Non-Coding Y RNA Expression in Glioma Cells Following Temozolomide Treatment and in Patient Gliomas

Glioma is malignant central nervous system tumor, and the most malignant glioma, glioblastoma (GBM) is one of the deadliest tumors that can cause death approximately to 93% of patients within 5 years after diagnosis. This study aimed to determine the expression of non-coding Y RNAs in glioma cell model after Temozolomide (TMZ) exposure and in patients’ tumor samples to assess RNY involvement in glioma therapy resistance in vitro, and diagnostic and prognostic significance in clinical cohort. Glioblastoma cell lines U251, A172, and LN229 were treated for 2 weeks with the alkylating agent Temozolomide. A number of 32 glioma patient tumor tissues were obtained for analysis: 23 patients had glioblastoma multiforme (grade 4, GBM) and 7 patients had diffuse astrocytoma (grade 2, DA). Total RNA was isolated using TRIzol reagent, and cDNA was synthesised from RNA using reverse transcriptase enzymes. Gene expression analysis of RNY1, 3, 4, and 5 was performed by real-time PCR with SYBR Green detection, enabling quantitative assessment of transcript levels. GAPDH, 18S rRNA, and ACTB were used as reference genes for data normalisation. A statistically significant upregulation of RNY1 and RNY4 was observed in grade 4 and grade 2 gliomas as compared to normal brain tissue, respectively. RNY4 expression was also higher in patients aged up to 55 years. In treated A172 cells, RNY1 expression was approximately 5-fold higher than in the control cells. In U251 cells treated with TMZ, RNY3 expression was 1.8-fold higher compared with the control. In contrast, in treated LN229 cells, RNY5 expression was approximately 7.7-fold higher than in the control cells. It was found that RNY1 and RNY4 may represent potential diagnostic biomarkers for gliomas, as their expression in tumor specimens differed significantly between grade 2 and grade 4 tumors. Treatment of different glioblastoma cell lines induced gene- and cell line–specific alterations in RNY expression. The marked increase of RNY1 expression in A172 cells suggests that this gene may be involved in cellular response mechanisms to treatment. Temozolomide-treated cells may be linked to the development and progression of glioma.