Basally located epithelial cell surface component identified by a novel monoclonal antibody technique

Abnormal expression of epiligrin and alpha 6 beta 4 integrin in basal cell carcinoma

BACKGROUND

Basal cell carcinoma is characterized by local invasion, and only rarely metastasizes. The role of the containing basement membrane (BM) in this tumor is unclear. Several BM components have been shown to be absent or significantly reduced in BM surrounding infiltrating tumor.

OBJECTIVE

The purpose of this study is to examine the expression of epiligrin, a BM-associated glycoprotein, and the integrin chains alpha 3, alpha 6, beta 1, and beta 4 in the basement membranes surrounding basal cell carcinoma.

METHODS

Samples were obtained from 20 patients with basal cell carcinomas and subjected to a standard avidin biotin complex/alkaline phosphatase immunohistochemical technique using a panel of antibodies.

RESULTS

There was a consistent abnormality of expression of epiligrin, alpha 6, and beta 4.

CONCLUSION

We propose that reduced expression of epiligrin is involved in the pathogenesis of the local invasion by tumor and that an altered integrin ratio in basal cell carcinoma enhances tumor spread.

Abnormal expression of integrin alpha 6 beta 4 in cervical intraepithelial neoplasia

We have used subunit-specific monoclonal antibodies (MAbs) and immunohistochemistry to examine the distribution of integrin alpha 6 beta 4 in normal ectocervical epithelium and various grades of cervical intraepithelial neoplasia (CIN). Antibodies were first characterised by immunoprecipitation from two surface-labelled tumour cell lines. Monoclonal antibody G71 was found to precipitate integrin beta 4 from BeWo but not T47D cells, while other anti-beta 4 antibodies precipitated beta 4 from both cell lines. Both G71 and an antiserum to the C-terminal peptide of beta 4 precipitated free beta 4 from surface-iodinated BeWo cells. Neither antibody recognised truncated beta 4 chains observed at approximately 160 kDa. These data suggest that different isoforms of beta 4 are expressed in different tumour cell lines, and that there may be a pool of beta 4 at the cell surface that is not complexed to alpha 6. In normal cervix, both the alpha 6 and beta 4 subunits occur at the basal surface of the basal cell layer. In CIN, the distribution is markedly altered, with strong expression of alpha 6 and beta 4 in the upper cell layers of the ectocervical epithelium. All 40 cases of CIN that were studied exhibited this alteration. Furthermore, the extent of extrabasal staining appeared to correspond with the grade of CIN. The form of integrin beta 4 recognised by antibody G71 also appears in the upper cell layers in CIN, but it shows a more restricted distribution than the normal isoform.

Antigenic expression of integrin alpha 6 beta 4 in junctional epidermolysis bullosa

Integrin alpha 6 beta 4 is a major component of hemidesmosomes, considered to play a central role in the adhesion of basal epidermal cells to the underlying dermis. It is therefore of considerable interest in the study of the aetiology of inherited blistering disorders. We have examined the immunohistochemical characteristics of skin from 16 patients with epidermolysis bullosa using two antibodies directed against epitopes on the beta 4 subunit of alpha beta 4 integrin (G71, 3E1), one antibody directed against an epitope on the alpha 6 subunit (GoH3), GB3 an antibody for nicein, and LH7.2, an anticollagen type VII antibody. All 10 patients with junctional epidermolysis bullosa showed markedly reduced or no immunoreactivity with G71. These patients included two with GB3-positive junctional epidermolysis bullosa associated with pyloric atresia, and four with other subtypes. By contrast, five patients with dystrophic epidermolysis bullosa and one patient with epidermolysis bullosa simplex showed normal immunoreactivity with G71. In this study, G71 is shown to have a high specificity and sensitivity for the diagnosis of junctional epidermolysis bullosa. Immunoreactivity with 3E1 and GoH3 was normal in most patients, consistent with published reports showing normal immunoreactivity with other beta 4 and alpha 6 subunit antibodies. The data suggest a modification of the beta 4 subunit of integrin alpha 6 beta 4 at the dermo-epidermal junction in junctional epidermolysis bullosa.

