RESUMO
The role of B cells in anti-tumour immunity is still debated and, accordingly, immunotherapies have focused on targeting T and natural killer cells to inhibit tumour growth1,2. Here, using high-throughput flow cytometry as well as bulk and single-cell RNA-sequencing and B-cell-receptor-sequencing analysis of B cells temporally during B16F10 melanoma growth, we identified a subset of B cells that expands specifically in the draining lymph node over time in tumour-bearing mice. The expanding B cell subset expresses the cell surface molecule T cell immunoglobulin and mucin domain 1 (TIM-1, encoded by Havcr1) and a unique transcriptional signature, including multiple co-inhibitory molecules such as PD-1, TIM-3, TIGIT and LAG-3. Although conditional deletion of these co-inhibitory molecules on B cells had little or no effect on tumour burden, selective deletion of Havcr1 in B cells both substantially inhibited tumour growth and enhanced effector T cell responses. Loss of TIM-1 enhanced the type 1 interferon response in B cells, which augmented B cell activation and increased antigen presentation and co-stimulation, resulting in increased expansion of tumour-specific effector T cells. Our results demonstrate that manipulation of TIM-1-expressing B cells enables engagement of the second arm of adaptive immunity to promote anti-tumour immunity and inhibit tumour growth.
Assuntos
Linfócitos B , Melanoma , Animais , Camundongos , Linfócitos B/citologia , Linfócitos B/imunologia , Linfócitos B/metabolismo , Ativação Linfocitária , Melanoma/imunologia , Melanoma/patologia , Melanoma/prevenção & controle , Linfócitos T/citologia , Linfócitos T/imunologia , Citometria de Fluxo , Melanoma Experimental/imunologia , Melanoma Experimental/patologia , Linfonodos/citologia , Linfonodos/imunologia , Apresentação de Antígeno , Receptores de Antígenos de Linfócitos B/genética , Análise da Expressão Gênica de Célula Única , Carga Tumoral , Interferon Tipo IRESUMO
One effort to combat the rising incidence of malignant melanoma is focused on early detection by the clinical and dermoscopic screening of melanocytic nevi. However, the interaction between nevi, which are congenital or acquired benign melanocytic proliferations, and melanoma is still enigmatic. On the one hand, the majority of melanomas are thought to form de novo, as only a third of primary melanomas are associated with a histologically identifiable nevus precursor. On the other hand, an increased number of melanocytic nevi is a strong risk factor for developing melanoma, including melanomas that do not derive from nevi. The formation of nevi is modulated by diverse factors, including pigmentation, genetic risk factors, and environmental sun exposure. While the molecular alterations that occur during the progression of a nevus to melanoma have been well characterized, many unanswered questions remain surrounding the process of nevus to melanoma evolution. In this review, we discuss clinical, histological, molecular, and genetic factors that influence nevus formation and progression to melanoma.
Assuntos
Melanoma , Nevo de Células Epitelioides e Fusiformes , Nevo Pigmentado , Nevo , Neoplasias Cutâneas , Humanos , Melanoma/patologia , Neoplasias Cutâneas/patologia , Nevo/patologia , Fatores de RiscoRESUMO
Pyogenic granulomas are benign vascular proliferations of the skin and mucous membranes that tend to bleed easily. They typically require procedural treatments that can be difficult for patients with intellectual disabilities or behavioral concerns to tolerate. In our practice, we have found the use of topical clobetasol to be effective to induce regression of cutaneous pyogenic granulomas. We present here a case of an adolescent patient with autism and two bleeding pyogenic granulomas who poorly tolerated a biopsy of the first lesion and could not tolerate subsequent procedures. Topical therapy with clobetasol effectively managed the second pyogenic granuloma, an approach representative of a noninvasive practice utilized in our clinic.
