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Pietri E, Conteduca V, Andreis D, Massa I, Melegari E, Sarti S, Cecconetto L, Schirone A, Bravaccini S, Serra P, Fedeli A, Maltoni R, Amadori D, De Giorgi U, Rocca A. Androgen receptor signaling pathways as a target for breast cancer treatment. Endocr Relat Cancer 2016; 23:R485-98. [PMID: 27528625 DOI: 10.1530/erc-16-0190] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 08/12/2016] [Indexed: 12/23/2022]
Abstract
The androgen receptor (AR) is a ligand-dependent transcription factor, and its effects on breast range from physiological pubertal development and age-related modifications to cancer onset and proliferation. The prevalence of AR in early breast cancer is around 60%, and AR is more frequently expressed in ER-positive than in ER-negative tumors. We offer an overview of AR signaling pathways in different breast cancer subtypes, providing evidence that its oncogenic role is likely to be different in distinct biological and clinical scenarios. In particular, in ER-positive breast cancer, AR signaling often antagonizes the growth stimulatory effect of ER signaling; in triple-negative breast cancer (TNBC), AR seems to drive tumor progression (at least in luminal AR subtype of TNBC with a gene expression profile mimicking luminal subtypes despite being negative to ER and enriched in AR expression); in HER2-positive breast cancer, in the absence of ER expression, AR signaling has a proliferative role. These data represent the rationale for AR-targeting treatment as a potentially new target therapy in breast cancer subset using androgen agonists in some AR-positive/ER-positive tumors, AR antagonists in triple-negative/AR-positive tumors and in combination with anti-HER2 agents or with other signaling pathways inhibitors (including PI3K/MYC/ERK) in HER2-positive/AR-positive tumors. Only the ongoing and future prospective clinical trials will allow us to establish which agents are the best option in every specific condition, keeping in mind that there is evidence of opposite androgens and AR agonist/antagonist drug effects on cell proliferation particularly in AR-positive/ER-positive tumors.
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Affiliation(s)
- Elisabetta Pietri
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Vincenza Conteduca
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Daniele Andreis
- Unit of Biostatistics and Clinical TrialsIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Ilaria Massa
- Unit of Biostatistics and Clinical TrialsIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Elisabetta Melegari
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Samanta Sarti
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Lorenzo Cecconetto
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Alessio Schirone
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Sara Bravaccini
- Biosciences LaboratoryIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Patrizia Serra
- Unit of Biostatistics and Clinical TrialsIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Anna Fedeli
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Roberta Maltoni
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Dino Amadori
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Ugo De Giorgi
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
| | - Andrea Rocca
- Department of Medical OncologyIstituto Scientifico Romagnolo per lo Studio e la Cura dei Tumori (IRST) IRCCS, Meldola, Forlì-Cesena, Italy
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Abstract
PURPOSE OF REVIEW The review is targeted at describing the advances in our understanding of androgen actions in the breast over the last 18 months. Androgens are current 'hot topics' in breast cancer because of their potential as therapeutics in situations where we currently do not have good clinical options. This is true for both estrogen receptor alpha (ERα) negative and ERα positive cancers. RECENT FINDINGS The review has focused on examining associations between androgen receptor and patient prognosis and outcomes in different breast cancer subtypes. A logical extension of this is covering the timely topic of the use of androgen-directed therapy in these patients. The principle settings in which this is being considered is in ERα positive cancer with therapeutic resistance to ER-directed therapies and in ERα negative breast cancer that lack current standard targeted therapies. Finally interactions between mutations, and the potential role of androgen in the normal hierarchy of mammary cell differentiation and the relationship of this to cancer, are considered. SUMMARY Androgens are firmly established as important factors across multiple breast cancer subtypes. The future challenge for basic researchers and important development for clinicians is going to be translating this understanding into effective therapeutics for the benefit of breast cancer patients.
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Affiliation(s)
- Keely M McNamara
- Department of Anatomical Pathology, Tohoku University School of Graduate Medicine, 2-1 Seiryo-machi Aoba-Ku, Sendai, Japan
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