title: Fas-associated phosphatase-1 promotes Fas-mediated apoptosis in human colon cancer cells: novel function of FAP-1.
abstract: OBJECTIVE
  Fas-associated phosphatase-1 (FAP-1) has been thought as an inhibitor in Fas-mediated apoptosis. Here, we investigated the role of FAP-1 in Fas-mediated apoptosis of human colon cancer cells.
  
  
  METHODS
  The viability of four colon cancer cell lines treated with agonistic anti-Fas antibody was determined using WST-1 assay and cell death detection ELISA. pRc/CMV-FAP-1 was transfected to a FAP-1-negative, Fas-resistant colon cancer cell line SW480 by lipofection and the clones expressing FAP-1 protein were selected by limiting dilution. In the clones, expression of 550 genes was analyzed by cDNA microarrays. Protein expression of FAP-1 and molecules related to apoptosis was examined by western blot.
  
  
  RESULTS
  We obtained two FAP-1 overexpressed clones which were much more susceptible to Fas-mediated apoptosis than control cells. In the clones, caspase 8 and caspase 3 were fully activated by agonistic anti-Fas antibody treatment. Bcl-2 family proteins were not related to the high susceptibility of these clones, because caspase 9 was not activated. Transfection of FAP-1 did not suppress the survival actions of insulin-like growth factor (IGF-1) which enhanced survival signal through Akt phosphorylation. Upregulation in 21 genes and downregulation in 29 genes was revealed by cDNA arrays. We confirmed protein expression of p21 and phosphorylated p21 were much more enhanced in the clones than in control cells.
  
  
  CONCLUSIONS
  Overexpression of FAP-1 enhanced susceptibility to Fas-mediated apoptosis in SW480 and upregulation of p21 may contribute to this phenomenon. Our results indicate a novel function of FAP-1 in Fas-mediated apoptosis of human colon cancer cells.
authors.affiliation: Third Department of Internal Medicine, Division of Transfusion Medicine and Cell Therapy, Toyama Medical and Pharmaceutical University, Toyama, Japan.
authors.forename: Takako
authors.initials: T
authors.lastname: Miyazaki
authors.forename: Yoshinari
authors.initials: Y
authors.lastname: Atarashi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Yasumura
authors.forename: Isao
authors.initials: I
authors.lastname: Minatoya
authors.forename: Kohei
authors.initials: K
authors.lastname: Ogawa
authors.forename: Masaya
authors.initials: M
authors.lastname: Iwamoto
authors.forename: Masami
authors.initials: M
authors.lastname: Minemura
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Shimizu
authors.forename: Taka-Aki
authors.initials: TA
authors.lastname: Sato
authors.forename: Akiharu
authors.initials: A
authors.lastname: Watanabe
authors.forename: Toshiro
authors.initials: T
authors.lastname: Sugiyama
mesh_terms: D000906:Antibodies; D017209:Apoptosis; D051017:Apoptosis Regulatory Proteins / Q000235:genetics / Q000378:metabolism; D053148:Caspase 3 / Q000378:metabolism; D053181:Caspase 8 / Q000378:metabolism; D045744:Cell Line, Tumor; D002470:Cell Survival; D003110:Colonic Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D020869:Gene Expression Profiling; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000494:pharmacology; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D020411:Oligonucleotide Array Sequence Analysis; D010766:Phosphorylation / Q000187:drug effects; D054645:Protein Phosphatase 1; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D014162:Transfection; D019014:fas Receptor / Q000276:immunology / Q000378:metabolism*
chemical_list: D000906:Antibodies; D051017:Apoptosis Regulatory Proteins; C493956:CDKN1A protein, human; C481004:CH-11 anti-fas antibody, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; C491901:FAS protein, human; C112037:FCMR protein, human; D008565:Membrane Proteins; D012333:RNA, Messenger; D019014:fas Receptor; D007334:Insulin-Like Growth Factor I; D051057:Proto-Oncogene Proteins c-akt; D054645:Protein Phosphatase 1; C516742:PTPN13 protein, human; D054595:Protein Tyrosine Phosphatase, Non-Receptor Type 13; D017027:Protein Tyrosine Phosphatases; D053148:Caspase 3; D053181:Caspase 8