Modulation of Genes and MicroRNAs in the Neurospheres of Glioblastoma Cell Lines U343 and T98G Induced by Ionizing Radiation and Temozolomide Therapy.

Introduction: Glioblastoma is the most prevalent primary malignant neoplasm of the central nervous system. It has increased its incidence, while the overall survival remains over 14 months.

Purpose: The purpose is to evaluate the expression of the genes EGFR, PTEN, MGMT, and IDH1/2, and microRNAs miR-181b, miR-145, miR-149, and miR-128a in adhered cells (AC) and neurospheres (NS) from cell lines (T98G and U343) submitted to temozolomide (TMZ) and ionizing radiation (IR).

Methods: T98G and U343 were treated with TMZ, IR, and TMZ+IR. The analysis of gene expression and miRNAs was performed using real-time PCR.

Results: This study demonstrated: a) an improvement in the expression of IDH1 after IR and TMZ + IR in the NS (T98G); b) an increase in the expression of MGMT in NS (T98G) in IR groups and TMZ + IR. The expression of miRNAs results as a) AC (U343) expressed more miR-181b after TMZ, IR, and TMZ + IR; and miR-128a improved after TMZ, IR, and TMZ + IR; b) NS (T98G) after TMZ + IR expressed: miR-181b; miR-149; miR-145 and miR-128a; c) NS (U343) after IR huge expressed miR-149 and miR-145.

Conclusion: IR was an independent and determining radioresistance factor in NS. However, we observed no complementarity action of oncomiRs regulation.