title: NDRG1 promotes the multidrug resistance of neuroblastoma cells with upregulated expression of drug resistant proteins.
abstract: BACKGROUND
  Resistance to chemotherapeutic drugs and recurrence are two major causes of poor prognosis in many tumors including neuroblastoma. This study aimed to investigate the effect of the elevated intracellular NDRG1 expression on drug resistance of human neuroblastoma cells to chemotherapy, for exploring novel approaches for biotherapy of neuroblastoma.
  
  
  METHODS
  Human neuroblastoma KP-N-Ns cell lines were transfected with the lentivirus vector containing human NDRG1 cDNA, with empty vector-transfected or blank cells as controls. Transfection status was confirmed under fluorescence microscope, while PCR assay and western blot analysis were performed to determine the expression changes. MTT and TUNEL assays were used to detect the resistance of the cells to anticancer drugs, including vincristine, cyclophosphamide and so on. Additionally, the expression of drug resistant proteins was detected.
  
  
  RESULTS
  Stable lentiviral transfection cell line was successfully established with significantly upregulated NDRG1 expression. MTT assay revealed greater cell growth under NDRG1 overexpression with drugs stimulation, as compared to controls. TUNEL assay also showed less apoptosis of NDRG1 overexpressing cells than those of controls when exposed to these drugs, suggesting the increasing drug resistance through NDRG1 overexpression. Besides, the expression of MDR, LRP-1 and MRP-1 was also increased in NDRG1 overexpressing cells, implying NDRG1-mediated pathways in multidrug resistance of neuroblastoma.
  
  
  CONCLUSIONS
  NDRG1 could increase the resistance of neuroblastoma cells to chemotherapeutic drugs, with its positive regulation on drug resistant proteins. This study provided new insights for exploring the mechanism of the resistance to chemotherapeutic drugs and also novel approach for biotherapy in neuroblastoma.
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China.
authors.forename: Da
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China.
authors.forename: Jia
authors.initials: J
authors.lastname: Jia
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China.
authors.forename: Ge
authors.initials: G
authors.lastname: Zhao
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China.
authors.forename: Min
authors.initials: M
authors.lastname: Yue
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China.
authors.forename: Heying
authors.initials: H
authors.lastname: Yang
authors.affiliation: Department of Pediatric Surgery, the First Affiliated Hospital of Zhengzhou University, Zhengzhou 450052, Henan Province, China. Electronic address: jiaxiang_w@163.com.
authors.forename: Jiaxiang
authors.initials: J
authors.lastname: Wang
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D018797:Cell Cycle Proteins / Q000235:genetics*; D045744:Cell Line, Tumor; D018432:Drug Resistance, Multiple; D019008:Drug Resistance, Neoplasm; D015972:Gene Expression Regulation, Neoplastic; D005822:Genetic Vectors; D006801:Humans; D020287:In Situ Nick-End Labeling; D047908:Intracellular Signaling Peptides and Proteins / Q000235:genetics*; D016086:Lentivirus / Q000235:genetics; D008856:Microscopy, Fluorescence; D009447:Neuroblastoma / Q000188:drug therapy* / Q000235:genetics / Q000473:pathology; D014162:Transfection; D015854:Up-Regulation; D000099259:N-myc Downstream-Regulated Gene 1 Protein
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D047908:Intracellular Signaling Peptides and Proteins; D000099259:N-myc Downstream-Regulated Gene 1 Protein
keywords: Biotherapy; Multidrug resistance; NDRG1; Neuroblastoma; Resistance gene