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M Pignatelli

Publications and source records attributed to M Pignatelli.

At least 109 records · Page 6Linked to original sources
PubMed1993

Expression of gelatinase A and TIMP-2 mRNAs in desmoplastic fibroblasts in both mammary carcinomas and basal cell carcinomas of the skin.

AIMS: To compare the localisation of mRNAs for the basement membrane degrading enzyme gelatinase A (72 kilodalton type IV collagenase) and its inhibitor TIMP-2 in carcinomas of the breast and basal cell carcinomas of the skin which have little or no ability to metastasize. METHODS: In situ hybridisation was performed on formalin fixed, paraffin wax embedded blocks using 35S-labelled riboprobes on 16 mammary carcinomas, three fibroadenomas, and a benign phyllodes tumour, and on 15 basal cell carcinomas of the skin (BCC). RESULTS: Labelling for both mRNAs was detectable in 14 of 16 mammary carcinomas and in 13 of 15 BCC, most often over organising desmoplastic fibroblasts in the stroma around invasive epithelial aggregates. Some sparse labelling was seen over malignant epithelial cells in six of the mammary carcinomas but not in the BCC. Some expression of gelatinase A mRNA was also seen in fibroblasts of breast lobules adjacent to the mammary carcinomas and around engulfed adnexal elements in the BCC, but not in unaffected breast tissues, fibroadenomas, the phyllodes tumour or unaffected skin. CONCLUSIONS: Maximal expression of gelatinase A and TIMP-2 mRNAs occurs in malignant neoplasms as part of the host response to the presence of established neoplastic cells rather than as an initial response to invasion. The degree to which this is present suggests this may be a highly relevant mechanism modulating tumour differentiation, growth and progression, possibly entailing uptake via specific receptors on the tumour cell surface.

Actins↗
PubMed1993

Models of colorectal tumour differentiation.

In vitro models in which colorectal tumour cells express differentiated and undifferentiated phenotypes have been developed and used to identify the molecular mechanisms of cellular and morphological differentiation of colorectal epithelial cells. Our data indicate that both cell-cell and cell-collagen interactions are required for the induction and maintenance of the glandular differentiation of colon carcinoma cell lines in vitro. These interactions are primarily mediated by two classes of adhesion molecules, E-cadherin and alpha 2/beta 1 integrin. Both cell surface adhesion receptors are lost in poorly differentiated colorectal tumours, and these changes may explain in part the phenotype and behaviour in vivo. Further investigation of the molecular control of integrin and cadherin function, localization and level of cell surface expression will constitute the basis of new functional assessment of tumour differentiation and likely response to treatment in colorectal cancer.

Animals↗
PubMed1992

Over-expression of p53 nuclear oncoprotein in colorectal adenomas.

p53 is a nuclear phosphoprotein which controls normal cell growth. Normal p53 protein is undetectable by standard immunohistochemical staining and the over-expression found in neoplastic cells correlates with the presence of point mutations of evolutionary conserved regions of the p53 gene. We examined the expression of p53 protein in a series of 36 colorectal adenomas (13 tubular, 17 tubulovillous, 6 villous) showing different degrees of dysplasia (11 mild, 19 moderate, 6 severe), 11 moderately differentiated adenocarcinomas (6 Duke's A, 4 Duke's B, 1 Duke's C) and 5 metaplastic polyps using the polyclonal antibody CM1 which recognises p53 protein in conventionally fixed and processed histological material. We found that 15 out of 36 colorectal adenomas showed p53 immunoreactivity, although in 4 positive cases (26%) the staining was very focal (less than 0.1% positive cells). More than 80% of severely dysplastic adenomas showed strong p53 immunoreactivity and this over-expression was correlated with increased cell proliferative rate as detected by the proliferating-cell-nuclear-antigen (PCNA) staining. p53 nuclear staining was also seen in 8 out of 11 (65%) colorectal adenocarcinomas as previously shown. Our data suggest that the p53 gene mutation, with the subsequent over-expression of the protein, occurs in colorectal adenomas and may therefore be a fundamental genetic event underlying the dysplasia and loss of proliferative control that are characteristic of adenomas with malignant potential.

Adenoma↗
PubMed1992

Lysozyme gene expression in inflammatory bowel disease.

