Cornelia S. L. Müller

Inverse regulation of melanoma growth and migration by Orai1/STIM2‐dependent calcium entry

Spontaneous melanoma phenotype switching is controlled by unknown environmental factors and may determine melanoma outcome and responsiveness to anticancer therapy. We show that Orai1 and STIM2 are highly expressed and control store‐operated Ca2+ entry in human melanoma. Lower extracellular Ca2+ or silencing of Orai1/STIM2 caused a decrease in intracellular Ca2+, which correlated with enhanced proliferation and increased expression of microphthalmia‐associated transcription factor, a marker for proliferative melanoma phenotype. In contrast, the invasive and migratory potential of melanoma cells was reduced upon silencing of Orai1 and/or STIM2. Accordingly, markers for a non‐proliferative, tumor‐maintaining phenotype such as JARID1B and Brn2 decreased. Immunohistochemical staining of primary melanomas and lymph node metastases revealed a heterogeneous distribution of Orai1 and STIM2 with elevated expression in the invasive rim of the tumor. In summary, our results support a dynamic model in which Orai1 and STIM2 inversely control melanoma growth and invasion. Pharmacological tuning of Orai1 and particularly STIM2 might thus prevent metastatic spread and render melanomas more susceptible to conventional therapy.

ORAI1 Ca2+ Channels Control Endothelin-1-Induced Mitogenesis and Melanogenesis in Primary Human Melanocytes

UV radiation of the skin triggers keratinocytes to secrete endothelin-1 (ET-1) that binds to endothelin receptors on neighboring melanocytes. Melanocytes respond with a prolonged increase in intracellular Ca(2+) concentration ([Ca(2+)](i)), which is necessary for proliferation and melanogenesis. A major fraction of the Ca(2+) signal is caused by entry through Ca(2+)-permeable channels of unknown identity in the plasma membrane. ORAI Ca(2+) channels are molecular determinants of Ca(2+) release-activated Ca(2+) (CRAC) channels and are expressed in many tissues. Here, we show that ORAI1-3 and their activating partners stromal interaction molecules 1 and 2 (STIM1 and STIM2) are expressed in human melanocytes. Although ORAI1 is the predominant ORAI isoform, STIM2 mRNA expression exceeds STIM1. Inhibition of ORAI1 by 2-aminoethoxydiphenyl borate (2-APB) or downregulation of ORAI1 by small interfering RNA (siRNA) reduced Ca(2+) entry and CRAC current amplitudes in activated melanocytes. In addition, suppression of ORAI1 caused reduction in the ET-1-induced cellular viability, melanin synthesis, and tyrosinase activity. Our results imply a role for ORAI1 channels in skin pigmentation and their potential involvement in UV-induced stress responses of the human skin.

High-Level Expression of Wild-Type p53 in Melanoma Cells is Frequently Associated with Inactivity in p53 Reporter Gene Assays

Background Inactivation of the p53 pathway that controls cell cycle progression, apoptosis and senescence, has been proposed to occur in virtually all human tumors and p53 is the protein most frequently mutated in human cancer. However, the mutational status of p53 in melanoma is still controversial; to clarify this notion we analysed the largest series of melanoma samples reported to date. Methodology/Principal Findings Immunohistochemical analysis of more than 180 melanoma specimens demonstrated that high levels of p53 are expressed in the vast majority of cases. Subsequent sequencing of the p53 exons 5–8, however, revealed only in one case the presence of a mutation. Nevertheless, by means of two different p53 reporter constructs we demonstrate transcriptional inactivity of wild type p53 in 6 out of 10 melanoma cell lines; the 4 other p53 wild type melanoma cell lines exhibit p53 reporter gene activity, which can be blocked by shRNA knock down of p53. Conclusions/Significance In melanomas expressing high levels of wild type p53 this tumor suppressor is frequently inactivated at transcriptional level.

Changing a concept – controversy on the confusing spectrum of the reticulate pigmented disorders of the skin

Galli‐Galli disease (GGD) and Dowling‐Degos disease (DDD) are inherited skin diseases with variable progressive course. They are of benign and harmless behaviour but aesthetically annoying. They are subsumed within the group of reticulate pigmented disorders of the skin to which, additionally, Kitamura’s and Haber’s diseases are counted. Clinical appearance is approximately similar, with slight differences in age of onset and associated disorders. Histopathological features are almost similar aside from the unique hallmark of suprabasal acantholysis, which can exclusively be observed in GGD. We report four typical cases of reticulate pigmented disorders, clinically accordable to DDD but histopathologically allocated to GGD. In conclusion, we purpose the idea of a wide spectrum of reticulate pigmented disorders in which Morbus Galli‐Galli should probably be reclassified as a subset of DDD.

Clinicopathologic features of early lesions of primary cutaneous follicle center lymphoma, diffuse type: Implications for early diagnosis and treatment

BACKGROUND Data on early lesions of primary cutaneous follicle center lymphoma (PCFCL), diffuse type are very limited. OBJECTIVE We sought to elucidate the early clinicopathologic features of PCFCL, diffuse type. METHODS Clinical, histologic, immunohistologic, molecular, and fluorescence in situ hybridization data from 24 patients with early lesions of PCFCL, diffuse type (male:female = 19:5; median age: 57 years) were determined. RESULTS Lesions consisted mostly of solitary or clustered papules and small nodules located on the trunk (21 cases), arm (two cases), and scalp (one case). In 3 patients small papules were located at a distance from the main affected area. All biopsy specimens from early lesions showed aggregates of medium and large centrocytes admixed with small lymphocytes without formation of clear-cut lymph follicles. Staining for Bcl-2 was positive in only 7 cases, one revealing also a rearranged BCL2 signal by fluorescence in situ hybridization. Data on treatment and follow-up were available for 22 patients. At last examination 13 patients were in complete remission (median follow-up: 60 months), 6 were alive with skin disease alone (median follow-up: 60 months), two were alive with skin disease and bone-marrow or lymph node involvement, respectively, and one died of unrelated causes while in complete remission. LIMITATIONS The retrospective study and the fact that patients were treated at different institutions are limitations. CONCLUSIONS Early lesions of PCFCL, diffuse type present with characteristic clinicopathologic features. Dermatologists should be alert particularly to the early clinical manifestations of this lymphoma and to the presence of small, inconspicuous lesions at a distance from the main affected area in order to plan treatment properly.

