c-Rel is a cell cycle modulator in human melanoma cells.

Melanoma progression and resistance to therapy are associated with faulty regulation of signalling molecules including the central transcription factor NF-κB. Increased expression of the c-Rel subunit of NF-κB has been described in progressing melanoma, though mechanistic implications of this upregulation remain unclear. To elucidate the functional role of c-Rel in melanoma biology, we have assessed its expression in human melanoma as well as in melanoma cell lines. Suppression of c-Rel expression in four melanoma cell lines resulted in reduced growth and altered cell cycle regulation, namely G2/M and polyploid phase induction. Moreover, mitotic spindle morphology was profoundly altered in three of the cell lines with a predominance of monopolar structures. These findings suggest that c-Rel is involved in G2/M phase regulation, prevention of polyploidy and, consequently, chromosomal stability. Our results highlight a novel tumor-promoting function of c-Rel in human melanoma cells through governing cell cycle regulation.

Morphologische Kriterien vesikulobullöser Hauterkrankungen in der konfokalen In-vivo-Laserscanmikroskopie.

HINTERGRUND UND ZIELVORGABEN: Konfokale Laserscanmikroskopie (Reflectance confocal microscopy; RCM) kann eine nützliche Methode für die genaue, schnelle und nicht-invasive Diagnose für vesikullobullöse Hauterkrankungen (VSD) am Krankenbett sein. Das primäre Ergebnis dieser Studie war eine deskriptive statistische Analyse von RCM-Merkmalen, die mit einer ausgewählten Gruppe an VSD einhergehen. PATIENTEN UND METHODEN: Monozentrische Beobachtungsstudie an einer Universitätsklinik für Dermatologie. Vierzig Hautläsionen bei 24 Patienten mit bullösem Pemphigoid (BP), Infektion mit Varizella Zoster (VZI) oder allergischer Kontaktdermatitis (ACD) wurden ausgewertet. ERGEBNISSE: Patienten mit BP, VZI und ACD wurden auf die Anwesenheit eines großen Spektrums an RCM-Merkmalen hin untersucht, darunter die histopathologische Korrelation von Spongiose, Vesikel/Hautblasen, epidermaler Nekrose, pleomorphen, ballonierte Keratinozyten und entzündlichen Infiltraten. Die drei Erkrankungen zeigten spezifische Muster für Auftreten dieser RCM-Merkmale. Wir identifizierten mit Hilfe einer multivariaten Regressionsanalyse einen Satz morphologischer Merkmale bei BP (Vesikel/Hautblasen an der dermoepidermalen Junktionszone, entzündliche Infiltrate in Hautblasen und basalen Epidermisschichten, Spongiose in basalen Epidermisschichten), VZI (Akantholyse im Stratum spinosum, epidermale Nekrose, pleomorphe, ballonierte Keratinozyten, multinukleäre Riesenzellen) und ACD (Mikrovesikel, Spongiose und auffällige entzündliche Infiltrate im Stratum granulosum/spinosum). SCHLUSSFOLGERUNGEN: RCM scheint ein nützliches Werkzeug bei der Analyse und der Unterscheidung einer ausgewählten Gruppe von VSDs zu sein und bietet eine gute Korrelation mit histopathologischen Untersuchungsergebnissen.

Morphologic criteria of vesiculobullous skin disorders by in vivo reflectance confocal microscopy.

BACKGROUND AND OBJECTIVES: Reflectance confocal microscopy (RCM) may be a useful method for accurate, rapid, and noninvasive bedside diagnosis of vesiculobullous skin diseases (VSD). The main outcome measure of this study was a descriptive statistical analysis of RCM features associated with selected group of VSD. PATIENTS AND METHODS: Single-center, observational study at a university-based dermatology department. Forty skin lesions in 24 patients with bullous pemphigoid (BP), varicella zoster virus infection (VZI), or allergic contact dermatitis (ACD) were assessed. RESULTS: Patients with BP, VZI, and ACD were assessed for the presence of a large spectrum of RCM features, among others including histopathological correlates for spongiosis, vesicles/blisters, epidermal necrosis, pleomorphic ballooned keratinocytes, and inflammatory infiltrate. The three conditions showed distinct patterns of occurrence with respect to these RCM features. Using a multivariate regression model, we identified sets of morphologic features in BP (vesicles/blisters at the dermoepidermal junction, inflammatory infiltrate within blisters and basal epidermal layers, spongiosis in basal epidermal layers), VZI (acantholysis in the stratum spinosum, epidermal necrosis, pleomorphic ballooned keratinocytes, multinucleated giant cells), and ACD (microvesicles, spongiosis, and prominent inflammatory infiltrate in the stratum granulosum/spinosum). CONCLUSIONS: RCM seems to be a useful tool in the evaluation and differentiation of a selected group of VSD, and offers a good correlation with histopathological findings.

c-Rel in Epidermal Homeostasis: A Spotlight on c-Rel in Cell Cycle Regulation.

