Effects of glycolic acid on desquamation-regulating proteinases in human stratum corneum.

In order to investigate the mechanism of glycolic acid (GA) function in human stratum corneum, we monitored changes in cathepsin D-like (CD) and chymotrypsin-like (SCCE) proteinases for 3 weeks following topical GA application (50% w/v, pH 0.9) for 30 min to human skin. In the early phase, weakened stratum corneum cohesion in the lower layers was observed on day 2 and the amount of active CD in the upper layer of the stratum corneum was significantly decreased from 30 min until day 2, whereas that in the lower layer remained normal.

Cathepsin D, but not cathepsin E, degrades desmosomes during epidermal desquamation.

Background: We previously reported that an ambient aspartic proteinase is crucial to desquamation of the stratum corneum at pH 5. Identification of this aspartic proteinase by using enzyme inhibitors suggested it to be cathepsin D, although we could not exclude cathepsin E.

Objectives: To determine the identity of this aspartic proteinase and its distribution within the stratum corneum.

Differentiation-dependent expression of signal transducers and activators of transcription (STATs) might modify responses to growth factors in the cancers of the head and neck.

Overexpression of the epidermal growth factor receptor (EGFR) in the cancers of the head and neck is well demonstrated. In addition, copy numbers of the EGFR mRNA were significantly higher in poorly differentiated tumors than in tumors that had a differentiated phenotype. Studies by others also showed that the constitutively activated signal transducer and activator of transcription-3 (STAT3), but not STAT1, is required for EGFR-mediated cell growth.

Zinc-alpha(2)-glycoprotein hinders cell proliferation and reduces cdc2 expression.

Zinc-alpha(2)-glycoprotein (Znalpha(2)gp) is widely distributed in body fluids and epithelia. Its expression in stratified epithelia increases with differentiation. We previously showed that Zn alpha(2)gp has ribonuclease activity, and that squamous tumor cells grown on a matrix of Znalpha(2)gp were growth-inhibited.

Correlation between pretreatment levels of interferon response genes and clinical responses to an immune response modifier (Imiquimod) in genital warts.

Imiquimod (IQ) has been successfully used in treatment of genital warts. In clinical settings, patients responded well but wart reduction rates varied. Our aim was to find a correlation between clinical responses and pretreatment (constitutive) levels of genes that might be involved in the molecular action of IQ.

Response of keratinocytes from normal and psoriatic epidermis to interferon-gamma differs in the expression of zinc-alpha(2)-glycoprotein and cathepsin D.

Psoriasis is a T cell-mediated inflammatory disease characterized by hyperproliferation and by aberrant differentiation. We found cathepsin D and zinc-alpha(2)-glycoprotein, two catalytic enzymes associated with apoptosis and desquamation, to be present in the stratum corneum of the normal epidermis but absent from the psoriatic plaque. Psoriasis is characterized by an altered response to interferon-gamma (IFN-gamma), including the induction of apoptosis in normal but not in psoriatic keratinocytes, often with opposite effects on gene expression of suprabasal proteins.

Differentiation-dependent expression of growth regulatory cytokines and their receptors in squamous cell carcinomas of the head and neck.

Cytokines, such as IFN-alpha and TNF-alpha are capable of affecting keratinocyte proliferation in the microenvironment of the tumor. Their elevated expression along with high levels of their receptor mRNAs was determined by a semiquantitative reverse transcription- polymerase chain reaction (RT-PCR) method in biopsies of head and neck squamous cell carcinomas that were established as histologically well or moderately differentiated. In contrast, tumors with poor differentiation exhibited low levels of these growth suppressive factors, although levels of their receptors were elevated.

Role of endogenous cathepsin D-like and chymotrypsin-like proteolysis in human epidermal desquamation.

Even though the skin surface is acidic (about pH 5), most in vitro studies on desquamation have been performed at alkaline pH. We demonstrate that the standard in vitro model system, which achieves squame shedding upon incubation of plantar stratum corneum for 1 day in an alkaline buffer that must include a chelating agent, can be extended to a more realistic model in which the incubation is for 4 days, at varying pHs from 5 to 8, without exogenous chelators. Desmoglein I from stratum corneum was degraded by the squames shed at pH 5 as well as at pH 8.