Riboprobe in situ hybridization (rISH) demonstrates active lysozyme synthesis in ulcerative colitis and Crohn's disease. Maximal labeling was seen in Paneth cells, macrophages, and granulomas. Diffuse infiltration of the mucosa by lysozyme-rich polymorphs characterizes ulcerative colitis but obscures reactivity in other cell lineages in immunohistochemical studies; lysozyme mRNA is not detected in polymorphs, rISH giving a clearer picture than immunohistochemical studies of the active synthesis of lysozyme within the gut in inflammatory bowel disease. In ulcerative colitis, strong signals localized to Paneth cell metaplasia were found in 11 of 20 cases and to a lesser degree in non-Paneth cell lineages in regenerative mucosa in 13 of 20 cases. In Crohn's disease, abundant labeling was seen in tuberculoid granulomas (5 of 20) and over macrophage aggregates in the lamina propria in another 7, characteristic patterns not encountered in ulcerative colitis. Low levels of lysozyme messenger RNA were found in the ulceration-associated cell lineage ("pseudopyloric metaplasia"). These results support the view that neutrophils are largely responsible for elevated fecal lysozyme levels in ulcerative colitis and macrophages for elevated serum lysozyme levels in Crohn's disease.

Colitis, Ulcerative↗
PubMed1992

Integrins and their accessory adhesion molecules in mammary carcinomas: loss of polarization in poorly differentiated tumors.

The integrins are alpha beta heterodimeric transmembrane proteins mediating cell-substratum as well as cell-cell interactions. To identify the pattern of expression of the beta 1, beta 3, and beta 4 integrins and their accessory adhesion molecules in relation to the malignant phenotype of invasive breast cancer, we performed an immunohistochemical study for the alpha 2 beta 1 (VLA-2), alpha 6 beta 1 (VLA-6), alpha v and alpha v beta 3 (vitronectin receptor), alpha 6 beta 4, carcinoembryonic antigen, and carcinoembryonic antigen-related molecules in a series of 37 invasive breast carcinomas. All integrin chains examined showed similar patterns in nonneoplastic breast tissue, with strong membrane staining of the myoepithelial cells and weak to moderate staining on the basolateral surfaces of the luminal cells. We found that downregulation of the alpha 2 chain of VLA-2 occurs more frequently in poorly differentiated grade III invasive ductal carcinomas (IDCs) (P = .048). Loss of alpha 6 beta 4 seems also to occur more frequently in grade III IDC (seven of 11 cases, 63.6%) than in grade I/II IDC (two of eight cases, 25%), although this did not reach statistical significance. Carcinoembryonic antigen and carcinoembryonic antigen-related antigens, which are known to function as accessory adhesion molecules, were found mainly in the cytoplasm of neoplastic cells and there was reduced membrane polarization in poorly organized tumors. In contrast the alpha v beta 3, vitronectin receptor heterodimer recognized by the 23C6 monoclonal antibody was weak or absent in normal breast epithelium, and was weakly expressed in two of 19 (10%) IDCs and in nine of 18 (50%) invasive lobular carcinomas (P = .008). However, the alpha v chain detected with the antibody 13C2 was weakly to moderately expressed on nonneoplastic epithelium and at a similar intensity in 13 of 19 IDCs and 15 of 17 invasive lobular carcinomas, suggesting that in IDC the alpha v chain may be associated with a different beta chain (possibly beta 1 or beta 5). No correlation between integrin expression and estrogen/progesterone receptor status was found. These data provide further evidence that in invasive breast carcinomas there is a widespread deregulated expression of integrins and their accessory adhesion molecules with loss of polarization. Changes in the expression and function of cell adhesion molecules, which control growth and differentiation, may have clinical relevance in the behavior of breast cancer.

Antigens, Surface↗
PubMed1992

Morphoregulatory activities of E-cadherin and beta-1 integrins in colorectal tumour cells.

