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Biomedical subjects

M D Kramer

Publications and source records attributed to M D Kramer.

At least 37 records · Page 2Linked to original sources
PubMed1997

Prognostic relevance of urokinase plasminogen activator detection in micrometastatic cells in the bone marrow of patients with primary breast cancer.

Patients with an elevated level of urokinase plasminogen activator (uPA) in breast cancer tissue have an adverse prognosis. This study evaluated the prognostic relevance of uPA detection in disseminated tumour cells in bone marrow. Bone marrow was sampled intraoperatively from both iliac crests in 280 patients with primary breast cancer. Interphase cells were enhanced and stained immunocytologically with two antibodies: 2E11, which detects TAG 12--a tumour-associated glycoprotein typically expressed by almost all breast cancer cells--and the anti-uPA antibody HD-UK9. Thirty-five of the 2E11-positive women (n = 132, 47%) developed metastatic disease (median follow-up time 44 months). Of these, most were uPA positive (n = 23, 65%) and only 12 were uPA negative. Patients with uPA-positive cells in bone marrow (n = 98, 35%) had a significantly shorter metastasis-free interval (36 months) than women who were uPA negative (44.5 months). The worst prognosis was seen in patients positive for both markers (29.5 months), followed by those who were uPA negative and 2E11 positive (37 months). The detection of uPA on disseminated tumour cells characterizes a subgroup of patients with an even worse prognosis, who should undergo more aggressive adjuvant systemic therapy. For the first time, it was possible to evaluate an important qualitative parameter involved in the process of breast cancer metastases.

Antibodies, Monoclonal↗
PubMed1996

Dispase-mediated basal detachment of cultured keratinocytes induces urokinase-type plasminogen activator (uPA) and its receptor (uPA-R, CD87).

Keratinocytes synthesize and secrete urokinase-type plasminogen activator (uPA), which is bound in an autocrine manner to a specific receptor (uPA-R, CD87) at their surface. Plasminogen, which is also bound to membrane binding sites, is readily activated by uPA-R-bound uPA. Thus, plasmin for proteolysis of pericullular glycoproteins is provided. While uPA-R and uPA are at low to undetectable levels in keratinocytes of the normal epidermis, both compounds are upregulated in migrating keratinocytes during reepithelialization of epidermal defects and in affected keratinocytes of various epidermal disorders, including bullous dermatoses. We have hypothesized that the disturbance of cell/matrix interactions--a common feature of these diverse pathological situations--induces uPA/uPA-R. Accordingly, we explored whether the dispase-mediated detachment of cultured keratinocytes, which have formed a multilayered epidermis-like structure in vitro, induced uPA and uPA-R. We found increases in uPA secretion, cell-associated uPA activity, and uPA- and uPA-R-antigen in keratinocytes upon dispase-mediated detachment from their growth substratum. The increase was preceded by an increase in uPA-R- and uPA-specific mRNA, which was not observed when the proteinase inhibitor phosphoramidon was added together with dispase. In conclusion, we present evidence that experimental detachment with dispase provides signals for the concomitant upregulation of uPA-R and uPA. The findings support the hypothesis that cell/matrix interactions may influence the expression of the cell surface-associated PA system in human keratinocytes.

Cell Adhesion↗
PubMed1996

Tumor necrosis factor-alpha-induced apoptosis in a human keratinocyte cell line (HaCaT) is counteracted by transforming growth factor-alpha.

