LncRNA NEAT1 is involved in temozolomide resistance by regulating MGMT in glioblastoma multiforme

Abstract

Introduction: As one of the most aggressive and lethal tumors, glioblastoma multiforme (GBM) is commonly treated by surgical resection combined with radiotherapy and chemotherapy. Temozolomide (TMZ) is the preferred chemotherapy medicine against GBM. However, recurrent GBM patients exhibit TMZ resistance. As reported in previous studies, NEAT1 is over-expressed in glioma cells; thus, we explored the relationship between NEAT1 and TMZ resistance in GBM. Materials and Methods: The expression levels of NEAT1 and O -6-methylguanine-DNA methyltransferase (MGMT) in GBM tissues and cells were determined by quantitative real-time PCR. Si-RNA and the over-expression vector were transfected into GBM cells to modulate the level of related molecules. Western blot analysis was used to investigate the protein expression of MGMT. The cell viability and IC-50 were analyzed by CCK-8, and apoptosis was detected by flow cytometry assay. Result: The expression level of NEAT1 in the TMZ-sensitive GBM tissues and cells was lower than that in the TMZ-resistant GBM tissues and cells. Furthermore, due to the down-regulation of NEAT1 in TMZ-resistant GBM cells transfected with Si-RNA, the viability and IC-50 value of the GBM cell lines were decreased, and the knockdown of NEAT1 significantly enhanced TMZ-induced cell apoptosis in GBM cells. We also determined that the mRNA and protein level of MGMT were up-regulated in TMZ-resistant GBM cells. Interference with MGMT expression led to a decrease in viability and IC-50 value in the GBM cells, and the knockdown of NEAT1 suppressed the transcription and translation levels of MGMT. However, the over-expression of MGMT enhanced TMZ resistance in NEAT1-silenced U87 and U251 cells. Conclusion: NEAT1 participates in the TMZ resistance of GBM cells by regulating MGMT.