title: Selective androgen receptor modulators (SARMs) negatively regulate triple-negative breast cancer growth and epithelial:mesenchymal stem cell signaling.
abstract: BACKGROUND
  The androgen receptor (AR) is the most highly expressed steroid receptor in breast cancer with 75-95% of estrogen receptor (ER)-positive and 40-70% of ER-negative breast cancers expressing AR. Though historically breast cancers were treated with steroidal androgens, their use fell from favor because of their virilizing side effects and the emergence of tamoxifen. Nonsteroidal, tissue selective androgen receptor modulators (SARMs) may provide a novel targeted approach to exploit the therapeutic benefits of androgen therapy in breast cancer.
  
  
  METHODS
  Since MDA-MB-453 triple-negative breast cancer cells express mutated AR, PTEN, and p53, MDA-MB-231 triple-negative breast cancer cells stably expressing wildtype AR (MDA-MB-231-AR) were used to evaluate the in vitro and in vivo anti-proliferative effects of SARMs. Microarray analysis and epithelial:mesenchymal stem cell (MSC) co-culture signaling studies were performed to understand the mechanisms of action.
  
  
  RESULTS
  Dihydrotestosterone and SARMs, but not bicalutamide, inhibited the proliferation of MDA-MB-231-AR. The SARMs reduced the MDA-MB-231-AR tumor growth and tumor weight by greater than 90%, compared to vehicle-treated tumors. SARM treatment inhibited the intratumoral expression of genes and pathways that promote breast cancer development through its actions on the AR. SARM treatment also inhibited the metastasis-promoting paracrine factors, IL6 and MMP13, and subsequent migration and invasion of epithelial:MSC co-cultures.
  
  
  CONCLUSIONS
  1. AR stimulation inhibits paracrine factors that are important for MSC interactions and breast cancer invasion and metastasis. 2. SARMs may provide promise as novel targeted therapies to treat AR-positive triple-negative breast cancer.
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Ramesh
authors: R
authors: Narayanan
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Sunjoo
authors: S
authors: Ahn
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Misty D
authors: MD
authors: Cheney
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Muralimohan
authors: M
authors: Yepuru
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Duane D
authors: DD
authors: Miller
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: Mitchell S
authors: MS
authors: Steiner
authors: Preclinical Research and Development, GTx, Inc., Memphis, Tennessee, United States of America.
authors: James T
authors: JT
authors: Dalton
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004195:Disease Models, Animal; D005260:Female; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000187:drug effects* / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D009362:Neoplasm Metastasis; D019899:Paracrine Communication / Q000187:drug effects; D011944:Receptors, Androgen / Q000378:metabolism*; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D064726:Triple Negative Breast Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D047368:Tumor Burden / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays
chemical_list: D011944:Receptors, Androgen; D020845:Selective Estrogen Receptor Modulators