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Biomedical subjects

Louise Smith

Publications and source records attributed to Louise Smith.

10 recordsLinked to original sources
PubMed2006

Nicorandil-associated para-stomal ulceration: Case series.

Nicorandil is a vasodilator used to control severe angina. It has been associated with oral and anal ulceration that resolves upon withdrawal of the drug. We report a series of four patients, all of whom were receiving nicorandil therapy and developed nonspecific para-stomal ulcerations of similar clinical and histological appearance. All ulcers healed on withdrawal of nicorandil with no relapse. To the best of our knowledge, nicorandil-associated para-stomal ulcers have not been reported before. It is imperative to be aware of this association to prevent the persistence of these extremely painful ulcerations, and to avoid unnecessary and inappropriate interventions with substantial morbidity in a group of high-risk patients.

Aged, 80 and over↗
PubMed2005

E2F suppression and Sp1 overexpression are sufficient to induce the differentiation-specific marker, transglutaminase type 1, in a squamous cell carcinoma cell line.

Recently, E2F function has expanded to include the regulation of differentiation in human epidermal keratinocytes (HEKs). We extend these findings to report that in HEKs, Sp1 is a differentiation-specific activator and a downstream target of E2F-mediated suppression of the differentiation-specific marker, transglutaminase type 1 (TG-1). Deletion of elements between -0.084 to -0.034 kb of the TG-1 promoter disabled E2F1-induced suppression of promoter activity. Electrophoretic mobility shift assays (EMSAs) demonstrated that Sp1 and Sp3 bound this region. Protein expression analysis suggested that squamous differentiation was accompanied by increased Sp1/Sp3 ratio. Cotransfection of proliferating HEKs or the squamous cell carcinoma (SCC) cell line, KJD-1/SV40, with an E2F inhibitor (E2Fd/n) and Sp1 expression plasmid was sufficient to activate the TG-1 promoter. The suppression of Sp1 activity by E2F in differentiated cells appeared to be indirect since we found no evidence of an Sp1/E2F coassociation on the TG-1 promoter fragment. Moreover, E2F inhibition in the presence of a differentiation stimulus induced Sp1 protein. These data demonstrate that (i) Sp1 can act as a differentiation stimulus, (ii) E2F-mediated suppression of differentiation-specific markers is indirect via Sp1 inhibition and (iii) a combination of E2F inhibition and Sp1 activation could form the basis of a differentiation therapy for SCCs.

Biomarkers, Tumor↗
PubMed2005

Rheumatoid arthritis synovium contains plasmacytoid dendritic cells.

We have previously described enrichment of antigen-presenting HLA-DR+ nuclear RelB+ dendritic cells (DCs) in rheumatoid arthritis (RA) synovium. CD123+HLA-DR+ plasmacytoid DCs (pDCs) and their precursors have been identified in human peripheral blood (PB), lymphoid tissue, and some inflamed tissues. We hypothesized recruitment of pDCs into the inflamed RA synovial environment and their contribution as antigen-presenting cells (APCs) and inflammatory cells in RA. CD11c+ myeloid DCs and CD123+ pDCs were compared in normal and RA PB, synovial fluid (SF), and synovial tissue by flow cytometry, immunohistochemistry, and electron microscopy and were sorted for functional studies. Nuclear RelB-CD123+ DCs were located in perivascular regions of RA, in a similar frequency to nuclear RelB+CD123- DCs, but not normal synovial tissue sublining. Apart from higher expression of HLA-DR, the numbers and phenotypes of SF pDCs were similar to those of normal PB pDCs. While the APC function of PB pDCs was less efficient than that of PB myeloid DCs, RA SF pDCs efficiently activated resting allogeneic PB T cells, and high levels of IFN-gamma, IL-10, and tumor necrosis factor alpha were produced in response to incubation of allogeneic T cells with either type of SF DCs. Thus, pDCs are recruited to RA synovial tissue and comprise an APC population distinct from the previously described nuclear RelB+ synovial DCs. pDCs may contribute significantly to the local inflammatory environment.

Antigen Presentation↗
PubMed2004

E2F6: a member of the E2F family that does not modulate squamous differentiation.

