Biomedical subjects

E Kozlowska

Publications and source records attributed to E Kozlowska.

10 recordsLinked to original sources

PubMed2002

The promoter polymorphism of the matrix metalloproteinase 3 (MMP-3) gene in women with ovarian cancer.

Matrix metalloproteinases (MMPs) comprise family proteolytic enzymes that degrade extracellular matrix components and therefore play an important role in tumour cell invasion and cancer metastasis. Overexpression of matrix metalloproteinase 3 (MMP-3 or stromelysin 1) gene has been demonstrated in various types of cancers and high level of MMP-3 protein in tumour is a poor prognostic factor for patients. The insertion (6A)/deletion (5A) polymorphism (5A/6A polymorphism) located at the promoter of the MMP-3 gene may have functional significance in the regulation of its expression. In the present work the distribution of genotypes and frequencies of alleles of the 5A/6A polymorphism in subjects with ovarian cancer were investigated. Paraffin embedded tumour tissues were obtained from 100 women with ovarian cancer. The genotypes of 5A/6A polymorphism were determined by PCR amplification using the allele specific primers. The distribution of the genotypes of the 5A/6A polymorphism in both control and patients did not differ significantly (p > 0.05) from those predicted by the Hardy-Weinberg distribution. Additionally, there were no significant differences (p > 0.05) in genotype distributions and allele frequencies between subgroups assigned to histological stage. The results suggest that the 5A/6A polymorphism of MMP-3 gene may not be linked with appearance and development to ovarian cancer.

Aged↗

PubMed2001

Her4 mediates ligand-dependent antiproliferative and differentiation responses in human breast cancer cells.

The function of the epidermal growth factor receptor (EGFR) family member HER4 remains unclear because its activating ligand, heregulin, results in either proliferation or differentiation. This variable response may stem from the range of signals generated by HER4 homodimers versus heterodimeric complexes with other EGFR family members. The ratio of homo- and heterodimeric complexes may be influenced both by a cell's EGFR family member expression profile and by the ligand or even ligand isoform used. To define the role of HER4 in mediating antiproliferative and differentiation responses, human breast cancer cell lines were screened for responses to heregulin. Only cells that expressed HER4 exhibited heregulin-dependent antiproliferative responses. In-depth studies of one line, SUM44, demonstrated that the antiproliferative and differentiation responses correlated with HER4 activation and were abolished by stable expression of a kinase-inactive HER4. HB-EGF, a HER4-specific ligand in this EGFR-negative cell line, also induced an antiproliferative response. Moreover, introduction and stable expression of HER4 in HER4-negative SUM102 cells resulted in the acquisition of a heregulin-dependent antiproliferative response, associated with increases in markers of differentiation. The role of HER2 in these heregulin-dependent responses was examined through elimination of cell surface HER2 signaling by stable expression of a single-chain anti-HER2 antibody that sequestered HER2 in the endoplasmic reticulum. In the cell lines with either endogenously (SUM44) or exogenously (SUM102) expressed HER4, elimination of HER2 did not alter HER4-dependent decreases in cell growth. These results suggest that HER4 is both necessary and sufficient to trigger an antiproliferative response in human breast cancer cells.

Breast Neoplasms↗

PubMed2000

Does long-term compressive loading on the intervertebral disc cause degeneration?

STUDY DESIGN: Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs of dogs for up to 53 weeks. OBJECTIVE: To test the hypothesis that compressive forces applied to the intervertebral disc for a long period of time cause disc degeneration in vivo in a dog model. SUMMARY OF BACKGROUND DATA: It is a commonly held belief that high forces applied to the intervertebral disc, and to joints in general, play a role in causing degeneration. METHODS: Coil springs were stretched and attached to produce a compressive force across the lumbar intervertebral discs (L3/L4) of 12 dogs. After up to a year, the dogs were killed, and their lumbar spines were removed and radiographed. The L3/L4 disc and the controls (T13/L1 and L4/L5) were excised and examined for visible signs of degeneration. The discs then were assessed using immunohistochemical analysis and enzyme-linked immunosorbent assay. Disc chondrocytes also were assayed for apoptosis. RESULTS: No obvious signs of degeneration in the discs (L3/L4) that had been under compression for up to a year could be observed. There was no disc bulging, anular fissures, or disc space narrowing. Some changes were observed at the microscopic level, although no thickening of the endplate was apparent. The enzyme-linked immunosorbent assay analysis provided significant data for all three regions of the disc (nucleus, inner anulus, and outer anulus). When comparing the compressed disc (L3/L4) with either of the control discs (T13/L1 and L4/L5), in the compressed disc: 1) the nucleus contained less proteoglycan and more collagen I and II; 2) the inner anulus contained less proteoglycan and collagen I; and 3) the outer anulus contained more proteoglycan and less collagen I. The collagen II differences for the inner and outer anulus were not significant. CONCLUSION: Compression applied to the lumbar intervertebral discs of dogs for up to a year does not produce degeneration in any visible form. It does produce microscopic changes and numerical changes, however, in the amounts of proteoglycan and collagen in the nucleus, inner anulus, and outer anulus. The present results add no credence to the commonly held belief that high compressive forces play a causative role in disc degeneration.

