RESUMO
Histone deacetylase inhibitors (HDACi) have been described as multifunctional anticancer agents. The failure of conventional therapy for glioblastoma (GBM) renders this tumor an attractive target for immunotherapy. Innate immune cells, such as natural killer (NK) cells, play a crucial role in antitumor immune responses. Here, we describe how the HDACi trichostatin A (TSA) promotes apoptosis of tumor cells, as well as augments anti-GBM innate immune responses. In vitro treatment of GBM cells with TSA results in an up-regulation of the natural killer group-2 member-D (NKG2D) ligands major histocompatibility complex class I-related chain (MIC)-A and UL16 binding protein (ULBP)-2 at both mRNA and protein levels, rendering them susceptible to NK cell-mediated lysis. In vivo, TSA delays tumor growth of GBM xenografts. Both the in vitro and in vivo antitumor effect of TSA was significantly reduced by blocking NK cell activity. Our data suggest that HDACi, especially in combination with other clinical immunotherapeutical approaches, may be considered in a combined therapeutic approach for GBM.
Assuntos
Apoptose/efeitos dos fármacos , Neoplasias Encefálicas/patologia , Proliferação de Células/efeitos dos fármacos , Glioblastoma/patologia , Inibidores de Histona Desacetilases/farmacologia , Ácidos Hidroxâmicos/farmacologia , Células Matadoras Naturais/imunologia , Animais , Western Blotting , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/imunologia , Citotoxicidade Imunológica , Feminino , Citometria de Fluxo , Proteínas Ligadas por GPI/genética , Proteínas Ligadas por GPI/metabolismo , Glioblastoma/tratamento farmacológico , Glioblastoma/imunologia , Antígenos de Histocompatibilidade Classe I/genética , Antígenos de Histocompatibilidade Classe I/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/genética , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Células Matadoras Naturais/metabolismo , Células Matadoras Naturais/patologia , Camundongos , Camundongos Nus , Subfamília K de Receptores Semelhantes a Lectina de Células NK/genética , Subfamília K de Receptores Semelhantes a Lectina de Células NK/metabolismo , RNA Mensageiro/genética , Reação em Cadeia da Polimerase em Tempo Real , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/genética , Receptores do Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais/efeitos dos fármacos , Ligante Indutor de Apoptose Relacionado a TNF/genética , Ligante Indutor de Apoptose Relacionado a TNF/metabolismo , Células Tumorais CultivadasRESUMO
In Europe, commercially available extracts from the white-berry mistletoe (Viscum album L.) are widely used as a complementary cancer therapy. Mistletoe lectins have been identified as main active components and exhibit cytotoxic effects as well as immunomodulatory activity. Since it is still not elucidated in detail how mistle toe extracts such as ISCADOR communicate their effects, we analyzed the mechanisms that might be responsible for their antitumoral function on a molecular and functional level. ISCADOR-treated glioblastoma (GBM) cells down-regulate central genes involved in glioblastoma progression and malignancy such as the cytokine TGF-ß and matrix-metalloproteinases. Using in vitro glioblastoma/immune cell co-cultivation assays as well as measurement of cell migration and invasion, we could demonstrate that in glioblastoma cells, lectin-rich ISCADOR M and ISCADOR Q significantly enforce NK-cell-mediated GBM cell lysis. Beside its immune stimulatory effect, ISCADOR reduces the migratory and invasive potential of glioblastoma cells. In a syngeneic as well as in a xenograft glioblastoma mouse model, both pretreatment of tumor cells and intratumoral therapy of subcutaneously growing glioblastoma cells with ISCADOR Q showed delayed tumor growth. In conclusion, ISCADOR Q, showing multiple positive effects in the treatment of glioblastoma, may be a candidate for concomitant treatment of this cancer.
