ABSTRACT
INTRODUCTION: Astrocytomas are common brain tumors. Increased expression levels of Interleukin-13 Receptor α2 (IL-13RA2) have been reported in astrocytomas. The Interleukin-13 signaling pathway may be associated with cell migration when binding to Interleukin-13 Receptor α1. OBJECTIVE: To investigate Interleukin-13 Receptor α1 (IL-13RA1) and IL13RA2 expression levels in human diffusely infiltrative astrocytomas and test the involvement of Interleukin-13 levels in cell migration in two glioblastoma cell lines. METHODS: IL13RA expression levels were accessed by quantitative real time PCR in 128 samples of astrocytomas and 18 samples of non-neoplastic brain tissues from temporal lobe epilepsy surgery. The impact of IL-13 levels (10 and 20 ng/mL) on cell migration was analyzed by the wound assay in U87MG and A172 cells. RESULTS: Glioblastoma presented higher IL13RA1 and IL13RA2 expression levels compared to lower grades astrocytomas and to non-neoplastic cases. U87MG and A172 cells presented higher expression levels of IL-13RA1 vs. IL-13RA2. A significant difference in migration rate was observed in A172 cells treated with 10 ng/mL of IL-13 vs. control: treated cells presented slower migration than non-treated cells. U87MG cells treated with IL-13 20ng/mL presented slower migration than non-treated cells. This indicates that the IL13Rα1 signaling pathway was not activated, indeed inhibited by the decoy IL-13Rα2, slowing cell migration. This impact occurred with a lesser concentration of IL-13 on the A172 than on the U87MG cell line, because A172 cells have a higher IL-13RA2/A1 ratio. CONCLUSION: The present results suggest IL-13 receptors as possible targets to decrease tumor cell migration.
INTRODUÇÃO Astrocitomas são os tumores cerebrais mais frequentes. Nestes tumores foi observada maior expressão do receptor de Interleucina-13 α2 (IL13RA2). A cascata de sinalização da Interleucina-13 pode estar associada com a migração celular, após sua ligação com o receptor de Interleucina-13 α1 (IL13Rα1). OBJETIVO: Investigar os níveis de expressão dos receptores de Interleucina-13 (IL13RA1 e IL13RA2) em astrocitomas difusamente infiltrativos e avaliar o envolvimento da Interleucina-13 na migração celular de duas linhagens de glioblastoma. MÉTODOS: A expressão dos receptores IL13RA foi analisada por PCR em tempo real, em 128 amostras de astrocitomas e 18 amostras de tecido cerebral não neoplásico, provenientes de cirurgia de epilepsia do lobo temporal. E o impacto da quantidade de IL-13 (10ng/ml e 20ng/ml) em ensaio de migração celular. RESULTADOS: As amostras de Glioblastoma apresentaram maior expressão de IL13RA1 and IL13RA2 comparados com astrocitomas de baixo grau e os casos não-neoplásicos. Nas células U87MG e A172 foi observado maior nível de expressão de IL-13RA1 do que IL-13RA2. Uma diferença significativa na taxa de migração foi obtida em células A172 tratadas com 10 ng/mL comparadas com o controle: as células tratadas apresentaram menor migração que as células não tratadas. As células U87MG tratadas com 20ng/mL de IL-13 apresentaram menor migração celular que as células não tratadas. A diferença na migração celular indica que o caminho de sinalização de IL13Rα1 não foi ativado e foi inibido pelo IL-13Rα2, diminuindo a migração celular. Esse impacto ocorreu com uma concentração menor de IL-13 nas células A172 ao contrário da U87MG, porque as células A172 possuem uma razão IL-13RA2/A1 maior. CONCLUSÃO: os resultados sugerem que os receptores de IL-13 podem ser utilizados como possíveis alvos para a diminuição da migração celular tumoral.
Subject(s)
Humans , Astrocytoma , Brain Neoplasms , Cell Movement/drug effects , Interleukin-13/administration & dosage , Receptors, Interleukin-13/administration & dosageABSTRACT
PURPOSE: Diffuse brainstem gliomas (BSGs) and other high-grade gliomas (HGGs) of childhood carry a dismal prognosis despite current treatments, and new therapies are needed. Having identified a series of glioma-associated antigens (GAAs) commonly overexpressed in pediatric gliomas, we initiated a pilot study of subcutaneous vaccinations with GAA epitope peptides in HLA-A2-positive children with newly diagnosed BSG and HGG. PATIENTS AND METHODS: GAAs were EphA2, interleukin-13 receptor alpha 2 (IL-13Rα2), and survivin, and their peptide epitopes were emulsified in Montanide-ISA-51 and given every 3 weeks with intramuscular polyinosinic-polycytidylic acid stabilized by lysine and carboxymethylcellulose for eight courses, followed by booster vaccinations every 6 weeks. Primary end points were safety and T-cell responses against vaccine-targeted GAA epitopes. Treatment response was evaluated clinically and by magnetic resonance imaging. RESULTS: Twenty-six children were enrolled, 14 with newly diagnosed BSG treated with irradiation and 12 with newly diagnosed BSG or HGG treated with irradiation and concurrent chemotherapy. No dose-limiting non-CNS toxicity was encountered. Five children had symptomatic pseudoprogression, which responded to dexamethasone and was associated with prolonged survival. Only two patients had progressive disease during the first two vaccine courses; 19 had stable disease, two had partial responses, one had a minor response, and two had prolonged disease-free status after surgery. Enzyme-linked immunosorbent spot analysis in 21 children showed positive anti-GAA immune responses in 13: to IL-13Rα2 in 10, EphA2 in 11, and survivin in three. CONCLUSION: GAA peptide vaccination in children with gliomas is generally well tolerated and has preliminary evidence of immunologic and clinical responses. Careful monitoring and management of pseudoprogression is essential.
