Biomedical subjects

M Liebert

Publications and source records attributed to M Liebert.

At least 37 records · Page 2Linked to original sources

PubMed1996

Characterization of the DD23 tumor-associated antigen for bladder cancer detection and recurrence monitoring. Marker Network for Bladder Cancer.

Bladder cancer detection, monitoring, and prevention represent major problems that could be addressed with sensitive and specific biomarkers. The antigen recognized by the DD23 antibody, previously developed against a tumor-related antigen, was partially biochemically characterized, and its sensitivity and specificity in cancer detection and recurrence monitoring was evaluated. Quantitative fluorescence image analysis was used to quantify antigen content in exfoliated urothelial cells in a cross-section of patients with bladder cancers of all grades and stages and control populations. The antigen was found in tumor cells as well as normal-appearing urothelial cells, suggesting it represents a marker induced by the altered growth factor environment of a cancer-containing bladder. When used as a quantitative marker, the sensitivity for bladder cancer detection was 85%, and the specificity was 95%. No significant difference was seen between symptomatic and asymptomatic control populations, including patients with previous bladder cancers in the absence of a recurrence. In bladder cancer recurrence monitoring, results were consistently negative until just before detection of a recurrence. The biomarker reflects a "field effect" that occurs very late in tumorigenesis and seems to represent events common to most cancers involving the genitourinary tract. Western blotting showed the antibody recognized a dimeric protein. DD23 quantification in single cells may be particularly useful in targeting cystoscopic intervention for recurrence monitoring and, because of its high specificity, could be a tool for bladder cancer screening in high-risk groups.

Antibodies, Monoclonal↗

PubMed1996

G-actin as a risk factor and modulatable endpoint for cancer chemoprevention trials.

Because tumorigenesis is an ongoing process, biomarkers can be used to identify individuals at risk for bladder cancer, and treatment of those at risk to prevent or slow further progression could be an effective means of cancer control given accurate individual risk assessment. Tumorigenesis proceeds through a series of defined phenotypic changes, including those in genetically altered cells destined to become cancer as well as in surrounding normal cells responding to the altered cytokine environment. A panel of biomarkers for the changes can provide a useful system for individual risk assessment in cancer patients and in individuals exposed to carcinogens. The use of such markers can increase the specificity of chemoprevention trials by targeting therapy to patients likely to respond, and thereby markedly reduce the costs of the trials. Previous studies in our laboratories showed the cytoskeletal proteins G- and F-actin reflect differentiation-related changes in cells undergoing tumorigenesis and in adjacent "field" cells, and a pattern of low F-actin and high G-actin is indicative of increased risk. Actin changes may be a common feature in genetic and epigenetic carcinogenic mechanisms. In a group of over 1600 workers exposed to benzidine, G-actin correlated with exposure, establishing it as an early marker of effect. In another study, a profile of biomarkers was monitored in patients who underwent transurethral resection of bladder tumor (TURBT) and received Bacillus Calmette Guerin (BCG) and/or DMSO. The primary objective was to determine how the defined biomarkers expressed in the tumor and the field correlate with clinical response and recurrence. DMSO, known to modulate G-actin in vitro, was used as an agent. Results strongly support the hypothesis that cytosolic G-actin levels measured by quantitative fluorescence image analysis (QFIA) can be an important intermediate endpoint marker for chemoprevention and that the p300 (M344) and DNA ploidy markers identify a high-risk group that requires more aggressive therapy and recurrence monitoring. Further research with other markers has shown that DD23 and nuclear actin, both of which identify late, specific changes, may increase the battery of useful markers. Taken together these studies show how biomarkers are employed to study individuals at risk, aid in the selection of chemopreventive compounds and assist in the understanding of the pathogenesis of malignancy.

Actins↗

PubMed1995

Growth factors in bladder cancer.

This article is an overview of peptide growth factors, their receptors, and signal-transduction pathways that play a role in bladder cancer. Included in this overview are epidermal growth factor receptor and its ligands, erbB2, fibroblast growth factors, insulin-like growth factor, the transferrin receptor, and transforming growth factor-beta. The use of growth factors or growth factor receptors for diagnostic and therapeutic interventions is also discussed.

