Feedforward miR-181d degradation modulates population variance of methyl-guanine methyl transferase and temozolomide resistance
- Cell Rep. 2025 Nov 25;44(11):116516. doi: 10.1016/j.celrep.2025.116516.
- 1. Department of Neurosurgery, University of Minnesota, Minneapolis, MN 55455, USA. Electronic address: [email protected].
- 2. Department of Neurosurgery, University of Minnesota, Minneapolis, MN 55455, USA.
- 3. Department of Veterinary Biomedical Sciences, St. Paul, MN 55108, USA.
- 4. VisiCELL Medical Inc., San Diego, CA 92121, USA.
- 5. Department of Pediatrics, Stanford University, Stanford, CA 94304, USA.
- 6. Department of Neurology, Warren Alpert School of Medicine, Rhode Island Hospital, Brown University, Providence, RI 02903, USA.
- 7. Department of Neurosurgery, Warren Alpert School of Medicine, Rhode Island Hospital, Brown University, Providence, RI 02903, USA.
- 8. Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
- 9. Department of Molecular Biology, Cell Biology, and Biochemistry, Brown University, Providence, RI 02903, USA.
- 10. Department of Pathology and Laboratory Medicine, Legorreta Cancer Center, Brown University, Providence, RI 02903, USA.
Intratumoral heterogeneity plays a pivotal role in Cancer evolution, providing the substrate for adaptation to selective pressures, including chemotherapy treatment. Here, we demonstrate that miR-181d modulates variability in methyl-guanine methyl transferase (MGMT) expression, contributing to this heterogeneity in glioblastoma, the most common form of adult primary brain tumor. Treatment with standard-of-care temozolomide (TMZ) chemotherapy triggers a feedforward loop that accelerates polyribonucleotide nucleotidyltransferase 1 (PNPT1)-dependent miR-181d degradation. This degradation requires the activation of ataxia-telangiectasia and Rad3-related (ATR) kinase. The degradation of miR-181d in glioblastoma cells increases the variance of MGMT expression in the cell population, contributing to acquired TMZ resistance. This resistance is suppressed by exogenously transfected miR-181d. These findings suggest that MicroRNA regulates intratumoral heterogeneity by modulating the transcriptional variability of key DNA repair Enzymes, providing a compelling rationale for miRNA delivery as a platform for glioblastoma therapy.