LncRNA HOXA-AS2 Promotes Temozolomide Resistance in Glioblastoma by Regulated miR-302a-3p/IGF1 Axis.

Background: Glioblastoma (GBM) is a highly prevalent brain tumor characterized by high rates of morbidity, recurrence, and mortality. While temozolomide (TMZ) is commonly used as a first-line treatment for this cancer, the emergence of TMZ resistance limits its utility. The long noncoding RNA HOXA-AS2 reportedly drives GBM progression, but whether it can influence therapeutic resistance to TMZ has yet to be established. Methods: HOXA-AS2 expression was analyzed in TMZ-resistant and sensitive GBM tissue samples and cell lines by qPCR. A siRNA-based approach was used to knock down HOXA-AS2 in GBM cells, after which TMZ resistance was tested. Bioinformatics approaches were used to predict miRNA binding targets of HOXA-AS2, after which a series of luciferase reporter assay and rescue experiments with appropriate miRNA inhibitor/mimic constructs were performed to validate these predictions and to clarify the ability of HOXA-AS2 to regulate chemoresistant activity. Results: TMZ-resistant GBM patients and cell lines exhibited increased HOXA-AS2 expression that was correlated with worse overall survival. Knocking down HOXA-AS2 increased the sensitivity of resistant GBM cells to TMZ. miR-302a-3p was identified as a HOXA-AS2 target confirmed through luciferase reporter assays and rescue experiments, and IGF1 was further identified as a confirmed miR-302a-3p target. In addition, HOXA-AS2 knockdown resulted in a corresponding drop in IGF1 expression consistent with indirect regulation mediated by miR-302a-3p. Conclusion: In summary, these results highlight the role of HOXA-AS2 as a driver of TMZ resistance in GBM through its ability to regulate the miR-302a-3p/IGF1 signaling axis, highlighting this pathway as a promising target for the diagnosis, therapeutic sensitization, and/or treatment of affected patients.

MicroRNA-193a-5p exerts a tumor suppressor role in glioblastoma via modulating NOVA1.

BACKGROUND AND OBJECTIVES: Glioblastoma (GBM) is the most common and lethal of intracranial tumors, which is characterized by extensive proliferation and the diffused invasion of tumor cells. MicroRNA-193a-5p (miR-193a-5p) have been demonstrated previously as a functional suppressor in the development and progression of various cancers. The current study aimed to investigate whether miR-193a-5p influences cell proliferation and migration through the mitogen-activated protein kinase/extracellular signal-regulated kinase signaling pathway by targeting neuro-oncological ventral antigen 1 (NOVA1) in glioblastoma. MATERIALS AND METHODS: The miR-193a-5p expression was detected by quantitative real-time polymerase chain reaction assay in GBM tissues and cell lines. Cell Counting Kit-8 assay, colony formation analysis, wound-healing, and transwell invasion assays were performed to evaluate cell proliferation, colony formation, migration, and invasion, respectively. Western blot analysis and luciferase reporter gene assay were performed to verify the downstream target gene of miR-193a-5p. RESULTS: The expression of miR-193a-5p was significantly downregulated in GBM tissues and cell lines. Kaplan-Meier analysis showed that patients with low miR-193a-5p expression had a shorter disease-free survival (P < 0.05). Functionally, miR-193a-5p overexpression dramatically suppressed the proliferation, colony formation, migration, and invasion in glioma cells. Bioinformatics prediction and a luciferase assay confirmed that NOVA1 was a direct functional target of miR-193a-5p. Moreover, ectopic expression of NOVA1 could partially reverse the inhibitory effects of miR-193a-5p on glioma cell proliferation, colony formation, migration, and invasion. NOVA1 overexpression abrogated the inhibitory effect of miR-193a-5p on the PTEN/PI3k/AKT pathway. CONCLUSION: Taken together, our findings suggested that miR-193a-5p functions as a tumor suppressor in glioma cells by directly targeting NOVA1.