Suprabasal Cell Layer (suprabasal + cell_layer)

Distribution by Scientific Domains

Selected Abstracts

Apoptosis in oral lichen planus

Evelyn Neppelberg
Apoptotic cell death may be a contributory cause of basal cell destruction in oral lichen planus (OLP). Therefore, the purpose of this study was to investigate the rate of apoptosis in OLP and the expression of two proteins (FasR and FasL) regulating this process. Biopsies from 18 patients with histologically diagnosed OLP were investigated, with comparison to normal oral mucosa of healthy persons. For visualisation of DNA fragmentation, the TUNEL method was used. In order to characterise the infiltrating cell population (CD3, CD4, CD8) and expression of FasR and FasL, we used an immunohistochemical technique. The results showed that T cells dominated in the subepithelial cell infiltrate. Within the epithelium the apoptotic cells were confined to the basal cell layer, and more apoptotic cells were seen in areas with basal cell degeneration and atrophic epithelium. There was a prominent expression of FasR/FasL in OLP, with a rather uniform distribution throughout the inflammatory cell infiltrate. In the epithelium, the FasR/FasL expression was more abundant in the basal cell area compared to the suprabasal cell layer. In conclusion, apoptosis within the epithelium is significantly increased in situ in OLP compared to normal oral mucosa, and seems to be related to the epithelial thickness. [source]

Immunohistochemical analysis of the biological potential of odontogenic keratocysts

k Kolá
Background:, The aim of this study was to analyse the usefulness of detecting important apoptosis and proliferation markers in assessing the biological potential of odontogenic keratocysts (OKC) and thus selecting the optimal diagnostic algorithm for these lesions. Methods:, Indirect immunohistochemistry and relevant statistical methods were used for analysis of formalin-fixed and paraffin-embedded samples from 98 patients. Results:, Nevoid basal cell carcinoma syndrome (NBCCS) keratocysts were characterized by higher expression of Bcl-2, p27Kip1 and c-erbB-2 as well as by lower proliferative activity measured by Ki-67 in basal cell epithelium and by a lower inflammatory response in comparison with sporadic keratocysts. Dentigerous, radicular and non-specified odontogenic cysts differed from both NBCCS and sporadic keratocysts in a wide spectrum of apoptosis and/or cell cycle-related protein expressions, higher proliferation in the basal cell layer, and vice versa, lower proliferation in the suprabasal cell layer. Conclusions:, The NBCCS keratocysts have a different immunophenotype from sporadic keratocysts and both types are distinguishable from dentigerous, radicular and non-specified odontogenic cysts. These findings confirm the separate biological potential of these lesions and the results of the immunohistochemical analysis have diagnostic and prognostic implications. [source]

Cloning and molecular dissection of the 8.8 kb pig uroplakin II promoter using transgenic mice and RT4 cells

