Effects of photodynamic therapy evaluated in a novel three-dimensional squamous cell carcinoma organ construct of the skin.

Squamous cell carcinoma (SCC) of the skin is a malignant neoplasm that occurs in all ethnic groups primarily due to chronic sun exposure and constitutes a major health problem worldwide. Novel therapies for SCC are in development but as yet no in vitro models capable of screening these therapies and their mechanism of action before proceeding to clinical trials in human subjects have emerged. For this reason we have developed and characterized a novel three-dimensional human SCC construct and validated it using photodynamic therapy (PDT), a well-established modality for treating in situ SCCs. Histologic and immunohistochemical characterization of these SCC constructs revealed epidermal and dermal de-differentiation, increased cell proliferation and expression of immunohistochemical markers specific for cutaneous SCC. Application of PDT to these constructs led to tumor regression with widespread apoptosis and necrosis within 5 days. This in vitro model consistently reproduces the tumor development and dynamics of growing SCCs in vivo and provides a useful approach for screening new treatment modalities for this form of cutaneous cancer.

Allelic loss underlies type 2 segmental Hailey-Hailey disease, providing molecular confirmation of a novel genetic concept.

Hailey-Hailey disease (HHD) is an autosomal dominant trait characterized by erythematous and oozing skin lesions preponderantly involving the body folds. In the present unusual case, however, unilateral segmental areas along the lines of Blaschko showing a rather severe involvement were superimposed on the ordinary symmetrical phenotype. Based on this observation and similar forms of mosaicism as reported in other autosomal dominant skin disorders, we postulated that in such cases, 2 different types of segmental involvement can be distinguished. Accordingly, the linear lesions as noted in the present case would exemplify type 2 segmental HHD. In the heterozygous embryo, loss of heterozygosity occurring at an early developmental stage would have given rise to pronounced linear lesions reflecting homozygosity or hemizygosity for the mutation. By analyzing DNA and RNA derived from blood and skin samples as well as keratinocytes of the index patient with various molecular techniques including RT-PCR, real-time PCR, and microsatellite analysis, we found a consistent loss of the paternal wild-type allele in more severely affected segmental skin regions, confirming this hypothesis for the first time, to our knowledge, at the molecular and cellular level.

Retinoic acid and its 4-oxo metabolites are functionally active in human skin cells in vitro.

Retinoic acid exerts a variety of effects on gene transcription that regulate growth, differentiation, and inflammation in normal and neoplastic skin cells. Because there is a lack of information regarding the influence of metabolic transformation of retinoids on their pharmacologic effects in skin, we have analyzed the functional activity of all-trans-, 9-cis-, and 13-cis-retinoic acid and their 4-oxo-metabolites in normal human epidermal keratinocytes (NHEKs) and dermal fibroblasts using gene and protein expression profiling techniques, including cDNA microarrays, two-dimensional gel electrophoresis, and MALDI-MS. It was previously thought that the 4-oxo-metabolites of RA are inert catabolic end-products but our results indicate instead that they display strong and isomer-specific transcriptional regulatory activity in both NHEKs and dermal fibroblasts. Microarray and proteomic analyses identified a number of novel genes/gene products that are influenced by RA treatment of NHEKs or fibroblasts, including genes for enzymes catalyzing biotransformation of retinoids, corticosteroids, and antioxidants and structural and transport proteins known to be essential for homeostasis. Our results expand current knowledge regarding retinoic acid action within skin cells and the target tissue/cell regulatory systems that are important for modulating the physiological and pharmacological effects of this important class of dermatological drugs.

Phenotype diversity in familial cylindromatosis: a frameshift mutation in the tumor suppressor gene CYLD underlies different tumors of skin appendages.

Familial cylindromatosis (turban tumor syndrome; Brooke-Spiegler syndrome) (OMIM numbers 123850, 132700, 313100, and 605041) is a rare autosomal dominantly inherited tumor syndrome. The disorder can present with cutaneous adnexal tumors such as cylindromas, trichoepitheliomas, and spiradenomas, and tumors preferably develop in hairy areas of the body such as head and neck. In affected families, mutations have been demonstrated in the CYLD gene located on chromosome 16q12-13 and reveal the characteristic attributes of a tumor suppressor. Here, we studied familial cylindromatosis in a multigeneration family of German origin. Clinically, some individuals only revealed discrete small skin-colored tumors localized in the nasolabial region whereas one family member showed expansion of multiple big tumors on the trunk and in a turban-like fashion on the scalp. Histologically, cylindromas as well as epithelioma adenoides cysticum were found. We detected a frameshift mutation in the CYLD gene, designated 2253delG, underlying the disorder and were able to show that a single mutation can result in distinct clinical and histologic expression in familial cylindromatosis. The reasons for different expression patterns of the same genetic defect in this disease remain elusive, however. Identification of mutations in the CYLD gene enable us to rapidly confirm putative diagnoses on the genetic level and to provide affected families with genetic counseling.