Animals↗

PubMed1995

DNA and PCNA content of renal cell carcinoma and prognosis.

Robson stage I or II renal carcinomas have a heterogenous clinical outcome. A variety of morphologic features and other parameters have been proposed as prognostically useful. The authors measured the DNA content and PCNA expression of 47 stage I or II renal carcinomas, and assessed the association of these measures with pathologic stage, nuclear grade, and clinical course. Approximately 56% of stage I neoplasms and 40% of stage II neoplasms were diploid. Five of 9 neoplasms in which multiple samples were analyzed manifested both aneuploid and diploid regions. PCNA expression was noted in 20 of 32 stage I neoplasms and 9 of 15 stage II neoplasms, and varied greatly among the neoplasms. Neither ploidy nor PCNA expression is associated with clinical behavior in these data. These results are different from some of those previously reported by others. These discrepancies are likely to be due to differences in methodology and the fact that there were only eight cases of metastatic disease. No single parameter will serve as a completely accurate prognostic indicator. Most individuals with these neoplasms will do well because all of the tumor has been excised.

Carcinoma, Renal Cell↗

PubMed1995

Diminished expression of the extracellular domain of bullous pemphigoid antigen 2 (BPAG2) in the epidermal basement membrane of patients with generalized atrophic benign epidermolysis bullosa.

Generalized atrophic benign epidermolysis bullosa (GABEB) is a nonlethal form of junctional epidermolysis bullosa characterized by generalized skin and mucosal blisters that heal with atrophy; other features include alopecia, nail dystrophy, large melanocytic nevi, and autosomal recessive inheritance. The specific aim of this study was to identify an abnormality in epidermal basement membrane adhesion molecules in well characterized GABEB patients that would explain why these subjects' epidermis separates from their epidermal basement membrane. Cryostat sections of nonlesional skin from 8 GABEB patients in 5 different families as well as skin from normal volunteers (controls) were studied by indirect immunofluorescence microscopy using rabbit antiserum directed against a BPAG1 fusion protein or monoclonal antibodies directed against the extracellular domain of BPAG2 (HD18 and 233), epiligrin (P1E1), laminin 5 (GB3), types IV and VII collagen, or integrin subunits alpha 2, alpha 3, beta 1, alpha 6, or beta 4. In these studies, monoclonal antibodies HD18 and 233 showed no reactivity and diminished reactivity, respectively, to the epidermal BM of all GABEB patients. Interestingly, in one patient, the absent or diminished reactivities of monoclonal anti-BPAG2 antibodies were limited to well demarcated portions of an otherwise intact epidermal basement membrane. Moreover, BPAG1, epiligrin, laminin 5, types IV and VII collagen, and all integrin subunits under study were expressed in the same manner in both GABEB and normal human skin. These findings identify an abnormality in the extracellular domain of BPAG2 in the skin of GABEB patients. BPAG2 (type XVII collagen) is a transmembrane, hemidesmosome-associated molecule whose extracellular domain resides at the exact level where blisters develop in the skin of patients with GABEB.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Expression of cell surface adhesion molecules on the epithelium of Organ-cultured skin.

Human neonatal foreskin was maintained in organ culture under serum-free, growth-factor-free conditions or in the presence of a combination of growth factors that are known to stimulate keratinocyte proliferation in monolayer culture. Previously, we have shown that normal histology is maintained when growth-factor-free conditions are used but that the epithelium undergoes a hyperproliferative response and invades the dermis in the presence of the exogenous growth factors. In the present study, the tissue was examined by immunofluorescence for expression of alpha 6 and beta 4 integrin components and for E-cadherin. Under growth factor-free conditions, both alpha 6 and beta 4 were localized to the basal surface of epithelial cells in contact with the basement membrane. In contrast, both epitopes were diffusely distributed throughout the basal epithelium in the presence of growth factors. E-cadherin expression was rapidly lost from the tissue in organ culture. This occurred in both the presence and absence of exogenous growth factors. On the basis of these immunochemical results, we conclude that the same changes in alpha 6 and beta 4 expression that are seen in rapidly proliferating keratinocytes and squamous epithelial cell tumors can be seen in the epidermis of organ-cultured skin when it is maintained in the presence of epithelial growth factors. The observed loss of E-cadherin, in contrast, appears to be a consequence of incubation in organ culture.

