Melanoma
HPV8 Field Cancerization in a Transgenic Mouse Model Is due to Lrig1+ Keratinocyte Stem Cell Expansion
β-Human papillomaviruses (HPVs) cause near ubiquitous latent skin infection within long-lived hair follicle (HF) keratinocyte stem cells. In patients with epidermodysplasia verruciformis, β-HPV viral replication is associated with skin keratosis and cutaneous squamous cell carcinoma. To determine the role of HF keratinocyte stem cells in β-HPV-induced skin carcinogenesis, we utilized a transgenic mouse model in which the keratin 14 promoter drives expression of the entire HPV8 early region (HPV8tg).miR-146b Probably Assists miRNA-146a in the Suppression of Keratinocyte Proliferation and Inflammatory Responses in Psoriasis
miR-146a inhibits inflammatory responses in human keratinocytes and in different mouse models of skin inflammation. Little is known about the role of miR-146b in the skin. In this study, we confirmed the increased expression of miR-146a and miR-146b (miR-146a/b) in the lesional skin of patients with psoriasis. The expression of miR-146a was approximately twofold higher than that of miR-146b in healthy human skin, and it was more strongly induced by stimulation of proinflammatory cytokines in keratinocytes and fibroblasts.p63 Transcription Factor Regulates Nuclear Shape and Expression of Nuclear Envelope-Associated Genes in Epidermal Keratinocytes
The maintenance of a proper nuclear architecture and three-dimensional organization of the genes, enhancer elements, and transcription machinery plays an essential role in tissue development and regeneration. Here we show that in the developing skin, epidermal progenitor cells of mice lacking p63 transcription factor display alterations in the nuclear shape accompanied by a marked decrease in expression of several nuclear envelope-associated components (Lamin B1, Lamin A/C, Sun1, Nesprin-3, Plectin) compared with controls.CXCR3 Depleting Antibodies Prevent and Reverse Vitiligo in Mice
Vitiligo is a disfiguring skin disease in which melanocytes with intrinsic abnormalities are targeted and destroyed by autoreactive CD8+ T cells in the epidermis, resulting in patchy depigmentation (Palermo et al., 2001; van den Boorn et al., 2009, and reviewed in Richmond et al., 2013). Although it is one of the most common autoimmune diseases, affecting 1% of the population worldwide, there are no Food and Drug Administration-approved treatments. Previous work from our lab has shown that CD8+ T-cell recruitment to the skin in a mouse model of vitiligo is dependent on IFNγ (Harris et al., 2012) and the downstream CXCR3 chemokine system (Rashighi et al., 2014).GPR56/ADGRG1 Activation Promotes Melanoma Cell Migration via NTF Dissociation and CTF-Mediated Gα12/13/RhoA Signaling
GPR56/ADGRG1 is a versatile adhesion G protein-coupled receptor with diverse biological functions. GPR56 expression is variably detected in human melanoma cell lines and correlates inversely with the metastatic potential of melanoma lesions. GPR56 associates with the tetraspanins CD9 and CD81 on the melanoma cell surface. GPR56 activation by immobilized CG4 monoclonal antibody facilitates N-terminal fragment dissociation in a CD9/CD81-dependent manner specifically inducing IL-6 production, which promotes cell migration and invasion.RASopathy Gene Mutations in Melanoma
Next-generation sequencing of melanomas has unraveled critical driver genes and genomic abnormalities, mostly defined as occurring at high frequency. In addition, less abundant mutations are present that link melanoma to a set of disorders, commonly called RASopathies. These disorders, which include neurofibromatosis and Noonan and Legius syndromes, harbor germline mutations in various RAS/mitogen-activated protein kinase signaling pathway genes. We highlight shared amino acid substitutions between this set of RASopathy mutations and those observed in large-scale melanoma sequencing data, uncovering a significant overlap.Promoter Methylation of PTEN Is a Significant Prognostic Factor in Melanoma Survival
Structural compromise of the tumor suppressor gene, phosphatase and tensin homolog (PTEN), occurs in 10% of melanoma specimens, and loss of PTEN expression through DNA methylation of the PTEN promoter region has also been reported in a number of other malignancies. However, the role of PTEN promoter methylation in melanoma is not well understood. We thus sought to elucidate the prevalence of PTEN promoter methylation in melanoma specimens, its relationship to clinical features, and its impact on the outcome of patients with melanoma.Mosaic Activating Mutations in GNA11 and GNAQ Are Associated with Phakomatosis Pigmentovascularis and Extensive Dermal Melanocytosis
Common birthmarks can be an indicator of underlying genetic disease but are often overlooked. Mongolian blue spots (dermal melanocytosis) are usually localized and transient, but they can be extensive, permanent, and associated with extracutaneous abnormalities. Co-occurrence with vascular birthmarks defines a subtype of phakomatosis pigmentovascularis, a group of syndromes associated with neurovascular, ophthalmological, overgrowth, and malignant complications. Here, we discover that extensive dermal melanocytosis and phakomatosis pigmentovascularis are associated with activating mutations in GNA11 and GNAQ, genes that encode Gα subunits of heterotrimeric G proteins.
