摘要:

AbstractThe wild‐type tumor‐suppressor TP53 gene encodes for a nuclear protein which has been shown to act as a transcriptional modulator. The cellular role of the p53 protein is the control of cell proliferation, particularly important in stressed cells. The TP53 gene is frequently mutated in sporadic and familial human cancers. Most transforming mutations localize in highly conserved domains of the gene and define hot‐spot regions that have a certain degree of tissue specificity. Moreover, most mutations are point mutations and the type and localization of the nucleotide substitution may sometimes help in recognizing the carcinogenic agent. This is the case for C to T transitions at dipyrimidine sites induced by UV radiation in cutaneous epitheliomas. Inactivation of p53 protein can also occur through mechanisms other than genetic alteration, such as binding to viral or cellular proteins. Loss of wild‐type TP53 function seems therefore to play a crucial role in cell transformation in human cancers, either during carcinogenesis or later in tumor prog

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00016.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe extent of diversity of the γδ T‐cell receptor (TCR) in normal human skin and Oriental Cutaneous Leishmaniasis (OCL) was examined by molecular analysis of the variable (V) δ gene segment, junctional (J) δ gene segment and junctional regions. To examine the expression of TCR δ genes, segments of γδ T lymphocytes, DNA isolated from normal human skin and from OCL were subjected to enzymatic gene amplification by the polymerase chain reaction (PCR) method using TCR Vδ‐and Jδ‐specific oligonucleotides as primers. PCR amplification using these primers indicated that the Vδ2 gene segment was predominantly used by γδ T lymphocytes in both normal human skin and OCL. To determine the extent of junctional diversity in the δ gene of γδ T cells in normal human skin and OCL, we sequenced the nucleic acid sequences corresponding to the V δ2/Jδ1 junctional regions. Sequence analysis of junctional regions demonstrated broad junctional diversity in normal skin but only limited diversity in OCL. Our findings support the hypothesis that skin γδ T lymphocytes may derive from a fetal subset of γδ T lymphocytes that leaves the thymus early and colonizes (he periphery. The limited junctional diversity demonstratd in OCL lesions indicates that γδ T cells can undergo oligoclonal expansion following recognition of a specific ligand and supports the idea that junctional regions are important in the recognit

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00017.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

Abstract1,25‐dihydroxyvitamin D3 (calcitriol) affects differentiation and proliferation of epidermal keratinocytesin vitroandin vivo. We have studied the topical effects of calcitriol (0.08 2.0 μg/ml) and of a new vitamin D analogue, the epi‐20‐analogue KH1060 (0.4 –2.0 μg/ml) on epidermal proliferation in normal hairless mice. Epidermis was examined at intervals from 4 h to 8 days after a single‐dose application. The mitotic rate was assessed by the stathmokinetic method and hyperplasia was scored in histological sections. Cell cycle parameters were measured by bivariale bromodeoxyuridine (BrdUrd)/DNA flow cytometry on isolated epidermal basal cells after pulse‐labelling with BrdUrd. Both calcitriol and KM 1060 induced a dose‐ and time‐dependent increase in the mitotic rate and in hyperplasia, the latter drug being the most effective. Calcitriol and KH1060 induced changes in the cell cycle traverse compatible with the regenerative reaction seen after other hyperplasiogens, but with an additionally increased accumulation of cells in the G2phase. This is similar to that seen after topical application of retinoic acid to mouse skin. Our results are thus in contrast to the anti‐proliferative effects of calcitriol observedin vitroand following treatment of the hyperproliferative disease psoriasis with calcitriol as well as other

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00018.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractKeratinocytes have been shown to express interleukin‐8 (IL‐8) mRNA on stimulation with IL‐1 and other substances. This has been assumed to account for the large amount of this neutrophil chemotaclic cytokine in psoriasis. We found that, without any added agents, commercially available normal human epidermal keratinocytes proliferating in Keratinocyte Growth Medium® (KGM) released a chemotactic peptide extracellularly, which was confirmed to be IL‐8. To determine whether most of the IL‐8 is secreted extracellularly from proliferating keratinocytes or is mainly stored to be released only on stimulation. We quantified cell‐associated and released immunoreactive IL‐8 from keratinocytes cultured in KGM for up to 11 days at the peptide level. The keratinocytes proliferated, taking a sigmoid growth curve, to reach a plateau at day 7. We found that the amounts of immunoreactive IL‐8 gradually increased in the culture supernatant with cell growth but its prominent release took place only after the cell growth reached a plateau. The cell‐associated IL‐8 was much smaller in amount than that noted in the supernatant. These results suggest that the IL‐8 constitutively produced by keratinocytes was mostly released extracellularly but that the production by actively proliferating cells seems to be far less than that by non‐proliferating cells that probably occurred in an autocrine fashion under the stimulation of keratinocyte‐derived cytokines accumulated in the culture medium. Neutrophil chemotactic activity assayed concomitantly showed a consistent increase during the culture period, indicating that, with their growth, the keratinocytes release substances other than IL‐8 that exert an influence on neut