Laryngo-onycho-cutaneous syndrome: an inherited epithelial defect

Three children with an unusual but clearly defined combination of clinical findings that appear to have been inherited in an autosomal recessive manner are described. All had developed laryngeal abnormalities, chronic skin ulceration, nail dystrophy, and conjunctival disease in infancy. In every case, dental enamel was hypoplastic and both skin and mucosal surfaces demonstrated increased susceptibility to trauma. Progression of disease occurred, to life threatening respiratory obstruction in two cases and to effective blindness and fatal respiratory obstruction in the third child. All of these children came from the Pakistani ethnic group. No medical treatment has halted progression of this disease but laser therapy has been partially successful in alleviating laryngeal manifestations. Ultrastructural and immunohistological examination of unaffected skin was undertaken in each child. No abnormality was found in the child with the mildest clinical disease. Both of the other children showed abnormal hemidesmosomes on ultrastructural examination. The most severely affected child also had abnormally weak immunoreactivity with antibodies G71 and GB3 directed against basal cell alpha 6 beta 4 integrin and the basement membrane glycoprotein nicein respectively. These abnormal findings are also seen in skin from patients with junctional epidermolysis bullosa. These three children have the laryngo-onycho-cutaneous syndrome, which may not be rare in their ethnic group. The available clinical and pathological evidence is consistent with this syndrome being caused by an inherited defect affecting the lamina lucida of the skin basement membrane zone. The laryngo-onycho-cutaneous syndrome may therefore represent a new and distinctive type of junctional epidermolysis bullosa.

Immunohistochemical markers of uterine receptivity in the human endometrium

The factors responsible for the initial interaction between maternal and fetal epithelium leading to the establishment of pregnancy remain poorly understood. Temporal and spatial expression of specific endometrial peptides in response to ovarian steroids is thought to contribute to the development of a period of uterine receptivity, whereby the endometrium becomes hospitable to the implanting blastocyst. The failure to establish receptivity may account for a significant percentage of the cases of infertility in the female, especially affecting women with luteal phase deficiency, leiomyomata uteri, endometriosis, habitual abortion, and unexplained infertility. In addition, despite increasing global experience with advanced reproductive technologies, the majority of In Vitro Fertilization (IVF) attempts remain unsuccessful, most likely on the basis of implantation failure. In this article, we review the concepts involved in the study of uterine receptivity in the human, highlight potential immunohistochemical (IHC) markers that have recently been discovered, and discuss how IHC assessment of the endometrium is a potentially valuable method for the evaluation of the receptive endometrial state. Using this approach we have examined several new potential markers of uterine receptivity. Endometrial progesterone receptors and one of the integrin cell adhesion molecules appear to undergo changes in expression around the time of implantation, and may be sensitive indicators of the receptive state. Further, these markers are delayed in women with infertility and luteal phase deficiency. These studies illustrate the utility of IHC diagnosis for the evaluation of endometrial function.

Expression of integrin alpha 6 beta 4 in human trophoblast and its loss from extravillous cells

Villous trophoblast from first trimester and term placenta expresses the integrin subunits alpha 6 and beta 4, as monitored by immunohistochemistry. The subunits, which co-distribute in all locations, are present at the basal cell surface where cyto- and syncytiotrophoblast make contact with the villous basement membrane and, in addition, in areas of contact between cytotrophoblast or cyto- and syncytiotrophoblast, but both are absent from the apical syncytial surface. This distribution, which together with other evidence suggests that the two subunits are associated in trophoblast as the heterodimer alpha 6 beta 4, differs from other epithelia in which alpha 6 beta 4 is predominantly basally disposed. Anti-cytokeratin antibodies were used to identify cytotrophoblast columns at the tips of anchoring villi and the migratory interstitial extravillous cytotrophoblast population in the placental bed. Cells in the columns showed a level of expression that diminished with distance from the villous basement membrane, and the alpha 6 and beta 4 subunits were not detected in interstitial cytotrophoblast. In trophoblast of the chorion laeve, both the subunits were expressed in all layers from the pseudobasement membrane to the edge of the parietal decidua, but not in the decidua itself. Integrin alpha 6 beta 4 distribution was also examined in primary cultures of term trophoblast and in the choriocarcinoma cell line BeWo. The alpha 6 and beta 4 subunits were present at or near cell contact areas, where basement membrane components including laminin were also detected. The results suggest that integrin alpha 6 beta 4 plays a role in anchoring trophoblast to basement membrane and its loss may play a role in enabling cells to migrate into the maternal tissue compartment.

Variant choriocarcinoma (BeWo) cells that differ in adhesion and migration on fibronectin display conserved patterns of integrin expression

