Mitochondrial DNA Content Modulates Chemosensitivity and Cellular Adaptation in Glioblastoma Cells

Mitochondrial DNA (mtDNA) copy number alterations are closely associated with glioblastoma (GBM) progression and therapeutic resistance. This study investigates how changes in mitochondrial content affect the chemotherapeutic response of GBM cells in vitro.

Glioblastoma cell lines (U87 and LN18) were initially treated with ethidium bromide (EtBr) to deplete mtDNA, followed by EtBr withdrawal to enable mtDNA restoration. Real-time Polymerase Chain Reaction (PCR) was subsequently employed to quantify mtDNA levels. To assess cellular responses, cell viability was measured using the CCK-8 assay, while wound healing and Transwell assays were conducted to evaluate cell migration and invasion. Apoptosis was analyzed via flow cytometry using the Annexin V-FITC/ PI kit. In addition, intracellular reactive oxygen species (ROS) and mitochondrial membrane potential (ΔΨm) were examined by flow cytometry, and Adenosine triphosphate (ATP) levels were quantified using a luminescent ATP detection assay.

Glioblastoma cells with depleted mtDNA exhibited an increase in mtDNA content following temozolomide (TMZ) exposure. Despite this, these cells showed reduced viability, migration, and invasion, while also displaying adaptive responses suggestive of emerging resistance. In contrast, cells in which mtDNA content had been restored demonstrated recovery across all parameters, indicating enhanced sensitivity to TMZ.

This study highlights the essential role of mtDNA content in modulating GBM cell sensitivity to chemotherapy, as variations in mtDNA levels can influence cellular responses to treatment. These findings suggest that mtDNA content could act as a potential biomarker and that its modulation may offer a promising strategy to overcome drug resistance in GBM. Cite this article as: Radzak SMA, Patar A, Lee H, Yusoff AAM. Mitochondrial DNA content modulates chemosensitivity and cellular adaptation in glioblastoma cells. Eurasian J Med. 2026, 58(2), 1207, doi: 10.5152/eurasianjmed.2026.251207.