RESUMEN
Ras acts with other proteins to induce neoplasia. By itself, however, strong Ras signaling can suppress proliferation of normal cells. In primary epidermal cells, we found that oncogenic Ras transiently decreases cyclin-dependent kinase (CDK) 4 expression in association with cell cycle arrest in G1 phase. CDK4 co-expression circumvents Ras growth suppression and induces invasive human neoplasia resembling squamous cell carcinoma. Tumorigenesis is dependent on CDK4 kinase function, with cyclin D1 required but not sufficient for this process. In facilitating escape from G1 growth restraints, Ras and CDK4 alter the composition of cyclin D and cyclin E complexes and promote resistance to growth inhibition by INK4 cyclin-dependent kinase inhibitors. These data identify a new role for oncogenic Ras in CDK4 regulation and highlight the functional importance of CDK4 suppression in preventing uncontrolled growth.
Asunto(s)
Quinasas Ciclina-Dependientes/metabolismo , Epidermis/metabolismo , Epidermis/patología , Proteínas Proto-Oncogénicas , Proteínas ras/metabolismo , Animales , Cadherinas/metabolismo , Carcinoma de Células Escamosas/metabolismo , Carcinoma de Células Escamosas/patología , Ciclo Celular/fisiología , Células Cultivadas , Ciclina D1/metabolismo , Ciclina E/metabolismo , Quinasa 4 Dependiente de la Ciclina , Quinasas Ciclina-Dependientes/genética , Factores de Crecimiento Endotelial/metabolismo , Células Epidérmicas , Técnicas de Transferencia de Gen , Genes Reporteros , Humanos , Péptidos y Proteínas de Señalización Intercelular/metabolismo , Queratinocitos/metabolismo , Pulmón/patología , Linfocinas/metabolismo , Ratones , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Proteínas Recombinantes de Fusión/metabolismo , Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/patología , Telómero/metabolismo , Factor A de Crecimiento Endotelial Vascular , Factores de Crecimiento Endotelial Vascular , Proteínas ras/genéticaRESUMEN
Current therapeutic strategies for genetic skin disorders rely on the complex process of grafting genetically engineered tissue to recipient wound beds. Because fibroblasts synthesize and secrete extracellular matrix, we explored their utility in recessive dystrophic epidermolysis bullosa (RDEB), a blistering disease due to defective extracellular type VII collagen. Intradermal injection of RDEB fibroblasts overexpressing type VII collagen into intact RDEB skin stably restored correctly localized type VII collagen expression in vivo and normalized hallmark RDEB disease features, including subepidermal blistering and anchoring fibril defects. This article was published online in advance of the print edition. The date of publication is available from the JCI website, http://www.jci.org.
Asunto(s)
Colágeno Tipo VII/genética , Epidermólisis Ampollosa Distrófica/terapia , Fibroblastos/metabolismo , Ingeniería Genética , Terapia Genética , Animales , Humanos , Inyecciones , Ratones , Ratones SCIDRESUMEN
Background Excessive gambling is considered to be a part of the addiction spectrum. Stress-like emotional states are a key feature both of pathological gambling (PG) and of substance addiction. In substance addiction, stress symptomatology has been attributed in part to "anti-reward" allostatic neuroadaptations, while a potential involvement of anti-reward processes in the course of PG has not yet been investigated. Methods To that end, individuals with PG (n = 22) and mentally healthy subjects (n = 13) were assessed for trauma exposure and post-traumatic stress symptomatology (PTSS) using the Life Events Checklist and the Civilian Mississippi Scale, respectively. Results In comparison with healthy subjects, individuals with PG had significantly greater PTSS scores including greater physiological arousal sub-scores. The number of traumatic events and their recency were not significantly different between the groups. In the PG group, greater gambling severity was associated with more PTSS, but neither with traumatic events exposure nor with their recency. Conclusions Our data replicate prior reports on the role of traumatic stress in the course of PG and extend those findings by suggesting that the link may be derived from the anti-reward-type neuroadaptation rather than from the traumatic stress exposure per se.
