1. AP-2α decreases TMZ resistance of recurrent GBM by downregulating MGMT expression and improving DNA damage.
- Author
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Huang G, Ouyang M, Xiao K, Zhou H, Zhong Z, Long S, Li Z, Zhang Y, Li L, Xiang S, and Ding X
- Subjects
- Animals, Female, Humans, Mice, Middle Aged, Cell Line, Tumor, Gene Expression Regulation, Neoplastic drug effects, Mice, Inbred BALB C, Mice, Nude, Neoplasm Recurrence, Local genetics, Neoplasm Recurrence, Local drug therapy, Neoplasm Recurrence, Local metabolism, Promoter Regions, Genetic, Xenograft Model Antitumor Assays, Antineoplastic Agents, Alkylating pharmacology, Brain Neoplasms drug therapy, Brain Neoplasms genetics, Brain Neoplasms pathology, Brain Neoplasms metabolism, DNA Damage drug effects, DNA Modification Methylases metabolism, DNA Modification Methylases genetics, DNA Repair Enzymes genetics, DNA Repair Enzymes metabolism, Down-Regulation drug effects, Drug Resistance, Neoplasm genetics, Glioblastoma drug therapy, Glioblastoma genetics, Glioblastoma pathology, Glioblastoma metabolism, Temozolomide pharmacology, Transcription Factor AP-2 genetics, Transcription Factor AP-2 metabolism, Tumor Suppressor Proteins genetics, Tumor Suppressor Proteins metabolism
- Abstract
Aims: The incidence of recurrent gliomas is high, exerting low survival rates and poor prognoses. Transcription factor AP-2α has been reported to regulate the progression of primary glioblastoma (GBM). However, the function of AP-2α in recurrent gliomas is largely unclear., Methods: The expression of AP-2α and O6-methylguanine DNA-methyltransferase (MGMT) was detected in recurrent glioma tissues and cell lines by Western blots, the regulation mechanisms between AP-2α/MGMT promoter and RA/AP-2α promoter were studied by luciferase reporter assays, EMSA, and chIP assays. The effects of AP-2α and TMZ/RA treatment on cell viability in vitro and in vivo were investigated by MTT assays, γH
2 AX staining, comet assays and intracranial injection., Key Findings: AP-2α expression negatively correlates with the expression of MGMT in glioma samples. AP-2α could directly bind with the promoter of the MGMT gene, suppresses transcriptional levels of MGMT and downregulate MGMT expression in TMZ-resistant U87MG-R and T98G cells, but TMZ treatment decreases AP-2α expression and increases MGMT expression. The extended TMZ treatment and increased TMZ concentrations reversed these effects. Moreover, AP-2α overexpression combines with TMZ to decrease cell viability, concurrently with improved DNA damage marker γH2 AX. Furthermore, retinoic acid (RA) activates RAR/RXR heterodimers, which bind to RA-responsive elements (RAREs) of the AP-2α promoter, and activates AP-2α expression in recurrent glioma cells. Finally, in intracranial relapsed glioma mouse model, both RA and TMZ could retard tumor development and prolong the mouse survival., Significance: AP-2α activation by gene overexpression or RA treatment reveals the suppressive effects on glioma relapse, providing a novel therapeutic strategy against malignant refractory gliomas., Competing Interests: Declaration of competing interest The authors declare no competing interests., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)- Published
- 2024
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