Induction of oncoprotein down-modulation by anti-integrin antibodies and coprecipitation of the oncoprotein with the beta 4 integrin subunit indicate that the interaction between p185HER2 and laminin occurs through integrin molecules. The relevance of this in vitro observation was verified in vivo by analysing the prognostic value of p185HER2 overexpression as a function of laminin production on archival paraffin-embedded sections of 887 primary breast tumours. The results revealed an association between p185HER2 overexpression and unfavourable prognosis in tumours negative for laminin production, whereas in laminin-producing tumours, the oncoprotein overexpression was not associated with tumour aggressiveness.

Breast Neoplasms↗
PubMed1996

1975-1995 revised anti-cancer serological response: biological significance and clinical implications.

In the 1970s a considerable amount of work was carried out in an attempt to identify an anti-tumor serological response in cancer patients. These analyses have not been very informative due to the complexity and heterogeneity of the response. More recently, the availability of recombinant molecules, synthetic peptides and analytic and semi-quantitative assays has enabled a better dissection of humoral immunity. Antibodies against intracellular antigens (c-myb, c-myc, p53 and p21 ras) have been found in a significant, albeit varying, proportion of patients bearing various tumors. Association with a poor prognosis is documented for anti-p53 antibodies in breast carcinoma patients. A number of cell surface antigens, including mucins, oncoproteins and carbohydrate antigens have been found to elicit a humoral immune response and, in some instances, circulating immune complexes were observed. A protective role for or, on the other hand, masking effects of such antibodies is still controversial. An indication that a serological response can be beneficial comes from vaccination studies. A significant association between the development of an anti-tumor antigen antibody response and prolonged survival was observed following vaccination of melanoma patients with GM2 or anti-idiotypic antibodies which molecularly mimic tumor-associated antigens. It is to be hoped that in the near future the numerous ongoing immunization trials and prognostic studies demonstrate whether antibody response can exert a protective role in vivo.

Antibody Formation↗
PubMed1996

Macrophage infiltrate and prognosis in c-erbB-2-overexpressing breast carcinomas.

PURPOSE: Experiments were designed to investigate the association between tumor leukocytic infiltrates with other pathologic and biologic variables in primary tumors and with prognosis, and to define the phenotype of the infiltrating leukocytes. PATIENTS AND METHODS: A retrospective series of 1,207 primary breast carcinomas was studied according to different prognostic variables, including the presence of lymphoplasmacytic infiltrate (LPI). LPI was analyzed in association with other variables and survival. Additionally, a small prospective series of surgical specimens from 75 primary breast carcinomas with infiltrating leukocytes was tested by immunohistochemistry on frozen sections to phenotypically characterize the infiltrate, using anti-CD reagents, and the tumor, using anti-c-erbB-2 oncoprotein monoclonal antibody. RESULTS: In the retrospective series, menopausal status, nodal status, tumor size, stage, grade, and p185HER2 overexpression but not LPI were found to be associated with prognosis and maintained their prognostic significance in a multivariate analysis. LPI was significantly associated with some of these independent prognostic factors, such as tumor size (P = .03), stage (P = .004), grade III carcinomas (P < .000001), and overexpression of the p185HER2 (P < .000001). In some subgroups of patients in whom LPI was found more frequently, such as grade III cases or N- and c-erbB-2-positive cases, LPI was found to be indicative of a good prognosis (P = .008 and P = .03, respectively). Phenotypic analysis of the infiltrating leukocytes revealed a preponderance of macrophages in high-grade (P = .05) or c-erbB-2-positive (P = .008) tumors, whereas T cells constituted most of the infiltrate in the other tumors. CONCLUSION: Our data demonstrate different leukocytic types in the infiltrate of breast tumors with different prognostic significance.

Antigens, CD↗
PubMed1996

Tumor-necrosis-factor-induced fibroblast growth factor-1 acts as a survival factor in a transformed endothelial cell line.

