RESUMO
Ewing family tumors (EFTs) are associated with a chromosomal translocation resulting in a fusion of the amino-terminus of EWS with the DNA-binding domain of an ETS transcription factor. Although previous reports suggested that these chimeric proteins would act as aberrant transcription factors, their downstream targets have not been fully elucidated. To identify downstream targets of these EWS-ETS fusion proteins, we introduced EWS-ETS fusion constructs into a human fibrosarcoma cell line, HT-1080, by retroviral transduction. Here we report that the LAMB3 gene encoding the beta3 chain of basement membrane protein laminin-5 is induced to a significantly higher level in cells expressing EWS-ETSs than in cells expressing normal ETSs. Additionally through use of an antisense oligonucleotide for EWS-ERG in the W-ES EFT cell line, laminin beta3 protein was reduced coordinately with EWS-ERG fusion protein expression. Furthermore, we found small mRNAs were preferentially transcribed from the LAMB3 gene in EFT cell lines. Molecular cloning of the entire coding region shows that the alternative transcripts from different promoter(s) located within the intron 14, which encode small proteins, likely are major products of the LAMB3 gene in EFT cells. We show that the small isoforms conferred increased anchorage-independent proliferation to NIH3T3 cells. Together with previous studies showing that laminin-5 is involved in the invasive and malignant phenotype of several tumor types, our data suggest that the oncogenic effect of EWS-ETS may be mediated in part by upregulation of LAMB3 expression.
Assuntos
Moléculas de Adesão Celular/genética , Proteínas de Fusão Oncogênica/genética , Proteínas Proto-Oncogênicas c-ets/genética , Proteína EWS de Ligação a RNA/genética , Sarcoma de Ewing/genética , Animais , Moléculas de Adesão Celular/metabolismo , Linhagem Celular Tumoral , Clonagem Molecular , Humanos , Camundongos , Células NIH 3T3 , Oligonucleotídeos Antissenso/farmacologia , Proteínas de Fusão Oncogênica/metabolismo , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , RNA Mensageiro/metabolismo , Proteínas Recombinantes de Fusão/metabolismo , Retroviridae/genética , Sarcoma de Ewing/metabolismo , Sarcoma de Ewing/patologia , CalininaRESUMO
We examined the characteristics of melanin distribution, the possible mechanisms underlying the histological incontinence of pigment, and the significance of epidermal macrophages in photodamaged skin. We used electron microscopy to compare and quantitate melanin distribution in various types of cells and structures, to qualitatively observe associations of melanin granules with melanophages, and to examine morphological differences of epidermal macrophages in sun-exposed versus sun-protected facial skin. Melanin-containing cells (such as Langerhans' cells) and melanin-containing structures (such as colloid bodies) in photodamaged skin were more numerous than in sun-protected skin, in proportion to differences in melanocyte density and in epidermal melanin content. Although the precise mechanism(s) of histological incontinence of pigment in photoaging skin appear to be very complicated, it is certainly one of the morphological hallmarks of photodamaged facial skin, and the degeneration of keratinocytes (noted by their electron-lucent properties), a feature characteristic of photoaging, contributes to that process. Furthermore, the increased numbers of epidermal macrophages in sun-exposed skin may be associated with photoaging processes (probably through their phagocytic function) as well as alterations of the cutaneous immune system.
Assuntos
Queratinócitos/ultraestrutura , Células de Langerhans/ultraestrutura , Macrófagos/ultraestrutura , Melaninas/metabolismo , Pele/ultraestrutura , Idoso , Feminino , Humanos , Imuno-Histoquímica , Queratinócitos/metabolismo , Células de Langerhans/metabolismo , Macrófagos/metabolismo , Masculino , Microscopia Eletrônica de Transmissão , Pele/metabolismo , Pele/patologia , Queimadura Solar/metabolismo , Queimadura Solar/patologiaRESUMO
Nevus lipomatosus cutaneous superficialis (NLCS) is a rare hamartomatous skin lesion histopathologically characterized by the presence of mature fat tissue even within the upper dermis. Clinically, two types of NLCS can be distinguished; a multiple type and a solitary type. We here report a 10-month-old girl showing multiple type NLCS as a collection of a nodule and papules on her right abdomen. Histological examination revealed that the lesion was composed of a lobular proliferation of fat tissue throughout the dermis and immature hair follicle-like structures with perifollicular fibrosis. Histological alterations of the dermal connective tissue components were also seen, including thickening of collagen bundles and increased numbers of both fibroblasts and blood vessels. This is the first reported case of NLCS with perifollicular fibrosis.
Assuntos
Folículo Piloso/patologia , Neoplasias Primárias Múltiplas/patologia , Nevo/patologia , Neoplasias Cutâneas/patologia , Feminino , Fibrose , Doenças do Cabelo/complicações , Doenças do Cabelo/patologia , Humanos , Lactente , Neoplasias Primárias Múltiplas/congênito , Nevo/complicações , Nevo/congênito , Neoplasias Cutâneas/complicações , Neoplasias Cutâneas/congênitoRESUMO
S100A3, a unique protein among all members of the calcium-binding S100 family, is specifically expressed at the inner endocuticle of human hair fibers. Upon hair damage, S100A3 is released from hair fibers and possibly destabilizes the hair tissue architecture. This study describes the purification and characterization of native S100A3 isolated from human hair fibers. We extracted native S100A3 from cuticles and purified the protein by anion-exchange chromatography. The results of 2D gel electrophoresis showed that cuticle S100A3 has a slightly lower isoelectric point compared to the recombinant protein. Tandem mass spectrometry of the peptides resulting from endoproteinase digest of cuticle S100A3 revealed that the N-terminal methionine is replaced with an acetyl group. This is the first report on biochemical characteristics of S100A3 in hair cuticle.
Assuntos
Proteínas de Ligação ao Cálcio/química , Folículo Piloso/química , Proteínas S100 , Proteínas de Ligação ao Cálcio/isolamento & purificação , Cromatografia por Troca Iônica , Cisteína/análise , Eletroforese em Gel Bidimensional , Humanos , Masculino , Espectrometria de Massas por Ionização por ElectrosprayRESUMO
This review provides a new insight into the participation of neuropeptides, notably substance P (SP), in the pathophysiology of acne. We show morphological alterations of sebaceous glands elicited by SP and differences in expression of various neurogenic factors in association with sebaceous glands in acne-prone versus normal facial skin. In vitro studies reveal that SP promotes both the proliferation and the differentiation of sebaceous glands. SP induces the expression of neutral endopeptidase, a potent neuropeptide-degrading enzyme, in sebaceous germinative cells and of E-selectin by perisebaceous venules. Facial skin from acne patients is characterized by rich innervation, by increased numbers of SP-containing nerves and mast cells, and by strong expression of neutral endopeptidase in sebaceous glands and E-selectin in venules around sebaceous glands, compared with normal skin. Mast cell-derived IL-6 and TNF-alpha, followed by SP-stimulated degranulation, have the potential to induce nerve growth factor expression by sebaceous cells which results in the promotion of innervation and in the expression of E-selectin, respectively. SP enhances mast cell proliferation through up-regulation of stem cell factor expression in fibroblasts. These findings suggest the involvement of neurogenic factors, such as neuropeptides, in the disease process of acne and explain the possible mechanism of the exacerbation of acne from a neurological point of view.