Global Characterization of the SRC-1 Transcriptome Identifies ADAM22 as an ER-Independent Mediator of Endocrine-Resistant Breast Cancer

Endocrine Oncology Research, Department of Surgery, Royal College of Surgeons in Ireland, Dublin, Ireland.
Cancer Research (Impact Factor: 9.28). 11/2011; 72(1):220-9. DOI: 10.1158/0008-5472.CAN-11-1976
Source: PubMed

ABSTRACT The development of breast cancer resistance to endocrine therapy results from an increase in cellular plasticity that permits the emergence of a hormone-independent tumor. The steroid coactivator protein SRC-1, through interactions with developmental proteins and other nonsteroidal transcription factors, drives this tumor adaptability. In this discovery study, we identified ADAM22, a non-protease member of the ADAM family of disintegrins, as a direct estrogen receptor (ER)-independent target of SRC-1. We confirmed SRC-1 as a regulator of ADAM22 by molecular, cellular, and in vivo studies. ADAM22 functioned in cellular migration and differentiation, and its levels were increased in endocrine resistant-tumors compared with endocrine-sensitive tumors in mouse xenograft models of human breast cancer. Clinically, ADAM22 was found to serve as an independent predictor of poor disease-free survival. Taken together, our findings suggest that SRC-1 switches steroid-responsive tumors to a steroid-resistant state in which the SRC-1 target gene ADAM22 has a critical role, suggesting this molecule as a prognostic and therapeutic drug target that could help improve the treatment of endocrine-resistant breast cancer.

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