RESUMO
The alpha4beta1 integrin very late activation antigen-4 (VLA-4) is an alpha4 (CD49d)/beta1 (CD29) heterodimer. It plays a key role in the adhesion of both hematopoietic progenitor cells and leukemic blast cells to bone marrow stromal cells which express the vascular cell adhesion molecule-1 (VCAM-1) or produce fibronectin. VLA-4 expression has been associated with bone-marrow minimal residual disease, which causes relapse after chemotherapy in patients with acute myelogenous leukemia. Conversely, the absence of VLA-4 reduces bone marrow retention of both hematopoietic progenitor and leukemic blast cells. We report on the downregulation of VLA-4/CD49d for various acute myelogenous leukemia cells lines, on primary cells from patients with acute myelogenous leukemia, and on hematopoietic stem cells and peripheral blood mononuclear cells from healthy donors on treatment with the histone deacetylase inhibitors suberoylanilide hydroxamic acid and valproic acid, which is associated with decreased adhesion to mesenchymal stromal cells. These findings suggest that HDAC-inhibitor treatment may on the one hand impair stem cell homing, while on the other it may improve peripheral blood stem cell mobilization and significantly help to reduce minimal residual disease from acute myelogenous leukemia.
Assuntos
Adesão Celular/efeitos dos fármacos , Células-Tronco Hematopoéticas/efeitos dos fármacos , Inibidores de Histona Desacetilases , Ácidos Hidroxâmicos/farmacologia , Integrina alfa4beta1/biossíntese , Leucemia Mieloide/patologia , Células-Tronco Neoplásicas/efeitos dos fármacos , Ácido Valproico/farmacologia , Doença Aguda , Células da Medula Óssea/citologia , Células da Medula Óssea/efeitos dos fármacos , Células da Medula Óssea/metabolismo , Linhagem Celular Tumoral/citologia , Linhagem Celular Tumoral/efeitos dos fármacos , Linhagem Celular Tumoral/metabolismo , Movimento Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Mobilização de Células-Tronco Hematopoéticas , Células-Tronco Hematopoéticas/citologia , Células-Tronco Hematopoéticas/metabolismo , Humanos , Integrina alfa4beta1/genética , Leucócitos Mononucleares/citologia , Leucócitos Mononucleares/efeitos dos fármacos , Leucócitos Mononucleares/metabolismo , Proteínas de Neoplasias/antagonistas & inibidores , Proteínas de Neoplasias/biossíntese , Proteínas de Neoplasias/genética , Neoplasia Residual/prevenção & controle , Células-Tronco Neoplásicas/citologia , Células-Tronco Neoplásicas/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , RNA Neoplásico/biossíntese , RNA Neoplásico/genética , VorinostatRESUMO
Interleukin-10 (IL-10), originally identified as an inhibitor of pro-inflammatory cytokine production, exerts multiple immunomodulatory functions. Its ability to inhibit a Th1 response has been used in clinical trials for the treatment of inflammatory diseases including psoriasis. However, little is known about the molecular mechanisms of IL-10 functions. We aimed at identifying possible mediators of in vitro IL-10 treatment in monocytes by gene chip technology using Hu95a Affymetrix mRNA arrays with 12,000 genes. To prove relevance of the identified genes for the clinical situation we compared these in vitro results with genes being regulated by IL-10 in peripheral blood mononuclear cells from psoriatic patients undergoing IL-10 therapy. A high proportion of the 1,600 genes up-regulated and 1,300 genes down-regulated in vitro was found to be similarly regulated in vivo. Some genes, which were previously unknown to be regulated by IL-10, can be assigned to known IL-10 functions like e.g. the increase of pathogen clearance. Other new potentially immunomodulating genes have been identified to be regulated by IL-10, but their impact needs to be experimentally evaluated. We could confirm a recently reported up-regulation of heme oxygenase-1 (HO-1). However, we demonstrate that the anti-inflammatory mechanisms of IL-10 remain functional even when HO-1 is irreversibly inhibited.
Assuntos
Quimiocinas/genética , Citocinas/genética , Interleucina-10/farmacologia , Monócitos/efeitos dos fármacos , Psoríase/tratamento farmacológico , Psoríase/genética , Receptores Imunológicos/genética , Antígenos CD , Fatores de Transcrição de Zíper de Leucina Básica , Quimiocinas/biossíntese , Citocinas/biossíntese , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/imunologia , Citometria de Fluxo , Perfilação da Expressão Gênica , Regulação da Expressão Gênica/efeitos dos fármacos , Glicoproteínas/genética , Glicoproteínas/imunologia , Heme Oxigenase (Desciclizante)/antagonistas & inibidores , Heme Oxigenase (Desciclizante)/genética , Heme Oxigenase (Desciclizante)/imunologia , Humanos , Imunoglobulinas/genética , Imunoglobulinas/imunologia , Imunoterapia , Interleucina-10/imunologia , Interleucina-10/uso terapêutico , Monócitos/imunologia , Monócitos/metabolismo , Análise de Sequência com Séries de Oligonucleotídeos , Psoríase/imunologia , Psoríase/metabolismo , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Receptores de Superfície Celular , Receptores Imunológicos/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Membro 1 da Família de Moléculas de Sinalização da Ativação Linfocitária , Fatores de Transcrição/genética , Fatores de Transcrição/imunologiaRESUMO
Ultraviolet irradiation represents a well-established treatment modality for inflammatory skin diseases. The aim of this study was to investigate the mechanisms of ultraviolet B radiation-induced keratinocyte insensitivity towards interferon-gamma. Flow cytometric analyses indicated that ultraviolet B radiation temporarily inhibits the interferon-gamma-induced activation of primary keratinocyte and HaCaT cells as measured by reduced intercellular adhesion molecule-1 (CD54) and HLA-DR upregulation. Western blot experiments have suggested that this is mediated by the ultraviolet B radiation-induced inhibition of signal transduction and transcription factor-1 phosphorylation. Neither interleukin-10 neutralization nor interleukin-10 addition had any effect on the ultraviolet B radiation-induced inhibition of interferon-gamma induced intercellular adhesion molecule-1 expression. Furthermore, the supernatant from ultraviolet B-irradiated cells failed to inhibit the interferon-gamma-induced CD54 and HLA-DR upregulation in nonradiated HaCaT cells. Moreover, irradiated cells from whom the supernatant was withdrawn 4 h after irradiation still showed a diminished interferon-gamma-induced response after 24 h. Thus, not soluble but intracellular factors might be involved in the ultraviolet B radiation-induced inhibition of interferon-gamma-induced keratinocyte activation. Therefore, we analyzed the expression of members of suppressors of cytokine-signaling (SOCS) molecules using real-time polymerase chain reaction. We found a fast and strong upregulation of SOCS1 and SOCS3 but not of SOCS2 after ultraviolet B radiation. Similarly, ultraviolet B radiation induced the expression of these particular SOCS molecules in lesional psoriatic skin. As SOCS molecules are known inhibitors of signal transduction and transcription factor phosphorylation, which is essential for interferon-gamma-induced intercellular adhesion molecule-1 and HLA-DR upregulation, this may explain the interferon-gamma unresponsiveness after ultraviolet B radiation.
