title: Simultaneous Interference with HER1/EGFR and RAC1 Signaling Drives Cytostasis and Suppression of Survivin in Human Glioma Cells in Vitro.
abstract: We have previously reported that combined inhibition of the epidermal growth factor receptor by erlotinib and of RAC1 by NSC23766 yielded a synergistic antiproliferative effect on established and primary cultured glioblastoma cells. The current study aimed at identifying the molecular mechanism. Staining for annexin V/PI or carboxyfluorescein succinimidyl ester was performed in order to determine the induction of apoptosis, necrosis or cytostasis in established and primary cultured glioblastoma cells. Moreover, expression of Ki-67 was determined by immunofluorescence, and the expression of cell cycle proteins was analysed by Western blot. Our data show that combined treatment with erlotinib and NSC23766 resulted in a reduced number of cell divisions, a significantly decreased Ki-67 expression, increased apoptosis and autophagy when compared to single agent treatments. On the molecular level, concomitant treatment with both agents resulted in a pronounced downregulation of cyclin D1, cyclin-dependent kinases 2, 4 and 6, as well as of survivin when compared to treatments with either agent alone. In conclusion, we demonstrate that combined treatment of human glioma cell lines in vitro with erlotinib and NSC23766 markedly inhibits cell division, induces apoptosis independent of caspase-3 activation and induces autophagy concomitant with suppression of survivin.
authors.affiliation: Department of Neurosurgery, Ulm University Medical Center, Ulm, Germany. georg.karpel@gmail.com.|Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm, Germany. georg.karpel@gmail.com.|Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY, USA. georg.karpel@gmail.com.|Department of Pathology & Cell Biology, Columbia University Medical Center, 630 West 168th Street, New York, NY, 10032, USA. georg.karpel@gmail.com.
authors.forename: G
authors.identifier: http://orcid.org/0000-0001-8236-5369
authors.initials: G
authors.lastname: Karpel-Massler
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm, Germany.
authors.forename: M-A
authors.initials: MA
authors.lastname: Westhoff
authors.affiliation: IIAIGC Study Center, Burlington, VT, USA.
authors.forename: R E
authors.initials: RE
authors.lastname: Kast
authors.affiliation: Department of Neurosurgery, Ulm University Medical Center, Ulm, Germany.
authors.forename: A
authors.initials: A
authors.lastname: Dwucet
authors.affiliation: Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY, USA.
authors.forename: S
authors.initials: S
authors.lastname: Karpel-Massler
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm, Germany.
authors.forename: L
authors.initials: L
authors.lastname: Nonnenmacher
authors.affiliation: Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY, USA.
authors.forename: M D
authors.initials: MD
authors.lastname: Siegelin
authors.affiliation: Department of Neurosurgery, Ulm University Medical Center, Ulm, Germany.
authors.forename: C R
authors.initials: CR
authors.lastname: Wirtz
authors.affiliation: Department of Pediatrics and Adolescent Medicine, Ulm University Medical Center, Ulm, Germany.
authors.forename: K-M
authors.initials: KM
authors.lastname: Debatin
authors.affiliation: Department of Neurosurgery, Ulm University Medical Center, Ulm, Germany.
authors.forename: M-E
authors.initials: ME
authors.lastname: Halatsch
mesh_terms: D000634:Aminoquinolines / Q000008:administration & dosage / Q000633:toxicity; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000008:administration & dosage / Q000633:toxicity; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D045744:Cell Line, Tumor; D054697:Cytostatic Agents / Q000008:administration & dosage* / Q000633:toxicity; D066246:ErbB Receptors / Q000037:antagonists & inhibitors / Q000378:metabolism*; D000069347:Erlotinib Hydrochloride / Q000008:administration & dosage / Q000633:toxicity; D005910:Glioma / Q000378:metabolism*; D006801:Humans; D051034:Inhibitor of Apoptosis Proteins / Q000037:antagonists & inhibitors / Q000378:metabolism*; D011743:Pyrimidines / Q000008:administration & dosage / Q000633:toxicity; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D000077022:Survivin; D020830:rac1 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000634:Aminoquinolines; C107489:BIRC5 protein, human; D054697:Cytostatic Agents; D051034:Inhibitor of Apoptosis Proteins; C487513:NSC 23766; D011743:Pyrimidines; C107953:RAC1 protein, human; D000077022:Survivin; D000069347:Erlotinib Hydrochloride; C512478:EGFR protein, human; D066246:ErbB Receptors; D020830:rac1 GTP-Binding Protein
keywords: Apoptosis; Cytostasis; Glioma; HER1/EGFR; RAC1; Survivin; Synergy