Exosome-Mediated Transfer of Long Noncoding RNA HOTAIR Regulates Temozolomide Resistance by miR-519a-3p/RRM1 Axis in Glioblastoma.

Chemoresistance obstructs the treatment of glioblastoma (GB). Exosome-mediated transfer of long noncoding RNAs (lncRNAs) was reported to regulate chemoresistance in diverse cancers. The authors aimed to investigate the underlying mechanism of lncRNA HOX transcript antisense intergenic RNA (HOTAIR) in regulating temozolomide (TMZ) resistance in GB. 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was utilized to check TMZ resistance and cell proliferation. The abilities of cell migration and invasion were evaluated by transwell assay. The protein levels of E-cadherin, N-cadherin, Vimentin, CD63, CD81, and ribonucleoside-diphosphate reductase subunit M1 (RRM1) were measured by western blot. Quantitative real-time polymerase chain reaction was conducted to detect the levels of HOTAIR, microRNA (miR)-519a-3p, and RRM1. The starBase was hired to predict the target sites between miR-519a-3p and HOTAIR or RRM1 and the dual-luciferase reporter assay was performed to verify the interaction. Xenograft tumor model was established to investigate the biological role of HOTAIR . The high abilities of cell viability and metastasis were observed in TMZ-resistant GB cells. LncRNA HOTAIR was significantly upregulated in TMZ-resistant GB cells and its downregulation inhibited proliferation, migration, invasion, and epithelial/mesenchymal transition in TMZ-resistant GB cells. Further analysis indicated that exosomal lncRNA HOTAIR induced TMZ resistance and modulated TMZ resistance through miR-519a-3p/RRM1 axis. Besides, serum exosomal lncRNA HOTAIR was stable and had diagnostic value. Moreover, knockdown of lncRNA HOTAIR reduced TMZ resistance . Exosomal lncRNA HOTAIR mediated TMZ resistance through miR-519a-3p/RRM1 axis in GB.