Antigens, CD↗

PubMed1994

Decreased connexin expression and intercellular communication in human bladder cancer cells.

Connexins make up a gene family encoding proteins that form intercellular channels known as gap junctions. Decreases in connexin expression and loss of intercellular communication have been associated with the malignant phenotype in some animal and human cells. The expression of connexin 26 and 43 mRNA was evaluated in cultured normal and malignant human urothelial cells. The normal urothelial cells were shown by Northern analysis to express both connexins. Increased confluence of the cultured normal human urothelial cells was associated with upregulation of connexin 26 mRNA. Connexin 26 mRNA expression was decreased in the bladder cancer cells. Using a human connexin 26 complementary DNA probe, nuclear run-on assays demonstrated that the decreased expression in the cancer cells was due to a failure of transcription. Southern blot analysis did not reveal any alterations in the genomic DNA. Assessment of gap junction function by scrape loading of lucifer yellow demonstrated dye transfer in normal urothelial cells but not in bladder cancer cells. Downregulation of connexin 26 mRNA was associated with functional loss of intercellular communication in the human bladder cancer cells. Connexin 43 expression varied considerably in the bladder cancer cell lines and did not correlate with dye transfer of lucifer yellow. These data suggest that alterations in the regulation of connexin 26 expression are associated with and may contribute to the malignant phenotype in bladder cancer.

Cell Communication↗

PubMed1994

Immunologic detection of the cellular receptor for urokinase plasminogen activator.

The cellular receptor for urokinase plasminogen activator (uPA-R) is a monomeric phosphatidylinositol-linked glycoprotein (gp40-65) that may contribute to the invasive capacity of tumor and inflammatory cells by focusing the activity of urokinase (uPA) in converting plasminogen to plasmin, a serine protease capable of degrading extracellular matrix proteins. The further characterization of uPA-R has been facilitated by our recent development of a monoclonal antibody, anti-Mo3f, specific for uPA-R. This mAb bound to uPA-R expressed by phorbol myristate acetate-stimulated U-937 cells and by NIH-3T3 cells permanently transfected with uPA-R cDNA. In competitive binding assays, anti-Mo3f inhibited the binding of fluorescein-conjugated uPA ligand to uPA-R expressed by U-937 cells and uPA-R transfectants; conversely, preexposure of cells to saturating quantities of exogenous uPA partially blocked the subsequent binding of anti-Mo3f mAb to uPA-R. Anti-Mo3f mAb was employed as the capture reagent in an ELISA for the quantitation of soluble forms of uPA-R (derived from U-937 cells and recombinant uPA-R) which had a sensitivity of approximately 4-12 ng/ml. Anti-Mo3f mAb was also applied as a serologic probe for the detection of uPA-R expressed by human tumor tissues. By immunoperoxidase staining, anti-Mo3f demonstrated positive tumor cell staining in 4 of 16 breast and 7 of 31 prostate carcinomas in formalin-fixed, paraffin-embedded specimens. These data indicate that the anti-Mo3f mAb detects an epitope proximate to or within the ligand binding domain (domain 1) of uPA-R and may be useful as a tool for the serologic detection of uPA-R in soluble form or associated with human tumors.

3T3 Cells↗

PubMed1994

P-glycoprotein expression in bladder cancer.