The cadherin family of adhesion molecules are prime mediators of cell-cell interactions while the integrins predominantly mediate cell-matrix and to a lesser extent cell-cell binding specificity. We have recently shown that a human colon carcinoma cell line (SW1222) organizes into glandular structures, with well defined polarity when cultured in three-dimensional type I collagen gel. The current study indicates that SW1222 cells display high levels of E-cadherin (E-cd, epithelial cadherin) by western blotting and immunohistochemical staining. A monoclonal antibody (HECD-1) specific for human E-cd blocks cell-cell adhesion (100%) and inhibits (up to 75%) the glandular differentiation of SW1222 cells growing in collagen gel. Furthermore the anti-beta 1 integrin monoclonal antibody (mAb13) inhibits the glandular differentiation of SW1222 cells (61%) and their cellular binding to type I collagen (60%). However, no significant inhibition of cell-cell adhesion was demonstrated using mAb13 nor the anti-carcinoembryonic antigen monoclonal antibody (PR3B10). These results are consistent with E-cd being a cell-cell adhesion molecule expressed by SW1222 cells. These data indicate that E-cd and beta 1 integrins mediate cell-cell and cell-collagen interactions required for the induction and maintenance of the glandular differentiation of colorectal tumour cells. Thus the down-regulation or loss of E-cd and beta 1 integrins seen in poorly differentiated colorectal tumours may represent one of the abnormalities underlying their progression towards an undifferentiated phenotype in vivo.

Blotting, Western↗
PubMed1992

Stromal expression of 72 kda type IV collagenase (MMP-2) and TIMP-2 mRNAs in colorectal neoplasia.

We undertook an in situ hybridization study to localize the mRNAs for the 72 kda type IV collagenase (MMP-2) and its specific inhibitor (TIMP-2) in 12 colorectal carcinomas, 3 adenomas, and 4 uninvolved resection margins to see how their distributions correlated with that of the reported distribution of MMP-2 protein. Labeling for MMP-2 and TIMP-2 mRNAs was detectable in 10 of 12 carcinomas and in 2 of 3 adenomas. Unexpectedly, we found much stronger signals for MMP-2 and TIMP-2 mRNAs within the mesenchymal cells in the desmoplastic stroma, of endothelial and/or (myo)fibroblastic nature, rather than in tumor epithelial cells in which localization of MMP-2 was anticipated. Our data indicate that stromal cells may have the ability to synthesize a metalloproteinase that degrades basement membrane, and may together with the neoplastic epithelial cells participate actively in the tissue remodeling and disruption of the basement membrane integrity which is characteristic of invasive tumors.

Actins↗
PubMed1991

Distribution of beta 1, alpha 1, alpha 2 and alpha 3 integrin chains in basal cell carcinomas.

The integrins are alpha beta heterodimeric transmembrane proteins mediating cell-substratum as well as cell-cell interactions. Changes in their expression and/or function seem to occur in a number of malignant epithelial neoplasms and may in part explain their abnormal patterns of growth and differentiation. Using monoclonal antibodies to the beta 1 (DH12), alpha 1 (TS2/7), alpha 2 (B1.515), and alpha 3 (E1.56) integrin chains, the alpha 1 beta 1 (VLA-1), alpha 2 beta 1 (VLA-2), and alpha 3 beta 1 (VLA-3) integrin receptors were studied on cryostat sections of 22 basal cell carcinomas (BCCs) and adjacent normal tissues by a standard peroxidase-antiperoxidase technique. In non-neoplastic skin, VLA-2 and VLA-3 were found in the basal layer, eccrine glands, and cells of the outer root sheath in which VLA-1 was detected. In BCCs, there was a considerably higher expression of VLA-2 and VLA-3 compared with epidermal basal cells but similar to that seen in hair bulb and outer root sheath. In two cases of nodular BCC showing evidence of regression, both VLA-2 and VLA-3 were completely negative, in contrast to non-regressing foci which were strongly positive. The high level of expression of two adhesion molecules (VLA-2 and VLA-3) involved in cell-substratum as well as cell-cell interactions may account for the more indolent pattern of growth characteristic of BCC and perhaps reflect its high degree of differentiation towards the hair follicle.

Basal Cell Carcinoma↗
PubMed1991

Control of differentiation in a rectal adenocarcinoma cell line: the role of diffusable and cell-associated factors.

