Giulia Spallone

Pharmacogenetics of psoriasis: HLA-Cw6 but not LCE3B/3C deletion nor TNFAIP3 polymorphism predisposes to clinical response to interleukin 12/23 blocker ustekinumab

Our understanding of the genetic basis of predisposition to psoriasis is increasing exponentially due to the progress of genetic studies. However, so far little is known about genetic predisposition in relation to the response to psoriasis treatments. Recent data identified genetic predictors for the clinical outcome of conventional treatments such as methotrexate, acitretin and vitamin D derivatives, but few studies are available on genetic predictors of response to biologics. We hypothesized that genetic variations associated with increased risk of developing psoriasis may also act as predictors for the outcome of biologic therapy.

A regulatory feedback loop involving p63 and IRF6 links the pathogenesis of 2 genetically different human ectodermal dysplasias.

The human congenital syndromes ectrodactyly ectodermal dysplasia-cleft lip/palate syndrome, ankyloblepharon ectodermal dysplasia clefting, and split-hand/foot malformation are all characterized by ectodermal dysplasia, limb malformations, and cleft lip/palate. These phenotypic features are a result of an imbalance between the proliferation and differentiation of precursor cells during development of ectoderm-derived structures. Mutations in the p63 and interferon regulatory factor 6 (IRF6) genes have been found in human patients with these syndromes, consistent with phenotypes. Here, we used human and mouse primary keratinocytes and mouse models to investigate the role of p63 and IRF6 in proliferation and differentiation. We report that the DeltaNp63 isoform of p63 activated transcription of IRF6, and this, in turn, induced proteasome-mediated DeltaNp63 degradation. This feedback regulatory loop allowed keratinocytes to exit the cell cycle, thereby limiting their ability to proliferate. Importantly, mutations in either p63 or IRF6 resulted in disruption of this regulatory loop: p63 mutations causing ectodermal dysplasias were unable to activate IRF6 transcription, and mice with mutated or null p63 showed reduced Irf6 expression in their palate and ectoderm. These results identify what we believe to be a novel mechanism that regulates the proliferation-differentiation balance of keratinocytes essential for palate fusion and skin differentiation and links the pathogenesis of 2 genetically different groups of ectodermal dysplasia syndromes into a common molecular pathway.

Developmental factor IRF6 exhibits tumor suppressor activity in squamous cell carcinomas

The transcription factor interferon regulatory factor 6 (IRF6) regulates craniofacial development and epidermal proliferation. We recently showed that IRF6 is a component of a regulatory feedback loop that controls the proliferative potential of epidermal cells. IRF6 is transcriptionally activated by p63 and induces its proteasome-mediated down-regulation, thereby limiting keratinocyte proliferative potential. We hypothesized that IRF6 may also be involved in skin carcinogenesis. Hence, we analyzed IRF6 expression in a large series of squamous cell carcinomas (SCCs) and found a strong down-regulation of IRF6 that correlated with tumor invasive and differentiation status. IRF6 down-regulation in SCC cell lines and primary tumors correlates with methylation on a CpG dinucleotide island located in its promoter region. To identify the molecular mechanisms regulating IRF6 potential tumor suppressive activity, we performed a genome-wide analysis by combining ChIP sequencing for IRF6 binding sites and gene expression profiling in primary human keratinocytes after siRNA-mediated IRF6 depletion. We observed dysregulation of cell cycle-related genes and genes involved in differentiation, cell adhesion, and cell–cell contact. Many of these genes were direct IRF6 targets. We also performed in vitro invasion assays showing that IRF6 down-regulation promotes invasive behavior and that reintroduction of IRF6 into SCC cells strongly inhibits cell growth. These results indicate a function for IRF6 in suppression of tumorigenesis in stratified epithelia.

Psoriasis, from Pathogenesis to Therapeutic Strategies: IL-21 as a Novel Potential Therapeutic Target

Psoriasis is a common (1-3% of the population worldwide), multifactorial, immune-mediated chronic skin disease. In psoriasis pathogenesis an over-reaction of local innate immune response initiates inflammation with subsequent involvement of adaptive immune response leading to the production of a panel of cytokines, chemokines and growth factors leading to epidermal hyperplasia. Recently, IL-21 has been involved in this process as this cytokine is overexpressed in psoriatic skin and can cause epidermal hyperplasia and inflammation when injected intradermally into mice. Moreover blockade of IL-21 with a human antibody against IL-21 reduces the epidermal thickness and the expression of Th1 and Th17 genes in the well-characterized model of human psoriasis-xenograft mouse. Therefore, the inhibition of this cytokine may be therapeutically effective in the treatment of psoriasis. Here we will review recent data on psoriasis pathogenesis focusing on the role of IL-21 as novel therapeutic target.

Programmed cell death in the skin

Differently from the other cells of the body, epidermal cells of the skin undergo a specific programmed cell death form named cornification. Many events take part to control this process, which has been described as a terminal differentiation program. Going from the innermost layer to the outermost, epidermal cells stop dividing, change their shape, acquire new cellular structures and strengthen their cytoskeleton. This is corroborated by the fact that during this physical transition they change their gene expression, reprogramming in some way their biochemical activity. The activation of critical enzymes, including proteases and transglutaminases is a fundamental cellular event. These enzymes are involved in building the supramolecular and cornified structures which confer resistance to the epidermis which carries out a vital function as a skin barrier, preserving the organism from various insults. Here we review current concepts about cornification and the mechanisms by which this process is preserved in species.