Starting from the BeWo choriocarcinoma cell line, two stable variant cell lines (epi and lc) were isolated. Epi cells displayed an epithelioid colony morphology while lc were fibroblastoid. lc cells attached and spread on fibronectin-coated surfaces at significantly lower density of fibronectin than epi or the parent cell line. lc also migrated more efficiently to fibronectin in a trans-filter assay than either epi or parent cells. Integrin expression by the cell lines was investigated by flow cytometry and immunoprecipitation from surface-labelled cells with a panel of subunit-specific antibodies. Integrins alpha 2 beta 1, alpha 5 beta 1, alpha v beta 1 and alpha 6 beta 4 were detected in each case, and levels of expression were identical in the two variant lines. Anti-functional antibodies were used to probe the role of integrins in fibronectin- and vitronectin-mediated adhesion. Complete inhibition of adhesion to fibronectin was observed with anti-beta 1 antibody, and partial inhibition with anti-alpha 5, suggesting that integrin alpha 5 beta 1 is mainly responsible for the interaction. Adhesion to vitronectin was inhibitable using anti-alpha v and anti-beta 1 antibodies, suggesting that integrin alpha v beta 1 is active in these cells as a vitronectin receptor. There was a correlation between the altered morphology of the variant cells and alterations in the distribution of integrin alpha 6 beta 4 and laminin in monolayer cultures. The results support the idea that fibronectin may mediate the migratory behaviour of extravillous trophoblast in vivo. Switch to a more migratory phenotype may be mediated by the selective activation of integrins and altered interaction with basement membrane.

The distribution of alpha 6 beta 4 integrins in lesional and non-lesional skin in bullous pemphigoid

The alpha 6 beta 4 integrin is associated ultrastructurally with the hemidesmosomes of the basal keratinocytes and with the bullous pemphigoid antigen (BPA), suggesting an important role in adhesion of epidermal cells to the basement membrane. Using an immunofluorescence technique with chain-specific monoclonal antibodies to the alpha and beta subunits we have investigated the distribution of the alpha 6 beta 4 integrin in normal skin (n = 3) and in BP skin (uninvolved, perilesional and lesional) [n = 11]). The findings have been compared with other types of subepidermal blisters and with normal skin split by chemical means (n = 2) and by suction (n = 2). The distribution of alpha 6 beta 4 integrin was compared with that of bullous pemphigoid antigen (BPA) and with other basement membrane zone (BMZ) macromolecules, laminin, collagen type IV, collagen type VII and the BM600 antigen. In uninvolved, perilesional and early pre-blistered lesional BP skin the distribution of both the alpha 6 and beta 4 integrin subunits, BPA laminin, collagen types IV and VII and the BM600 antigen was identical to normal skin, i.e. a linear band in the BMZ. Within BP blisters, both alpha 6 and beta 4 integrin subunits and BPA were absent, except in two blisters in which the integrin expression was retained in the blister roof, despite loss of BPA. The other BMZ components were expressed on the blister floor.(ABSTRACT TRUNCATED AT 250 WORDS)

The epidermal basement membrane in basal cell carcinoma: an immunohistochemical study

An immunohistochemical study of basal cell carcinomas of varying histological type, using a panel of antibodies to constituents of the epidermal basement membrane, showed marked deficiencies in the expression of the antigens identified by the antibodies LH7.2, GB3 and G71. There was no correlation between loss of immunoreactivity to these antibodies and the histological features of the tumour.

Abnormal expression of G71 antibody at the epidermal basement membrane in basal cell carcinoma

The antibody G71 is a murine monoclonal antibody directed against an antigen in the basement membrane zone of many human epithelia. Ultrastructurally it is located in the lamina lucida. The epitope is carried on glycoprotein components with molecular weights of 160, 125 and 115 kilodaltons. The authors examined the immunohistochemical expression of G71 antigen, using a standard indirect immunoperoxidase technique, in benign and malignant tumors derived from the epidermis. G71 staining was consistently absent or reduced around basal cell carcinomas (n = 44). In contrast, G71 was present at the basement membrane zone of squamous cell carcinomas (n = 18) and was also frequently expressed within the cytoplasm and on the cell surface of the malignant keratinocytes. The staining pattern of G71 at the basement membrane zone was essentially normal in keratoacanthomas (n = 10), solar keratoses (n = apart from foci of attenuation. In both seborrheic keratoses and intraepidermal squamous 13), seborrheic keratoses (n = 6), and intraepidermal squamous cell carcinomas (n = 8), cell carcinomas cell-surface and cytoplasmic staining were inconstant features. In conclusion, there appears to be a specific defect of G71 antigen expression in basal cell carcinomas.

Menstrual-cycle-dependent expression of keratan sulphate in human endometrium

Immunochemical methods have been used to detect and characterize two classes of polypeptide-associated keratan sulphate (KS) in epithelial secretions from human endometrium. Monoclonal antibody D9B1 binds to a hormonally regulated sialylated epitope associated with KS in a high relative molecular mass (250,000-350,000) component that bands as a doublet in SDS/PAGE. These KS chain(s) are sensitive to keratanase, endo-beta-galactosidase and N-glycanase. A second, more highly sulphated, type of KS is also present, that is resistant to all three enzymes. This can be detected using monoclonal antibody 5D4. It is present throughout the menstrual cycle and is associated principally with a component of Mr 140,000. Thus secretory KS contributes to the environment of the implanting embryo, may be used as a molecular index of endometrial function and could be important in the establishment of pregnancy.

