title: Pharmacology of novel small-molecule tubulin inhibitors in glioblastoma cells with enhanced EGFR signalling.
abstract: We recently reported that CMPD1, originally developed as an inhibitor of MK2 activation, primarily inhibits tubulin polymerisation and induces apoptosis in glioblastoma cells. In the present study we provide detailed pharmacological investigation of CMPD1 analogues with improved molecular properties. We determined their anti-cancer efficacy in glioblastoma cells with enhanced EGFR signalling, as deregulated EGFR often leads to chemoresistance. Eight analogues of CMPD1 with varying lipophilicity and basicity were synthesised and tested for efficacy in the cell viability assay using established glioblastoma cell lines and patient-derived primary glioblastoma cells. The mechanism of action for the most potent analogue 15 was determined using MK2 activation and tubulin polymerisation assays, together with the immunofluorescence analysis of the mitotic spindle formation. Apoptosis was analysed by Annexin V staining, immunoblotting analysis of bcl-2 proteins and PARP cleavage. The apoptotic activity of CMPD1 and analogue 15 was comparable across glioblastoma cell lines regardless of the EGFR status. Primary glioblastoma cells of the classical subtype that are characterized by enhanced EGFR activity were most sensitive to the treatment with CMPD1 and 15. In summary, we present mechanism of action for a novel small molecule tubulin inhibitor, compound 15 that inhibits tubulin polymerisation and mitotic spindle formation, induces degradation of anti-apoptotic bcl-2 proteins and leads to apoptosis of glioblastoma cells. We also demonstrate that the enhanced EGFR activity does not decrease the efficacy of tubulin inhibitors developed in this study.
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
authors.forename: Athena F
authors.initials: AF
authors.lastname: Phoa
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
authors.forename: Stephen
authors.initials: S
authors.lastname: Browne
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
authors.forename: Fadi M S
authors.initials: FM
authors.lastname: Gurgis
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia.
authors.forename: Mia C
authors.initials: MC
authors.lastname: Åkerfeldt
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia; Institute of Pharmacy, Christian-Albrechts-University of Kiel, Gutenbergstraße 76, 24118 Kiel, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Döbber
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia; Institute of Pharmacy, Christian-Albrechts-University of Kiel, Gutenbergstraße 76, 24118 Kiel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Renn
authors.affiliation: Institute of Pharmacy, Christian-Albrechts-University of Kiel, Gutenbergstraße 76, 24118 Kiel, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Peifer
authors.affiliation: QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia.
authors.forename: Brett W
authors.initials: BW
authors.lastname: Stringer
authors.affiliation: QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Day
authors.affiliation: Children's Medical Research Institute, The University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2154, Australia.
authors.forename: Chin
authors.initials: C
authors.lastname: Wong
authors.affiliation: Children's Medical Research Institute, The University of Sydney, 214 Hawkesbury Road, Westmead, NSW 2154, Australia.
authors.forename: Megan
authors.initials: M
authors.lastname: Chircop
authors.affiliation: Oncogenic Signalling Laboratory and Brain Cancer Discovery Collaborative, Centre for Cancer Research, Hudson Institute of Medical Research, 27-31 Wright Street, Clayton, VIC 3168, Australia; Monash University, Wellington Road, Clayton, VIC 3800, Australia.
authors.forename: Terrance G
authors.initials: TG
authors.lastname: Johns
authors.affiliation: School of Chemistry and Faculty of Health Sciences, The University of Sydney, NSW 2006, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Kassiou
authors.affiliation: School of Medical Sciences, The University of Sydney, NSW 2006, Australia. Electronic address: lenka.munoz@sydney.edu.au.
authors.forename: Lenka
authors.initials: L
authors.lastname: Munoz
mesh_terms: D045744:Cell Line, Tumor; D066246:ErbB Receptors / Q000378:metabolism*; D005909:Glioblastoma / Q000188:drug therapy / Q000378:metabolism* / Q000473:pathology; D006801:Humans; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014404:Tubulin / Q000378:metabolism*; D050257:Tubulin Modulators / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D014404:Tubulin; D050257:Tubulin Modulators; C512478:EGFR protein, human; D066246:ErbB Receptors
keywords: Apoptosis; CMPD1; CMPD1 (Pubmed CID 11382492); Glioblastoma; MK2; Paclitaxel (Pubmed CID 36314); Tubulin inhibitors; Vinblastine (Pubmed CID 13342)