title: Cancer/testis antigen SSX2 enhances invasiveness in MCF-7 cells by repressing             ERα signaling.
abstract: Cancer/testis antigen (CTA) SSX2, which is silent in most normal adult tissues             and expressed in various malignant tumors, has been identified for decades. Expression             of SSX in tumors has been associated with advanced stages and worse patient prognosis.             However, little is known about its role in breast cancer. The SSX2 expression             plasmid constructed was stably transfected into the breast cancer cell line MCF-7.             The influence of SSX2 on MCF-7 cells was assessed using MTT assay, flow cytometry,             transwell invasion assay and in vivo tumorigenicity assay. A comparative proteomic             approach was performed to identify and clarify the underlying molecular mechanisms.             SSX2 expression was more pronounced in ERα-negative breast cancer cells compared             with the positive ones. Overexpression of SSX2 induced cell growth and prompted             cell invasion. Both ERα and E-cadherin expression were suppressed in the SSX2             overexpressing MCF-7 cells. Eleven known proteins were identified with significant             differential expression. Among these, five were decreased, while other six were             increased in the SSX2 overexpressing MCF-7 cells. These results suggested SSX2             may enhance invasiveness in MCF-7 cells both in vivo and in vitro. The regulation             of ERα signaling by target proteins of SSX2 may explain the metastatic potential             of breast cancer cells.
authors.affiliation: Department of Breast Surgery, The First Affiliated Hospital with                     Nanjing Medical University, Nanjing, P.R. China.
authors.forename: Ling
authors.initials: L
authors.lastname: Chen
authors.forename: Wen-Bin
authors.initials: WB
authors.lastname: Zhou
authors.forename: Yi
authors.initials: Y
authors.lastname: Zhao
authors.forename: Xiao-An
authors.initials: XA
authors.lastname: Liu
authors.forename: Qiang
authors.initials: Q
authors.lastname: Ding
authors.forename: Xiao-Ming
authors.initials: XM
authors.lastname: Zha
authors.forename: Shui
authors.initials: S
authors.lastname: Wang
mesh_terms: D000818:Animals; D000951:Antigens, Neoplasm / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D001943:Breast Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D002465:Cell Movement; D049109:Cell Proliferation; D047628:Estrogen Receptor alpha / Q000235:genetics / Q000378:metabolism*; D005260:Female; D020869:Gene Expression Profiling; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D009368:Neoplasm Transplantation; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism / Q000502:physiology*; D015398:Signal Transduction; D013737:Testis / Q000378:metabolism; D014158:Transcription, Genetic; D047368:Tumor Burden
chemical_list: D000951:Antigens, Neoplasm; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D009363:Neoplasm Proteins; D012097:Repressor Proteins; C093962:synovial sarcoma X breakpoint proteins