The inhibition of E2F has been demonstrated to be important in the initiation of squamous differentiation by two independent manners: promotion of growth arrest and the relief of the differentiation-suppressive properties of E2Fs. E2F6 is reported to behave as a transcriptional repressor of the E2F family. In this study, we examined the ability of E2F6 to act as the molecular switch required for E2F inhibition in order for keratinocytes to enter a terminal differentiation programme. Results demonstrated that whilst E2F6 was able to suppress E2F activity in proliferating keratinocytes, it did not modulate squamous differentiation in a differentiated keratinocyte. Furthermore, inhibition of E2F, by overexpressing E2F6, was not sufficient to sensitise either proliferating keratinocytes or the squamous cell carcinoma cell line, KJD-1/SV40, to differentiation-inducing agents. Significantly, although E2F6 could suppress E2F activity in proliferating cells, it could not inhibit proliferation of KJD-1/SV40 cells. These results demonstrate that E2F6 does not contain the domains required for modulation of squamous differentiation and imply isoform-specific functions for individual E2F family members.

Bromodeoxyuridine↗
PubMed2004

Modulation of proliferation-specific and differentiation-specific markers in human keratinocytes by SMAD7.

We examined the potential role of SMAD7 in human epidermal keratinocyte differentiation. Overexpression of SMAD7 inhibited the activity of the proliferation-specific promoters for the keratin 14 and cdc2 genes and reduced the expression of the mRNA for the proliferation-specific genes cdc2 and E2F1. The ability of SMAD7 to suppress cdc2 promoter activity was lost in transformed keratinocyte cell lines and was mediated by a domain(s) located between aa 195-395 of SMAD7. This domain lies outside the domain required to inhibit TGFbeta1 signaling, suggesting that this activity is mediated by a novel functional domain(s). Examination of AP1, NFkappaB, serum response element, Gli, wnt, and E2F responsive reporters indicated that SMAD7 significantly suppressed the E2F responsive reporter and modestly increased AP1 activity in proliferating keratinocytes. These data suggest that SMAD7 may have a role in TGFbeta-independent signaling events in proliferating/undifferentiated keratinocytes. The effects of SMAD7 in differentiated keratinocytes indicated a more traditional role for SMAD7 as an inhibitor of TGFbeta action. SMAD7 was unable to initiate the expression of differentiation markers but was able to superinduce/derepress differentiation-specific markers and genes in differentiated keratinocytes. This latter role is consistent with the ability of SMAD7 to inhibit TGFbeta-mediated suppression of keratinocyte differentiation and suggest that the opposing actions of SMAD7 and TGFbeta may serve to modulate squamous differentiation.

Antigens, Differentiation↗
PubMed2004

AP-2 transcription factor family member expression, activity, and regulation in human epidermal keratinocytes in vitro.

The AP-2 transcription factor family is presumed to play an important role in the regulation of the keratinocyte squamous differentiation program; however, limited functional data are available to support this. In the present study, the activity and regulation of AP-2 were examined in differentiating human epidermal keratinocytes. We report that (1) AP-2 transcriptional activity decreases in differentiated keratinocytes but remains unchanged in differentiation-insensitive squamous cell carcinoma cell lines, (2) diminished AP-2 transcriptional activity is associated with a loss of specific DNA-bound AP-2 complexes, and (3) there is an increase in the ability of cytoplasmic extracts, derived from differentiated keratinocytes, to phosphorylate AP-2 alpha and AP-2 beta when cells differentiate. In contrast, extracts from differentiation-insensitive squamous cell carcinoma cells are unable to phosphorylate AP-2 proteins. Finally, the phosphorylation of recombinant AP-2 alpha by cytosolic extracts from differentiated keratinocytes is associated with decreased AP-2 DNA-binding activity. Combined, these data indicate that AP-2 trans-activation and DNA-binding activity decrease as keratinocytes differentiate, and that this decreased activity is associated with an enhanced ability to phosphorylate AP-2 alpha and beta.

Blotting, Western↗
PubMed2003

E2F modulates keratinocyte squamous differentiation: implications for E2F inhibition in squamous cell carcinoma.