The integrity of the human epidermis is guaranteed by a regulated balance of proliferation, differentiation, and physiologic cell death of its main cellular constituent, the epidermal keratinocyte. Physiologic cell death is known as apoptosis and has been recognized as an active regulatory mechanism, complementary to, but functionally opposite of, proliferation. The regulators of the delicate balance between cell death and proliferation are only partially understood in human keratinocytes. Transforming growth factor-alpha (TGF-alpha) has been identified as a positive regulator of proliferation and growth, while tumor necrosis factor-alpha (TNF-alpha) induces apoptosis. Both mediators are thought to influence epidermal keratinocytes under various physiological and pathophysiological conditions. In the current study we have begun to investigate potential regulatory interactions between these two mediators in the human keratinocyte cell line HaCaT. We have found that, when the HaCaT cells were sensitized by the translation inhibitor cycloheximide, TNF-alpha induced apoptosis, as evidenced by nuclear disintegration, DNA fragmentation ("DNA laddering"), and the appearance of soluble DNA/histone complexes. Moreover, we found that the induction of apoptosis was reduced by preincubation of the cells with TGF-alpha. The protective effect of TGF-alpha was abrogated by translation inhibition, indicating that it depended on de novo protein synthesis. Moreover, the protective effect was not accompanied by a reduced surface expression of TNF receptor molecules. We postulate that TNF-alpha-induced apoptosis in HaCaT cells is counteracted by constitutively produced suppressors of apoptosis, the synthesis of which can be downregulated by inhibition of translation and upregulated by the cytokine TGF-alpha.

Apoptosis↗
PubMed1996

Upregulation of cell-surface-associated plasminogen activation in cultured keratinocytes by interleukin-1 beta and tumor necrosis factor-alpha.

Keratinocytes synthesize and secrete urokinase-type plasminogen activator (uPA) which is bound in an autocrine manner to a specific receptor (uPA-R) at the keratinocyte surface. Plasminogen that is also bound to specific membrane binding sites is readily activated by uPA-R-bound uPA. Thus, plasmin is provided for proteolysis of pericellular glycoproteins. The expression of uPA and the uPA-R is confined to migrating keratinocytes during epidermal wound healing, rather than to keratinocytes of the normal epidermis. The regulatory factors of uPA/uPA-R expression in keratinocytes remained largely elusive. Proinflammatory cytokines, such as tumor necrosis factor-alpha (TNF-alpha) or interleukin-1 beta (IL-1 beta), are present in epidermal wounds. We have therefore tested IL-1 beta and TNF-alpha for their influence on surface-associated plasminogen activation in a human keratinocyte cell line (HaCaT) as well as in primary cultures of normal human epidermal keratinocytes. Both cytokines induced the secretion of uPA into the culture supernatants and a concomitant increase in uPA activity as well as in uPA and uPA-R antigen at the cell surface. The increase was preceded by an increase in specific mRNA. The induction was accompanied by an accelerated uPA-dependent and plasmin-mediated detachment of HaCaT cells from the culture substratum. Taken together, the proinflammatory cytokines IL-1 beta and TNF-alpha induced a coordinated increase in uPA and uPA-R as well as increased pericellular plasmin-mediated proteolysis in human epidermal keratinocytes. This function might be an element of the molecular cell biological events during epidermal wound healing.

Cell Adhesion↗
PubMed1996

Plasminogen activator inhibitor type-2 (PAI-2) in human keratinocytes regulates pericellular urokinase-type plasminogen activator.

Plasminogen activation is observed in the human epidermis during reepithelialization of epidermal defects and under certain pathological conditions. The activation reaction depends on keratinocyte-associated plasminogen activators (PAs), which convert the ubiquitous proenzyme plasminogen into the active trypsin-like serine proteinase plasmin. The PAs are controlled by PA inhibitors (PAIs), of which two major types are known: PAI-1 and PAI-2. In vitro and in vivo keratinocytes express both PAIs. In the current study, we have addressed the possible function of PAI-2 in regulating extracellular PA activity in cultured normal human epidermal keratinocytes (NHEK), the human keratinocyte cell line (HaCaT), and a Ha-ras transfected HaCaT variant (HaRas). PAI-2 was detected intracellularly in all three cell types. Whereas only the NHEK and the HaCaT cells secreted detectable levels of PAI-2 into the culture medium, all three cell types released urokinase-type PA (uPA) into the supernatants. When comparing HaCaT and HaRas cells, we found that the cell lines secreted comparable levels of uPA antigen, whereas the levels of uPA activity were low in the presence of PAI-2, indicating that PAI-2 serves to regulate uPA activity. This assumption was supported by the findings that PAI-2 formed complexes with secreted uPA and that uPA/PAI-2 complexes were present at the surface of the PAI-2-secreting HaCaT cells but not at the surface of PAI-2 nonsecreting HaRas cells. Finally, PAI-2 was found to counteract the uPA-dependent and plasmin-mediated detachment of cultured HaCaT cells. Taken together, our findings indicate that secreted PAI-2 serves to regulate the activity of extracellular uPA in keratinocytes.