Luteal phase defect: the possibility of an immunohistochemical diagnosis

Monoclonal antibody D9B1 has been shown to bind to a carbohydrate epitope associated with high molecular weight secretory sialoglycoprotein(s) of human endometrium. The authors demonstrate that, in a group of 28 patients diagnosed on the basis of histopathologic assessment as exhibiting luteal phase defect, 68% reveal significantly diminished expression of the epitope. Furthermore, histologic assessment of the secretory activity in single glands does not correlate simply with the level of expression of the epitope. Of specimens from patients complaining of infertility, 92% showed defective production of the D9B1 epitope. Thus, D9B1 immunohistochemistry provides a new molecular criterion for defective endometrial function.

A novel approach for monitoring the endometrial cycle and detecting ovulation

We report the presence of a cycle-dependent sialoglycoprotein in the endometrium. A monoclonal antibody (D9B1) to this glycoprotein has been derived and used to study tissue from 24 women with normal menstrual cycles. Results obtained with peroxidase immunohistochemistry suggest a highly significant variation in concentration of the glycoprotein, which is absent in the proliferative phase and present at maximal levels in the early secretory phase. The amount of antigen then diminishes slowly through the latter part of the secretory phase. The glycoprotein is produced in epithelial cells of glands and uterine lumen before being secreted across the apical cell surface. The secretory response is uniform in different areas of the tissue and within individual glands. However, considerable differences in secretory activity can be observed between adjacent glands in any part of the endometrium. Binding of the antibody is shown to be a new and novel parameter in characterization and standardization of the normal function of endometrium in response to ovarian hormones.

An immunohistochemical study of human endometrial extracellular matrix during the menstrual cycle and first trimester of pregnancy

Changes in the organisation and composition of extracellular matrix in human endometrium during the menstrual cycle and early pregnancy have been assessed by immunofluorescence. Amongst interstitial components, type-III and type V-collagens and fibronectin are present in endometrial stroma throughout the menstrual cycle as well as in first trimester decidua. Type V-collagen epitopes are masked early in the cycle, but become accessible in first trimester decidua. Type VI-collagen is abundant in endometrium in the proliferative phase, but is progressively lost in the secretory phase and decidua, in which it is retained only in blood vessel walls. Vitronectin is present in some blood vessels in decidua. Decidualising stromal cells also produce basement membrane components (type IV-collagen, laminin, heparan sulphate proteoglycan and a glycoprotein family recognised by monoclonal antibody G71) and these become organised into a pericellular aura.

A monoclonal antibody to a cell surface determinant in human endometrial epithelium: stage-specific expression in the menstrual cycle

A monoclonal antibody (CC25) was obtained after immunization of mice with intact glandular epithelial cells from secretory phase endometrium. Here we report a preliminary immunohistologic study in the endometrium of 29 patients in different phases of the menstrual cycle and early pregnancy. In immunofluorescence, CC25 binds to a basolaterally oriented epithelial cell surface antigen that is absent during the proliferative phase and appears suddenly in both glandular and uterine surface locations soon after ovulation. In mid and late secretory phase, the level of expression diminishes slowly. The epitope is absent from glandular epithelial cells in first-trimester decidua. However, it is associated with vascular smooth muscle cells in endometrium and decidua. CC25 promises to be a useful reagent for the analysis of endometrial function during the menstrual cycle.

Reactions of seven basic fluorochromes with unfixed cells obtained from the salivary glands of the dipteran fly Megaselia scalaris Loew (Phoridae)

Seven basic fluorochromes with varying specificities were used to stain the large squamous epithelial cells isolated from the larval salivary glands of Megaselia scalaris (Phoridae). Although the EDTA-based method selected for isolating the cells produced permeabilization and a loss of viability of the cells, consistent results were obtained with the various fluorochromes. The "classical" pattern of green nuclear and red cytoplasmic fluorescence observed in cells stained with acridine orange could be changed to green cytoplasmic and red nuclear fluorescence by pretreatment with RNase. The predominantly cytoplasmic and nucleolar fluorescence obtained with pyronine Y could be changed to mainly nuclear fluorescence by RNase pretreatment. The other five fluorochromes tested were not affected appreciably by extraction with RNase. Quinacrine mustard, dicarbocyanine (DiOC3(3)), and rhodamine 123 produced primarily cytoplasmic and nucleolar fluorescence, while nile red revealed mainly cytoplasmic lipid droplets. Phosphine 3R initially stained lipid droplets but very rapidly redistributed throughout the cytoplasm and nucleus. Because of their large size, flatness, and content of histochemically demonstrable components, the cells of Megaselia are especially appropriate for use as "optical objects" or controls in various studies. New methods of isolating the cells, however, will be needed to prevent permeabilization and loss of viability of the cells.