The rectal adenocarcinoma cell line, HRA-19a1.1, was cultured in a three-dimensional type I collagen gel and then xenografted in nu/nu mice to determine whether the in vivo environment could induce further morphological differentiation of the in vitro collagen gel cultures. Three phenotypic changes were observed. Type I collagen induces glandular differentiation in vitro in which well polarized cells are organized around a central lumen, as has been previously reported. Seven days after xenografting this structure in nu/nu mice, the glandular structures appeared to have 'ballooned' forming cyst-like structures lined by a monolayer of flattened cells. There were no stromal cells associated with the graft at this stage, but with time stromal cells invaded the collagen. At points where these cells were closely associated with the HRA-19 cells there was a marked phenotypic change, with the flattened lining cells seen at day 7 becoming columnar. By 21 days the stromal cells had replaced the collagen and the histology of the graft now resembled that of an adenocarcinoma. Placing this cell-collagen culture in a Millipore chamber prior to grafting resulted in cyst-like structures only. Here we provide conclusive evidence that heterologous connective tissue cells can induce differentiation of a rectal adenocarcinoma cell line by a non- or poorly diffusible factor(s). Furthermore, we show that this cell-collagen xenograft method has certain advantages over conventional xenograft methods: notably, a consistent 100 per cent take rate; considerably fewer cells are required to form a tumour; and the time taken to form a tumour is dramatically reduced.

Adenocarcinoma↗
PubMed1991

Low expression of beta 1, alpha 2 and alpha 3 subunits of VLA integrins in malignant mammary tumours.

The Very Late Antigens (VLAs) are alpha beta heterodimeric transmembrane proteins mediating cell-substratum as well as cell-cell interactions. Changes in their expression and/or function seem to occur in a number of invasive carcinomas and may at least in part explain their abnormal patterns of growth and differentiation. Using monoclonal antibodies to the beta 1 (DH12, A1A-5), alpha 2 (B1.515) and alpha 3 (E1.56) chains, VLA-2 (alpha 2 beta 1) and VLA-3 (alpha 3 beta 1) were studied on cryostat sections of three fibroadenomas and 43 invasive breast carcinomas (29 ductal, 14 lobular) by the avidin-biotin complex immunoperoxidase technique. In non-neoplastic breast tissue and in fibroadenomas VLA-2 and VLA-3 were expressed by myoepithelial cells and on the basolateral surface of the luminal cells. There was weak or absent expression of alpha 2, alpha 3 and the common beta 1 chain in the majority of invasive carcinomas compared to the adjacent normal breast epithelium and preinvasive (in-situ) carcinomas. In addition, the expression of the alpha 2 chain of VLA-2 was reduced significantly (P less than 0.005) in the poorly differentiated ductal breast carcinomas (Grade III) compared to the well (Grade I) and moderately (Grade II) differentiated ductal tumours. These data give further evidence that loss or down-regulation of VLA-2 and VLA-3 occur relatively frequently in invasive cancers, and, at least in the invasive ductal breast carcinomas. Loss of an extracellular matrix receptor controlling growth and differentiation seems to be one of the abnormalities underlying the progression towards an undifferentiated morphology.

Adenofibroma↗
PubMed1991

The role of the arginine-glycine-aspartic acid-directed cellular binding to type I collagen and rat mesenchymal cells in colorectal tumour differentiation.

The relationship between the adhesion of five human colorectal carcinoma cell lines to extracellular matrix (ECM) proteins, namely type I collagen, type IV collagen, fibronectin, laminin and basement membrane extract (Matrigel), and the ability of these cells to express morphological differentiation when grown in a basement membrane extract (Matrigel) or on normal rat mesenchymal cells has been examined. Two cell lines, SW1222 and HRA-19, organised into glandular structures, with well-defined polarity when cultured on both substrata as well as in three-dimensional (3D) collagen gel culture as previously shown. The remaining three cell lines (SW620, SW480 and HT29) grew as loose aggregates or as they would normally grow on tissue culture plastic. Addition to the culture medium of a hexapeptide, containing the cell-matrix recognition sequence arginine-glycine-aspartic acid (RGD), inhibited attachment and glandular formation of SW1222 and HRA-19 when these cells were grown on living mesenchymal cells, but not in Matrigel. The morphological differentiation of HRA-19 cells in 3D-collagen was also inhibited by the same RGD-containing peptide, as previously shown for SW1222 cells. Attachment of the remaining three cell lines was inhibited on mesenchyme but not in Matrigel, further supporting the specificity of the peptide effect on epithelial-mesenchymal binding. In conclusion we have shown that colorectal tumour cells are able to bind ECM proteins and that the cellular binding is an essential step in the induction of the morphological differentiation seen on living mesenchymal cells, in basement membrane extracts and in type I collagen gel.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1990

Carcinoembryonic antigen functions as an accessory adhesion molecule mediating colon epithelial cell-collagen interactions.

