Abstract BACKGROUND The Rho GTPase activating proteins (ARHGAPs) perform vital roles in the regulation of the Rho GTPases with direct effect on cellular plasticity and cell migration/invasion. We recently reported on the role of five ARHGAPs, identified by a microarray screen, in morphological plasticity in established and patient-derived Glioblastoma (GBM) cell lines and associated clinical relevance in terms of tumour recurrence after treatment. We established that the ARHGAPs either promoted or targeted cell migration/invasion by allowing cells to undergo morphological changes in preparation for dissemination. We also showed that co-expression of two ARHGAPs, 12 and 29, is associated with reduced time to recurrence after initial treatment in patients. ARHGAP activity has been also reported in metastatic cancers including breast and colorectal cancer highlighting the biological relevance of these, as yet understudied, proteins. MATERIAL AND METHODS Here, we explored the GBM microenvironment and the effect of hypoxia on ARHGAP expression and localisation in glioma cell lines. RESULTS Using immunocytological and in vitro migration and invasion assays we were able to ascertain that ARHGAP4, 12, 22, 25 and 29 acquired subcellular distributions different to those recorded under normoxia and expression also decreased or increased under hypoxia. We also found that the effect of the migrastatic inhibitor 6-bromo-indirubin-3′-oxime (BIO) targeting GSK-3 signalling was potentiated when cells were challenged with the drug under hypoxic conditions. CONCLUSION Our results confirm our initial findings of biological relevance of the ARHGAPs in cellular activities and highlight important roles for the ARHGAPs for promoting migratory/invasive activity and behaviour in GBM cells. We also conclude that migrastatic inhibitors will exert enhanced activity on GBM cells under hypoxic conditions making them excellent candidates for complement treatment with cytotoxic drugs or radiotherapy for an improved management of GBM.