Temozolomide (TMZ) is the first-line chemotherapy drug for glioblastoma (GBM) but acquired TMZ resistance is frequently observed. Thus, a TMZ resistant GBM cell line U87-R was established to search for potential long noncoding RNAs (lncRNAs) used in TMZ resistance. In our study, LINC00511 was identified as a TMZ resistance-associated lncRNA in U87-R cells by transcriptome RNA sequencing. The potential functions of LINC00511 were evaluated by quantitative real-time polymerase chain reaction, cell viability assay, colony formation assay, western blot, soft agar assay, flow cytometry, tumor xenograft model, immunofluorescence, sphere formation assay, fluorescent in situ hybridization, luciferase reporter assay, and RNA pull-down assay. We found that LINC00511 was upregulated in U87-R cells and GBM samples, and correlated with poor prognosis of GBM patients. Silencing LINC00511 impaired TMZ tolerance of U87-R cells, while LINC00511 overexpression increased TMZ resistance of sensitive GBM cells. Wnt/β-catenin signaling was activated in U87-R cells, and inhibiting Wnt/β-catenin signaling enhanced TMZ sensitivity. Furthermore, LINC00511 was mainly distributed in the cytoplasm of GBM cells and regulated Wnt/β-catenin activation by acting as a molecular sponge for miR-126-5p. Multiple genes of Wnt/β-catenin signaling such as DVL3, WISP1, and WISP2 were targeted by miR-126-5p. MiR-126-5p restoration impaired TMZ resistance of GBM cells. In conclusion, our results provided a novel insight into acquired TMZ resistance of GBM cells and suggested LINC00511 as a potential biomarker or therapeutic target for GBM patients.

中文翻译：

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LINC00511 通过海绵 miR-126-5p 和激活 Wnt/β-catenin 信号促进胶质母细胞瘤细胞对替莫唑胺的抗性

替莫唑胺 (TMZ) 是胶质母细胞瘤 (GBM) 的一线化疗药物，但经常观察到获得性 TMZ 耐药性。因此，建立了 TMZ 抗性 GBM 细胞系 U87-R，以寻找用于 TMZ 抗性的潜在长链非编码 RNA (lncRNA)。在我们的研究中，通过转录组 RNA 测序，LINC00511 在 U87-R 细胞中被鉴定为与 TMZ 抗性相关的 lncRNA。通过实时定量聚合酶链反应、细胞活力测定、集落形成测定、蛋白质印迹、软琼脂测定、流式细胞术、肿瘤异种移植模型、免疫荧光、球形成测定、荧光原位杂交、荧光素酶评估 LINC00511 的潜在功能报告基因检测和 RNA 下拉检测。我们发现 LINC00511 在 U87-R 细胞和 GBM 样本中上调，并与 GBM 患者的不良预后相关。沉默 LINC00511 会损害 U87-R 细胞的 TMZ 耐受性，而 LINC00511 过表达会增加敏感 GBM 细胞的 TMZ 耐受性。重量/β -catenin 信号在 U87-R 细胞中被激活，抑制 Wnt/ β -catenin 信号增强了 TMZ 敏感性。此外，LINC00511主要分布在GBM细胞的细胞质中，通过充当miR-126-5p的分子海绵来调节Wnt/ β -catenin的活化。miR-126-5p 靶向多个 Wnt/ β -catenin 信号基因，如 DVL3、WISP1 和 WISP2。MiR-126-5p 修复损害了 GBM 细胞的 TMZ 抗性。总之，我们的结果提供了对 GBM 细胞获得性 TMZ 抗性的新见解，并建议 LINC00511 作为 GBM 患者的潜在生物标志物或治疗靶点。