RESUMO
miR-200a has been implicated in the pathogenesis of meningiomas, one of the most common central nervous system tumors in humans. To identify how miR-200a contributes to meningioma pathogenesis at the molecular level, we used a comparative protein profiling approach using Gel-nanoLC-MS/MS and identified approximately 130 dysregulated proteins in miR-200a-overexpressing meningioma cells. Following the bioinformatic analysis to identify potential genes targeted by miR-200a, we focused on the non-muscle heavy chain IIb (NMHCIIb), and showed that miR-200a directly targeted NMHCIIb. Considering the key roles of NMHCIIb in cell division and cell migration, we aimed to identify whether miR-200a regulated these processes through NMHCIIb. We found that NMHCIIb overexpression partially rescued miR-200a-mediated inhibition of cell migration, as well as cell growth in vitro and in vivo. Moreover, siRNA-mediated silencing of NMHCIIb expression resulted in a similar migration phenotype in these cells and inhibited meningioma tumor growth in mice. Taken together, these results suggest that NMHCIIb might serve as a novel therapeutic target in meningiomas.
Assuntos
Neoplasias Meníngeas/patologia , Meningioma/patologia , MicroRNAs/genética , Cadeias Pesadas de Miosina/genética , Miosina não Muscular Tipo IIB/genética , Animais , Linhagem Celular Tumoral , Movimento Celular , Proliferação de Células/genética , Feminino , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Meníngeas/genética , Meningioma/genética , Camundongos , Camundongos Nus , Cadeias Pesadas de Miosina/antagonistas & inibidores , Cadeias Pesadas de Miosina/biossíntese , Transplante de Neoplasias , Miosina não Muscular Tipo IIB/antagonistas & inibidores , Miosina não Muscular Tipo IIB/biossíntese , Interferência de RNA , RNA Interferente Pequeno , Transplante HeterólogoRESUMO
Minichromosome maintenance (MCM) proteins are key elements that function as a part of the pre-replication complex to initiate DNA replication in eukaryotes. Consistent with their roles in initiating DNA replication, overexpression of MCM family members has been observed in several malignancies. Through bioinformatic analysis of The Cancer Genome Atlas's data on glioblastoma multiforme (GBM), we found that the genomic region containing MCM7 gene was amplified in more than 80% of the present cases. To validate this finding and to identify the possible contribution of the remaining members of the MCM family to GBM progression, we used quantitative real-time PCR to analyze the gene expression profiles of all MCM family members in Grade IV (GBM) tissue samples and observed a significant upregulation in GBM samples compared with normal white matter tissues. In addition, we compared the observed gene expression profiles with those of Grade II and Grade III astrocytoma samples and determined that the observed upregulation was restricted and specific to Grade IV. MCM7 was the most upregulated gene in the gene set we analyzed, and therefore we wanted to identify the role of MCM7 in GBM progression. We determined that siRNA-mediated knockdown of MCM7 expression reduced GBM cell proliferation and also inhibited tumor growth in both xenograft and orthotopic mouse models of GBM. Taken together, our data suggest that MCM7 can be a potential prognostic marker and a novel therapeutic target in GBM therapy.