Assuntos
Granuloma Piogênico , Neoplasias Cutâneas , Adolescente , Biópsia , Glucocorticoides , Granuloma Piogênico/tratamento farmacológico , Humanos , PeleRESUMO
Merkel cells are mechanosensitive skin cells whose production requires the basic helix-loop-helix transcription factor Atoh1. We induced ectopic Atoh1 expression in the skin of transgenic mice to determine whether Atoh1 was sufficient to create additional Merkel cells. In embryos, ectopic Atoh1 expression drove ectopic expression of the Merkel cell marker keratin 8 (K8) throughout the epidermis. Epidermal Atoh1 induction in adolescent mice similarly drove widespread K8 expression in glabrous skin of the paws, but in the whisker pads and body skin ectopic K8+ cells were confined to hair follicles and absent from interfollicular regions. Ectopic K8+ cells acquired several characteristics of mature Merkel cells in a time frame similar to that seen during postnatal development of normal Merkel cells. Although ectopic K8+ cell numbers decreased over time, small numbers of these cells remained in deep regions of body skin hair follicles at 3â months post-induction. In adult mice, greater numbers of ectopic K8+ cells were created by Atoh1 induction during anagen versus telogen and following disruption of Notch signaling by conditional deletion of Rbpj in the epidermis. Our data demonstrate that Atoh1 expression is sufficient to produce new Merkel cells in the epidermis, that epidermal cell competency to respond to Atoh1 varies by skin location, developmental age and hair cycle stage, and that the Notch pathway plays a key role in limiting epidermal cell competency to respond to Atoh1 expression.
Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Epiderme/embriologia , Epiderme/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Células de Merkel/citologia , Animais , Animais Recém-Nascidos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/fisiologia , Linhagem Celular , Linhagem da Célula , Doxiciclina/química , Células Epidérmicas , Deleção de Genes , Cabelo/embriologia , Folículo Piloso/metabolismo , Queratinócitos/citologia , Camundongos , Camundongos Transgênicos , Transdução de Sinais , Pele/embriologia , Tamoxifeno/química , Transgenes , Vibrissas/metabolismoRESUMO
Cutaneous melanoma is an aggressive form of skin cancer derived from skin melanocytes and is associated with significant morbidity and mortality. A significant fraction of melanomas are associated with precursor lesions, benign clonal proliferations of melanocytes called nevi. Nevi can be either congenital or acquired later in life. Identical oncogenic driver mutations are found in benign nevi and melanoma. While much progress has been made in our understanding of nevus formation and the molecular steps required for transformation of nevi into melanoma, the clinical diagnosis of benign versus malignant lesions remains challenging.
RESUMO
Resistance to targeted therapy and immunotherapy remains a major obstacle in improving care for patients with advanced melanoma. MicroRNAs play important roles in regulating gene networks involved in disease progression and resistance to therapy in cancers such as melanoma. MicroRNA miR-211 contributes to melanocyte and melanoma biology and has been implicated in targeted therapy resistance. Lee et al. (2020) report a novel mechanism by which miR-211 promotes resistance to BRAFV600E inhibitor therapy via the upregulation of the extracellular signal-regulated kinase 5 signaling pathway.
Assuntos
Melanoma/tratamento farmacológico , MicroRNAs/fisiologia , Inibidores de Proteínas Quinases/uso terapêutico , Proteínas Proto-Oncogênicas B-raf/antagonistas & inibidores , Resistencia a Medicamentos Antineoplásicos , Humanos , Sistema de Sinalização das MAP Quinases/fisiologia , Proteína Quinase 7 Ativada por Mitógeno/fisiologia , Canais de Cátion TRPM/fisiologiaRESUMO
Melanoma skin cancer is derived from skin melanocytes and has a high risk of metastatic spread. The era of molecular genetics and next-generation sequencing has uncovered the role of oncogenic BRAFV600E mutations in many melanomas, validated the role of ultraviolet-induced DNA mutations in melanoma formation, and uncovered many of the molecular events that occur during melanoma development. Targeted therapies and immunotherapy have dramatically improved outcomes and provided an increased rate of cure for metastatic melanoma. This article reviews the formation of melanoma, the molecular events involved in melanoma growth and metastasis, and the biology underlying resistance to melanoma therapies.
