MicroRNA-1269 is downregulated in glioblastoma and its maturation is regulated by long non-coding RNA SLC16A1 Antisense RNA 1.

MicroRNA-1269 (miR-1296) promotes esophageal cancer. However, its role in other cancers, such as glioblastoma (GBM) is unclear. We predicted that miR-1269 might interact with long non-coding RNA (lncRNA) SLC16A1 Antisense RNA 1 (SLC16A1-AS1), a critical player in GBM. We then studied the interaction between SLC16A1-AS1 and miR-1269 in GBM. In this study, paired GBM and non-tumor tissues were used to analyze the expression of SLC16A1-AS1 and premature and mature miR-1269. The interaction of SLC16A1-AS1 with premature miR-1269 was analyzed with RNA pull-down assay and dual-luciferase reporter assay. Cellular fractionation assay was applied to determine the subcellular location of SLC16A1-AS1. Overexpression assays were applied to determine the role of SLC16A1-AS1 in miR-1269 maturation. BrdU, Transwell and cell apoptosis assays were performed to analyze the role of SLC16A1-AS1 and miR-1269 in GBM cell proliferation, migration, and invasion. Interestingly, we observed the upregulation of premature miR-1269 and downregulation of mature miR-1269 in GBM. SLC16A1-AS1 was also overexpressed in GBM. The direct interaction of SLC16A1-AS1 with premature miR-1269 was observed. SLC16A1-AS1 suppressed miR-1269 maturation and promoted cell proliferation, migration, and invasion, and inhibited cell apoptosis, while miR-1269 displayed the opposite trend. SLC16A1-AS1 partly reversed the effects of miR-1269 on GBM cell proliferation, movement and apoptosis. Moreover, SLC16A1-AS1 overexpression increased the level of ki-67, CDK4 and Bcl-2 in LN-229 and LN-18 cells. However, miR-1269 could partly reverse the effect of SLC16A-AS1 on protein levels. Overall, miR-1269 is downregulated in GBM and its maturation is regulated by SLC16A1-AS1.

LncRNA SLC16A1-AS1 is Upregulated in Glioblastoma and Promotes Cancer Cell Proliferation by Regulating miR-149 Methylation.

INTRODUCTION: LncRNA SLC16A1-AS1 has been characterized as a critical player in lung cancer, while its role in glioblastoma (GBM) is unknown. By analyzing the TCGA dataset, we observed the upregulation of SLC16A1-AS1 expression in GBM. Therefore, we aimed to investigate the role of SLC16A1-AS1 in this cancer. METHODS: GBM tissues and paired non-tumor tissues were collected from 62 GBM patients through biopsy. RT-qPCR was performed to determine the expression of SLC16A1-AS1 and miR-149. Linear regression was used to analyze their correlations. The relationship between SLC16A1-AS1 and miR-149 was assessed by gain and loss of function experiments. Methylation-specific PCR (MSP) and bisulfite sequencing PCR (BSP) were performed to analyze the methylation status of miR-149. Cell proliferation was evaluated by CCK-8 assay and colony formation experiments in GBM cells. RESULTS: We found that SLC16A1-AS1 expression was upregulated in GBM tissues, and the upregulated expression of SLC16A1-AS1 predicted poor survival of GBM patients. MiR-149 was downregulated in GBM tissues and inversely correlated with the expression of SLC16A1-AS1. In GBM cells, overexpression of SLC16A1-AS1 downregulated the expression of miR-149 and increased the methylation of miR-149 gene. In cell proliferation and colony formation assay, overexpression of SLC16A1-AS1 reduced the inhibitory effects of miR-149 on GBM cell proliferation. CONCLUSION: SLC16A1-AS1 may promote GBM cell proliferation by regulating miR-149 methylation. SLC16A1-AS1 can be considered as a potential diagnostic marker in GBM.

Nobiletin inhibits invasion via inhibiting AKT/GSK3ß/ß-catenin signaling pathway in Slug-expressing glioma cells.

Epithelial-mesenchymal transition (EMT) is a pivotal event in tumor progression during which cancer cells undergo dramatic changes acquiring highly invasive properties. In this study, we found that nobiletin, a polymethoxylated flavone, suppressed migration and invasion in both U87 and U251 glioma cells. Expression of epithelial markers (E-cadherin and occludin) was upregulated; mesenchymal markers (N-cadherin, fibronectin) and the transcriptional factor Slug were downregulated after nobiletin treatment. Transforming growth factor ß (TGF-ß) was applied to stimulate EMT and the results showed that nobiletin not only influenced basal level cell migration but also prevented TGF-ß-triggered migration and EMT, with the AKT/GSK3ß/ß-catenin signaling pathway greatly involved. Furthermore, nobiletin remarkably diminished TGF-ß-induced ß-catenin nuclear translocation and the binding to the Slug promoter. It is worth noting that nobiletin almost blocked invasion in Slug-expressing U87 and U251 cells, and only exhibiting faint effect on non-Slug-expressing U343 glioma cells. Reinforced Slug expression in U343 cells by transfecting Slug plasmid was significantly attenuated by nobiletin, demonstrating the essential role of Slug in the anti-metastasis effect of nobiletin. Nobiletin repressed tumor growth in vivo and abrogated EMT in nude mice bearing U87-Luc xenografts, as demonstrated by Xenogen IVIS imaging and immunohistochemistry assay. Our findings suggested that nobiletin might have a great potential for treating glioblastoma.