Animals↗

PubMed1997

Sensitivity of mouse lymphoid and nonlymphoid organs to Silesian air pollutants.

The toxic effect of Silesian air pollutants to mouse organs was examined. Histological changes were found in the examined lymphoid organs (thymus, spleen) as well nonlymphoid organs (liver, kidneys). The alterations in weight indexes of lymphoid organs were also observed. Considerable changes in cellularity, weight index, and histology of the thymus in the mice exposed to air pollutants suggest the atrophy of this organ, which may lead to extrathymic T-cell differentiation and even acceleration of thymocytes maturation, which may lead to certain allergic or auto-immune pollutants of all investigated mouse organs in the following order: thymus, liver, kidneys, and spleen.

Air Pollutants, Occupational↗

PubMed1996

Decreased expression of alpha 2 beta 1 integrin in scleroderma fibroblasts.

Systemic scleroderma (SSc) is a complex connective tissue disorder of unknown etiology. In early stages of the disease, fibroblasts are activated to produce large amounts of collagen with subsequent fibrosis. Collagen metabolism of fibroblasts is modulated by their contact with the extracellular matrix (ECM), which involves distinct receptors on the cell surface, mainly belonging to the integrins. We investigated the expression of collagen receptor alpha 2 beta 1 in SSc and normal fibroblasts, since this receptor has been shown to be utilized by fibroblasts for adhesion to and reorganization of collagen I. 9 strains of scleroderma fibroblasts grown as monolayer cultures were first analyzed with respect to their collagen I expression. 6 of these strains were similar to controls "low" producers) and 3 strains showed up to 2-3 x higher levels of collage I mRNA expression ("high" producers). Northern hybridization using a cDNA probe specific for the alpha 2 integrin subunit revealed a decrease of the corresponding mRNA in SSc fibroblasts as compared to controls (75% versus 100%). "High" collagen producing cell strains displayed the lowest values for alpha 2 integrin mRNA. The decrease of alpha 2 integrin subunit expression at the mRNA level in selected fibroblasts was further substantiated by radioimmunoprecipitation using specific mAbs directed against alpha 2 integrin subunit. No significant changes in beta 1 integrin expression could be observed - neither at mRNA nor at the protein level. Our data indicate a correlation between excessive synthesis of collagen and low levels of alpha 2 integrin subunit expression in SSc fibroblasts. Further experiments should clarify whether this observation is a phenomenon specific for scleroderma or whether it reflects an "activated" state of fibroblasts.

Cells, Cultured↗

PubMed1995

Different T-cell activation by streptozotocin and Freund's adjuvant in popliteal lymph node (PLN).

A popliteal lymph node (PLN) test was further validated for predictive screening of autoimmunity-inducing drugs. Autoimmune-like T-cell activation of streptozotocin (STZ) was compared with the effect of Freund's complete adjuvant (FCA), injected locally into the foot pad of BALB/c mice. Early cell activation in enlarged PLN was monitored by flow cytometry. Injection of both STZ and FCA markedly increased the absolute PLN cell number as well as specific T-helper (CD4+), T-suppressor/cytotoxic (CD8+), and B (Ig+) subsets. However, quantitative analysis of early T-cell activation revealed important differences between STZ-induced PLN reaction and FCA-related lymphoproliferation. At 72 h, the number of cells stained with anti-early activation marker (EAM+; CD69+) increased over 10 times in STZ-enlarged nodes and only 3 times in the FCA-inflamed nodes. Furthermore, different cytometric profiles were noted for STZ-activated and FCA-activated cells stained with anti-interleukin-2 receptor (IL-2R) (CD25+). The data suggest the applicability of early cytometric screening of enlarged PLN for predictive analysis detection of chemicals inducing an autoimmune-like reaction.

Animals↗

PubMed1995

Collagen and collagenase gene expression in three-dimensional collagen lattices are differentially regulated by alpha 1 beta 1 and alpha 2 beta 1 integrins.