E2F regulation is essential for normal cell cycle progression. Therefore, it is not surprising that squamous cell carcinoma cell lines (SCC) overexpress E2F1 and exhibit deregulated E2F activity when compared with normal keratinocytes. Indeed, deliberate E2F1 deregulation has been shown to induce hyperplasia and skin tumor formation. In this study, we report on a dual role for E2F as a mediator of keratinocyte proliferation and modulator of squamous differentiation. Overexpression of E2F isoforms in confluent primary keratinocyte cultures resulted in suppression of differentiation-associated markers. Moreover, we found that the DNA binding domain and the trans-activation domain of E2F1 are important in mediating suppression of differentiation. Use of a dominant/negative form of E2F1 (E2F d/n) found that E2F inhibition alone is sufficient to suppress the activity of proliferation-associated markers but is not capable of inducing differentiation markers. However, if the E2F d/n is expressed in differentiated keratinocytes, differentiation marker activity is further induced, suggesting that E2F may act as a modulator of squamous differentiation. We therefore examined the effects of E2F d/n in a differentiation-insensitive SCC cell line. We found that treatment with the differentiating agent, 12-O-tetradecanoyl-phorbol-13-acetate (TPA), or expression of E2F d/n alone had no effect on differentiation markers. However, a combination of E2F d/n + TPA induced the expression of differentiation markers. Combined, these data indicate that E2F may play a key role in keratinocyte differentiation. These data also illustrate the unique potential of anti-E2F therapies in arresting proliferation and inducing differentiation of SCCs.

Binding Sites↗
PubMed2002

Alterations in gene expression and activity during squamous cell carcinoma development.

This study focuses on characterizing the genetic and biological alterations associated with squamous cell carcinoma development. Normal human epidermal keratinocytes (HEKs), cells isolated from a preneoplastic lesion (IEC-1), and two neoplastic cell lines, SCC-25 and COLO-16, were grown as raft cultures, and their gene expression profiles were screened using cDNA arrays. Our data indicated that the expression levels of at least 37 genes were significantly (P <or= 0.05; 1.9% of genes screened) altered in neoplastic cells compared with normal cells. Of these genes, 10 genes were up-regulated and 27 genes were down-regulated in the neoplastic cells. In addition, 51% of the genes altered in the neoplastic cells were already altered in the preneoplastic IEC-1 cells. Immunohistochemical staining of patient tumors was used to verify the cDNA array analysis. Our analysis indicated that alterations in genes associated with extracellular matrix production and apoptosis are disrupted in preneoplastic cells, whereas later stages of neoplasia are associated with alterations in gene expression for genes involved in DNA repair or epidermal growth factor (EGF) receptor/mitogen-activated protein kinase kinase (MAPKK)/MAPK/activator protein-1 (AP-1) signaling. Subsequent functional analysis of the alterations in expression of the EGF receptor/MAPKK/MAPK/AP-1 genes suggested they did not contribute to the neoplastic phenotype.

Carcinoma, Squamous Cell↗
PubMed2002

Effect of interleukin-8 (IL-8), anti-IL-8, and IL-12 on endometrial cell survival in combined endometrial gland and stromal cell cultures derived from women with and without endometriosis.

OBJECTIVE: To study the affects of interleukin-8 (IL-8), anti-IL-8, and IL-12 on in vitro proliferation of endometrial cells. DESIGN: An in vitro study. SETTING: Department of Obstetrics and Gynecology, University of Aberdeen, UK. PATIENT(S): Women attending a fertility clinic. INTERVENTION(S): In vitro cell cultures using culture media supplemented with IL-8 (100 ng/mL, 200 ng/mL, and 500 ng/mL), IL-12 (1 ng/mL, 5 ng/mL, and 25 ng/mL), and anti-IL-8 (0.1 microg/mL, 1 microg/mL, 10 microg/mL). MAIN OUTCOME MEASURE(S): In vitro survival of dispersed endometrial cells (combined epithelial and glandular) at 5 and 9 days of culture. RESULT(S): There was a dose-dependent stimulatory effect of IL-8 on survival of cells. From women with and without endometriosis, IL-12 at 1 ng/mL significantly inhibited the survival of endometrial cells from women without endometriosis as compared with cells from women with endometriosis. At 1 microg/mL, anti-IL-8 significantly inhibited the survival of endometrial cells from women with endometriosis compared with cells from women without endometriosis on day 5 of culture. CONCLUSION(S): Our findings confirm the stimulatory effects of IL-8 and its possible role in the pathogenesis of endometriosis. The effects of IL-12 and anti-IL-8 on endometrial cell survival varied according to the disease state and the concentration of the cytokines. Future in vitro studies on the role of anti-IL-8 and IL-12 should aim to use a greater range of concentrations and a higher density of endometrial cells in cultures supplemented with monocytes.

Cell Culture Techniques↗