title: Downregulation of Notch-regulated Ankyrin Repeat Protein Exerts Antitumor Activities against Growth of Thyroid Cancer.
abstract: BACKGROUND
  The Notch-regulated ankyrin repeat protein (NRARP) is recently found to promote proliferation of breast cancer cells. The role of NRARP in carcinogenesis deserves extensive investigations. This study attempted to investigate the expression of NRARP in thyroid cancer tissues and assess the influence of NRARP on cell proliferation, apoptosis, cell cycle, and invasion in thyroid cancer.
  
  
  METHODS
  Thirty-four cases with thyroid cancer were collected from the Department of General Surgery, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine between 2011 and 2012. Immunohistochemistry was used to detect the level of NRARP in cancer tissues. Lentivirus carrying NRARP-shRNA (Lenti-NRARP-shRNA) was applied to down-regulate NRARP expression. Cell viability was tested after treatment with Lenti-NRARP-shRNA using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Apoptosis and cell cycle distribution were determined by flow cytometry. Cell invasion was tested using Transwell invasion assay. In addition, expressions of several cell cycle-associated and apoptosis-associated proteins were examined using Western blotting after transfection. Student's t-test, one-way analysis of variance (ANOVA), or Kaplan-Meier were used to analyze the differences between two group or three groups.
  
  
  RESULTS
  NRARP was highly expressed in thyroid cancer tissues. Lenti-NRARP-shRNA showed significantly inhibitory activities against cell growth at a multiplicity of infection of 10 or higher (P < 0.05). Lenti-NRARP-shRNA-induced G1 arrest (BHT101: 72.57% ± 5.32%; 8305C: 75.45% ± 5.26%) by promoting p21 expression, induced apoptosis by promoting bax expression and suppressing bcl-2 expression, and inhibited cell invasion by suppressing matrix metalloproteinase-9 expression.
  
  
  CONCLUSIONS
  Downregulation of NRARP expression exerts significant antitumor activities against cell growth and invasion of thyroid cancer, that suggests a potential role of NRARP in thyroid cancer targeted therapy.
authors.affiliation: Graduate School, Shanghai Second Military Medical University, Shanghai 200433; Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
authors.forename: Bing-Feng
authors.initials: BF
authors.lastname: Chu
authors.affiliation: Clinical College, Yancheng Institute of Health Sciences, Yancheng, Jiangsu 224000, China.
authors.forename: Yi-Yu
authors.initials: YY
authors.lastname: Qin
authors.affiliation: Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
authors.forename: Sheng-Lai
authors.initials: SL
authors.lastname: Zhang
authors.affiliation: Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
authors.forename: Zhi-Wei
authors.initials: ZW
authors.lastname: Quan
authors.affiliation: Department of General Surgery, Xinhua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai 200092, China.
authors.forename: Ming-Di
authors.initials: MD
authors.lastname: Zhang
authors.affiliation: Department of First General Surgery, Changhai Hospital, Second Military Medical University, Shanghai 200433, China.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Bi
mesh_terms: D000328:Adult; D000368:Aged; D000818:Animals; D017209:Apoptosis / Q000235:genetics / Q000502:physiology; D002453:Cell Cycle / Q000235:genetics / Q000502:physiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000235:genetics / Q000502:physiology; D002470:Cell Survival / Q000235:genetics / Q000502:physiology; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D047908:Intracellular Signaling Peptides and Proteins; D053208:Kaplan-Meier Estimate; D008297:Male; D051379:Mice; D008819:Mice, Nude; D008875:Middle Aged; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D011506:Proteins / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D013964:Thyroid Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000401:mortality / Q000473:pathology*
chemical_list: D047908:Intracellular Signaling Peptides and Proteins; C000588990:NRARP protein, human; D009363:Neoplasm Proteins; C499040:Nrarp protein, mouse; D011506:Proteins; D034741:RNA, Small Interfering