Dynamic structural remodeling of LINC01956 enhances temozolomide resistance in MGMT-methylated glioblastoma

Sci Transl Med. 2024 Oct 2;16(767):eado1573. doi: 10.1126/scitranslmed.ado1573. Epub 2024 Oct 2.

Abstract

The mechanisms underlying stimuli-induced dynamic structural remodeling of RNAs for the maintenance of cellular physiological function and survival remain unclear. Here, we showed that in MGMT promoter-methylated glioblastoma (GBM), the RNA helicase DEAD-box helicase 46 (DDX46) is phosphorylated by temozolomide (TMZ)-activated checkpoint kinase 1 (CHK1), resulting in a dense-to-loose conformational change and an increase in DDX46 helicase activity. DDX46-mediated tertiary structural remodeling of LINC01956 exposes the binding motifs of LINC01956 to the 3' untranslated region of O6-methylguanine DNA methyltransferase (MGMT). This accelerates recruitment of MGMT mRNA to the RNA export machinery and transportation of MGMT mRNA from the nucleus to the cytoplasm, leading to increased MGMT abundance and TMZ resistance. Using patient-derived xenograft (PDX) and tumor organoid models, we found that treatment with the CHK1 inhibitor SRA737abolishes TMZ-induced structural remodeling of LINC01956 and subsequent MGMT up-regulation, resensitizing TMZ-resistant MGMT promoter-methylated GBM to TMZ. In conclusion, these findings highlight a mechanism underlying temozolomide-induced RNA structural remodeling and may represent a potential therapeutic strategy for patients with TMZ-resistant MGMT promoter-methylated GBM.

MeSH terms

  • Animals
  • Brain Neoplasms / drug therapy
  • Brain Neoplasms / genetics
  • Brain Neoplasms / metabolism
  • Brain Neoplasms / pathology
  • Cell Line, Tumor
  • Checkpoint Kinase 1 / genetics
  • Checkpoint Kinase 1 / metabolism
  • DEAD-box RNA Helicases* / genetics
  • DEAD-box RNA Helicases* / metabolism
  • DNA Methylation / drug effects
  • DNA Methylation / genetics
  • DNA Modification Methylases* / genetics
  • DNA Modification Methylases* / metabolism
  • DNA Repair Enzymes / genetics
  • DNA Repair Enzymes / metabolism
  • Drug Resistance, Neoplasm* / drug effects
  • Drug Resistance, Neoplasm* / genetics
  • Gene Expression Regulation, Neoplastic / drug effects
  • Glioblastoma* / drug therapy
  • Glioblastoma* / genetics
  • Glioblastoma* / metabolism
  • Glioblastoma* / pathology
  • Humans
  • Mice
  • Phosphorylation / drug effects
  • Promoter Regions, Genetic / genetics
  • RNA, Long Noncoding* / genetics
  • RNA, Long Noncoding* / metabolism
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Temozolomide* / pharmacology
  • Temozolomide* / therapeutic use
  • Tumor Suppressor Proteins* / genetics
  • Tumor Suppressor Proteins* / metabolism

Substances

  • Temozolomide
  • RNA, Long Noncoding
  • Tumor Suppressor Proteins
  • DEAD-box RNA Helicases
  • DNA Modification Methylases
  • DNA Repair Enzymes
  • MGMT protein, human
  • Checkpoint Kinase 1
  • RNA, Messenger
  • CHEK1 protein, human