Multi-drug resistance is a phenomenon by which tumor cells express resistance to a variety of chemically unrelated chemotherapeutic drugs. The classical form of multi-drug resistance is mediated through the expression of P-glycoprotein, which acts as an energy dependent drug efflux pump. P-glycoprotein expression was evaluated in 29 cystectomy specimens from patients with bladder cancer with no prior exposure to chemotherapeutic drugs, and in bladder biopsies from 9 subjects before treatment with intravesical doxorubicin. Furthermore, the strategy of circumvention of P-glycoprotein-mediated resistance using the combination of doxorubicin and verapamil intravesically was tested in 5 patients. P-glycoprotein was expressed in 75% of the cystectomy specimens. In the doxorubicin treated patients no correlation was noted between P-glycoprotein expression on the initial tumors and subsequent response to doxorubicin. The pilot trial of verapamil and doxorubicin was well tolerated but did not suggest increased efficacy of this combination. P-glycoprotein can be expressed on bladder cancer cells without prior chemotherapy. The role of P-glycoprotein mediated multi-drug resistance in bladder cancer treatment failure remains to be defined.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1994

Loss of co-localization of alpha 6 beta 4 integrin and collagen VII in bladder cancer.

In normal epithelial cells, the alpha 6 beta 4 integrin co-localizes with the hemidesmosomal anchoring complex on the basolateral surface of basal cells. We studied the co-expression of alpha 6 beta 4 integrin with collagen VII, a component of the hemidesmosomal anchoring complex, in normal bladder tissues and in bladder cancers. In normal bladder, the alpha 6 beta 4 integrin co-localized with collagen VII at the junction of the basolateral surface of the basal urothelial cells and the lamina propria. In five of six noninvasive bladder cancers, the localization of collagen VII remained unchanged, found at the junction of the basal cells and the papillary connective tissue. However, in these tumors the alpha 6 beta 4 expression was not polarized and was expressed on suprabasal as well as basal cells. In invasive bladder cancers, the majority (25 of 30) showed either loss of alpha 6 beta 4 and/or collagen VII expression or showed a lack of co-localization of alpha 6 beta 4 and collagen VII. Our results show derangement of the co-localization of these two components of the hemidesmosomal anchoring complex is a consistent event in bladder cancer. Furthermore, the degree of derangement increases in invasive cancers. Loss of co-expression and co-localization of alpha 6 beta 4 and collagen VII may predispose cancer cells to local invasion and may facilitate metastasis as well.

Antigens, Neoplasm↗

PubMed1994

Expression of the VLA beta 1 integrin family in bladder cancer.

Integrins are a family of transmembrane heterodimers, many of which function as receptors for extracellular matrix molecules and play a role in adherence to and motility on matrix components. Because of these functions, integrins are suspected of participating in metastatic processes. We investigated the expression of beta 1 integrins in human bladder cancer cell lines and tissues. Expression of beta 1 integrins on cultured bladder cancer cell lines was evaluated by flow cytometry, of 8 cell lines tested, alpha 1 was found in 4, alpha 2 and alpha 3 in all 8, alpha 4 in 1, and alpha 5 in 3. These results were in sharp contrast to the expression detected by immunostaining tissues containing normal urothelium and low stage (noninvasive) and high stage (invasive) bladder cancers. All normal urothelial tissues tested expressed alpha 2 and alpha 3 and none expressed alpha 1, alpha 4, or alpha 5. Similarly, a majority (77%) of low stage (noninvasive) bladder cancers stained positively for alpha 3, whereas only 6 of 13 expressed alpha 2 and none expressed alpha 1, alpha 4, or alpha 5. Among invasive bladder cancers, alpha 1 was detected in 7%, alpha 2 in 24%, alpha 3 in 68%, alpha 5 in 10%, and alpha 4 was not found in any samples. These results indicate that integrin expression in cultured human bladder cancer cell lines does not represent expression observed in tissue samples and may reflect adaption to or selection during tissue culture conditions. A progressive loss of alpha 2 expression is seen from normal urothelial cells through invasive bladder cancers. This loss may contribute to an invasive phenotype by a loss of the cell-cell adherence function mediated by the alpha 2 beta 1 and alpha 3 beta 1 integrins.

Humans↗

PubMed1993

Blood group antigens and integrins as biomarkers in head and neck cancer: is aberrant tyrosine phosphorylation the cause of altered alpha 6 beta 4 integrin expression?