Aprotinin↗
PubMed1996

The outer surface lipoprotein OspA of Borrelia burgdorferi provides co-stimulatory signals to normal human peripheral CD4+ and CD8+ T lymphocytes.

Studies in man and mice have indicated that T cells induced during Borrelia burgdorferi infection are involved in the pathogenesis of the disease. We analyzed the ability of B. burgdorferi to provide co-stimulatory signals to highly enriched normal human CD2+ T lymphocytes in the presence of suboptimal concentrations of immobilized anti-CD3 antibodies. Here we show that the lipid-containing recombinant outer surface lipoprotein A (rlip-OspA) of B. burgdorferi but not its delipidated derivative rNS1-OspA augmented CD3-induced T cell proliferation in a dose-dependent manner and at levels similar to that obtained with anti-CD28 antibodies. Lipopolysaccharide had no effect in this system at any concentration tested, suggesting that the active principle of co-stimulation is associated with the lipid moiety of rlip-OspA and distinct from conventional lipid A. Furthermore, incubation of CD2+ T cells or selected CD4+ as well as CD8+ subpopulations with rlip-OspA, but not with rNS1-OspA led to the production of interferon (IFN)-gamma, interleukin (IL)-6 and tumor necrosis factor (TNF)-alpha, but not IL-4. In contrast, co-stimulation of the respective T cell populations with anti-CD28 antibodies resulted in the generation of IFN-gamma, IL-4 and TNF-alpha, but not IL-6. This indicated that the signal transduction pathway induced by rlip-OspA is distinct from that elicited via the CD28 receptor. Co-stimulation of T cells with rlip-OspA also resulted in the development of cytolytic effector cells. In light of the fact that inflamed tissues of B. burgdorferi-infected hosts contain blood leukocytes together with spirochetes, their degradation products, or both, these results suggest that infiltrating CD4+ and CD8+ T cells of any specificities, including spirochetes, autoantigens, or both, participate in the pathogenesis of Lyme disease.

Adjuvants, Immunologic↗
PubMed1996

Plasmid DNA and protein vaccination of mice to the outer surface protein A of Borrelia burgdorferi leads to induction of T helper cells with specificity for a major epitope and augmentation of protective IgG antibodies in vivo.

Plasmid DNA-based vaccination is an efficient way to evoke various forms of protective immunity in laboratory animals. Our previous experiments have shown that mice immunized with either plasmid DNA encoding the outer surface lipoprotein A (pOspA) of Borrelia burgdorferi or the respective lipoprotein (Lip-OspA) produce protective antibodies against subsequent challenge with virulent spirochetes. In the present study, we compared the specificity and function of T cells generated in AKR/N mice previously immunized to either pOspA or Lip-OspA. T cell populations derived by either of the two protocols consistently responded by proliferation in vitro to one (residues 186-203; B4) out of a panel of 27 overlapping 20-mer peptides spanning the entire OspA molecule of strain ZS7. B4 was shown to express allele-specific ligand motifs for I-Ek. Most of the other peptides produced variable and much less pronounced or marginal proliferative T cell responses. T cells reactive to B4 as well as to some minor epitopes were CD4+CD8- T cells which produced IFN-gamma but no detectable IL-4 upon antigen stimulation in vitro. Priming of AKR/N mice with B4 but not with inactive peptides of OspA led to an enhanced production of IgG antibodies, mainly of the IgG1 isotype, including those to a prominent protective epitope (LA-2) upon subsequent challenge with Lip-OspA or intact spirochetes. The data demonstrate that both plasmid DNA and protein immunization with OspA results in T cell responses with specificity for a dominant OspA epitope and suggest that priming of mice with immunodominant peptides accelerates the appearance of protective antibodies in vivo. The identification of T helper cell epitopes relevant for the induction of protective antibodies will also facilitate the design of more potent vaccines against Lyme disease.