The reorganization of extracellular matrix (ECM) is an important function in many biological and pathophysiological processes. Culture of fibroblasts in a three-dimensional collagenous environment represents a suitable system to study the underlying mechanisms resulting from cell-ECM interaction, which leads to reprogramming of fibroblast biosynthetic capacity. The aim of this study was to identify receptors that transduce ECM signals into cellular events, resulting in reprogramming of connective tissue metabolism. Our data demonstrate that in human skin fibroblasts alpha 1 beta 1 and alpha 2 beta 1 integrins are the major receptors responsible for regulating ECM remodeling: alpha 1 beta 1 mediates the signals inducing downregulation of collagen gene expression, whereas the alpha 2 beta 1 integrin mediates induction of collagenase (MMP-1). Applying mAb directed against different integrin subunits resulted in triggering the heterodimeric receptors and enhancing the normal biochemical response to receptor ligation. Different signal transduction inhibitors were tested for their influence on gel contraction, expression of alpha 1(I) collagen and MMP-1 in fibroblasts within collagen gels. Ortho-vanadate and herbimycin A displayed no significant effect on any of these three processes. In contrast, genistein reduced lattice contraction, and completely inhibited induction of MMP-1, whereas type I collagen down-regulation was unaltered. Calphostin C inhibited only lattice contraction. Taken together, these data indicate a role of tyrosine-specific protein kinases in mediating gel contraction and induction of MMP-1, as well as an involvement of protein kinase C in the contraction process. The data presented here indicate that different signaling pathways exist leading to the three events discussed here, and that these pathways do not per se depend upon each other.

Antibodies, Monoclonal↗

PubMed1993

Control of fibrosis in systemic scleroderma.

Scleroderma is characterized by an excessive deposition of collagen in all involved organs. This is due to an overproduction of extracellular matrix (ECM) molecules following induction of gene expression, whereas there is no evidence that the composition of the connective tissue matrix is altered. Several in vivo studies and in vitro experiments suggest that a close interaction between inflammatory cells and fibroblasts is required for the initial activation of fibroblasts. TGF-beta presumably plays an important role, but other cytokines, e.g., PDGF or FGF, may also be involved. Many of the ECM molecules have been shown to interact closely with fibroblasts and provide signals that regulate fibroblast metabolism. The cellular response towards those signals is a further aspect of fibrosis that has attracted attention during recent years. The altered expression of receptor proteins on the cell surface of scleroderma fibroblasts for example might explain in part the lack of down-regulation of collagen synthesis in late phases of the disease. This review summarizes the alterations of connective tissue in scleroderma, and discusses the role of cytokines as well as the ECM for the regulation of fibroblast function and their implication for the development of fibrosis.

Cells, Cultured↗

PubMed1992

Altered regulation of collagen metabolism in scleroderma fibroblasts grown within three-dimensional collagen gels.

In systemic scleroderma (SSc) excessive deposition of collagen leads to fibrosis of various tissues including the skin. Previous studies have demonstrated that scleroderma fibroblasts in explant monolayer cultures are heterogeneous with respect to their levels of collagen synthesis. The critical role played by the extracellular matrix (ECM) in the modulation of fibroblast metabolism prompted us to study the regulation of collagen synthesis in scleroderma fibroblasts grown within three-dimensional collagen gels, a culture system representing more physiological conditions than monolayer cultures. Normal fibroblasts grown in this system dramatically reduce their collagen synthesis as compared to monolayer cultures. Quantification of total protein and collagen synthesis showed that scleroderma fibroblasts did not demonstrate the down regulation of collagen synthesis as observed in control fibroblasts, resulting in a much higher collagen synthesis in scleroderma fibroblasts compared to controls. However, also in this system scleroderma fibroblasts were heterogeneous in their response to the collagenous lattice. Ten strains were investigated, of which 3 were indistinguishable from controls, while 7 maintained higher levels of collagen production. In addition, our data showed that the changes in collagen synthesis on the protein level were accompanied by respective up- or downregulation on the mRNA level. These results indicate that an altered response to the surrounding ECM is an important factor in the disturbed regulation of connective tissue synthesis in scleroderma fibroblasts observed in vivo.

Adult↗

PubMedDate not supplied

Human brain S100 beta and S100 beta mRNA expression increases with age: pathogenic implications for Alzheimer's disease.

S100 beta is a neurite extension factor that has been implicated in the development of neuritic plaques in Alzheimer's disease. We analyzed the expression of S100 beta and its encoding mRNA, using immunohistochemistry, enzyme-linked immunosorbent assay, and Northern blot analysis, in postmortem brain tissue from 26 neurologically normal patients, aged 1-80 years. Tissue levels of S100 beta and S100 beta mRNA, as well as the number of S100 beta-immunoreactive (S100 beta +) astrocytes, increased with advancing age (r = 0.60, p = 0.008; r = 0.65, p = 0.007: and r = 0.73, p = 0.001, respectively). In patients more than 60 years old, the number of S100 beta + astrocytes and the tissue levels of S100 beta and S100 beta mRNA were significantly higher than those in patients less than 60 years of age (p = 0.001, p = 0.035, and p = 0.047, respectively). All of these values, however, were significantly less than those found in Alzheimer patients (p < 0.05 or better). Our findings, together with the known functions of S100 beta, suggest that age-related increases in S100 beta expression are important in the pathogenesis of Alzheimer's disease and may explain in part the increased incidence of this disease with advancing age.

Adolescent↗