title: Macrophage migration inhibitory factor as a potential prognostic factor in gastric cancer.
abstract: OBJECTIVE
  To investigate macrophage migration inhibitory factor (MIF) expression and its clinical relevance in gastric cancer, and effects of MIF knockdown on proliferation of gastric cancer cells.
  
  
  METHODS
  Tissue microarray containing 117 samples of gastric cancer and adjacent non-cancer normal tissues was studied for MIF expression by immunohistochemistry (IHC) semiquantitatively, and the association of MIF expression with clinical parameters was analyzed. MIF expression in gastric cancer cell lines was detected by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot. Two pairs of siRNA targeting the MIF gene (MIF si-1 and MIF si-2) and one pair of scrambled siRNA as a negative control (NC) were designed and chemically synthesized. All siRNAs were transiently transfected in AGS cells with Oligofectamine(TM) to knock down the MIF expression, with the NC group and mock group (Oligofectamine(TM) alone) as controls. At 24, 48, and 72 h after transfection, MIF mRNA was analyzed by RT-PCR, and MIF and proliferating cell nuclear antigen (PCNA) proteins were detected by Western blot. The proliferative rate of AGS cells was assessed by methylthiazolyl tetrazolium (MTT) assay and colony forming assay.
  
  
  RESULTS
  The tissue microarray was informative for IHC staining, in which the MIF expression in gastric cancer tissues was higher than that in adjacent non-cancer normal tissues (P < 0.001), and high level of MIF was related to poor tumor differentiation, advanced T stage, advanced tumor stage, lymph node metastasis, and poor patient survival (P < 0.05 for all). After siRNA transfection, MIF mRNA was measured by real-time PCR, and MIF protein and PCNA were assessed by Western blot analysis. We found that compared to the NC group and mock group, MIF expression was knocked down successfully in gastric cancer cells, and PCNA expression was downregulated with MIF knockdown as well. The cell counts and the doubling times were assayed by MTT 4 d after transfection, and colonies formed were assayed by colony forming assay 10 d after transfection; all these showed significant changes in gastric cancer cells transfected with specific siRNA compared with the control siRNA and mock groups (P < 0.001 for all).
  
  
  CONCLUSIONS
  MIF could be of prognostic value in gastric cancer and might be a potential target for small-molecule therapy.
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Long-Jun
authors.initials: LJ
authors.lastname: He
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Dan
authors.initials: D
authors.lastname: Xie
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Pin-Jin
authors.initials: PJ
authors.lastname: Hu
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Yi-Ji
authors.initials: YJ
authors.lastname: Liao
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Hai-Xia
authors.initials: HX
authors.lastname: Deng
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Hsiang-Fu
authors.initials: HF
authors.lastname: Kung
authors.affiliation: Long-Jun He, Pin-Jin Hu, Sen-Lin Zhu, Department of Gastroenterology, the First Affiliated Hospital, Sun Yat-sen University, Guangzhou 510080, Guangdong Province, China.
authors.forename: Sen-Lin
authors.initials: SL
authors.lastname: Zhu
mesh_terms: D014408:Biomarkers, Tumor / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D005260:Female; D015972:Gene Expression Regulation, Neoplastic; D006801:Humans; D019746:Intramolecular Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D008263:Macrophage Migration-Inhibitory Factors / Q000235:genetics / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D009367:Neoplasm Staging; D018809:Proliferating Cell Nuclear Antigen / Q000378:metabolism; D016016:Proportional Hazards Models; D034622:RNA Interference; D012189:Retrospective Studies; D015398:Signal Transduction; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology / Q000628:therapy; D013997:Time Factors; D014162:Transfection
chemical_list: D014408:Biomarkers, Tumor; D008263:Macrophage Migration-Inhibitory Factors; D018809:Proliferating Cell Nuclear Antigen; D019746:Intramolecular Oxidoreductases; C515598:MIF protein, human
keywords: Macrophage migration inhibitory factor; Proliferation; RNA interference; Stomach neoplasm; Survival