Assuntos
Carcinogênese , Melanócitos , Melanoma , Fator de Transcrição Associado à Microftalmia , Neoplasias Cutâneas , Carcinogênese/patologia , Resistencia a Medicamentos Antineoplásicos/genética , Resistencia a Medicamentos Antineoplásicos/fisiologia , Humanos , Imunoterapia , Melanócitos/patologia , Melanócitos/fisiologia , Melanoma/classificação , Melanoma/genética , Melanoma/fisiopatologia , Melanoma/terapia , Fator de Transcrição Associado à Microftalmia/fisiologia , Neoplasias Cutâneas/classificação , Neoplasias Cutâneas/genética , Neoplasias Cutâneas/fisiopatologia , Neoplasias Cutâneas/terapia , Raios Ultravioleta/efeitos adversosRESUMO
Skin pigmentation is a result of melanin produced by melanocytes in the epidermis. Melanocyte activity, along with the type and distribution of melanins, is the main driver for diversity of skin pigmentation. Dark melanin acts to protect against the deleterious effects of ultraviolet (UV) radiation, including photo-aging and skin cancer formation. In turn, UV radiation activates skin melanocytes to induce further pigmentation (i.e., "tanning pathway"). The well-characterized MSH/MC1R-cAMP-MITF pathway regulates UV-induced melanization. Pharmacologic activation of this pathway ("sunless tanning") represents a potential strategy for skin cancer prevention, particularly in those with light skin or the "red hair" phenotype who tan poorly after UV exposure due to MC1R inactivating polymorphisms. Skin hyperpigmentation can also occur as a result of inflammatory processes and dermatological disorders such as melasma. While primarily of cosmetic concern, these conditions can dramatically impact quality of life of affected patients. Several topical agents are utilized to treat skin pigmentation disorders. Here, we review melanogenesis induced by UV exposure and the agents that target this pathway.
Assuntos
Fármacos Dermatológicos/farmacologia , Fármacos Dermatológicos/uso terapêutico , Melaninas/metabolismo , Transtornos da Pigmentação/tratamento farmacológico , Transtornos da Pigmentação/fisiopatologia , Administração Cutânea , AMP Cíclico/biossíntese , Fármacos Dermatológicos/administração & dosagem , Sistemas de Liberação de Medicamentos , Humanos , Proteínas Quinases/metabolismo , Pigmentação da Pele/fisiologia , Raios Ultravioleta/efeitos adversosRESUMO
Evidence suggests that 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors, or statins, may reduce the risk of Alzheimer's disease (AD). Statin action in patients with AD, as in those with heart disease, is likely to be at least partly independent of the effects of statins on cholesterol. Statins can alter cellular signaling and protein trafficking through inhibition of isoprenylation of Rho, Cdc42, and Rab family GTPases. The effects of statins on protein isoprenylation in vivo, particularly in the central nervous system, are poorly studied. We utilized two-dimensional gel electrophoresis approaches to directly monitor the levels of isoprenylated and non-isoprenylated forms of Rho and Rab family GTPases. We report that simvastatin significantly inhibits RhoA and Rab4, and Rab6 isoprenylation at doses as low as 50nM in vitro. We also provide the first in vivo evidence that statins inhibit the isoprenylation of RhoA in the brains of rats and RhoA, Cdc42, and H-Ras in the brains of mice treated with clinically relevant doses of simvastatin.