Head and neck cancer is a capricious disease that varies greatly in its clinical behavior. The development of biomarkers that can distinguish between biologically aggressive and indolent tumors has been a long term goal of our laboratories. Predictive markers applicable to biopsy specimens should facilitate clinical management through early identification of patients at greatest risk for early relapse or metastatic spread. Two prominent cell surface markers that we identified by raising monoclonal antibodies to squamous cell carcinomas are blood group antigens and the A9 antigen/alpha 6 beta 4 integrin. Both of these markers are abnormally displayed in squamous cancers of the head and neck and serve as indicators of early relapse. Loss of blood group antigen expression is a stronger single indicator than is overexpression of the alpha 6 beta 4 integrin. However, use of both markers together is a stronger predictive indicator than is either alone. We know little about the function of the blood group antigens in squamous cells except that the mature antigens are associated with differentiation. Similarly, the function of the alpha 6 beta 4 integrin is also not fully understood. Integrin alpha 6 beta 4 is thought to serve as an extracellular matrix receptor, but its ligand has not been confirmed. In resting epithelium, the alpha 6 beta 4 integrin is polarized to the basal aspect of the basal cell as a component of the hemidesmosome, the anchoring structures of the epithelia. This basal polarization is lost in migrating normal squamous cells and squamous carcinomas. Tyrosine phosphorylation of the beta 4 subunit is absent or greatly reduced in malignant cells and this may be a critical signal for subcellular localization of alpha 6 beta 4 and cell anchoring. On the basis of our current experimental results, we postulate that tyrosine phosphorylation of the beta 4 subunit is a reversible signal that regulates cell migration in normal and malignant cells, and may therefore be an important initial event in the metastatic cascade.

ABO Blood-Group System↗

PubMed1993

Evaluation of multiple drug resistance in human bladder cancer cell lines.

We evaluated multidrug resistance (MDR) in human bladder cancer cell lines UM-UC-2, UM-UC-6, UM-UC-9 and the UM-UC-6dox subline induced to doxorubicin resistance by in vitro doxorubicin exposure. We compared the profile of multidrug resistance in these cell lines with that of the UM-UC-3 human renal cancer cell line. Of these cell lines, UM-UC-2 was most sensitive to both doxorubicin and etoposide, while UM-UC-6, UM-UC-9 and UM-UC-3 showed 1.5-, 2.1-, and 5.4-fold more resistance to doxorubicin than UM-UC-2 cells. These cell lines were also more resistant to etoposide than UM-UC-2. Addition of verapamil at 10 microM. reduced the doxorubicin resistance in UM-UC-6 and UM-UC-6dox cells, but UM-UC-9 cells showed little change in doxorubicin sensitivity in the presence of verapamil. In a model of intravesical (short-term) treatment verapamil increased the doxorubicin sensitivity of UM-UC-6dox but not that of UM-UC-6 cells. This effect in UM-UC-6dox cells was enhanced by continuously treating with verapamil after doxorubicin had been removed. Western blot analysis with rabbit anti-human P-glycoprotein polyclonal antibody demonstrated a distinct increase in P-glycoprotein in the resistant cell lines as compared with UM-UC-2. P-glycoprotein expression was roughly proportional to the degree of resistance to both doxorubicin and etoposide, but did not always correlate with the effect of verapamil on decreasing doxorubicin resistance. These results suggest that multidrug resistance is an important phenomenon in bladder cancer and that more than one pathway of multidrug resistance may be present in human bladder cancer cell lines.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1993

Evidence for urothelial cell activation in interstitial cystitis.

