[Show abstract][Hide abstract] ABSTRACT: Plasmacytoid dendritic cells (pDCs) fulfil multiple roles in immunity, and can secrete large amounts of interferon (IFN)-α. However, the available evidence suggests that they may actually counteract efficient antitumour immunity. Thus in melanoma, pDCs are abundant, but they are anergic and deficient in IFN-α secretion. pDC anergy is thought to be caused by immunosuppressive factors secreted by melanoma cells. One factor strongly expressed by melanoma is Wnt5a, which is implicated in cancer tissue invasion. In this paper, we show that Wnt5a is able to block the upregulation of the activation markers CD80 and CD86 on naive human pDCs stimulated by CpG oligodeoxynucleotide, and CpG-triggered secretion of IFN-α by pDCs. Our results suggest that Wnt5a may not only initiate cancer invasion, but could also regulate activation of pDC. These data provide a clear rationale to investigate a role for Wnt5a in immune regulation.
Clinical and Experimental Dermatology 05/2012; 37(5):557-61. · 1.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Previous genetic and functional studies have implicated the human endogenous retrovirus K (HERV-K) dUTPase located within the PSORS1 locus in the major histocompatibility complex region as a candidate psoriasis gene. Here, we describe a variant discovery and case-control association study of HERV-K dUTPase variants in 708 psoriasis cases and 349 healthy controls. Five common HERV-K dUTPase variants were found to be highly associated with psoriasis, with the strongest association occurring at the missense single-nucleotide polymorphism (SNP) rs3134774 (K158R, P=3.28 × 10(-15), odds ratio =2.36 (95% confidence interval: 1.91-2.92)). After adjusting the association of the HERV-K dUTPase variants for the potential confounding effects of HLA alleles associated with psoriasis, the HERV-K SNPs rs9264082 and rs3134774 remained significantly associated. Haplotype analysis revealed that HERV-K haplotypes containing the non-risk alleles for rs3134774 and rs9264082 significantly reduced the risk of psoriasis. Functional testing showed higher antibody responses against recombinant HERV-K dUTPase in psoriasis patients compared with controls (P<0.05), as well as higher T-cell responses against a single HERV-K dUTPase peptide (P<0.05). Our data support an independent role for the HERV-K dUTPase on psoriasis susceptibility, and suggest the need for additional studies to clarify the role of this dUTPase in the pathogenesis of psoriasis.
Journal of Investigative Dermatology 03/2012; 132(7):1833-40. · 6.19 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We have previously shown that peroxisome proliferator activating receptor ß/δ (PPAR β/δ is overexpressed in psoriasis. PPAR β/δ is not present in adult epidermis of mice. Targeted expression of PPAR β/δ and activation by a selective synthetic agonist is sufficient to induce an inflammatory skin disease resembling psoriasis. Several signalling pathways dysregulated in psoriasis are replicated in this model, suggesting that PPAR β/δ activation contributes to psoriasis pathogenesis. Thus, inhibition of PPAR β/δ might harbour therapeutical potential. Since PPAR β/δ has pleiotropic functions in metabolism, skin-targeted inhibition offer the potential of reducing systemic adverse effects. Here, we report that three selective PPAR β/δ antagonists, GSK0660, compound 3 h, and GSK3787 can be formulated for topical application to the skin and that their skin concentration can be accurately quantified using ultra-high performance liquid chromatography (UPLC)/mass spectrometry. These antagonists show efficacy in our transgenic mouse model in reducing psoriasis-like changes triggered by activation of PPAR β/δ. PPAR β/δ antagonists GSK0660 and compound 3 do not exhibit systemic drug accumulation after prolonged application to the skin, nor do they induce inflammatory or irritant changes. Significantly, the irreversible PPAR β/δ antagonist (GSK3787) retains efficacy when applied topically only three times per week which could be of practical clinical usefulness. Our data suggest that topical inhibition of PPAR β/δ to treat psoriasis may warrant further exploration.
PLoS ONE 01/2012; 7(5):e37097. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Fumaric acid esters (FAE) have been used in the treatment of psoriasis for many years. In general, they are regarded as relatively safe compared with other antipsoriatic systemic treatments, with the most notable adverse effects being gastrointestinal upset, lymphopenia and transient flushing. Renal toxicity has only rarely been reported, and was not found in two independent prospective trials nor in a large retrospective evaluation of almost 1000 patients treated for a median of 44 months. We report three patients developing reversible proteinuria during FAE treatment. One of these displayed the same pattern upon repeated drug administration, thereby clearly indicating FAE treatment to be the causal trigger. The presented cases highlight proteinuria as a clinical concern in FAE treatment. Furthermore, as the novel FAE agent dimethylfumaric (DMF) ester (contained in BG00012/Panaclar) has previously been shown to be effective in psoriasis in a phase III trial and not shown renal toxicity in a large trial for multiple sclerosis, the current report suggests that market introduction of DMF for psoriasis should be pursued.
Clinical and Experimental Dermatology 08/2011; 36(6):632-4. · 1.33 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Identifying therapeutic targets for cancer treatment relies on consistent changes within particular types or sub-types of malignancy. The ability to define either consistent changes or sub-types of malignancy is often masked by tumor heterogeneity. To elucidate therapeutic targets in cutaneous squamous cell carcinoma (cSCC), the most frequent skin neoplasm with malignant potential, we have developed an integrated approach to gene expression profiling beginning with primary keratinocytes in culture. Candidate drivers of cSCC development were derived by first defining a set of in vitro cancer genes and then comparing their expression in a range of clinical data sets containing normal skin, cSCC and the benign hyper-proliferative condition psoriasis. A small interfering RNA (siRNA) screen of the resulting 21 upregulated genes has yielded targets capable of reducing xenograft tumor volume in vivo. Small-molecule inhibitors for one target, Polo-like kinase-1 (PLK1), are already in clinical trials for other malignancies, and our data show efficacy in cSCC. Another target, C20orf20, is identified as being overexpressed in cSCC, and siRNA-mediated knockdown induces apoptosis in vitro and reduces tumor growth in vivo. Thus, our approach has shown established and uncharacterized drivers of tumorigenesis with potent efficacy as therapeutic targets for the treatment of cSCC.