SHARPIN regulates cell proliferation of cutaneous basal cell carcinoma via inactivation of the transcriptional factors GLI2 and c­JUN.

SHANK­associated RH domain­interacting protein (SHARPIN) is a component of the linear ubiquitin chain assembly complex that can enhance the NF­κB and JNK signaling pathways, acting as a tumor­associated protein in a variety of cancer types. The present study investigated the role of SHARPIN in cutaneous basal cell carcinoma (BCC). Human BCC (n=26) and normal skin (n=5) tissues, and BCC (TE354.T) and normal skin (HaCaT) cell lines were used to evaluate SHARPIN expression level using immunohistochemistry and western blotting, respectively. A lentivirus carrying SHARPIN­targeting or negative control short hairpin RNA was infected into TE354.T cells, and the infected stable cells were assayed to analyze tumor cell proliferation, cell cycle, apoptosis, migration and invasion by Cell Counting Kit­8 and 5­ethynyl­2'­deoxyuridine incorporation assays, flow cytometry and Transwell assays. Western blotting was performed to assess the protein expression levels of gene signaling in SHARPIN­silenced BCC cells. SHARPIN protein expression levels were downregulated or absent in BCC cancer nests and precancerous lesions compared with normal skin samples. In addition, SHARPIN expression levels were lower in TE354.T cells compared with HaCaT cells. SHARPIN shRNA enhanced tumor cell proliferation and the S phase of the cell cycle, whereas BCC cell apoptotic rates, and migratory and invasive abilities were not significantly altered. The expression levels of cyclin D1, cyclin­dependent kinase 4, phosphorylated­c­JUN and GLI family zinc finger 2 proteins were increased, whereas Patched 1 (PTCH1) and PTCH2 were decreased in the SHARPIN­shRNA­infected BCC cells. Therefore, the present results suggested that SHARPIN may act as a tumor suppressor during BCC development.

Mutation and expression of ABCA12 in keratosis pilaris and nevus comedonicus.

Keratosis pilaris (KP) and nevus comedonicus (NC) are congenital keratinized dermatoses; however, the exact etiology of these two diseases is unclear. The objective of the present study was to identify the disease­causing genes and their association with functional alterations in the development of KP and NC. Peripheral blood samples of one KP family, two NC families and 100 unrelated healthy controls were collected. The genomic sequences of 147 genes associated with 143 genetic skin diseases were initially analyzed from the KP proband using a custom­designed GeneChip. A novel heterozygous missense mutation in the ATP­binding cassette sub­family A member 12 (ABCA12) gene, designated c.6694G>T (p.Asp2232Tyr), was identified in the KP proband and confirmed by Sanger sequencing. The same mutation was also present in the affected family members but not in the healthy family members, the two patients with NC or population­matched controls. The predictions provided by PolyPhen­2 and SIFT analyses suggested that the mutation may produce a damaged protein. The region surrounding the mutation is the extra­membrane domain, which is conserved among particular species, as suggested by ClustalX; however, no ABCA12 mutations were reported in the patients with NC. As observed by immunofluorescence, ABCA12 expression was upregulated in the sebaceous glands of the patients with NC compared with that of normal controls. In summary, ABCA12­associated mutations or alterations in expression may exhibit causative or contributive effects to the development of keratinized dermatoses, including KP and NC.

Novel D323G mutation of DSG4 gene in a girl with localized autosomal recessive hypotrichosis clinically overlapped with monilethrix.

BACKGROUND: Localized autosomal recessive hypotrichosis (LAH) is an inherited rare disease caused by DSG4 mutations, characterized by short, sparse, brittle hair affecting restricted areas such as the scalp, trunk, and extremities. To date, DSG4 mutations have been reported in 14 pedigrees of LAH overlapping with monilethrix. METHODS: To clarify the etiology of hair defects for a 2-year-old Chinese girl, peripheral blood, skin, and hair samples were collected, and skin immunohistochemistry, electron microscopy (scanning and transmission types), Vivascope confocal microscopy, and DSG4 sequencing were investigated. RESULTS: The patient presented sparse hairs of various length and follicular hyperkeratotic papules. Eyebrows and lashes were also involved (broke or shed). The biopsy specimen revealed curled ingrown hair shafts within the hair follicle and keratin-filled hair follicles. Scanning electron microscopy revealed hair cuticle loosely and irregularly arranged, as well as a marked warping, curling, cracking, and detachment of hair cuticle. Transmission electron microscopy indicated notable dysadhesion between cells of the outer root sheath. A homozygous mutation A1103G in exon 8 of DSG4 was identified in the patient, resulting in the substitution of an aspartic acid by glycine (D323G) and reduced DSG4 expression in the affected scalp epidermis. CONCLUSIONS: The homozygous A1103G mutation in DSG4 was responsible for the disease development.