Amino Acid Sequence↗
PubMed1996

Protective immunization with plasmid DNA containing the outer surface lipoprotein A gene of Borrelia burgdorferi is independent of an eukaryotic promoter.

Plasmid DNA encoding the outer surface lipoprotein A (OspA) of Borrelia burgdorferi under the control of either strong eukaryotic/viral or its own bacterial promoter was injected intramuscularly (m. tibialis anterior) or intradermally into BALB/c and AKR/N mice. OspA-specific antibodies and OspA-reactive T helper 1 cells (Th1) were induced only with those plasmids containing the ospA structural gene including its own regulatory control region immediately upstream. In the absence of the ospA promoter, no or only marginal immune responses to OspA were obtained, even when strong eukaryotic promoter/enhancer elements were present. Together with the finding that the ospA promoter is active in a mouse B-lymphoma line, the data suggest that spirochetes are able to express at least part of their genes in the mammalian environment. Mice previously vaccinated with the relevant ospA plasmid DNA were protected against subsequent experimental challenge with a virulent strain of B. burgdorferi, as measured by the appearance of antibodies to a prominent protective epitope (LA-2) and the failure to re-isolate spirochetes from ear biopsies. In addition, C.B-17 severe-combined immunodeficient mice could be protected against infection by passive transfer of immune sera from ospA plasmid DNA-inoculated normal mice. Protective LA-2-related antibody titers obtained after repeated immunization persisted for 200 days and longer. This simple procedure of immunization using plasmid DNA consisting of a prokaryotic gene under the control of its own promoter holds great promise for the development of alternative subunit vaccines against bacterial infections, including Lyme disease. In addition, the availability of this novel prokaryotic promoter element now allows the study of the basis for the differential expression of bacterial genes in prokaryotic and eukaryotic environments.

Animals↗
PubMed1996

Interleukin-1 beta upregulates tissue-type plasminogen activator in a keratinocyte cell line (HaCaT).

Human keratinocytes synthesize and secrete tissue-type plasminogen activator (tPA). tPA converts the inactive precursor enzyme plasminogen into the trypsin-like proteinase plasmin. tPA is not found in normal epidermis, but in lesional epidermis from patients with a variety of cutaneous diseases, including psoriasis, pemphigus and pemphigoid. The presence of tPA is probably a reaction to the disease process rather than the initiating event in these etiologically and histopathologically diverse lesions. However, the factor(s) that upregulate tPA expression and secretion in keratinocytes have remained largely elusive. We sought to determine whether the inflammatory cytokine interleukin-1 beta (IL-1 beta), which is commonly present in diverse epidermal lesions, influences tPA production. Accordingly, we studied the influence of IL-1 beta on secretion of tPA by cells of the human keratinocyte cell line HaCaT. We found that IL-1 beta increased tPA secretion in these cells. Given the observation that IL-1 beta is a common proinflammatory mediator in cutaneous diseases, our findings may explain the increase in tPA in clinically and etiologically diverse inflammatory epidermal lesions.

Cell Division↗
PubMed1996

alpha 2-Antiplasmin and plasminogen activator inhibitors in healing human skin wounds.