To maintain proper skin barrier function, epidermal homeostasis requires a subtly governed balance of proliferating and differentiating keratinocytes. While differentiation takes place in the suprabasal layers, proliferation, including mitosis, is usually restricted to the basal layer. Only recently identified as an important regulator of epidermal homeostasis, c-Rel, an NF-κB transcription factor subunit, affects the viability and proliferation of epidermal keratinocytes. In human keratinocytes, decreased expression of c-Rel causes a plethora of dysregulated cellular functions including impaired cell viability, increased apoptosis, and abnormalities during mitosis and cell cycle regulation. On the other hand, c-Rel shows aberrant expression in many epidermal tumors. Here, in the context of its role in different cell types and compared with other NF-κB subunits, we discuss the putative function of c-Rel as a regulator of epidermal homeostasis and mitotic progression. In addition, implications for disease pathophysiology with perturbed c-Rel function and abnormal homeostasis, such as epidermal carcinogenesis, will be discussed.

Vasoactive Therapy in Systemic Sclerosis: Real-life Therapeutic Practice in More Than 3000 Patients.

OBJECTIVE: Vasculopathy is a key factor in the pathophysiology of systemic sclerosis (SSc) and the main cause for Raynaud phenomenon (RP), digital ulcers (DU), and/or pulmonary arterial hypertension (PAH). It is so far unknown how patients with SSc are treated with vasoactive agents in daily practice. To determine to which extent patients with SSc were treated with different vasoactive agents, we used data from the German Network for Systemic Scleroderma registry. METHODS: The data of 3248 patients with SSc were analyzed. RESULTS: Patients were treated with vasoactive drugs in 61.1% of cases (1984/3248). Of these, 47.6% received calcium channel inhibitors, followed by 34.2% treated with angiotensin-converting enzyme (ACE) inhibitors, 21.1% treated with intravenous (IV) prostanoids, 10.1% with pentoxifylline, 8.8% with angiotensin 1 receptor antagonists (AT1RA), 8.7% with endothelin 1 receptor antagonists (ET1RA), 4.1% with phosphodiesterase type 5 (PDE5) inhibitors, and 5.3% with others. Patients with RP received vasoactive therapy in 63.3% of cases, with DU in 70.1%, and with PAH in 78.2% of cases. Logistic regression analysis revealed that patients with PAH were significantly more often treated with PDE5 inhibitors and ET1RA, and those with DU with ET1RA and IV prostanoids. In addition, 41.8% of patients were treated with ACE inhibitors and/or AT1RA. Patients registered after 2009 received significantly more often ET1RA, AT1RA, and IV prostanoids compared with patients registered prior to 2005. CONCLUSION: These data clearly indicate that many patients with SSc do not yet receive sufficient vasoactive therapy. Further, in recent years, a marked change of treatment regimens can be observed.

The c-Rel subunit of NF-κB is a crucial regulator of phenotype and motility of HaCaT keratinocytes.

The transcription factor NF-κB exerts key functions in epidermal homeostasis and carcinogenesis. Its c-Rel subunit is expressed in squamous cell carcinoma, and c-Rel down-regulation results in increased apoptosis, G2/M cell cycle delay with reduced proliferation and aberrant mitotic spindle formation. To further study the impact of c-Rel on essential keratinocyte features such as migration and epithelial morphology, c-Rel was down-regulated in HaCaT keratinocytes by a siRNA approach. This inhibition of c-Rel impaired the keratinocyte-typical clustered growth leading to a more scattered appearance of the cultures. The cells were more spindle-shaped and elongated, albeit without expression changes of markers characteristic for epithelial mesenchymal transition. In addition, wound healing-related migration and adhesion to type I collagen, fibronectin, laminin and vitronectin were significantly impaired. On the sub-cellular level, these functional features were not associated with quantitatively altered adhesion receptor or Rho-GTPase expression, but rather with a significantly reduced length of cell-matrix adhesion complexes and altered appearance of filamentous actin. Thus, our studies support a role for c-Rel in processes crucial for keratinocyte integrity and malignant transformation such as adhesion and migration.

The novel PI3 kinase inhibitor, BAY 80-6946, impairs melanoma growth in vivo and in vitro.

Due to its almost universal resistance to chemotherapy, metastasized melanoma remains a major challenge in clinical oncology. Given that phosphatidyl inositol-3 kinase (PI3K) activation in melanoma cells is associated with poor prognosis, disease progression and resistance to chemotherapy, the PI3K-Akt signalling pathway is a promising therapeutic target for melanoma treatment. We analysed six human melanoma cell lines for their constitutive activation of Akt and then tested two representative lines, A375 and LOX, for their susceptibility to PI3K-inhibition by the highly specific small molecule inhibitor, BAY 80-6946. In addition, the effect of BAY 80-6946 on A375 and LOX melanoma cells was assessed in vivo in a xenotransplantation mouse model. We provide experimental evidence that specifically inhibiting the PI3K pathway and phosphorylation of Akt by this novel compound results in antitumoral activities including inhibition of proliferation, induction of apoptosis and cell cycle arrest in vitro and in vivo. However, the susceptibility did not show a clear-cut pattern and differed between the melanoma cell lines tested, resulting in in vivo growth inhibition of A375 but not LOX melanoma cells. Thus, in some cases BAY 80-6946 or related compounds may be a valuable addition to the therapeutic armamentarium.