Bladder biopsy samples from 17 interstitial cystitis patients and 20 controls were evaluated for urothelial cell activation using a panel of monoclonal antibodies to HLA-DR, intercellular adhesion molecule 1, interleukin 1 alpha and tumor necrosis factor alpha. Urothelial cells in the majority (13 of 16, 81%) of the biopsies from patients with interstitial cystitis showed increased expression of HLA-DR, while fewer samples were positive for intercellular adhesion molecule 1 (3 of 16, 19%), interleukin 1 alpha (2 of 17, 12%) or tumor necrosis factor alpha (1 of 15, 7%). No urothelial cell expression of intercellular adhesion molecule 1, interleukin 1 alpha or tumor necrosis factor alpha was detected in the controls, and only 1 of 20 control samples contained HLA-DR positive urothelial cells. These results suggest that an unusual type of cellular activation is present in interstitial cystitis. In vitro studies with cultured normal urothelial cells indicated that cells activated with gamma interferon and tumor necrosis factor alpha expressed intercellular adhesion molecule 1 and HLA-DR, although increases in intercellular adhesion molecule 1 expression occurred earlier. Urothelial cells in interstitial cystitis patients may be defective in ability to express intercellular adhesion molecule 1. Alternatively, the differential expression of HLA-DR and intercellular adhesion molecule 1 in interstitial cystitis specimens may represent a functional subset of interstitial cystitis or reflect different stages of the disease. Urothelial cell activation in interstitial cystitis may result in aberrant immune responses and immune activation within the bladder. Because HLA-DR can be detected in paraffin-embedded tissues, evaluation of urothelial cell HLA-DR expression, although not specific for interstitial cystitis, may become a useful tool in the pathological evaluation of biopsy tissues from patients with this disease.

Adult↗

PubMed1993

The monoclonal antibody BQ16 identifies the alpha 6 beta 4 integrin on bladder cancer.

Monoclonal antibody BQ16, raised against UM-UC-9, a human bladder cancer cell line, exhibited strong reactivity with most bladder carcinoma tissue samples and cell lines. In normal urothelium, BQ16 stained only the basal surface of urothelial cells at the junction with the lamina propria. BQ16 immunoprecipitated two protein bands of approximately 140 and 180 kDa (under non-reducing conditions), while on Western blots, BQ16 identified only the 140 kDa protein indicating that BQ16 binds to one chain of a dimeric protein complex. The dimeric structure, molecular size, and basal orientation of the BQ16 antigen prompted a comparison with the alpha 6 beta 4 integrin identified by monoclonal antibody UM-A9. In most tissues BQ16 and UM-A9 produced identical staining patterns. However, normal lymphocytes and certain bladder cancer cell lines were BQ16 positive but failed to react with UM-A9, indicating that the BQ16 and UM-A9 epitopes can be expressed independently. Pulse-chase immunoprecipitation experiments showed that the alpha 6 subunit was more prominent in early BQ16 precipitates and the beta 4 subunit was more prominent in early UM-A9 precipitates. Furthermore, preclearing cell extracts with the anti-alpha 6 antibody GoH3 removed all BQ16 reactivity and in UM-A9-negative, BQ16-positive cells, BQ16 precipitated the alpha 6 beta 1 complex. We conclude that BQ16 identifies the alpha 6 integrin subunit and that alpha 6 beta 4 integrin is strongly expressed in most bladder cancers.

Antibodies, Monoclonal↗

PubMed1992

Alterations in antigen expression in superficial bladder cancer.

Bladder cancer can be viewed as a prototype for carcinogen-induced neoplasia. This has been demonstrated experimentally in a variety of systems and in man through epidemiological studies of occupational exposure to putative carcinogens. The natural history of this neoplasm demonstrates recurrence in time and space, i.e., multifocal disease. This clinical scenario is precisely what would be expected if a target tissue, e.g., urothelium, was continuously exposed to a weak carcinogen. The detection of gross disease is clinically easy. However, the ability to intervene at early stages and monitor the success of this treatment requires the definition of early markers for bladder cancer. Integrins are a family of cell surface proteins, many of which function as receptors for extracellular matrix components. Normal epithelial cells express the integrin alpha 6 beta 4 in association with an anchoring structure known as the hemidesmosome. Urothelium expresses alpha 6 beta 4 on the basal layer of cells similar to the distribution seen on other epithelial surfaces. Even early stages of bladder cancer demonstrate an alteration in the expression of this integrin. Low-stage bladder tumors express alpha 6 beta 4 diffusely throughout the tumor as well as at the invading margin. Altered expression of alpha 6 beta 4 may be an early marker for bladder cancer which may contribute to an invasive phenotype. A second potential marker is detected by DD23, an IgG1 murine monoclonal antibody triggered by the immunization of a BALB/c mouse with a fresh human bladder tumor specimen. The antigen detected by DD23 is not present on normal urothelial specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Antibodies, Monoclonal↗

PubMed1992

Regulation of expression and phosphorylation of A9/alpha 6 beta 4 integrin in normal and neoplastic keratinocytes.