Mechanical injury of tissues is followed by the formation of a provisional fibrin matrix, which is later replaced by granulation tissue. The fibrinolytic proteinase, plasmin, is thought to contribute to the displacement of the primary matrix. Plasmin is generated from the ubiquitous proenzyme plasminogen by plasminogen activators. The system of plasminogen activation is controlled at several levels: plasminogen activator inhibitors (PAI-1 and PAI-2) counteract the activity of plasminogen activators and alpha 2-antiplasmin inhibits the activity of plasmin. In order to elucidate the mechanisms that regulate the plasminogen activator system in healing human skin wounds, we performed the immunohistological study reported here. The plasmin inhibitor alpha 2-antiplasmin and PAI-2 were found in the primary fibrin-rich matrix and in the granulation tissue. alpha 2-Antiplasmin was diffusely distributed in the tissue and its distribution correlated with the presence and localization of plasmin(ogen) except that, in contrast to plasmin(ogen), the alpha 2-antiplasmin was apparently not cell-associated. The stainings for PAI-2 increased with time and paralleled the development of the cellular infiltrate. PAI-2 was found in association with cells, which were identified by double immunofluorescence stainings as monocytes/macrophages and fibroblasts. In line with the immunohistological data, polymerase chain reaction after reverse transcription revealed mRNA for PAI-2 in healing human skin wounds. Taken together, our findings indicate that in healing human skin wounds, PAI-2 is the primary regulator of plasminogen activators, whereas alpha 2-antiplasmin may serve to control plasmin activity.

Base Sequence↗
PubMed1996

[Prognostic significance of plasminogen activator inhibitor-1 (PAI-1) in primary breast carcinoma].

The plasminogen activator system plays a key role in the proteolysis of malignant tumours. In 155 patients with primary breast cancer levels from PAI-1 and uPA were measured in cytosol with monoclonal antibodies and by an enzyme-linked immunosorbent assay. 35 tumour tissue samples form benign breast were also examined. Malignant tumours contain higher levels of PAI-1 (8.6 ng/mg) than benign tumours (1.28 ng/mg) (p < 0.01). Also the median level of uPA was significantly higher (p < 0.01) in malignant tissue (2.38 ng/mg) in comparison to benign disease (0.54 ng/mg). No correlation was found between the proteases and the classical prognostic parameters like axillary lymph node involvement, tumour size and menopausal status. However, a significant correlation (p < 0.01) was found in tumours with lymphangiosis carcinomatosa, negative hormone receptors, grade III tumour cells and high S-phase fractions (> 5%). After a median follow-up of 46 months we found that high levels of PAI-1 correlated with short DFS (p = 0.0005) and OAS (p = 0.003). However, in the Cox multivariate regression analysis only PAI-1 was significantly independent for OAS and could therefore give additional information. We conclude that levels from PAI-1 antigen measured in cytosol of primary breast cancer is an independent prognostic parameter to identify patients with high and low risk for relapse and for individualised treatment.

Adult↗
PubMed1996

Rapid normalization of epidermal integrin expression after allografting of human keratinocytes.

Allogeneic keratinocyte grafts have beneficial effects on skin wounds, but the underlying interactions between graft and woundbed remain to be explored in detail. The epidermal integrins play a pivotal role in mediating cell-to-cell and cell-to-matrix interactions. In unwounded epidermis, alpha 2 beta 1-, alpha 3 beta 1-, alpha 6 beta 4-, alpha 5 beta 1-, and alpha v beta 5-integrins are confined to basal cells. During healing of incisional wounds, these integrins are also expressed in suprabasal cells, where they remain detectable even after epidermal integrity is fully reestablished. We examined the integrin subunits alpha 2, alpha 3, alpha 6, alpha 5, and alpha v in partial thickness burn wounds grafted with allogeneic keratinocytes and asked whether the effect of allogeneic keratinocyte grafts, i.e., fast reepithelialization, is reflected by an accelerated reversion to a normal integrin pattern. Biopsies were taken after wound debridement before grafting and 10 d after transplantation. After 10 d, a stratified epidermis had developed in all cases and integrins were mainly restricted to the basal cell layer of the neo-epidermis. alpha 2-, alpha 3-, alpha 6-, and alpha v-subunits were present at basal and/or lateral cell borders, duplicating the integrin pattern in normal epidermis. The findings indicate that grafting accelerates the shift of the epidermis from an inflammatory to a regenerative state, as reflected by the reversion of the integrin pattern from a "spread-and-migrate" to the "steady-state" phenotype.

Biopsy↗
PubMed1996

Plasminogen activator system in pemphigus vulgaris.