Splicing mutation in MVK is a cause of porokeratosis of Mibelli.

Porokeratosis is a chronic skin disorder characterized by the presence of patches with elevated, thick, keratotic borders, with histological cornoid lamella. Classic porokeratosis of Mibelli (PM) frequently appears in childhood with a risk of malignant transformation. Disseminated superficial actinic porokeratosis (DSAP) is the most common subtype of porokeratosis with genetic heterogeneities, and mevalonate kinase gene (MVK) mutations have been identified in minor portion of DSAP families of Chinese origin. To confirm the previous findings about MVK mutations in DSAP patients and test MVK's role(s) in PM development, we performed genomic sequence analysis for 3 DSAP families and 1 PM family of Chinese origin. We identified a splicing mutation of MVK gene, designated as c.1039+1G>A, in the PM family. No MVK mutations were found in three DSAP families. Sequence analysis for complementary DNA templates from PM lesions of all patients revealed a mutation at splice donor site of intron 10, designated as c.1039+1G>A, leading to the splicing defect and termination codon 52 amino acids after exon 10. Although no MVK mutations in DSAP patients were found as reported previously, we identified MVK simultaneously responsible for PM development.

Genetic diagnosis in a Chinese Hailey-Hailey disease pedigree with novel ATP2C1 gene mutation.

Hailey-Hailey disease (HHD) is an autosomal dominant skin disorder characterized by recurrent eruption of vesicles and bullae at the sites of friction and in the intertriginous areas. Mutations in the ATP2C1 gene encoding the human secretory pathway calcium ATPase 1 (hSPCA1) have been identified as the causative mutations in HHD. In this study, we used direct sequencing and restriction endonuclease digestion to analyze mutations of the ATP2C1 gene in a Chinese three-generation pedigree. A heterozygous T-to-C transition at nucleotide 1004 in exon 12 of ATP2C1 gene was detected. After summarizing the reported cases with ATP2C1 mutation, we concluded that the T1004C transition resulted in a novel missense mutation of leucine condon (CTG) to proline (CCG) at amino acid residue 335(L335P) in hSPCA1. Here, a genetic diagnosis was made for the proband's daughter before the clinical presentation. The study realized the molecular diagnosis in the HHD pedigree. Our findings should be useful for genetic counseling and prenatal diagnosis for the affected family and in demonstrating the critical role of the ATP2C1 gene in the pathogenesis of HHD further.

Five mutations of ATP2A2 gene in Chinese patients with Darier's disease and a literature review of 86 cases reported in China.

Darier's disease (DD) is an autosomal dominantly inherited skin disorder characterized by loss of adhesion between epidermal cells (acantholysis) and abnormal keratinization. To date, at least 140 mutations in the ATP2A2 gene have been identified as the genetic basis of DD. Here we reported three familial and two sporadic Chinese DD patients totally with four missense mutations (N767D, M494I, M494L, C318F) and one splice-site mutation (1288-6A-->G) in ATP2A2 gene, and presented a literature review of DD cases reported in China since 1989. Our data add new variants to the repertoire of ATP2A2 gene in DD and confirms that most mutations in the ATP2A2 gene are private and missense type. Likewise, the literature review indicates that DD is not uncommon in China and presents more information about genotype-phenotype correlations.

Identification of the cylindromatosis tumor-suppressor gene responsible for multiple familial trichoepithelioma.

Multiple familial trichoepithelioma (MFT) is an autosomal dominant skin disease characterized by the presence of many small benign tumors with pilar differentiation predominantly on the face. The first locus has been previously mapped to chromosome 9p21, but no gene for MFT has been identified to date. To identify the disease gene in a large Chinese family, we initially performed linkage analysis with microsatellite markers from 9p21, but failed to confirm the linkage to this region. Previous publications showed MFT and familial cylindromatosis (FC) can occur within one family and in a single person. Therefore, we speculated that the cylindromatosis gene (CYLDI gene) responsible for FC may be related to the pathogenesis of MFT. In view of that, we genotyped all available individuals using 11 microsatellite markers spanning the CYLDI gene region at 16q12-q13. We identified the linkage of MFT to this region. Mutation analysis in the CYLDI gene detected a frameshift mutation, designated as c.2355-2358delCAGA. The study firstly identified the cylindromatosis gene responsible for MFT and showed that different mutations of the CYLDI gene can give rise to distinct clinical and histological expression such as FC and MFT.