Glioblastoma multiforme (GBM) is the most common and severe form of brain cancer. The median survival time of patients is approximately 12 months due to poor responses to surgery and chemoradiation. In order to understand the mechanisms involved in radioresistance, we conducted a genetic screen using an shRNA library to identify genes whose inhibition would sensitize cells to radiation. The results were cross-referenced with the Oncomine and Rembrandt databases to focus on genes that are highly expressed in GBM tumors and associated with poor patient outcomes. Spermidine/spermine-N1-acetyltransferase 1 (SAT1), an enzyme involved in polyamine catabolism, was identified as a gene that promotes resistance to ionizing radiation (IR), is overexpressed in brain tumors, and correlates with poor outcomes. Knockdown of SAT1 using shRNA and siRNA approaches in multiple cell and neurosphere lines resulted in sensitization of GBM cells to radiation in colony formation assays and tumors, and decreased tumorigenesis in vivo. Radiosensitization occurred specifically in G2/M and S phases, suggesting a role for SAT1 in homologous recombination (HR) that was confirmed in a DR-GFP reporter system. Mechanistically, we found that SAT1 promotes acetylation of histone H3, suggesting a new role of SAT1 in chromatin remodeling and regulation of gene expression. In particular, SAT1 depletion led to a dramatic reduction in BRCA1 expression, explaining decreased HR capacity. Our findings suggest that the biological significance of elevated SAT1 expression in GBM lies in its contribution to cell radioresistance and that SAT1 may potentially be a therapeutic target to sensitize GBM to cancer therapies.
Pharmacology, Toxicology and Pharmaceutical Science
5
6%
Nursing and Health Professions
2
2%
Other
7
9%
Unknown
22
27%
Attention Score in Context
Attention Score in Context
This research output has an Altmetric Attention Score of 7. This is our high-level measure of the quality and quantity of online attention that it has received. This Attention Score, as well as the ranking and number of research outputs shown below, was calculated when the research output was last mentioned on 06 November 2025.
All research outputs
#6,839,138
of 34,652,893 outputs
Outputs from Cancer Research
#10,587
of 35,659 outputs
Outputs of similar age
#76,762
of 427,394 outputs
Outputs of similar age from Cancer Research
#96
of 204 outputs
Altmetric has tracked 34,652,893 research outputs across all sources so far. Compared to these this one has done well and is in the 79th percentile: it's in the top 25% of all research outputs ever tracked by Altmetric.
So far Altmetric has tracked 35,659 research outputs from this source. They typically receive more attention than average, with a mean Attention Score of 8.8. This one has gotten more attention than average, scoring higher than 68% of its peers.
Older research outputs will score higher simply because they've had more time to accumulate mentions. To account for age we can compare this Altmetric Attention Score to the 427,394 tracked outputs that were published within six weeks on either side of this one in any source. This one has done well, scoring higher than 80% of its contemporaries.
We're also able to compare this research output to 204 others from the same source and published within six weeks on either side of this one. This one has gotten more attention than average, scoring higher than 52% of its contemporaries.