We have previously shown that a human colon carcinoma cell line (SW1222) expresses a collagen receptor recognizing the Arg-Gly-Asp tripeptide sequence found in collagen. This receptor mediates the cellular attachment to collagen and, subsequently, the glandular differentiation seen in a three-dimensional collagen gel culture. In a search to identify cell surface molecules mediating the adhesion and differentiation of SW1222 cells, we have screened a panel of monoclonal antibodies recognizing epithelial cell surface determinants for their ability to inhibit the collagen binding of SW1222 cells. We have found that four monoclonal antibodies recognizing the 180-kDa carcinoembryonic antigen (CEA) glycoprotein and other members of the CEA family inhibited (up to 87%) the binding of SW1222 cells to type I collagen matrix. Using a cell attachment assay, we have not detected any direct collagen binding of either purified CEA or another CEA-expressing human colon carcinoma cell line (LS174T). These data suggest that CEA is not a collagen-binding protein itself but is likely to be associated with the functional Arg-Gly-Asp collagen receptor expressed by SW1222 cells. We suggest that CEA may function as an accessory molecule, controlling the functional activity of the SW1222 collagen receptor.

Amino Acid Sequence↗
PubMed1989

Integrin-receptor-mediated differentiation and growth inhibition are enhanced by transforming growth factor-beta in colorectal tumour cells grown in collagen gel.

We have studied the role of cell-matrix interactions and the modulating effect on these of transforming growth factor-beta s (TGF-beta s) in controlling differentiation and proliferation in a series of human colorectal carcinoma cell lines. Two (SW1222 and SW480) out of 7 cell lines specifically bound type-I collagen, via integrin-like (SW1222) and non-integrin-like (SW480) collagen receptors. Binding of these receptors may be responsible for regulating the degree of epithelial differentiation of the cells when grown in a 3-dimensional (3D) collagen gel. We have also shown that TGF-beta s enhance the binding of SW1222 cells to collagen and that this is accompanied by greatly increased crypt-like glandular differentiation and inhibition of cell proliferation. Inhibition of cell proliferation was only seen when cells were grown in 3D collagen gel and were thus expressing a fully differentiated phenotype. The enhanced collagen binding induced by TGF-beta s was partially inhibited by an Arg-Gly-Asp (RGD)-containing peptide which is a cell recognition signal for collagen binding. This suggests that TGF-beta s mediate their effects on differentiation of SW1222 cells specifically by modulating the expression of the integrin-like collagen receptor. The other colorectal carcinoma cell lines which lack this integrin-like receptor either failed to bind collagen or, in the case of SW480 binding, exhibited differentiation and proliferation which were not affected by TGF-beta s. This suggests that cell responsiveness to TGF-beta s may depend, at least in part, upon the cell-matrix interaction.

Cell Differentiation↗
PubMed1988

Genetics and biochemistry of collagen binding-triggered glandular differentiation in a human colon carcinoma cell line.

We have examined the interaction between collagen binding and epithelial differentiation by using a human colon carcinoma cell line (SW1222) that can differentiate structurally when grown in a three-dimensional collagen gel to form glandular structures. As much as 66% inhibition of glandular differentiation can be achieved by addition to the culture of a synthetic peptide (2 mg/ml) containing the Arg-Gly-Asp-Thr (RGDT) sequence, which is a cell recognition site found in collagen. Arg-Gly-Asp-Thr also inhibited the cell attachment to collagen-coated plates. A control peptide containing the Arg-Gly-Glu-Thr (RGET) sequence had no effect on cell adhesion or cell differentiation. Chromosome 15 was found in all human-mouse hybrid clones [from a cross between SW1222 and a mouse rectal carcinoma cell line (CMT-93)] that could differentiate in the collagen gel and bind collagen. Both binding to collagen and glandular differentiation of the hybrid cells were also inhibited by Arg-Gly-Asp-Thr as for the parent cell line SW1222. The ability of SW1222 cells to express the differentiated phenotype appears, therefore, to be determined by an Arg-Gly-Asp-directed collagen receptor on the cell surface that is controlled by a gene on chromosome 15.

Animals↗