title: FOXA1 promotes tumor cell proliferation through AR involving the Notch pathway in endometrial cancer.
abstract: BACKGROUND
  Increasing evidence suggests that forkhead box A1 (FOXA1) is frequently dysregulated in many types of human cancers. However, the exact function and mechanism of FOXA1 in human endometrial cancer (EC) remains unclear.
  
  
  METHODS
  FOXA1 expression, androgen receptor (AR) expression, and the relationships of these two markers with clinicopathological factors were determined by immunohistochemistry analysis. FOXA1 and AR were up-regulated by transient transfection with plasmids, and were down-regulated by transfection with siRNA or short hairpin RNA (shRNA). The effects of FOXA1 depletion and FOXA1 overexpression on AR-mediated transcription as well as Notch pathway and their impact on EC cell proliferation were examined by qRT-PCR, western blotting, co-immunoprecipitation, ChIP-PCR, MTT, colony-formation, and xenograft tumor-formation assays.
  
  
  RESULTS
  We found that the expression of FOXA1 and AR in ECs was significantly higher than that in a typical hyperplasia and normal tissues. FOXA1 expression was significantly correlated with AR expression in clinical tissues. High FOXA1 levels positively correlated with pathological grade and depth of myometrial invasion in EC. High AR levels also positively correlated with pathological grade in EC. Moreover, the expression of XBP1, MYC, ZBTB16, and UHRF1, which are downstream targets of AR, was promoted by FOXA1 up-regulation or inhibited by FOXA1 down-regulation. Co-immunoprecipitation showed that FOXA1 interacted with AR in EC cells. ChIP-PCR assays showed that FOXA1 and AR could directly bind to the promoter and enhancer regions upstream of MYC. Mechanistic investigation revealed that over-expression of Notch1 and Hes1 proteins by FOXA1 could be reversed by AR depletion. In addition, we showed that down-regulation of AR attenuated FOXA1-up-regulated cell proliferation. However, AR didn't influence the promotion effect of FOXA1 on cell migration and invasion. In vivo xenograft model, FOXA1 knockdown reduced the rate of tumor growth.
  
  
  CONCLUSIONS
  These results suggest that FOXA1 promotes cell proliferation by AR and activates Notch pathway. It indicated that FOXA1 and AR may serve as potential gene therapy in EC.
authors: Meiting
authors: M
authors: Qiu
authors: Wei
authors: W
authors: Bao
authors: Jingyun
authors: J
authors: Wang
authors: Tingting
authors: T
authors: Yang
authors: Xiaoying
authors: X
authors: He
authors: Yun
authors: Y
authors: Liao
authors: Department of Obstetrics and Gynecology, Shanghai First People's Hospital, Shanghai Jiao Tong University School of Medicine, Xinsongjiang Road, Shanghai, China. wanxp@sjtu.edu.cn.
authors: Xiaoping
authors: X
authors: Wan
mesh_terms: D000818:Animals; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D016889:Endometrial Neoplasms / Q000378:metabolism* / Q000473:pathology; D005260:Female; D051541:Hepatocyte Nuclear Factor 3-alpha / Q000502:physiology*; D006801:Humans; D051379:Mice; D008819:Mice, Nude; D011944:Receptors, Androgen / Q000378:metabolism*; D051880:Receptors, Notch / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology*; D015854:Up-Regulation / Q000502:physiology; D023041:Xenograft Model Antitumor Assays / Q000379:methods
chemical_list: C410798:AR protein, human; C496499:FOXA1 protein, human; D051541:Hepatocyte Nuclear Factor 3-alpha; D011944:Receptors, Androgen; D051880:Receptors, Notch