Characterization of zinc-alpha(2)-glycoprotein as a cell adhesion molecule that inhibits the proliferation of an oral tumor cell line.

Zn-alpha(2)-glycoprotein (Znalpha(2)gp) is a soluble protein widely distributed in body fluids and glandular epithelia. We have found it to be expressed in stratified epithelia as well. Znalpha(2)gp is clinically correlated with differentiation in various epithelial tumors, including oral and epidermal tumors.

Zinc-alpha2-glycoprotein expression as a marker of differentiation in human oral tumors.

Zinc-alpha2-glycoprotein (Znalpha2gp) is a soluble major histocompatibility complex homolog widespread in body fluids and in glandular epithelia; the authors recently demonstrated its presence in stratified epithelia. Znalpha2gp has been associated with tumor differentiation in breast cancers and other carcinomas. We compare here its gene expression in histopathologically graded oral squamous cell carcinomas and in their perilesional normals.

Local inflammation may influence oral tumor cell differentiation.

The mRNA levels of keratin K13, involucrin, protein kinase C alpha and epsilon, and interferon-gamma and its receptors were examined in biopsies from human oral squamous cell carcinomas. Expression of all the genes was elevated in the histologically more differentiated tumors, but it was at or below normal (perilesional control) levels in the poorly differentiated ones. For the same set of biopsies, we had previously shown that the well differentiated tumors expressed higher levels of T cell markers.

Cytokine modulation of human corneal epithelial cell ICAM-1 (CD54) expression.

To determine whether pro-inflammatory cytokines modulate intercellular adhesion molecule-1 (ICAM-1; CD54) expression on cultured primary human corneal epithelial cells (HCEs), confluent HCEs were treated with various concentrations of interferon-gamma(IFN-gamma), interleukin-1alpha(IL-1alpha), IL-1beta, IL-4, tumor necrosis factor-alpha (TNF-alpha), or combinations over time. ICAM-1 expression was measured by flow cytometry and/or a cell-based ELISA using a monoclonal mouse anti-human CD54 antibody. The apparent MW of ICAM-1 protein was determined by immunoprecipitation of biotinylated HCEs.

Isoforms of cathepsin D and human epidermal differentiation.

Cathepsin D is an ubiquitously expressed lysosomal aspartic proteinase, with well-determined structural and chemical properties but a less clearly defined biological role. In stratified epithelia, the chronology of cathepsin D activation and degradation can be connected with stages of cellular differentiation. We partially purified cathepsin D from human epidermis and from separated stratum corneum by standard biochemical procedures, monitored by SDS-PAGE and Western blotting, and verified its identity as to molecular mass, pH optimum, N-terminal sequencing, reactivity with the specific antibody, inhibition by pepstatin A, and specific enzyme activity.

Differentiation and cathepsin D expression in human oral tumors.

Objectives/hypothesis: This study aimed to ascertain whether cathepsin D expression could be related to the stage of differentiation of oral tumors.

Study Design: Human oral biopsies of 10 squamous cell carcinomas and of the corresponding perilesional normal tissues were used. The tumors had all been clinically graded as advanced stage but nonmetastatic; five were classified histopathologically as poorly differentiated.

Induction by interferon-gamma of its receptor varies with epithelial differentiation and cell type.

Normal keratinocytes from epidermis and from buccal mucosa were cultured to confluence in three media with graded differentiation potential and treated with interferon-gamma (IFN-gamma). RT-PCR was used to measure the gene expression of the IFN-gamma receptor (IFNGR-1), as well as the immunomodulator HLA-DR and two enzymes of the 2-5 A pathway. We have previously reported results for a number of structural and regulatory genes in the same system (and include here involucrin for comparison).

Zinc-alpha 2-glycoprotein has ribonuclease activity.

Zinc-alpha 2-glycoprotein (Zn alpha 2gp) is widely distributed in body fluids and in various epithelia; its gene has been completely sequenced, but its function has long remained elusive. We have found that Zn alpha 2gp has RNase activity, comparable to onconase but two orders of magnitude less than RNase A. The RNase activity of Zn alpha 2gp is characterized by maxima in pH at 7.

