Marita Eckert1, Lukas Klumpp1,2, Stephan M Huber1. 1. Department of Radiation Oncology, University of Tübingen, Tübingen, Germany. 2. Dr. Margarete Fischer-Bosch-Institute of Clinical Pharmacology, Stuttgart, Germany.
Abstract
BACKGROUND/AIMS: Valproic acid (VPA), an anticonvulsant and mood-stabilizing drug is used to treat epileptic seizure of glioblastoma patients. Besides its antiepileptic activity, VPA has been attributed further functions that improve the clinical outcome of glioblastoma patients. Those comprise the inhibition of some histone deacetylase (HDAC) isoforms which reportedly may result in radiosensitization. Retrospective analysis of patient data, however, could not unequivocally confirm a prolonged survival of glioblastoma patients receiving VPA. The present study aimed to identify potential VPA targets at the cellular level. METHODS: To this end, the effect of VPA on metabolism, Ca2+-, biochemical and electro-signaling, cell-cycling, clonogenic survival and transfilter migration was analyzed in three human glioblastoma lines (T98G, U-87MG, U251) by MTT assay, Ca2+ imaging, immunoblotting, patch-clamp recording, flow cytometry, delayed plating colony formation and modified Boyden chamber assays, respectively. In addition, the effect of VPA on clonogenic survival of primary glioblastoma spheroid cultures treated with temozolomide and fractionated radiation was assessed by limited dilution assay. RESULTS: In 2 of 3 glioblastoma lines, clinical relevant concentrations of VPA slightly slowed down cell cycle progression and decreased clonogenic survival. Furthermore, VPA induced Ca2+ signaling which was accompanied by pronounced K+ channel activity and transfilter cell migration. VPA did not affect metabolic NAD(P)H formation or radioresistance of the glioblastoma lines. Finally, VPA did not impair clonogenic survival or radioresistance of temozolomide-treated primary spheroid cultures. CONCLUSIONS: Combined, our in vitro data do not propose a general use of VPA as a radiosensitizer in anti-glioblastoma therapy.
BACKGROUND/AIMS: Valproic acid (VPA), an anticonvulsant and mood-stabilizing drug is used to treat epilepticseizure of glioblastomapatients. Besides its antiepileptic activity, VPA has been attributed further functions that improve the clinical outcome of glioblastomapatients. Those comprise the inhibition of some histone deacetylase (HDAC) isoforms which reportedly may result in radiosensitization. Retrospective analysis of patient data, however, could not unequivocally confirm a prolonged survival of glioblastomapatients receiving VPA. The present study aimed to identify potential VPA targets at the cellular level. METHODS: To this end, the effect of VPA on metabolism, Ca2+-, biochemical and electro-signaling, cell-cycling, clonogenic survival and transfilter migration was analyzed in three humanglioblastoma lines (T98G, U-87MG, U251) by MTT assay, Ca2+ imaging, immunoblotting, patch-clamp recording, flow cytometry, delayed plating colony formation and modified Boyden chamber assays, respectively. In addition, the effect of VPA on clonogenic survival of primary glioblastoma spheroid cultures treated with temozolomide and fractionated radiation was assessed by limited dilution assay. RESULTS: In 2 of 3 glioblastoma lines, clinical relevant concentrations of VPA slightly slowed down cell cycle progression and decreased clonogenic survival. Furthermore, VPA induced Ca2+ signaling which was accompanied by pronounced K+ channel activity and transfilter cell migration. VPA did not affect metabolic NAD(P)H formation or radioresistance of the glioblastoma lines. Finally, VPA did not impair clonogenic survival or radioresistance of temozolomide-treated primary spheroid cultures. CONCLUSIONS: Combined, our in vitro data do not propose a general use of VPA as a radiosensitizer in anti-glioblastoma therapy.
Authors: A V Krauze; Mackey Megan; Cooley-Zgela Theresa; Mathen Peter; J H Shih; P J Tofilon; L Rowe; M Gilbert; K Camphausen Journal: Cancer Stud Ther Date: 2020-01-11
Authors: Falko Lange; Konrad Weßlau; Katrin Porath; Julia Hörnschemeyer; Carina Bergner; Bernd Joachim Krause; Christina Susanne Mullins; Michael Linnebacher; Rüdiger Köhling; Timo Kirschstein Journal: PLoS One Date: 2019-02-04 Impact factor: 3.240
Authors: Tatjana Vatter; Lukas Klumpp; Katrin Ganser; Nicolai Stransky; Daniel Zips; Franziska Eckert; Stephan M Huber Journal: Biomolecules Date: 2020-06-17