miRNA array screening reveals cooperative MGMT-regulation between miR-181d-5p and miR-409-3p in glioblastoma

Susanna Khalil, Enrica Fabbri, Alessandra Santangelo, Valentino Bezzerri, Cinzia Cantù, Gianfranco Di Gennaro, Alessia Finotti, Claudio Ghimenton, Albino Eccher, Maria Dechecchi, Aldo Scarpa, Brian Hirshman, Clark Chen, Manuela Ferracin, Massimo Negrini, Roberto Gambari, Giulio Cabrini

Research output: Contribution to journalArticlepeer-review

29 Scopus citations

Abstract

The levels of expression of O6-methylguanine-DNA methyltransferase (MGMT) are relevant in predicting the response to the alkylating chemotherapy in patients affected by glioblastoma. MGMT promoter methylation and the published MGMT regulating microRNAs (miRNAs) do not completely explain the expression pattern of MGMT in clinical glioblastoma specimens. Here we used a genome-wide microarraybased approach to identify MGMT regulating miRNAs. Our screen unveiled three novel MGMT regulating miRNAs, miR-127-3p, miR-409-3p, and miR-124-3p, in addition to the previously identified miR-181d-5p. Transfection of these three novel miRNAs into the T98G glioblastoma cell line suppressed MGMT mRNA and protein expression. However, their MGMT-suppressive effects are 30-50% relative that seen with miR-181d-5p transfection. In silico analyses of The Cancer Genome Atlas (TCGA) and Chinese Glioma Genome Atlas (CGGA) revealed that miR-181d-5p is the only miRNA that consistently exhibited inverse correlation with MGMT mRNA expression. However, statistical models incorporating both miR-181d-5p and miR-409-3p expression better predict MGMT expression relative to models involving either miRNA alone. Our results confirmed miR-181d-5p as the key MGMT-regulating miRNA. Other MGMT regulating miRNAs, including the miR-409-3p identified in this report, modify the effect of miR-181d-5p on MGMT expression. MGMT expression is, thus, regulated by cooperative interaction between key MGMT-regulating miRNAs.

Original languageEnglish (US)
Pages (from-to)28195-28206
Number of pages12
JournalOncotarget
Volume7
Issue number19
DOIs
StatePublished - May 10 2016

Keywords

  • Glioblastoma
  • MGMT
  • MiR-181d-5p
  • MiR-409-3p

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