Pemphigus vulgaris (PV) is caused by autoantibodies against desmosomes and is characterized by intra-epidermal blisters. The pathology of PV has been linked with plasminogen activation in lesional epidermis. The plasminogen activator system (PA system) consists of urokinase-type plasminogen activator (uPA), tissue-type PA (tPA), as well as the two types of plasminogen activator inhibitors (PAI-1 and PAI-2). In keratinocytes, uPA binds to a specific cell surface receptor for uPA (uPA-R = CD87) in an autocrine manner. Cell-bound uPA is regulated by PAIs. The central PA system component plasminogen, which is present in plasma and interstitial fluids, is bound to the keratinocyte surface via plasmin(ogen) binding sites, where it can be activated by uPA-R-bound uPA. Cell surface-associated plasmin then mediates pericellular proteolysis. As the topographical organization of the distinct PA system components in lesional epidermis of PV remained elusive, we have performed the present immunohistological analysis of lesional and non-lesional epidermis of PV. In keratinocytes directly involved in the epidermal split formation, plasmin(ogen) was stained in nine of 10 cases, uPA-R and uPA in four of 10 cases and PAI-2 in seven of 10 cases. Together, acantholytic plasmin(ogen)+ keratinocytes appeared in three different phenotypes: uPA-R+/uPA+ and PAI-2+, uPA-R-/uPA- and PAI-2+, as well as uPA-R-/uPA- and PAI-2-. Our findings demonstrate that, in acantholytic keratinocytes of PV, PAs and PAIs appear as differentially regulated components of the PA system.

Adult↗
PubMed1996

Borrelia burgdorferi induces secretion of pro-urokinase-type plasminogen activator by human monocytes.

Borrelia burgdorferi is transmitted by infected ticks and causes Lyme disease. To infect distant organ sites, B. burgdorferi spirochetes must disseminate from the site of the tick bite. During dissemination from the dermal tissue, they breach tissue barriers, probably by proteolysis. The previous findings that spirochetes bind serum-derived plasminogen and that plasmin favors spirochetal invasiveness and infectivity suggested a role for plasmin in the pathogenicity of B. burgdorferi. Binding of plasminogen to spirochetes and activation into plasmin is favored in a microenvironment that is rich in plasminogen and plasminogen activators. Plasminogen is abundant in plasma and interstitial fluids, and it is increased in inflammatory exudates. Since B. burgdorferi does not express endogenous plasminogen activators, the conversion of spirochete-bound plasminogen depends on host-derived plasminogen activators. In this report, we show that both intact B. burgdorferi organisms and its recombinant outer surface lipoprotein A induce human monocytes to express and secrete urokinase-type plasminogen activator in its zymogen form (pro-uPA). Moreover, we demonstrate that the presence of B. burgdorferi accelerates the interaction between (pro-)uPA and plasmin(ogen), leading to spirochete-bound plasmin. In a pro-uPA-serum mixture, spirochete-bound plasmin activity is generated. Taken together, the data suggest that B. burgdorferi may induce pro-uPA in a monocyte-containing inflammatory site and that the spirochetal surface provides an appropriate milieu for subsequent interactions between (pro-)uPA and plasmin(ogen), which result in spirochete-bound plasmin even in the presence of inhibitors for plasminogen activators and plasmin.

Borrelia burgdorferi Group↗
PubMed1996

Plasminogen activation in bullous pemphigoid immunohistology reveals urokinase type plasminogen activator, its receptor and plasminogen activator inhibitor type-2 in lesional epidermis.

