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ABSTRACT: Background
Histone deacetylase inhibitors (HDACis) like vorinostat are promising radiosensitisers in prostate cancer, but their effect under hypoxia is not known. We investigated gene expression associated with radiosensitisation of normoxic and hypoxic prostate cancer cells by vorinostat.Methods
Cells were exposed to vorinostat under normoxia or hypoxia and subjected to gene expression profiling before irradiation and clonogenic survival analysis.Results
Pretreatment with vorinostat led to radiosensitisation of the intrinsically radioresistant DU 145 cells, but not the radiosensitive PC-3 and 22Rv1 cells, and was independent of hypoxia status. Knockdown experiments showed that the sensitisation was not caused by repression of hypoxia-inducible factor HIF1 or tumour protein TP53. Global deregulation of DNA repair and chromatin organisation genes was associated with radiosensitisation under both normoxia and hypoxia. A radiosensitisation signature with expression changes of 56 genes was generated and valid for both conditions. For eight signature genes, baseline expression also correlated with sensitisation, showing potential as pretreatment biomarker. The hypoxia independence of the signature was confirmed in a clinical data set.Conclusions
Pretreatment with HDACi may overcome radioresistance of hypoxic prostate tumours by similar mechanisms as under normoxia. We propose a gene signature to predict radiosensitising effects independent of hypoxia status.
SUBMITTER: Jonsson M
PROVIDER: S-EPMC5061908 | biostudies-literature | 2016 Oct
REPOSITORIES: biostudies-literature
Jonsson Marte M Ragnum Harald Bull HB Julin Cathinka Halle CH Yeramian Andree A Clancy Trevor T Frikstad Kari-Anne Myrum KM Seierstad Therese T Stokke Trond T Matias-Guiu Xavier X Ree Anne Hansen AH Flatmark Kjersti K Lyng Heidi H
British journal of cancer 20160906 8
<h4>Background</h4>Histone deacetylase inhibitors (HDACis) like vorinostat are promising radiosensitisers in prostate cancer, but their effect under hypoxia is not known. We investigated gene expression associated with radiosensitisation of normoxic and hypoxic prostate cancer cells by vorinostat.<h4>Methods</h4>Cells were exposed to vorinostat under normoxia or hypoxia and subjected to gene expression profiling before irradiation and clonogenic survival analysis.<h4>Results</h4>Pretreatment wit ...[more]