Non-steroidal anti-inflammatory drug hypersensitivity: association with elevated basal serum tryptase?

BACKGROUND: It is hypothesized that because of higher mast cell numbers and mediator release, mastocytosis predisposes patients for systemic immediate-type hypersensitivity reactions to certain drugs including non-steroidal anti-inflammatory drugs (NSAID). OBJECTIVE: To clarify whether patients with NSAID hypersensitivity show increased basal serum tryptase levels as sign for underlying mast cell disease. METHODS: As part of our allergy work-up, basal serum tryptase levels were determined in all patients with a diagnosis of NSAID hypersensitivity and the severity of the reaction was graded. Patients with confirmed IgE-mediated hymenoptera venom allergy served as a comparison group. RESULTS: Out of 284 patients with NSAID hypersensitivity, 26 were identified with basal serum tryptase > 10.0 ng/mL (9.2%). In contrast, significantly (P = .004) more hymenoptera venom allergic patients had elevated tryptase > 10.0 ng/mL (83 out of 484; 17.1%). Basal tryptase > 20.0 ng/mL was indicative for severe anaphylaxis only in venom allergic subjects (29 patients; 4x grade 2 and 25x grade 3 anaphylaxis), but not in NSAID hypersensitive patients (6 patients; 4x grade 1, 2x grade 2). CONCLUSIONS: In contrast to hymenoptera venom allergy, NSAID hypersensitivity do not seem to be associated with elevated basal serum tryptase levels and levels > 20 ng/mL were not related to increased severity of the clinical reaction. This suggests that mastocytosis patients may be treated with NSAID without special precautions.

c-Rel downregulation affects cell cycle progression of human keratinocytes.

The c-Rel protein, a member of the NF-κB transcription factor family, exerts unique and distinctive functions in various cell types. Although c-Rel is expressed in human epidermis, its functions in keratinocytes are poorly understood. Our small interfering RNA-based approach of c-Rel silencing in HaCaT keratinocytes induced altered cell morphology toward a spindle-shaped appearance. In addition, c-Rel downregulation resulted in increased apoptosis and significantly reduced proliferation towing to G2/M cell cycle delay, concomitant aberrant mitotic spindle formation, and induction of phospho-aurora A(Thr288). The relevance of c-Rel in epithelial carcinogenesis was further supported by detection of c-Rel expression in squamous cell carcinomas of the skin. Our studies indicate that c-Rel is a key regulator of cell fate decisions in keratinocytes such as cell growth and death and may have a role in epidermal carcinogenesis.

Drug-induced exanthems: correlation of allergy testing with histologic diagnosis.

BACKGROUND: Skin biopsies are commonly performed to confirm drug-induced exanthem (DIE). However, the relevance of histologic examination in discriminating between DIE and non-DIE (NDIE) is controversial. OBJECTIVE: A retrospective analysis was performed to evaluate the reliability of histologic diagnosis of DIE. METHODS: In all, 91 patients with a skin biopsy specimen of an acute exanthem temporally related to a single identifiable drug underwent complete allergy testing. Their biopsy specimens were retrospectively re-evaluated by 2 dermatopathologists blinded to the original reports to test for discrimination between DIE versus NDIE. RESULTS: In 35 patients, non-IgE-mediated drug allergy was confirmed by allergy testing, whereas in 56 patients drug hypersensitivity could be excluded. Sensitivity of pathology reports for diagnosis of DIE reached 62.9% with a positive predictive value of 40.7%. Specificity was 41.1% with a negative predictive value of 69.7%. No significant difference in tissue eosinophilia was detected between DIE and NDIE. LIMITATIONS: This was a retrospective study. CONCLUSIONS: Dermatopathologic evaluation of skin biopsy specimens is of limited use in differentiating between DIE and NDIE. All efforts should be made to subject these patients to thorough allergy testing for definitely confirming or ruling out drug hypersensitivity.

Oxaliplatin-Induced Leukocytoclastic Vasculitis under Adjuvant Chemotherapy for Colorectal Cancer: Two Cases of a Rare Adverse Event.

Leukocytoclastic vasculitis is a multicausal systemic inflammatory disease of the small vessels, histologically characterized by inflammation and deposition of both nuclear debris and fibrin in dermal postcapillary venules. The clinical picture typically involves palpable purpura of the lower legs and may be associated with general symptoms such as fatigue, arthralgia and fever. Involvement of the internal organs, most notably the kidneys, the central nervous system or the eyes, is possible and determines the prognosis. Oxaliplatin-induced leukocytoclastic vasculitis is a very rare event that limits treatment options in affected patients. We report 2 patients who developed the condition under chemotherapy for advanced rectal and metastatic colon carcinoma, respectively; a termination of the therapy was therefore necessary. While current therapies for colorectal cancer include the combination of multimodal treatment with new and targeted agents, rare and unusual side effects elicited by established agents also need to be taken into account for the clinical management.