RESUMO
MicroRNAs (miRNAs) are small non-coding RNAs that function as negative gene regulators. Alterations in the expression of miRNAs have been implicated in the pathogenesis and development of most human malignancies. Recent data indicate that microRNA-21 and microRNA-10b are significantly elevated in glioblastoma multiforme (GBM) suggesting their role in the regulation of multiple genes associated with cancer. In this study, U87MG human glioblastoma cells were treated with miRNA inhibitors targeting miR-10b and miR-21, alone or in combination. The results showed that the miR-21 inhibitor additively interacted with miR-10b inhibitor on U87MG cells. The 50% inhibitory concentration values were dramatically decreased in cells treated with the combination of miR-10b and miR-21 inhibitors. Furthermore, inhibitors synergistically combined, enhanced apoptosis significantly and reduced invasion ability assessed by flow cytometry and Transwell migration assay. Thus, the miR-21 inhibitor may interrupt the activity of EGFR pathways, increasing PDCD4 and TPM1 expression and reducing MMP activities, independently of PTEN status. Meanwhile, miR-10b inhibitor reduced by Twist proceeds to inhibit translation of the mRNA encoding HOXD10 leading to the increase of the expression of the well-characterized pro-metastatic gene RHOC. Taken together, these data strongly suggest that a combination of miR-21 inhibitor and miR-10b inhibitor could be an effective therapeutic strategy for controlling the growth of GBM by inhibiting oncogene expression and overexpressing tumor suppressor genes. Moreover, a regulatory strategy based on the combination of miRNA inhibitors may provide insights into the mechanisms of the modulation of signaling genes involved in tumor cell apoptosis and invasiveness.
Assuntos
Neoplasias Encefálicas/metabolismo , Neoplasias Encefálicas/patologia , Glioma/metabolismo , Glioma/patologia , MicroRNAs/antagonistas & inibidores , Apoptose/genética , Proteínas Reguladoras de Apoptose/metabolismo , Pontos de Checagem do Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células , Receptores ErbB/metabolismo , Proteínas de Homeodomínio/genética , Humanos , Metaloproteinases da Matriz/metabolismo , Invasividade Neoplásica , PTEN Fosfo-Hidrolase/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA/metabolismo , Transdução de Sinais , Fatores de Transcrição/genética , Tropomiosina/biossíntese , Tropomiosina/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Proteína de Ligação a GTP rhoCRESUMO
Glioma is a highly fatal malignant disease and its treatment options are limited. microRNAs represent a novel target for the treatment of cancer. In the present study, we used a lentiviral vector to stably express anti-microRNAs targeting the oncogenic miR-27a in U87 glioma cells. The stable expression of anti-miR-27a significantly reduced the proliferation and increased the accumulation of U87 cells in the sub-G1 phase as determined by Cell Counting kit-8 (CCK-8) assays and flow cytometry, respectively. Results from the Matrigel transwell assay also indicated that the inhibition of miR-27a substantially impaired the invasiveness of U87 cells. By combining bioinformatic and proteomic approaches, we identified the mRNAs of 8 proteins upregulated in anti-miR-27a-expressing U87 cells as putative direct targets of miR-27a. Collectively, these data suggest that the lentiviral expression of anti-miR-27a is a feasible approach for the suppression of malignant phenotypes of glioma cells.