Accepted Preprint (first posted online 20 June 2012)

    An androgen receptor mutation in the MDA-MB-453 cell line model of molecular apocrine breast cancer compromises receptor activity

    1. Wayne D Tilley
    1. N Moore, Discipline of Medicine, University of Adelaide and Hanson Instutute, Adelaide, Australia
    2. G Buchanan, The Basil Hetzel Institute for Translational Health Research, University of Adelaide, Adelaide, Australia
    3. J Harris, Queensland University of Technology, Institute of Health and Biomedical Innovation, Brisbane, Australia
    4. L Selth, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    5. T Bianco-Miotto, School of Paediatrics and Reproductive Health, University of Adelaide, Adelaide, Australia
    6. A Hanson, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    7. S Birrell, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    8. L Butler, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    9. T Hickey, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    10. W Tilley, Discipline of Medicine, University of Adelaide and Hanson Institute, Adelaide, Australia
    1. Correspondence: Wayne Tilley, Email: wayne.tilley{at}health.sa.gov.au

    Abstract

    Recent evidence indicates that the estrogen receptor-α negative, androgen receptor (AR) positive molecular apocrine subtype of breast cancer is driven by AR signaling. The MDA-MB-453 cell line is the prototypical model of this breast cancer subtype; its proliferation is stimulated by androgens such as 5α-dihydrotestosterone (DHT) but inhibited by the progestin medroxyprogesterone acetate (MPA) via AR mediated mechanisms. We report here that the AR gene in MDA-MB-453 cells contains a G-T transversion in exon 7, resulting in a receptor variant with a glutamine to histidine substitution at amino acid 865 (Q865H) in the ligand binding domain. Compared to wild type AR, the Q865H variant exhibited reduced sensitivity to DHT and MPA in transactivation assays in MDA-MB-453 and PC-3 cells, but did not respond to non-androgenic ligands or receptor antagonists. Ligand binding, molecular modeling, mammalian 2-hybrid and immunoblot assays revealed effects of the Q865H mutation on ligand dissociation, AR intramolecular interactions and receptor stability. Microarray expression profiling demonstrated that DHT and MPA regulate distinct transcriptional programs in MDA-MB-453 cells. Gene Set Enrichment Analysis revealed that DHT- but not MPA-regulated genes were associated with estrogen responsive transcriptomes from MCF-7 cells and the Wnt signaling pathway. These findings suggest that the divergent proliferative responses of MDA-MB-453 cells to DHT and MPA result from the different genetic programs elicited by these two ligands through the AR-Q865H variant. This work highlights the necessity to characterize additional models of molecular apocrine breast cancer to determine the precise role of AR signaling in this breast cancer subtype.

    • Received 2 March 2012
    • Revision received 6 June 2012
    • Accepted 19 June 2012
    • Accepted Preprint first posted online on 20 June 2012

    This Article

    1. Endocr Relat Cancer ERC-12-0065
    1. Abstract
    2. Supplementary Data
    3. All Versions of this Article:
      1. ERC-12-0065v1
      2. 19/4/599 most recent