Deug-Nam Kwon
Abstract Uroplakin II (UPII) gene expression is highly tissue and cell specific, with mRNA present in the suprabasal cell layers of the bladder and urethra. Previous reports described the mouse UPII (mUPII) promoter as primarily urothelium selective. However, ectopic expression of a transgene under the 3.6 kb mUPII promoter was also detected in brain, kidney, and testis in some transgenic mouse lines. Here, we have cloned an 8.8 kb pig UPII (pUPII) promoter region and investigated which cells within the bladder and urethra express a transgene consisting of the pUPII promoter fused to human erythropoietin (hEPO) or a luciferase gene. pUPII-luciferase expression vectors with various deletions of the promoter region were introduced into mouse fibroblast (NIH3T3), Chinese hamster ovary (CHO), and human bladder transitional carcinoma (RT4). A 2.1 kb pUPII promoter fragment displayed high levels of luciferase activity in transiently transfected RT4 cells, whereas the 8.8 kb pUPII promoter region displayed only low levels of activity. The pUPII-hEPO expression vector was injected into the pronucleus of zygotes to make transgenic mice. To elucidate the in vivo molecular mechanisms controlling the tissue- and cell-specific expression of the pUPII promoter gene, transgenic mice containing 2.1 and 8.8 kb pUPII promoter fragments linked to the genomic hEPO gene were generated. An erythropoietin (EPO) assay showed that all nine transgenic lines carrying the 8.8 kb construct expressed recombinant human erythropoietin (rhEPO) only in their urethra and bladder, whereas two transgenic lines carrying the 2.1 kb pUPII promoter displayed hEPO expression in several organs including bladder, kidney, spleen, heart, and brain. These studies demonstrate that the 2.1 kb promoter contains the DNA elements necessary for high levels of expression, but lacks critical sequences necessary for tissue-specific expression. We compared binding sites in the 2.1 and 8.8 kb promoter sequences and found five peroxisome proliferator responsive elements (PPREs) in the 8.8 kb promoter. Our data demonstrated that proliferator-activated receptor (PPAR)-, activator treatment in RT4 cells induced the elevated expression of hEPO mRNA under the control of the 8.8 kb pUPII promoter, but not the 2.1 kb promoter. Collectively, our data suggested that all the major trans-regulatory elements required for bladder- and urethra-specific transcription are located in the 8.8 kb upstream region and that it may enhance tissue-specific protein production and be of interest to clinicians who are searching for therapeutic modalities with high efficacy and low toxicity. J. Cell. Biochem. 99: 462,477, 2006. © 2006 Wiley-Liss, Inc. [source]

Cyclooxygenase-2 Expression in Murine and Human Nonmelanoma Skin Cancers: Implications for Therapeutic Approaches,

Kathy P. An
ABSTRACT Inflammatory stimuli result in the production of cutaneous eicosanoids, which are known to contribute to the process of tumor promotion. Cyclooxygenase (COX), the rate-limiting enzyme for the production of prostaglandins (PG) from arachidonic acid, exists in at least two isoforms, COX-1 and COX-2. COX-1 is constitutively expressed in most tissues and plays various physiological roles, whereas increased COX-2 expression is known to occur in several types of epithelial neoplasms. Enhanced PG synthesis is a potential contributing factor in UVB-induced nonmelanoma skin cancers (NMSC). Increased COX-2 staining occurs in murine skin neoplasms after chronic exposure to carcinogenic doses of UVB. In this study, immunohistochemical and Western blot analyses were employed to assess longitudinally COX-2 expression in a standard mouse UVB complete carcinogenesis protocol and in human basal cell carcinomas (BCC) and squamous cell carcinomas (SCC). During UVB irradiation of mice, COX-2 expression consistently increased in the hyperplastic skin, the benign papillomas and the SCC. COX-2 expression was also increased in human actinic keratoses, SCC and BCC as well as in murine SCC and BCC. The pattern of COX-2 expression was quite variable, occurring in a patchy distribution in some lesions with staining confined mainly to suprabasal cell layers. In general, COX-2 expression progressively became more extensive in benign papillomas and well-differentiated murine SCC. The staining was predominantly cytoplasmic and perinuclear in some focal areas in tissue stroma around both murine and human tumors. Western blot analysis confirmed negative COX-2 expression in normal skin, whereas acute UVB exposure resulted in increased enzyme expression, which continued to increase in developing papillomas and SCC. Because of the evidence indicating a pathogenic role for eicosanoids in murine and human skin neoplasms, we performed studies to assess the anti-inflammatory and anticarcinogenic effects of green tea extracts, which are potent antioxidants. Acute exposure of the human skin to UVB (minimum erythema dose × 4) caused a transient enhancement of the COX-2 expression, which reverted to baseline within hours; however, in murine skin the expression persisted for several days. Pretreatment with the topically applied green tea extract (1 mg/cm2) largely abrogated the acute COX-2 response to UVB in mice or humans. In summary, enhanced COX-2 expression serves as a marker of epidermal UVB exposure for murine and human NMSC. These results suggest that COX-2 inhibitors could have potent anticarcinogenic effects in UVB-induced skin cancer. [source]