A genome-wide miRNA screen revealed miR-603 as a MGMT-regulating miRNA in glioblastomas

Deepa Kushwaha, Valya Ramakrishnan, Kimberly Ng, Tyler Steed, Thien Nguyen, Diahnn Futalan, Johnny C. Akers, Jann Sarkaria, Tao Jiang, Dipanjan Chowdhury, Bob S. Carter, Clark C. Chen

Research output: Contribution to journalArticle

48 Scopus citations

Abstract

MGMT expression is a critical determinant for therapeutic resistance to DNA alkylating agents. We previously demonstrated that MGMT expression is posttranscriptionally regulated by miR-181d and other miRNAs. Here, we performed a genome-wide screen to identify MGMT regulating miRNAs. Candidate miRNAs were further tested for inverse correlation with MGMT expression in clinical specimens. We identified 15 candidate miRNAs and characterized the top candidate, miR-603. Transfection of miR-603 suppressed MGMT mRNA/protein expression in vitro and in vivo; this effect was reversed by transfection with antimiR-603. miR-603 affinity-precipitated with MGMT mRNA and suppressed luciferase activity in an MGMT-3'UTR-luciferase assay, suggesting direct interaction between miR-603 and MGMT 3'UTR. miR-603 transfection enhanced the temozolomide (TMZ) sensitivity of MGMT-expressing glioblastoma cell lines. Importantly, miR-603 mediated MGMT suppression and TMZ resistance were reversed by expression of an MGMT cDNA. In a collection of 74 clinical glioblastoma specimens, both miR-603 and miR-181d levels inversely correlated with MGMT expression. Moreover, a combined index of the two miRNAs better reflected MGMT expression than each individually. These results suggest that MGMT is co-regulated by independent miRNAs. Characterization of these miRNAs should contribute toward strategies for enhancing the efficacy of DNA alkylating agents.

Original languageEnglish (US)
Pages (from-to)4026-4039
Number of pages14
JournalOncotarget
Volume5
Issue number12
DOIs
StatePublished - 2014

Keywords

  • Glioblastoma
  • MGMT
  • MiRNA cooperativity
  • MicroRNA
  • Temozolomide

ASJC Scopus subject areas

  • Oncology

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    Kushwaha, D., Ramakrishnan, V., Ng, K., Steed, T., Nguyen, T., Futalan, D., Akers, J. C., Sarkaria, J., Jiang, T., Chowdhury, D., Carter, B. S., & Chen, C. C. (2014). A genome-wide miRNA screen revealed miR-603 as a MGMT-regulating miRNA in glioblastomas. Oncotarget, 5(12), 4026-4039. https://doi.org/10.18632/oncotarget.1974