Proteasomal RNase activity in human epidermis.

The proteasome is a cytoplasmic high-molecular-weight structure composed of several smaller protein and RNA subunits. It has been associated with non-lysosomal pathways of intracellular degradation, expressing multicatalytic proteinase activities and specific RNase activity. By standard methods, we have isolated andpartially purified proteasomes from human epidermis.

Differentiation markers in oral carcinoma cell lines and tumors.

Cell lines are useful as models if they retain the relevant characteristics of the tissue of origin. We compared two human squamous carcinoma cell lines derived from tumors of the tongue that vary in their extent of differentiation, with human biopsies of carcinomas of the tongue that were either poorly or well-differentiated. The mRNA levels of suprabasal cell proteins (keratin K13, involucrin, transglutaminase) and of protein kinase C (PKC) isozymes were measured by RT-PCR.

Tumor differentiation-dependent local immunity in human head and neck cancers.

Distribution of markers of local cell-mediated immunity was examined in oral tumors exhibiting different histological stages of differentiation. Using a RT-PCR-based semiquantitative technique we determined levels of Langerhans cells, CD4- and CD8-positive T-cells, macrophages/NK cells, beta2-microglobulin and IFN-gamma mRNAs from tissue biopsies. A positive correlation was found between levels of these immunological markers and the tumor differentiation stage.

Desquamin is an epidermal ribonuclease.

Desquamin is a glycoprotein that we have isolated from the upper granular layer and the stratum corneum of human epidermis; it is not ordinarily expressed in submerged cultures, whose terminal differentiation stops short of formation of these layers. The exogenous addition of desquamin to human cultured keratinocytes extended their maturation, and hematoxylin staining indicated a loss of cell nuclei. For confirmation, cultured cells were lysed in situ, and the nuclei were incubated with desquamin for several days, then stained with hematoxylin.

Modulation by interferon-gamma of zinc-alpha 2-glycoprotein gene expression in human epithelial cell lines.

Zinc-alpha 2-glycoprotein has been detected in most body fluids, and its antibody labels the corresponding glandular epithelia. We have also detected it in human stratified epithelia (epidermis and buccal mucosa). In this study, the mRNA levels of zinc-alpha 2-glycoprotein were found to be about twice as high in epithelial cells of mucosal origin (whether normal primaries or neoplastic cell lines) as in epidermoid cells (normal epidermal primary cultures, an immortalized but non-tumorigenic epidermal cell line, and neoplastic vulvar and cervical cell lines).

Detection and cloning of epidermal zinc-alpha 2-glycoprotein cDNA and expression in normal human skin and in tumors.

Zinc-alpha 2-glycoprotein (Zn alpha 2gp) is almost ubiquitous in body fluids, and its antibody labels the corresponding secretory epithelia. We have found that Zn alpha 2gp is also expressed in human epidermis. We cloned the Zn alpha 2gp cDNA by screening our cDNA library, derived from epidermal keratinocytes, with a probe for prostate Zn alpha 2gp.

Gene expression of zinc-alpha 2-glycoprotein in normal human epidermal and buccal epithelia.

Zinc-alpha 2-glycoprotein (Zn alpha 2gp) is almost ubiquitous in body fluids. We have found it to be also present in stratified epithelia. We compare its mRNA expression in cells from human epidermis and buccal mucosa cultured in media of graded differentiation potential (attained by varying calcium ion concentration and adding serum).

Interferons alpha, beta and gamma induce different patterns of gene expression in cultured human epidermal keratinocytes.

Differences in the effects on confluent epidermal keratinocytes of treatment with interferons (IFNs) alpha, beta, and gamma were observed in their modulation of the mRNA levels of representative structural and functional cellular proteins. Comparisons of the responses in culture media with varying cellular maturation potential indicated the dependence of the modulation on the stage of differentiation. Differentiation was correlated with upregulation of all the genes by interferon gamma, but this effect was not seen with the other interferons.