Asunto(s)
Juego de Azar/psicología , Trastornos por Estrés Postraumático/psicología , Adulto , Nivel de Alerta , Comorbilidad , Escolaridad , Femenino , Juego de Azar/complicaciones , Humanos , Entrevista Psicológica , Masculino , Persona de Mediana Edad , Escalas de Valoración Psiquiátrica , Recompensa , Autoinforme , Trastornos por Estrés Postraumático/complicacionesAsunto(s)
Quinasas Ciclina-Dependientes/metabolismo , FN-kappa B/fisiología , Neoplasias/etiología , Proteína Oncogénica p21(ras)/fisiología , Proteínas Proto-Oncogénicas , Diferenciación Celular , División Celular , Quinasa 4 Dependiente de la Ciclina , Fase G1 , Regulación Neoplásica de la Expresión Génica , Humanos , Modelos BiológicosRESUMEN
An inverse relationship between initial level of physical capacity and the magnitude of response to training is termed the principle of initial value. We tested the operation of this principle under experimental conditions of minimal genetic and environmental variation. Inbred rat strains previously identified as genetic models of low [Copenhagen (COP)] and high [Dark Agouti (DA)] intrinsic (untrained) exercise capacity were trained for 8 wk on a treadmill using two disparate protocols: 1) a relative mode where each rat exercised daily according to its initial capacity, and 2) an absolute mode where both strains received the same amount of training independent of initial capacity. Response to exercise was the change in running capacity as estimated by meters run to exhaustion before and after training. When trained with the relative mode, COP rats gained 88 m (+21%; NS) whereas DA rats increased distance run by 228 m (+36%; P < 0.001). When each strain trained with the same absolute amount of training, the COP strain showed essentially no change (-6 m, -2%) and the DA strain gained 325 m (+49%; P < 0.009). Differences in response to exercise between the COP and DA could not be explained by body mass differences, oxidative enzyme activity (citrate synthase or ATP), or spontaneous behavioral activity. Our data demonstrate that genetic factors causative of high response to exercise are not uniquely associated with genetic factors for low intrinsic capacity and thus are not in accord with the principle of initial value.
Asunto(s)
Adaptación Fisiológica/genética , Condicionamiento Físico Animal/fisiología , Resistencia Física/fisiología , Ratas Endogámicas/fisiología , Animales , Peso Corporal , Femenino , Genotipo , Resistencia Física/genética , RatasRESUMEN
Type VII collagen defects cause recessive dystrophic epidermolysis bullosa (RDEB), a blistering skin disorder often accompanied by epidermal cancers. To study the role of collagen VII in these cancers, we examined Ras-driven tumorigenesis in RDEB keratinocytes. Cells devoid of collagen VII did not form tumors in mice, whereas those retaining a specific collagen VII fragment (the amino-terminal noncollagenous domain NC1) were tumorigenic. Forced NC1 expression restored tumorigenicity to collagen VII-null epidermis in a non-cell-autonomous fashion. Fibronectin-like sequences within NC1 (FNC1) promoted tumor cell invasion in a laminin 5-dependent manner and were required for tumorigenesis. Tumor-stroma interactions mediated by collagen VII thus promote neoplasia, and retention of NC1 sequences in a subset of RDEB patients may contribute to their increased susceptibility to squamous cell carcinoma.