Keratinocytes synthesize urokinase-type plasminogen activator (uPA) and a specific cell surface receptor for uPA (uPA-R, CD 87). Plasminogen is present in plasma and interstitial fluids from where it is bound to cell surfaces via plasmin(ogen) binding sites. uPA binds to the uPA-R in an autocrine manner and activates cell-bound plasminogen: a mechanism, which provides plasmin for pericellular proteolysis. Cell-bound uPA is regulated by plasminogen activator inhibitor type-1 (PAI-1) or type-2 (PAI-2). Bullous pemphigoid is an autoimmune inflammatory skin disease characterized by subepidermal blisters. Although circumstantial evidence suggested plasminogen activation in lesional epidermis of bullous pemphigoid, immunohistological data on the type of plasminogen activators, on the uPA-receptor or the type of plasminogen activator inhibitors in the lesions of bullous pemphigoid are lacking so far. To obtain this information we have performed the present immunohistological study. The presence of uPA and its receptor as well as PAI-2 was disclosed in epidermal keratinocytes in the roof of the subepidermal blisters. Moreover, keratinocytes at the bottom of the blister, which most likely represent keratinocytes during reepithelialization were stained. Co-localization was found for uPA and its receptor, uPA and plasmin(ogen) as well as for uPA and PAI-2. In non-lesional epidermis of bullous pemphigoid only PAI-2 was found. We propose that the expression of uPA and uPA-R, as well as the upregulation of PAI-2 in keratinocytes of lesional epidermis is part of the repair and reepithelialization process following lesion formation, i.e. epidermo-dermal dyshesion, in bullous pemphigoid.

Aged↗
PubMed1996

Plasminogen activator inhibitor type-2 in the lesional epidermis of lupus erythematosus.

Under certain pathophysiological conditions epidermal keratinocytes produce urokinase-type plasminogen activator (uPA) or tissue-type PA (tPA). These PAs are subject to regulation by PA inhibitors (PAI), including PAI type-2 (PAI-2). In the normal epidermis, PAI-2 is present in the differentiating suprabasal layers, albeit in the apparent absence of PAs. It has, therefore, been suggested that PAI-2 plays a role in epidermal differentiation not linked to its ability to inhibit PAs. In line with this hypothesis, we have studied, by immunohistochemistry, the distribution of PAI-2, uPA and tPA in the normal and in the lesional epidermis of patients with lupus erythematosus (LE), a disease in which epidermal differentiation is disturbed. The PAI-2 antigen was detectable in the normal epidermis and in the lesional epidermis of LE. In the normal epidermis, the PAI-2 antigen was most pronounced in the granular layer. In the hyperkeratotic epidermal lesions of LE, the PAI-2 antigen was increased. In normal and lesional skin, PAI-2 was distributed along the cell periphery, indicating its association with the cornified envelope. Neither uPA nor tPA was detectable in normal or lesional epidermis. Our findings show that PAI-2 is a major type of PAI in normal epidermis and in the lesional epidermis of LE, and that increased epidermal PAI-2 is observed in a disease which is not associated with an increase in epidermal PAs. The data support the hypothesis that epidermal PAI-2 may have other functions than the regulation of PA activity.

Humans↗
PubMed1995

Plasminogen activator inhibitor-2: prognostic relevance in 1012 patients with primary breast cancer.

The antigen levels of urokinase-type plasminogen activator (uPA) and its inhibitor plasminogen activator inhibitor (PAI) 1, as detected in tumor extracts by ELISA, have been reported to be correlated with a poor prognosis in primary breast cancer. In the present study we have characterized a novel PAI-2-specific ELISA, designed to measure PAI-2 antigen levels in tumor cytosols. We determined PAI-2 antigen levels along with those of uPA and PAI-1 in 1012 routinely prepared tumor cytosols of patients with primary breast cancer (median follow-up, 71 months). In the overall population there was no significant association between the level of PAI-2 and prognosis, while in tumors with high uPA values, PAI-2 (test for trend) was associated with a prolonged relapse-free survival, metastasis-free survival, and overall survival (for all analyses, P < 0.02). In Cox's multivariate analysis for relapse-free survival, metastasis-free survival, and overall survival in tumors with high uPA values (including patient's age, menopausal status, lymph node status, tumor size, estrogen and progesterone receptor status, uPA, and PAI-1), PAI-2 either dichotomized or, as a continuous variable, was independently associated with a favorable relapse-free survival, metastasis-free survival, and overall survival. We conclude that the PAI-2-specific ELISA described herein is well suited for the measurement of PAI-2 levels in cytosols routinely prepared for analysis of steroid hormone receptors. We speculate that PAI-2 may serve as an inhibitor for uPA in human primary breast cancers.

Adult↗