title: Role of Sphk1 in the malignant transformation of breast epithelial cells and breast cancer progression.
abstract: BACKGROUND
  The ojective of the following study is to investigate the role of sphingosine kinase 1 (Sphk1) in the malignant transformation of breast epithelial cells and breast cancer progression and its mechanism.
  
  
  METHODS
  Immunohistochemistry was performed to detect Sphk1 and E-cadherin (E-cad) in resected breast samples. Sphk1 was transfected in normal human breast epithelial cell line (MCF-10A) by Lentivirus and silenced in breast cancer cell line (MCF-7) using small interfering ribonucleic acid. The effect of tumor necrosis factor alpha (TNF-α) and/or N, N-dimethylsphingosine (DMS) on the Sphk1 and E-cad expression, MCF-10A cell proliferation and invasion was investigated. Real time-polymerase chain reaction and western-blot was used to detect messenger ribonucleic acid and protein. Cell counting kit-8 and transwell were used to measure cell proliferation and invasion.
  
  
  RESULTS
  Sphk1 was positive expression in 114 breast tumors (75.50%) but negative in fibroadenomas. The expression of E-cad and Sphk1 were negatively correlated and E-cad (-)/Sphk1 (+) carriers showed higher ratio of axillary lymph node metastasis than E-cad (+)/Sphk1 (-) carriers. Overexpression of Sphk1 in MCF-10A reduced E-cad expression and improved cell proliferation and invasion, but knockdown of Sphk1 in MCF-7 decreased cell proliferation and invasion. TNF-α increased Sphk1 expression, enhanced the ability of Sphk1 in decreasing E-cad expression, which could be blocked by DMS. TNF-α promoted MCF-10A cell proliferation and invasion.
  
  
  CONCLUSIONS
  Sphk1 plays an important role in the malignant transformation of breast epithelial cells and modulates breast cancer metastasis through the regulation of E-cad expression. TNF-α can up-regulate Sphk1 expression and reduce E-cad expression through Sphk1, which can be blocked by DMS. TNF-α/Sphk1/E-cad pathway may be a newly discovered pathway and plays an important role in tumorigenesis and metastasis.
authors: X D
authors: XD
authors: Zheng
authors: Y
authors: Y
authors: Zhang
authors: X W
authors: XW
authors: Qi
authors: M H
authors: MH
authors: Wang
authors: P
authors: P
authors: Sun
authors: Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
authors: Y
authors: Y
authors: Zhang
authors: Breast Disease Center, Southwest Hospital, Third Military Medical University, Chongqing, 400038, China.
authors: J
authors: J
authors: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D001365:Axilla; D001940:Breast / Q000166:cytology; D001943:Breast Neoplasms / Q000737:chemistry* / Q000473:pathology; D015820:Cadherins / Q000187:drug effects / Q000378:metabolism; D018270:Carcinoma, Ductal, Breast / Q000737:chemistry* / Q000556:secondary; D002465:Cell Movement / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002471:Cell Transformation, Neoplastic; D004847:Epithelial Cells / Q000473:pathology*; D005260:Female; D018226:Fibroadenoma / Q000737:chemistry*; D055785:Gene Knockdown Techniques; D006801:Humans; D008207:Lymphatic Metastasis; D061986:MCF-7 Cells; D008875:Middle Aged; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000032:analysis* / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000494:pharmacology; D013110:Sphingosine / Q000031:analogs & derivatives / Q000494:pharmacology; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D055815:Young Adult; D000099157:Sphingosine Kinase
chemical_list: D015820:Cadherins; D017853:Phosphotransferases (Alcohol Group Acceptor); D034741:RNA, Small Interfering; D013110:Sphingosine; D014409:Tumor Necrosis Factor-alpha; D000099157:Sphingosine Kinase; C061800:N,N-dimethylsphingosine