E-ISSN: 1019-5157
ISSN: 2651-5024
Research
REDOX MODULATION BY MELATONIN AND TROLOX IN TMZ-RESISTANT GLIOMA CELLS
MEHMET EMRE YILDIRIM✉ ,
BERKAY AYHAN
BERKAY AYHAN
Neurosurgery, SUAM ANKARA EĞİTİM VE ARAŞTIRMA HASTANESİ
DOI: 10.5137/1019-5149.JTN.51128-26.3
Accepted: 12/06/2026
Article in Press
Corresponding Author:
MEHMET EMRE YILDIRIM (memrenrs@gmail.com)
Abstract
Aim
Temozolomide-resistant glioblastoma cells maintain adaptive redox mechanisms that limit the effectiveness of single-agent therapies. This study examined whether Trolox and melatonin, alone or in combination, could modulate oxidative, inflammatory, and apoptotic responses in MGMT-positive T98G cells.
Material and Methods
T98G cells were exposed to Trolox or melatonin at concentrations of 25–200 µM, and a combination group received both agents at 100 µM each. Viability was quantified by MTT and CCK-8. Ferroptosis-related responses were assessed after erastin challenge by measuring lipid peroxidation (BODIPY-C11) and GPX4 protein levels. Inflammatory activation was induced with LPS, and NF-κB p65 activity along with IL-6 and TNF-α release were quantified. Additional endpoints included total intracellular ROS, mitochondrial membrane potential (JC-1), Annexin V/PI apoptotic fractions, and RT-qPCR expression of Nrf2, HO-1, GPX4, Bax, and Bcl-2.
Results
Melatonin reduced cell viability more steeply than Trolox across the dose range tested, and the combination produced the lowest survival (59 ± 3%, p < 0.001). Erastin-driven lipid peroxidation and GPX4 suppression were partially reversed by both agents, with melatonin outperforming Trolox; the combination yielded the strongest restoration. LPS-induced NF-κB activity and cytokine release were diminished most effectively under combined treatment. Changes in ROS levels, apoptotic signaling, and mitochondrial integrity generally followed the same treatment pattern, particularly in the combination group.
Conclusion
In MGMT-positive T98G cells, melatonin proved to be the more active single agent, engaging redox regulation, inflammatory suppression, and pro-apoptotic signaling in a way that Trolox, confined largely to membrane-level lipid peroxidation buffering, simply did not. Together, the two compounds achieved more than either managed independently. These findings make a case for coordinated, a combined, multi-target approach as a way of thinking about the resistant glioma problem.
Temozolomide-resistant glioblastoma cells maintain adaptive redox mechanisms that limit the effectiveness of single-agent therapies. This study examined whether Trolox and melatonin, alone or in combination, could modulate oxidative, inflammatory, and apoptotic responses in MGMT-positive T98G cells.
Material and Methods
T98G cells were exposed to Trolox or melatonin at concentrations of 25–200 µM, and a combination group received both agents at 100 µM each. Viability was quantified by MTT and CCK-8. Ferroptosis-related responses were assessed after erastin challenge by measuring lipid peroxidation (BODIPY-C11) and GPX4 protein levels. Inflammatory activation was induced with LPS, and NF-κB p65 activity along with IL-6 and TNF-α release were quantified. Additional endpoints included total intracellular ROS, mitochondrial membrane potential (JC-1), Annexin V/PI apoptotic fractions, and RT-qPCR expression of Nrf2, HO-1, GPX4, Bax, and Bcl-2.
Results
Melatonin reduced cell viability more steeply than Trolox across the dose range tested, and the combination produced the lowest survival (59 ± 3%, p < 0.001). Erastin-driven lipid peroxidation and GPX4 suppression were partially reversed by both agents, with melatonin outperforming Trolox; the combination yielded the strongest restoration. LPS-induced NF-κB activity and cytokine release were diminished most effectively under combined treatment. Changes in ROS levels, apoptotic signaling, and mitochondrial integrity generally followed the same treatment pattern, particularly in the combination group.
Conclusion
In MGMT-positive T98G cells, melatonin proved to be the more active single agent, engaging redox regulation, inflammatory suppression, and pro-apoptotic signaling in a way that Trolox, confined largely to membrane-level lipid peroxidation buffering, simply did not. Together, the two compounds achieved more than either managed independently. These findings make a case for coordinated, a combined, multi-target approach as a way of thinking about the resistant glioma problem.
Keywords
Temozolomide resistance
T98G glioma
redox
ferroptosis
apoptosis