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- Asplund, Anna, et al.
(författare)
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Expression profiling of microdissected cell populations selected from basal cells in normal epidermis and basal cell carcinoma
- 2008
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 158:3, s. 527-538
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Tidskriftsartikel (refereegranskat)abstract
- Background Basal cell carcinomas (BCCs) are prevalent tumours with uniform histology that develop without any known precursor lesion. Alterations in the sonic hedgehog-patched1 signalling pathway are accepted as necessary events for tumorigenesis, and mutations in the patched1 gene are frequently present in tumours. Objectives To analyse transcript profiles in BCC. Methods We used laser-assisted microdissection to isolate and collect cell populations defined under the microscope. Peripheral cells from nests of BCC were selected to represent tumour cells, and normal keratinocytes from epidermis basal layer were used as control. Extracted RNA was amplified and hybridized on to a cDNA microarray. Results Our results show that BCC cells express a transcript signature that is significantly different from that of normal keratinocytes, and over 350 genes with various functions were identified as differentially expressed. The compiled data suggest an upregulation of the Wnt signalling pathway as a major event in BCC cells. Furthermore, tumour cells appear to have an increased sensitivity to oxygen radicals and dysregulated genes involved in antigen presentation. Results were validated at both the transcriptional level using real-time polymerase chain reaction and at the protein level using immunohistochemistry. Conclusions We show that microdissection in combination with robust strategies for RNA extraction, amplification and cDNA microarray analysis allow for reliable transcript profiling and that antibody-based proteomics provides an advantageous strategy for the analysis of corresponding differentially expressed proteins. We found that expression patterns were significantly altered in BCC cells compared with basal keratinocytes and that the Wnt signalling pathway was upregulated in tumour cells.
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| 2. |
- Asplund, A, et al.
(författare)
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PTCH codon 1315 polymorphism and risk for nonmelanoma skin cancer
- 2005
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 152:5, s. 868-873
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Tidskriftsartikel (refereegranskat)abstract
- Background The PTCH tumour suppressor gene is involved in the development of nearly all basal cell carcinomas (BCCs) of the skin and a fraction of squamous cell carcinomas (SCCs). A nonconservative Pro/Leu nucleotide polymorphism within PTCH exon 23 at codon 1315 was recently reported to be potentially important for the development of breast epithelial cell cancers.Objectives Accordingly, the status of PTCH codon 1315 was analysed for a possible association with the development of nonmelanoma skin cancers (NMSCs) in a pilot study. Because skin cancer risk is affected by specific population-dependent phenotypes such as skin and hair colour, codon 1315 was also analysed for normal allele frequency variation in human populations having differing extents of eumelanin vs. phaeomelanin.Methods The single nucleotide polymorphism in codon 1315 of the human PTCH gene was analysed in genomic DNA from six different populations comprising 472 blood samples and from 170 patients in four different categories with NMSC. Polymerase chain reaction and pyrosequencing were used to determine the allele frequencies. Allelic loss was furthermore determined in tumours following microdissection.Results The Pro/Pro genotype frequency ranged from 30% to 65% between populations, with a significant trend for a reduced frequency of the Pro/Pro genotype in populations having lighter pigmentation (P = 0·020). Pro/Pro frequency showed an increasing trend with increasing tumour case severity (P = 0·027). In 260 samples from 180 Swedish patients with NMSC and a control group of 96 healthy ethnically matched volunteers, no statistically significant pairwise differences between groups were detected in the PTCH codon 1315 allelic distribution, neither was a difference seen for multiple or early onset cases of BCC in the Swedish population. In Swedish patients with single tumours, allelic loss (loss of heterozygosity) was observed in 20 of 30 (67%) patients with BCC and four of 22 (18%) patients with SCC, with no preference in the allele lost. In contrast, the Pro/Pro genotype was frequent in seven U.S. patients having multiple independent BCCs. One of these patients was heterozygous, enabling allelic loss studies. Of 20 independent tumours, 11 had lost an allele; 10 of the 11 had lost Leu, suggesting nonrandom loss that favoured retention of Pro (P = 0·0059).Conclusions Our results indicate an association between the eumelanin-to-phaeomelanin shift and a shift from the Pro/Pro genotype to Leu-containing genotypes. Failure to lose Pro during the shift to phaeomelanin may be associated with an increased population risk for BCC and increased individual risk for multiple BCC. During development of a tumour, the effect of Pro may be magnified by loss of the Leu allele.
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| 3. |
- Marchini, G., et al.
(författare)
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The newborn infant is protected by an innate antimicrobial barrier : peptide antibiotics are present in the skin and vernix caseosa
- 2002
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Ingår i: British Journal of Dermatology. - : Oxford University Press (OUP). - 0007-0963 .- 1365-2133. ; 147:6, s. 1127-1134
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Tidskriftsartikel (refereegranskat)abstract
- Background Peptide antibiotics are part of the surface defences against microbial intruders. However, the presence and significance of these innate immune effectors in the skin barrier of the newborn infant have not yet been appreciated. Erythema toxicum neonatorum is an inflammatory skin reaction of unknown aetiology and significance, commonly present in the healthy newborn infant. Objectives As peptide antibiotics are upregulated in inflammatory skin disorders, we hypothesized that this also could be the case in erythema toxicum. We also investigated if the vernix caseosa, a cream-like white substance present on the skin of the infant at birth, might contribute to host defences. Methods The presence of the human antibacterial peptide LL-37 was investigated by immunohistochemistry and confocal imaging of skin biopsies from four 1-day-old infants with an erythema toxicum rash and four matched newborns without the rash. In addition, we analysed the expression of LL-37 and human beta defensin-1, an antibacterial peptide of epithelial origin, by reverse transcriptase-polymerase chain reaction. Finally, we screened for antibacterial components in vernix material obtained from six healthy newborns by inhibition zone assays. Results All biopsies from the lesions of erythema toxicum showed a dense, nodular infiltrate with numerous LL-37-expressing cells located in the dermal layer and a clear localization of the peptide within CD15-expressing neutrophils, EG2-expressing eosinophils and CD1a-expressing dendritic cells. LL-37 was also found to be located in CD1a-expressing Langerhans cells and a positive staining for the peptide was seen throughout the whole epidermal layer, both in infants with and without the rash. Skin samples from infants with the rash of erythema toxicum showed a constitutive expression of human 0 defensin-1, while the expression of LL-37 seemed to be induced. Furthermore, LL-37 and lysozyme were detected in the protein fractions derived from the vernix caseosa, and these fractions exhibited a clear antibacterial activity. Conclusions Peptide antibiotics are present in the vernix caseosa and in the skin of the healthy newborn infant, indicating effective innate immune protection already during fetal and neonatal life.
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