Endothelial cells undergo apoptosis after withdrawal of growth factors, alterations in the extracellular matrix, or exposure to cytokines. Here we report that tumor necrosis factor (TNF)-alpha induces apoptosis of human endothelial cells derived from the umbilical vein in a dose-dependent fashion. Apoptosis is triggered through a pathway that is independent from the levels of Bcl-2. On the contrary, TNF stimulates the growth of spontaneously transformed human umbilical vein endothelial cells. This proliferative effect is mediated through the up-regulation of fibroblast growth factor-1 by TNF. The addition of specific fibroblast growth factor-1 antisense oligonucleotides inhibits TNF-induced fibroblast growth factor-1 expression, thus inhibiting the growth and triggering apoptosis of spontaneously transformed human umbilical vein endothelial cells.

Apoptosis↗
PubMed1996

Apoptosis of hair follicle cells during doxorubicin-induced alopecia in rats.

Alopecia is a common side effect of cancer chemotherapy, and to date, little progress has been made in alopecia prevention or treatment. The present studies were undertaken to topographically localize the site of injury in the hair follicle after doxorubicin (DXR) administration and to investigate the mechanism of DXR-induced alopecia. Tissue samples of head and proximal neck skin obtained from newborn rats treated with DXR were histologically examined by light and electron microscopy and stained by the terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick-end labeling method. Light microscopy revealed pyknotic cells in the matrix and in the upper bulb and a decrease in the number of mitotic cells. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-digoxigenin nick-end labeling analysis evidenced cells with nuclear staining indicative of apoptosis, as confirmed by ultrastructural analysis. Kinetics studies indicated that even a single DXR treatment induced apoptosis and a decrease in mitotically active cells. Our data show that DXR treatment induces injury in a cell subset localized in the hair matrix. The successful prevention of drug-induced alopecia in patients may depend on the selective protection of these cells of the hair follicle.

Alopecia↗
PubMed1996

Expression of the Mr 67,000 laminin receptor is an adverse prognostic indicator in human thyroid cancer: an immunohistochemical study.

Increased expression of the Mr 67,000 laminin receptor (LR) is a consistent event which appears as cancer cells acquire an invasive and metastatic phenotype. The Mr 67,000 LR is one of the many laminin-binding proteins able to interact with the major glycoprotein of basement membranes, laminin. The recent development of a specific monoclonal antibody directed against the Mr 67,000 LR MLuC5 has allowed us to study large retrospective groups of human cancers with the aim of correlating the Mr 67,000 LR expression to the clinical, pathological, and survival data of the patients. A significant correlation has already been established between the increased expression of Mr 67,000 LR and survival of patients with breast, colon, ovary, lung, and endometrial cancers. In this study, we investigated the possibility that the detection of Mr 67,000 LR in thyroid human cancers could also be of prognostic value. We analyzed the expression of Mr 67,000 LR with immunohistochemistry using MLuC5 antibodies in paraffin sections of 40 benign and 170 malignant thyroid human tumors. We found that Mr 67,000 LR was not usually detectable in normal thyroid tissues adjacent to the lesion. Only 3 of the 40 thyroid adenomas examined (7.5%) presented cells positive for Mr 67,000 LR. For the malignant thyroid tumors examined, we found that 22.3% of papillary thyroid carcinomas, 38% of follicular thyroid carcinomas, 40% of poorly differentiated carcinomas, 25% of medullary carcinomas, and 58.3% of anaplastic carcinomas expressed a high level of Mr 67,000 LR. Although no correlation between the Mr 67,000 LR expression and survival was found in patients with follicular thyroid carcinomas, papillary thyroid carcinomas, anaplastic carcinomas, and medullary carcinomas, there was a significant correlation in primary thyroid cancers. Our data represent the first extensive study of the Mr 67,000 LR expression in human thyroid cancers and strongly suggest that its detection could be of prognostic value in the investigation of primary thyroid cancers.

Adult↗
PubMed1995

A monoclonal antibody extends the half-life of an anti-HIV oligodeoxynucleotide and targets it to CD4+ cells.