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00019.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThe effect of epidermal growth factor (EGF) on the activity of ornithine decarboxylase (ODC) was evaluated and partially characterized in SV40‐transformed, immortalized cultured human keratinocytes. It was observed that the addition of fresh complete medium to confluent cultures resulted in a 10‐fold increase in ODC activity. Characterization of this activity using serum‐free medium revealed that the increase in ODC activity was primarily due to the presence of EGF (10 ng/ml). A dose‐dependent increase in ODC activity was observed when cultures were treated with EGF. Although near maximal induction occurred with EGF concentrations as low as 2.5–10 ng/ml, maximal induction of ODC (25‐fold) occurred with an EGF concentration of 50 ng/ml. The peak time for ODC induction was 10 hours following the addition of EGF to keratinocyte cultures. The induction of ODC by EGF was inhibited by pretreatment of cultures with either cycloheximide or actinomycin D, suggesting that both protein synthesis and gene transcription are important in the FGF induction of ODC. EGF significantly increased the steady stale levels of ODC mRNA with a peak at 4 hours, preceding the peak in observed enzyme activity as expected. Pretreatment of cultures with retinoic acid (10−5–10−7M) significantly inhibited the induction of ODC by EGF. Retinoic acid decreased the steady‐state levels of ODC mRNA. These data demonstrate that ODC is an enzyme that is induced by EGF in human keratinocytes; this induction probably involves both gene transcription and protein synthesis. Retinoic acid partially prevents the EGF induction of ornithine decarboxylase activity through a presently undefined mechanism(s), but appears to have effects that result in decrea

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00020.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractExpression of the adhesion molecules ICAM‐1 and LFA‐1 (CD11a/CD18) on mouse epidermal Lungerhans cells (LC) and on spleen dendritic cells (DC) from BALB/c mice was examined by staining with specific mAb and was evaluated by flow cytometry. LC were shown to express both ICAM‐1 and LFA‐1, whereas spleen DC expressed only LFA‐1. The contribution of these adhesion molecules to LC‐ or DC‐induced activation of keyhole limpet hemocyanin (KLH)‐specific, lad‐restricted, Th1 or Th2 clones was investigated in mAb blocking studies. At optimal doses, anti‐CD1la or anti‐CD18 mAb completely inhibited Th1 proliferation induced by either LC or DC. Anti‐ICAM‐1 also abrogated Th1 proliferation induced by LC, but only moderately reduced Th1 proliferation induced by DC. Inhibition in these experiments was specific, since isotype‐matched control Ab against other Ag constitutively expressed on LC (NLDC 145) or DC (33D1) had no effect on Th1 proliferation. In marked contradistinction, the capacity of LC to present KLH to our Th2 clones was resistant to treatment with the same mAb against ICAM‐1, CD11a or CD18. We conclude that interactions between ICAM‐1 and LFA‐1 on epidermal LC and LFA‐1 on spleen DC with their respective ligands on our Th1 clones are required for optimal presentation of protein Ag to Th1. Our results also indicate that neither ICAM‐1 nor LFA‐1 is required for the analo

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00021.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractWe have employed a panel of antibodies directed against several newly‐defined and well‐characterized components of the epidermal basement membrane (BM) to investigate the biology of basal cell carcinoma (BCC) by indirect immunofluorescence and to determine whether alterations in BM components may play a significant role in BCC tumor invasion. We found that the 230 KD bullons pemphigoid antigen (BPA) was either not detected (13/16) or significantly diminished (3/16) in BCC tumor BM. While the 180 KD BPA revealed less intense staining of the normal overlying epidermal BM than did the 230 KD BPA, the 180 KD BPA was uniformly undetectable in BCC tumor BM (16/16). Epiligrin was either not detected (9/15) or minimally detected (6/15) in BCC tumor BM. α6integrin was not detected (15/16) or minimally detected (1/16) in BCC tumor BM, whereas β4integrin was uniformly undetectable in BCC tumor BM (16/16). Type VII collagen was also not detected (9/16) or was significantly diminished (4/16) in BCC tumor BM. Laminin and type IV collagen were both at least as strong in BCC tumor BM as in adjacent normal BM. All of these components were present both in the epidermis of normal skin as well as in the normal epidermal BM overlying BCC tumor nests. Our findings reveal extensive alterations in numerous components of the hemidesmosome anchoring fibril complex of BCC's. As this complex is thought to play an important part in epidermal cell adhesion to the BM, our findings suggest that these extensive BM abnormalities may facilitate or contribute to BCC tumor inv

ISSN:0906-6705    

DOI:10.1111/j.1600-0625.1993.tb00022.x

出版商:Blackwell Publishing Ltd    

年代:1993

数据来源: WILEY