Assuntos
Encéfalo/efeitos dos fármacos , Encéfalo/metabolismo , Fármacos do Sistema Nervoso Central/farmacologia , Inibidores de Hidroximetilglutaril-CoA Redutases/farmacologia , Prenilação de Proteína/efeitos dos fármacos , Sinvastatina/farmacologia , Animais , Western Blotting , Linhagem Celular Tumoral , Avaliação Pré-Clínica de Medicamentos , Eletroforese em Gel Bidimensional , Focalização Isoelétrica , Camundongos Endogâmicos C57BL , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Ratos Endogâmicos SHR , Proteína cdc42 de Ligação ao GTP/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismoRESUMO
The embryonic cuticle of Drosophila melanogaster is deposited by the epidermal epithelium during stage 16 of development. This tough, waterproof layer is essential for maintaining the structural integrity of the larval body. We have characterized mutations in a set of genes required for proper deposition and/or morphogenesis of the cuticle. Zygotic disruption of any one of these genes results in embryonic lethality. Mutant embryos are hyperactive within the eggshell, resulting in a high proportion reversed within the eggshell (the "retroactive" phenotype), and all show poor cuticle integrity when embryos are mechanically devitellinized. This last property results in embryonic cuticle preparations that appear grossly inflated compared to wild-type cuticles (the "blimp" phenotype). We find that one of these genes, krotzkopf verkehrt (kkv), encodes the Drosophila chitin synthase enzyme and that a closely linked gene, knickkopf (knk), encodes a novel protein that shows genetic interaction with the Drosophila E-cadherin, shotgun. We also demonstrate that two other known mutants, grainy head (grh) and retroactive (rtv), show the blimp phenotype when devitellinized, and we describe a new mutation, called zeppelin (zep), that shows the blimp phenotype but does not produce defects in the head cuticle as the other mutations do.
Assuntos
Quitina Sintase/genética , Drosophila melanogaster/genética , Regulação da Expressão Gênica no Desenvolvimento , Sequência de Aminoácidos , Animais , Benzamidas/metabolismo , Caderinas/genética , Quitina/biossíntese , Quitina Sintase/antagonistas & inibidores , Mapeamento Cromossômico , Drosophila melanogaster/embriologia , Dados de Sequência Molecular , Mutação , Alinhamento de SequênciaRESUMO
Merkel cell polyomavirus (MCV) causes the majority of human Merkel cell carcinomas (MCC) and encodes a small T (sT) antigen that transforms immortalized rodent fibroblasts in vitro. To develop a mouse model for MCV sT-induced carcinogenesis, we generated transgenic mice with a flox-stop-flox MCV sT sequence homologously recombined at the ROSA locus (ROSAsT), allowing Cre-mediated, conditional MCV sT expression. Standard tamoxifen (TMX) administration to adult UbcCreERT2; ROSAsT mice, in which Cre is ubiquitously expressed, resulted in MCV sT expression in multiple organs that was uniformly lethal within 5 days. Conversely, most adult UbcCreERT2; ROSAsT mice survived low-dose tamoxifen administration but developed ear lobe dermal hyperkeratosis and hypergranulosis. Simultaneous MCV sT expression and conditional homozygous p53 deletion generated multi-focal, poorly-differentiated, highly anaplastic tumors in the spleens and livers of mice after 60 days of TMX treatment. Mouse embryonic fibroblasts from these mice induced to express MCV sT exhibited anchorage-independent cell growth. To examine Merkel cell pathology, MCV sT expression was also induced during mid-embryogenesis in Merkel cells of Atoh1CreERT2/+; ROSAsT mice, which lead to significantly increased Merkel cell numbers in touch domes at late embryonic ages that normalized postnatally. Tamoxifen administration to adult Atoh1CreERT2/+; ROSAsT and Atoh1CreERT2/+; ROSAsT; p53flox/flox mice had no effects on Merkel cell numbers and did not induce tumor formation. Taken together, these results show that MCV sT stimulates progenitor Merkel cell proliferation in embryonic mice and is a bona fide viral oncoprotein that induces full cancer cell transformation in the p53-null setting.
