Author:
Oliva Claudia R.,Ali Md Yousuf,Flor Susanne,Griguer Corinne E.
Abstract
Glioblastoma (GBM) is a fatal disease with recurrences often associated with radioresistance. Although often effective at treating newly diagnosed GBM, increasing evidence suggests that radiotherapy-induced alterations in tumor metabolism promote GBM recurrence and aggressiveness. Using isogenic radiosensitive and radioresistant GBM cell lines and patient-derived xenolines, we found that acquired radioresistance is associated with a shift from a glycolytic metabolism to a more oxidative metabolism marked by a substantial increase in the activity of the mitochondrial res-piratory chain complex cytochrome c oxidase (CcO). This elevated CcO ac-tivity was associated with a switch in the isoform expression of the CcO regulatory subunit COX4, from COX4-2 to COX4-1, assembly of CcO-containing mitochondrial supercomplexes (SCs), and reduced superoxide (O2●-) production. Overexpression of COX4-1 in the radiosensitive cells was sufficient to promote the switch from glycolytic to oxidative metabolism and the incorporation of CcO into SCs, with a concomitant reduction in O2●- production. Conversely, silencing of COX4-1 expression in normally radiore-sistant cells reduced CcO activity, promoted the disassembly of mitochon-drial SCs, and increased O2●- production. Additionally, gain or loss of COX4-1 expression was sufficient to induce the radioresistant or radiosensitive phenotype, respectively. Our results demonstrate that COX4-1 promotes SC assembly in GBM cells, and SC assembly may in turn regulate the pro-duction of reactive oxygen species and thus the acquisition of radiore-sistance in GBM.
Publisher
Shared Science Publishers OG
Subject
Cancer Research,Biochemistry, Genetics and Molecular Biology (miscellaneous),Molecular Medicine,Physiology
Cited by
8 articles.
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