Efficacy of Short-Term Cyclosporine Treatment to Control Psoriasis-Related Events during Efalizumab Therapy

Efalizumab is a recombinant humanized anti-CD11a monoclonal antibody that blocks the activation, adhesion and trafficking of T cells and has been approved for the treatment of moderate-to-severe plaque psoriasis. To document management of the fluctuations in symptom control that patients with psoriasis sometimes experience during treatment, we performed a retrospective analysis of our experience using cyclosporine as an intercurrent treatment to control psoriasis-related adverse events (AEs) in 10 patients who had received continuous efalizumab therapy for 20–200 weeks prior to recurrence of symptoms. Combination therapy with cyclosporine and efalizumab was generally well tolerated and controlled the relapse effectively. There were no reports of severe AEs during combination treatment, and no clinically significant changes were noted in clinical and laboratory values. Although mild, localized psoriasis recurred in most of these patients after cyclosporine termination, no patient experienced rebound or psoriasis flare and all continued with long-term efalizumab treatment.

Targeted therapy in nonmelanoma skin cancers.

Nonmelanoma skin cancer (NMSC) is the most prevalent cancer in light-skinned populations, and includes mainly Basal Cell Carcinomas (BCC), representing around 75% of NMSC and Squamous Cell Carcinomas (SCC). The incidence of these tumors is continuously growing. It was found that the overall number of procedures for NMSC in US rose by 76%, from 1,158,298 in 1992 to 2,048,517 in 2006. Although mortality from NMSC tends to be very low, clearly the morbidity related to these skin cancers is very high. Treatment options for NMSC include both surgical and nonsurgical interventions. Surgery was considered the gold standard therapy, however, advancements in the knowledge of pathogenic mechanisms of NMSCs led to the identification of key targets for drug intervention and to the consequent development of several targeted therapies. These represent the future in treatment of these common forms of cancer ensuring a high cure rate, preservation of the maximal amount of normal surrounding tissue and optimal cosmetic outcome. Here, we will review recent advancements in NMSC targeted therapies focusing on BCC and SCC.

Patients with Moderate to Severe Plaque Psoriasis: One Year after the European Medicines Agency Recommendation of Efalizumab Suspension

Background: In February 19, 2009, the European Medicines Agency (EMA) had recommended the suspension of the marketing authorization for efalizumab after the occurrence of cases of progressive multifocal leukoencephalopathy. Objective: To explore the efficacy of alternative therapies for psoriasis and the health status of patients who discontinued efalizumab. Methods: An observational study was performed on 101 patients. After the EMA communication, efalizumab was discontinued in the following 2–3 months. In agreement with the patients, we decided to either prescribe other treatments or none at all. Results: After 1 year, 11 patients are still not treated, 63 patients are treated with biologics, and 9 patients are treated with systemic conventional therapies. Conclusion: In order to prevent rebound or relapse, various approaches are available, including cyclosporine, methotrexate and biologic therapies. Interestingly, in 11 out of 31 patients who did not receive any systemic drug, psoriasis is still under control, suggesting a long-term effect of efalizumab.

Detection of Adalimumab and Anti-Adalimumab Levels by ELISA: Clinical Considerations

Enabling Technology, Genomics, Proteomics Clinical Development Phases I‐III Regulatory, Quality, Manufacturing

Efficacy of efalizumab in psoriasis patients previously treated with tumour necrosis factor blockers.

Background: Biological therapy for moderate to severe psoriasis includes tumour necrosis factor (TNF) blockers (infliximab, etanercept and adalimumab) and T-cell-targeting agents (efalizumab, alefacept) that act in different steps of a common pathogenic pathway. Large amounts of data coming from clinical trials indicate each of these drugs as highly effective and safe. However, little is known about the efficacy of a second biological therapy after the failure of the first. Objective: To evaluate whether the response to efalizumab in psoriasis patients was influenced by previous treatment with other biological agents. Patients and Methods: We have retrospectively analyzed a group of 155 psoriasis patients treated with efalizumab during the last 5 years and determined its efficacy in patients previously treated with anti-TNF drugs comparing it with the efficacy and safety observed in patients previously treated with traditional systemic drugs instead. Results: Efalizumab was shown to be as efficacious and safe in patients previously treated with biological agents as in those previously treated with traditional systemic drugs. Although not statistically significant, we observed a higher rate of response to efalizumab in patients previously treated with anti-TNF-α. PASI 75 was achieved at week 24 in 76.2% of the patients previously treated with biological agents versus 54.4% in patients previously treated with traditional drugs (OR = 2.9). Conclusions: These data suggest that efalizumab can be successfully used in psoriasis patients when TNF blockers cannot efficiently control the disease due to lack or loss of response, or when they have to be interrupted for intolerance or adverse events.