Assuntos
Antígenos Virais de Tumores/genética , Carcinoma de Célula de Merkel/patologia , Transformação Celular Viral , Embrião de Mamíferos/patologia , Células de Merkel/patologia , Poliomavírus das Células de Merkel/fisiologia , Neoplasias Cutâneas/patologia , Anaplasia , Animais , Carcinoma de Célula de Merkel/virologia , Contagem de Células , Diferenciação Celular , Linhagem Celular Tumoral , Proliferação de Células , Modelos Animais de Doenças , Feminino , Humanos , Fígado/patologia , Masculino , Poliomavírus das Células de Merkel/imunologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Gravidez , Neoplasias Cutâneas/virologia , Baço/patologia , Proteína Supressora de Tumor p53/deficiência , Proteína Supressora de Tumor p53/genéticaRESUMO
Nervous system involvement in psoriasis pathogenesis is supported by increases in nerve fiber numbers and neuropeptides in psoriatic skin and by reports detailing spontaneous plaque remission following nerve injury. Using the KC-Tie2 psoriasiform mouse model, we investigated the mechanisms by which nerve injury leads to inflammatory skin disease remission. Cutaneous nerves innervating dorsal skin of KC-Tie2 animals were surgically axotomized and beginning 1 day after denervation, CD11c(+) cell numbers decreased by 40% followed by a 30% improvement in acanthosis at 7 days and a 30% decrease in CD4(+) T-cell numbers by 10 days. Restoration of substance P (SP) signaling in denervated KC-Tie2 skin prevented decreases in CD11c(+) and CD4(+) cells, but had no effect on acanthosis; restoration of calcitonin gene-related peptide (CGRP) signaling reversed the improvement in acanthosis and prevented denervated-mediated decreases in CD4(+) cells. Under innervated conditions, small-molecule inhibition of SP in KC-Tie2 animals resulted in similar decreases to those observed following surgical denervation for cutaneous CD11c(+) and CD4(+) cell numbers; whereas small-molecule inhibition of CGRP resulted in significant reductions in CD4(+) cell numbers and acanthosis. These data demonstrate that sensory nerve-derived peptides mediate psoriasiform dendritic cell and T-cell infiltration and acanthosis and introduce targeting nerve-immunocyte/KC interactions as potential psoriasis therapeutic treatment strategies.
Assuntos
Queratinócitos/patologia , Neuropeptídeos/fisiologia , Psoríase/etiologia , Pele/inervação , Animais , Antígeno CD11c/análise , Contagem de Linfócito CD4 , Denervação , Modelos Animais de Doenças , Gânglios Espinais/química , Interleucina-23/análise , Isoindóis/farmacologia , Camundongos , Neuropeptídeos/análise , Fragmentos de Peptídeos/farmacologia , Psoríase/imunologia , Psoríase/patologia , Psoríase/terapia , Receptores Proteína Tirosina Quinases/fisiologia , Receptor TIE-2 , Receptores de Peptídeo Relacionado com o Gene de Calcitonina/fisiologia , Substância P/análogos & derivados , Substância P/farmacologiaRESUMO
Epidemiological evidence suggests that long term treatment with hydroxymethylglutaryl-CoA reductase inhibitors, or statins, decreases the risk for developing Alzheimer disease (AD). However, statin-mediated AD protection cannot be fully explained by reduction of cholesterol levels. In addition to their cholesterol lowering effects, statins have pleiotropic actions and act to lower the concentrations of isoprenoid intermediates, such as geranylgeranyl pyrophosphate and farnesyl pyrophosphate. The Rho and Rab family small G-proteins require addition of these isoprenyl moieties at their C termini for normal GTPase function. In neuroblastoma cell lines, treatment with statins inhibits the membrane localization of Rho and Rab proteins at statin doses as low as 200 nm, without affecting cellular cholesterol levels. In addition, we show for the first time that at low, physiologically relevant, doses statins preferentially inhibit the isoprenylation of a subset of GTPases. The amyloid precursor protein (APP) is proteolytically cleaved to generate beta-amyloid (Abeta), which is the major component of senile plaques found in AD. We show that inhibition of protein isoprenylation by statins causes the accumulation of APP within the cell through inhibition of Rab family proteins involved in vesicular trafficking. Moreover, inhibition of Rho family protein function reduces levels of APP C-terminal fragments due to enhanced lysosomal dependent degradation. Statin inhibition of protein isoprenylation results in decreased Abeta secretion. In summary, we show that statins selectively inhibit GTPase isoprenylation at clinically relevant doses, leading to reduced Abeta production in an isoprenoid-dependent manner. These studies provide insight into the mechanisms by which statins may reduce AD pathogenesis.