title: S100P enhances the chemosensitivity of human gastric cancer cell lines.
abstract: BACKGROUND
  The effect of the protein S100P on biological characteristics of cancer is not clear, especially in gastric cancer. We previously showed that S100P positive gastric cancer patients have a better cumulative survival than S100P negative patients.
  
  
  OBJECTIVE
  To study the possible mechanisms of S100P enhanced the chemosensitivity to oxaliplatin in gastric cancer cell lines.
  
  
  METHODS
  S100P was overexpressed in vitro by plasmid transfection and downregulated by siRNA transfection in the BGC823 and SGC7901 gastric cancer cell lines. Cell survival rate, changes in the chemoresistance gene, such as GST-π, MDR1, MRP1, Topo-II, MVP and BCRP, intake of anticancer drug were measured after oxaliplatin treatment.
  
  
  RESULTS
  In SGC7901 cells, MTT assay indicated that increased S100P expression levels decreased the survival rate and decreased S100P expression levels increased the survival rate. In BGC823 and SGC7901 cell lines, mRNA of MDR1, a chemoresistance genes, was decreased in cells that overexpressed S100P, and increased in cells with downregulation of S100P. Intracellular accumulation of platinum increased in cells with overexpressed S100P, and decreased in cells with S100P downregulation.
  
  
  CONCLUSIONS
  S100P contributes to oxaliplatin chemosensitivity in gastric cell lines by increasing drug inflow. It might also be a novel independent prognostic factor in gastric cancer patients who receive adjuvant chemotherapy with oxaliplatin.
authors.affiliation: Department of General Surgery, Beijing Friendship Hospital, Capital Medical University, Beijing, China. zhaoxmok@yahoo.com.cn
authors.forename: Xiaomu
authors.initials: X
authors.lastname: Zhao
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Bai
authors.forename: Ping
authors.initials: P
authors.lastname: Wu
authors.forename: Zhongtao
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D000970:Antineoplastic Agents / Q000493:pharmacokinetics / Q000494:pharmacology*; D002135:Calcium-Binding Proteins / Q000096:biosynthesis* / Q000235:genetics; D045744:Cell Line, Tumor; D019008:Drug Resistance, Neoplasm; D006801:Humans; D007150:Immunohistochemistry; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D009944:Organoplatinum Compounds / Q000493:pharmacokinetics / Q000494:pharmacology*; D000077150:Oxaliplatin; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000008:administration & dosage / Q000235:genetics; D013274:Stomach Neoplasms / Q000188:drug therapy* / Q000235:genetics / Q000378:metabolism*; D014162:Transfection
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D000970:Antineoplastic Agents; D002135:Calcium-Binding Proteins; D009363:Neoplasm Proteins; D009944:Organoplatinum Compounds; D012333:RNA, Messenger; D034741:RNA, Small Interfering; C103003:S100P protein, human; D000077150:Oxaliplatin