The A9 antigen is a basement membrane antigen of normal squamous epithelial cells that is strongly expressed in many squamous carcinomas. High expression of this antigen is associated with early relapse in squamous cell carcinomas of the head and neck. We now know that the A9 antigen is structurally, immunologically, and functionally similar to the alpha 6 beta 4 integrin that has been shown to be linked to metastatic behavior in murine tumor models. The alpha 6 and beta 4 genes have been cloned and sequenced, and a model has been constructed from the deduced amino acid composition. In this study we present a hypothetical model and use it to design experiments to assess the factors that influence the expression of the A9/alpha 6 beta 4 integrin in normal and malignant keratinocytes. High calcium induces down regulation of A9/alpha 6 beta 4 antigen in normal but not malignant keratinocytes within 24 hours. Although calcium can down-regulate beta 4 message in tumor cells in the absence of epidermal growth factor (EGF), transcription of beta 4 increased in the tumor cells under the conditions we used for assessing antigen expression (calcium plus EGF). Retinoic acid also stimulated transcription of beta 4 in tumor cells, but this was partially inhibited by the presence of high calcium. Phosphorylation of the beta 4 chain was stimulated by epidermal growth factor and calcium in normal keratinocytes, but in the malignant cells phosphorylation was constant regardless of the culture conditions. Our results indicate that high expression of the alpha 6 beta 4 integrin is associated with conditions that favor migration and undifferentiated proliferation of normal keratinocytes and that malignant keratinocytes differ from normal keratinocytes by constitutive phosphorylation of beta 4 and by failure to downregulate beta 4 transcription in response to calcium in the presence of EGF.

Antigens, Neoplasm↗

PubMed1992

Cytokine-induced gene expression of interleukin-8 in human transitional cell carcinomas and renal cell carcinomas.

Chemotactic cytokines play a critical role in recruiting leukocytes to sites of tissue injury. Interleukin-8 (IL-8) is a chemotactic cytokine secreted by a variety of cells (eg, monocytes, endothelial cells, fibroblasts) during the inflammatory response. In this report, the authors demonstrate that human transitional cell carcinomas and renal cell carcinomas have the capacity to elaborate IL-8 in response to the inflammatory mediators IL-1 beta and tumor necrosis factor (TNF)-alpha. All cell lines expressed high levels of IL-8 mRNA on stimulation with either IL-1 beta or TNF-alpha, but not lipopolysaccharide; one expressed the gene constitutively. The authors selected one transitional cell carcinoma cell line (UM-UC-9) and one renal cell carcinoma cell line (UM-RC-5) for further study. Both displayed a time- and dose-dependent increase in steady-state levels of IL-8 mRNA in response to IL-1 beta and TNF-alpha. Specific mRNA was detectable by 1 hour after stimulation. Secretion of antigenic IL-8 measured by enzyme-linked immunosorbent assay into culture supernatants reflected the kinetics of mRNA expression. Because heat-inactivated TNF-alpha failed to induce synthesis of IL-8 mRNA, and cycloheximide augmented TNF-alpha-induced synthesis, IL-8 expression appears to be a stimulus-specific primary induction phenomenon. As with other inflammatory mediators whose mRNA contains a 3' AU-rich sequence (eg, IL-2, TNF-alpha), the half-life of IL-8 mRNA was short, less than 1 hour. Our data suggest that secretion of IL-8 by malignant cells may partly account for the inflammatory infiltrates associated with some malignant neoplasms.

Base Sequence↗