Successful desensitization with human insulin in a patient with an insulin allergy and hypersensitivity to protamine: a case report

IntroductionInsulin allergy may occur in patients treated with subcutaneous applications of insulin preparations. Besides additives in the insulin preparation such as protamine, cresol, and phenol, the insulin molecule itself may be the cause of the allergy. In the latter case, therapeutic options are rare.Case presentationA 68-year-old man with poorly controlled type 2 diabetes mellitus received different insulin preparations subcutaneously while on oral medication. Six to eight hours after each subcutaneous application, he developed pruritic plaques with a diameter of >15 cm at the injection sites that persisted for several days. Allergologic testing revealed positive reactions against every insulin preparation and against protamine. Investigation of serum samples demonstrated IgG antibodies against human and porcine insulin. We treated the patient with human insulin using an ultra-rush protocol beginning with 0.004 IU and a rapid augmentation in dose up to 5 IU. Therapy was accompanied by antihistamine therapy. Subsequent conversion to therapy with glargine insulin (6 IE twice daily) was well-tolerated.ConclusionAs reported in this case, desensitization with subcutaneously administered human insulin using an ultra-rush protocol in patients with an insulin allergy may present an easy form of therapy that is successful within a few days.

Notch Signaling and Malignant Melanoma

Increasing evidence indicates that Notch signaling contributes to physiologic processes, including development, differentiation and tumorigenesis, either as a tumor promoter or suppressor depending on the cellular context, level of expression and cross-talk with other signaling systems. Notch signalling has been implicated in the regulation of self-renewal of adult stem cells and differentiation of precursors along a specific cell line in normal embryonic development and organogenesis. There is also evidence that signaling through Notch receptors regulates cell proliferation and cell survival in several types of cancer including malignant melanoma, with opposing results depending on the tissue context. Tumor progression/metastasis of malignant melanoma are complicated processes that require multiple cellular events, including cell proliferation, survival, migration and invasion. Notch signaling appears to be a promising system for new therapeutic targets for the treatment of melanoma and perhaps the prevention of melanoma metastasis.

Improved patient-centered care with effective use of Integra® in dermatologic reconstructive surgery

The incidence of skin tumors is increasing among elderly patients, and the multi‐morbidities which occur in the elderly are a great challenge for dermatologic surgeons. The currently required safety margins for different types of melanomas and non‐melanoma skin cancers lead to extensive and profound wounds.

The spectrum of reticulate pigment disorders of the skin revisited

Within the group of classical reticulate pigment disorders of the skin, Galli-Galli disease (GGD), Dowling-Degos disease (DDD), Kitamuras disease (RPK), Habers syndrome (HS), and reticulate acropigmentation of Dohi (RAD) are included and distinguished clinically and histopathologically. The clinical appearance of the reticulate pigment disorders of the skin is similar, with slight differences in age of onset and associated disorders. The histopathologic features of reticulate pigment disorders of the skin are comparable, with the exception of the unique hallmark of suprabasal acantholysis, which can be observed exclusively in GGD. Based on a critical discussion, we recommend using major and minor defining criteria for diagnosing skin lesions compatible with the reticulate pigment dermatoses of the skin. Herein we discuss a unifying nosological concept to provide straightforward diagnoses of the reticulate pigment disorders of the skin with a therapeutic impact.

Differential Regulation of Human Papillomavirus Type 8 by Interferon Regulatory Factors 3 and 7

ABSTRACT The genus β human papillomavirus (HPV) type 8 is associated with nonmelanoma skin cancer in patients with epidermodysplasia verruciformis, and evidence for its protumorigenic potential in the general population increases. To date, strategies to suppress genus β HPV infections are limited. Interferon regulatory factors IRF-3 and IRF-7 play key roles in the activation of the innate immune response to viral infections. In this study, we show for the first time that both IRF-3 and IRF-7 regulate transcription of a papillomavirus, but with opposing effects. IRF-7, expressed in the suprabasal layers of human epidermis, increased HPV8 late promoter activity via direct binding to viral DNA. UV-B light-induced activation of the HPV8 promoter involved IRF-7 as a downstream effector. In contrast, IRF-3, expressed in all layers of human epidermis, induced strong HPV8 suppression in primary keratinocytes. IRF-3-mediated suppression prevailed over IRF-7-induced HPV8 transcription. Unlike the E6 oncoprotein of the mucosal high-risk HPV16, the HPV8 E6 protein did not bind to IRF-3 and only weakly antagonized its activity. Strong antiviral activity was also observed, when keratinocytes were treated with potent IRF-3 activators, poly(I:C) or RNA bearing 5′ phosphates. In conclusion, we show that IRF-3 activation induces a state of cell-autonomous immunity against HPV in primary human keratinocytes. Our study suggests that local application of IRF-3-activating compounds might constitute an attractive novel therapeutic strategy against HPV8-associated diseases, particularly in epidermodysplasia verruciformis patients.