Oxidative stress induced protein aggregation via GGCT produced pyroglutamic acid in drug resistant glioblastoma

Summary: Drug resistance is a major barrier to cancer therapies and remains poorly understood. Recently, non-mutational mechanisms of drug resistance have been proposed where a more plastic metabolic response can play a major role. Here, we show that upon drug resistance, glioblastoma (GBM) cells ha...

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Main Authors: Deanna Tiek, Xiao Song, Xiaozhou Yu, Runxin Wu, Rebeca Iglesia, Alicia Catezone, Katy McCortney, Jordain Walshon, Craig Horbinski, Pouya Jamshidi, Rudolph Castellani, Robert Vassar, Jason Miska, Bo Hu, Shi-Yuan Cheng
Format: Article
Language:English
Published: Elsevier 2025-02-01
Series:iScience
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Online Access:http://www.sciencedirect.com/science/article/pii/S2589004225000288
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Summary:Summary: Drug resistance is a major barrier to cancer therapies and remains poorly understood. Recently, non-mutational mechanisms of drug resistance have been proposed where a more plastic metabolic response can play a major role. Here, we show that upon drug resistance, glioblastoma (GBM) cells have increased oxidative stress, mitochondria function, and protein aggregation. Gamma (γ)-glutamylcyclotranserase (GGCT), an enzyme in the γ-glutamyl cycle for glutathione production, located on chromosome 7 which is commonly amplified in GBM is also increased upon resistance. We further observe that the byproduct of GGCT—pyroglutamic acid—can bind aggregating proteins and that genetic and pharmacological inhibition of GGCT prevents protein aggregation. Finally, we found increased protein aggregation, GGCT expression, and pyroglutamic acid staining in recurrent GBM patient samples, adjacent non-tumor brain, and Alzheimer’s brains. These findings suggest a new pathway for protein aggregation within drug resistant brain cancer that should be further studied in other brain disorders.
ISSN:2589-0042