title: Baicalein suppresses metastasis of breast cancer cells by inhibiting EMT via downregulation of SATB1 and Wnt/β-catenin pathway.
abstract: BACKGROUND
  The flavonoid baicalein, a historically used Chinese herbal medicine, shows a wide range of biological and pharmaceutical effects, among which its potent antitumor activity has raised great interest in recent years. However, the molecular mechanism involved in the antimetastatic effect of baicalein remains poorly understood. This study aimed to verify the inhibitory effects of baicalein on metastasis of MDA-MB-231 human breast cancer cells both in vitro and in vivo, as well as to investigate the related mechanisms.
  
  
  METHODS
  MTT assay was used to examine the inhibition of baicalein on proliferation of MDA-MB-231 cells. Wound healing assay and the in vitro invasion assay was carried out to investigate the effects of baicalein on migration and invasion of MDA-MB-231 cells, respectively. In order to explore the effects of baicalein on tumor metastasis in vivo, xenograft nude mouse model of MDA-MB-231 cells was established. Animals were randomly divided into four groups (control, therapy group, and low-dose and high-dose prevention group, n=6), and treated with baicalein as designed. Following sacrifice, their lungs and livers were collected to examine the presence of metastases. qRT-PCR and Western blot were performed to study the effects of baicalein on expression of SATB1, EMT-related molecules, and Wnt/β-catenin signaling components of MDA-MB-231 cells as well as the metastatic tissue. Effects of baicalein on the expression of target proteins in vivo were also analyzed by immunohistochemistry.
  
  
  RESULTS
  Our results indicated that baicalein suppressed proliferation, migration, and invasion of MDA-MB-231 cells in a time- and dose-dependent manner. Based on assays carried out in xenograft nude mouse model, we found that baicalein inhibited tumor metastasis in vivo. Furthermore, baicalein significantly decreased the expression of SATB1 in MDA-MB-231 cells. It suppressed the expression of vimentin and SNAIL while enhancing the expression of E-cadherin. Baicalein also downregulated the expression of Wnt1 and β-catenin proteins and transcription level of Wnt/β-catenin-targeted genes.
  
  
  CONCLUSIONS
  Our results demonstrate that baicalein has the potential to suppress breast cancer metastasis, possibly by inhibition of EMT, which may be attributed to downregulation of both SATB1 and the Wnt/β-catenin pathway. Taken together, baicalein may serve as a promising drug for metastasis treatment of breast cancer.
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Xingcong
authors.initials: X
authors.lastname: Ma
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Wanjun
authors.initials: W
authors.lastname: Yan
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Zhijun
authors.initials: Z
authors.lastname: Dai
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Xiaoyan
authors.initials: X
authors.lastname: Gao
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Yinan
authors.initials: Y
authors.lastname: Ma
authors.affiliation: Department of Oncology, Institute of Health, China North Industries Group Corporation, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Quntao
authors.initials: Q
authors.lastname: Xu
authors.affiliation: Department of Thoracic Surgery, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Jiantao
authors.initials: J
authors.lastname: Jiang
authors.affiliation: Department of Oncology, the Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an, Shaanxi, People's Republic of China.
authors.forename: Shuqun
authors.initials: S
authors.lastname: Zhang
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000737:chemistry / Q000494:pharmacology; D001943:Breast Neoplasms / Q000188:drug therapy / Q000473:pathology*; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects*; D058750:Epithelial-Mesenchymal Transition / Q000187:drug effects*; D005260:Female; D044950:Flavanones / Q000737:chemistry / Q000494:pharmacology*; D006801:Humans; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy / Q000473:pathology; D036961:Matrix Attachment Region Binding Proteins / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D015394:Molecular Structure; D009362:Neoplasm Metastasis / Q000188:drug therapy*; D013329:Structure-Activity Relationship; D014407:Tumor Cells, Cultured; D060449:Wnt Signaling Pathway / Q000187:drug effects*; D014945:Wound Healing / Q000187:drug effects; D023041:Xenograft Model Antitumor Assays; D051176:beta Catenin / Q000378:metabolism*
chemical_list: D000970:Antineoplastic Agents; D044950:Flavanones; D036961:Matrix Attachment Region Binding Proteins; C076189:SATB1 protein, human; D051176:beta Catenin; C006680:baicalein
keywords: EMT; SATB1; Wnt/β-catenin pathway; baicalein; breast cancer; metastasis