Asunto(s)
Carcinoma de Células Escamosas/fisiopatología , Colágeno Tipo VII/genética , Colágeno Tipo VII/fisiología , Epidermólisis Ampollosa Distrófica/genética , Genes ras , Queratinocitos/metabolismo , Neoplasias Cutáneas/fisiopatología , Adolescente , Adulto , Animales , Anticuerpos/inmunología , Apoptosis , Carcinoma de Células Escamosas/etiología , Moléculas de Adhesión Celular/inmunología , Moléculas de Adhesión Celular/metabolismo , Proliferación Celular , Transformación Celular Neoplásica , Niño , Colágeno Tipo VII/química , Colágeno Tipo VII/inmunología , Susceptibilidad a Enfermedades , Epidermólisis Ampollosa Distrófica/complicaciones , Epidermólisis Ampollosa Distrófica/metabolismo , Epidermólisis Ampollosa Distrófica/patología , Femenino , Humanos , Proteínas I-kappa B/genética , Proteínas I-kappa B/metabolismo , Queratinocitos/patología , Masculino , Ratones , Ratones SCID , Persona de Mediana Edad , Mutación , Inhibidor NF-kappaB alfa , Invasividad Neoplásica , Estructura Terciaria de Proteína , Neoplasias Cutáneas/etiología , Neoplasias Cutáneas/patología , KalininaRESUMEN
Cancers of the skin encompass the first and second most common neoplasms in the United States, epidermal basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), respectively, as well as the melanocytic malignancy, malignant melanoma (MM). Recently identified alterations in the function of specific genes in these cancers provide new potential therapeutic targets. These alterations affect conserved regulators of cellular proliferation and viability, including the Sonic Hedgehog, Ras/Raf, ARF/p53, p16(INK4A)/CDK4/Rb and NF-kappaB pathways. New modalities designed to target these specific proteins may represent promising approaches to therapy of human skin cancers.
Asunto(s)
Neoplasias Cutáneas/metabolismo , Neoplasias Cutáneas/terapia , Animales , Humanos , Transducción de Señal , Neoplasias Cutáneas/genética , Neoplasias Cutáneas/patologíaRESUMEN
NF-kappaB inhibition promotes epidermal tumorigenesis; however, whether this reflects an underlying role in homeostasis or a special case confined to neoplasia is unknown. Embryonic lethality of mice lacking NF-kappaB RelA has hindered efforts to address this. We therefore generated developmentally mature RelA(-/-) skin. RelA(-/-) epidermis displays hyperplasia without abnormal differentiation, inflammation, or apoptosis. Hyperproliferation is TNFR1-dependent because Tnfr1 deletion normalized cell division. TNFR1-dependent JNK activation occurred in RelA(-/-) epidermis, and JNK inhibition abolished hyperproliferation due to RelA deficiency. Thus, RelA antagonizes TNFR1-JNK proliferative signals in epidermis and plays a nonredundant role in restraining epidermal growth.
Asunto(s)
División Celular/fisiología , Células Epidérmicas , Queratinocitos/citología , FN-kappa B/metabolismo , Receptores del Factor de Necrosis Tumoral/antagonistas & inhibidores , Animales , Antígenos CD , Western Blotting , Proteínas de Unión al ADN/metabolismo , Embrión de Mamíferos , Epidermis/fisiología , Queratinocitos/enzimología , Queratinocitos/fisiología , Ratones , Ratones SCID , FN-kappa B/deficiencia , FN-kappa B/genética , Receptores Tipo I de Factores de Necrosis Tumoral , Piel/citología , Piel/embriología , Factor de Transcripción ReIARESUMEN
The nuclear factor NF-kappaB and oncogenic Ras can alter proliferation in epidermis, the most common site of human cancer. These proteins are implicated in epidermal squamous cell carcinoma in mice, however, the potential effects of altering their function are uncertain. Whereas inhibition of NF-kappaB enhances apoptosis in certain tumours, blockade of NF-kappaB predisposes murine skin to squamous cell carcinoma. Because therapeutics inhibiting Ras and NF-kappaB pathways are being developed to treat human cancer, it is essential to assess the effects of altering these regulators. The medical relevance of murine studies is limited, however, by differences between mouse and human skin, and by the greater ease of transforming murine cells. Here we show that in normal human epidermal cells both NF-kappaB and oncogenic Ras trigger cell-cycle arrest. Growth arrest triggered by oncogenic Ras can be bypassed by IkappaBalpha-mediated blockade of NF-kappaB, generating malignant human epidermal tissue resembling squamous cell carcinoma. Human cell tumorigenesis is dependent on laminin 5 and alpha6beta4 integrin. Thus, IkappaBalpha circumvents restraints on growth promotion induced by oncogenic Ras and can act with Ras to induce invasive human tissue neoplasia.