An approach was sought to increase the half-life and target cell specificity of antisense oligodeoxynucleotides (oligos). A monoclonal antibody (MAb) was derived from mice immunised with an oligo complementary to a region (1-20) of the HIV genome. This MAb exerts a protective effect on the oligo from the degradation induced by plasma exonucleases in vitro and in vivo. Moreover the anti-oligo MAb dissociates from the oligo in the presence of its complementary sequence to allow hybridization of the two complementary strands. To direct the oligo to CD4+ cells the anti-oligo MAb was cross-linked to an anti-CD4 MAb. The heteroaggregate determines a 5-fold increase in the cellular membrane binding of the oligo to CD4+ lymphocytes. These findings suggest a new approach to enhancing the therapeutic action and the target specificity of antisense oligodeoxynucleotides useful for the selective inhibition of HIV replication in vivo.

Animals↗
PubMed1995

An in vivo model to compare human leukocyte infiltration in carcinoma xenografts producing different chemokines.

In this study we tested whether the pattern of cytokines expressed by human carcinomas could account for a different in vivo recruitment of leukocyte subpopulations as a part of the anti-tumor immune response. Two carcinoma cell lines, SK-OV-3 ovary carcinoma and CALU-3 lung carcinoma, were analyzed by reverse transcriptase-polymerase chain reaction (RT-PCR), immunofluorescence and ELISA for the expression and in vitro production of cytokines with chemotactic, proinflammatory and growth-stimulating activity. Although both cell lines displayed a constitutive expression of granulocyte colony-stimulating factor (G-CSF), granulocyte macrophage-CSF (GM-CSF), M-CSF, interleukin (IL-) 1 alpha and IL-8, only CALU-3 cell line expressed IL-10, RANTES (Regulated upon Activation, Normal T Expressed and Secreted) and monocyte-activating protein (MCP)-1. MCP-1 and IL-8 were detected by immunohistochemistry on sections from tumors xenografted in nude mice. To analyze whether the tumor-released cytokines modulate leukocytes in tumor infiltration, we studied the distribution of human peripheral blood leukocytes injected in the proximity of SK-OV-3 and of CALU-3 tumor xenografts. While SK-OV-3 was unable to recruit human leukocytes and appeared to be barely infiltrated by murine CD45+ cells, CALU-3 appeared to be rapidly and heavily infiltrated by human leukocytes which induced tumor necrosis within 18-24 hr.

Adenocarcinoma↗
PubMed1995

67-kDa laminin-receptor expression adds prognostic information to intra-tumoral microvessel density in node-negative breast cancer.

Experimental studies have shown that the 67-kDa laminin receptor (LRec) is an important molecule for the interaction of tumour cells with the extracellular matrix, and that it plays a role in the early steps of angiogenesis and in tumour invasion and metastasis. We performed a multi-parametric study in 171 node-negative breast cancers, followed for a median time of 6 years, to verify whether determination of the LRec provides prognostic information in addition to intra-tumoral microvessel density (IMD), a measure of tumour angiogenesis, and to other biological and conventional indicators. A positive association between LRec expression and high neovascularization was found, although it did not reach significance. LRec was not associated either with other biological markers (oestrogen receptor, progesterone receptor and p53 expression) or to the conventional prognostic features [menopausal status, tumour size, histological types, grading and peri-tumoral lymphatic vessel invasion (PLVI)]. In univariate analysis, IMD, p53, PgR, PLVI, grading and tumour size were significant prognostic indicators of relapse-free survival (RFS). LRec expression approached significance when considered as a dichotomous variable, after having selected the optimum cutoff of 10% to distinguish high-risk from low-risk patients. For overall survival (OS), tumour size and IMD (continuous variable) were significant prognostic factors, and p53 approached significance. In multivariate analysis for RFS, the joint variable LRec and vascularization was the strongest independent prognostic factor, followed by PgR, PLVI and p53. For OS, tumour size was the only independent prognostic indicator in this series.

Adult↗