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

Abstract

<jats:p>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<jats:italic>AR</jats:italic>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 with 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 two-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.</jats:p>

Multidimensional phenotyping of breast cancer cell lines to guide preclinical research

“…line (Fig. 2) [28]. p53 protein expression is associated with TP53 mutation status but is not a reliable surrogate in breast cancer cell lines Functional abrogation of TP53 through germline (LiFraumeni syndrome) or somatic mutation is an important driver of breast cancer development, particularly in HER2?…”

Complexities of androgen receptor signalling in breast cancer

“…These studies have formed the basis for trials of the AR antagonist bicalutamide (NCT00468715) and the new generation compound enzalutamide (NCT01889238 and NCT02091960) as therapy for ERa-negative, AR-positive metastatic breast cancer. However, a mutation in the ligand-binding domain of the AR in MDA-MB-453 cells compromises receptor activity in response to androgens (Moore et al 2012). This may limit the utility of this cell line as a model of molecular apocrine breast cancer, necessitating analysis of AR function in additional pre-clinical models of this disease subtype to inform development of suitable therapeutic strategies.…”

Activation of AR Sensitizes Breast Carcinomas to NVP-BEZ235's Therapeutic Effect Mediated by PTEN and KLLN Upregulation

“…To characterize the molecular differences between these two groups of cell lines, we first listed the cell lines' molecular status and subtypes (Table 1; refs. [15][16][17][18]. A previous study suggested that NVP-BEZ235 induces cell death in breast cancer cells with PIK3CA mutations or HER2 amplification, whereas all of the PTEN deleted, mutated, or silenced cell lines are insensitive to NVP-BEZ235 (5).…”