title: Effects of knockdown of miR-210 in combination with ionizing radiation on human hepatoma xenograft in nude mice.
abstract: BACKGROUND
  Solid tumors usually develop local hypoxia, which renders them resilient to radiotherapy. MiR-210 is the most consistently and robustly induced miRNA under hypoxia and functions as a micro-controller of a wide range of cellular responses to hypoxia. Hence, it is important to investigate the effect of knockdown of miR-210 in tumorigenesis and evaluate the efficacy of knockdown of miR-210 in combination with radiotherapy on human tumor xenograft in nude mice.
  
  
  METHODS
  SMMC-7721 Cells with stable integration of the anti-sense miR-210 were generated through lentiviral-mediated gene transfer and were subcutaneously implanted into nude mice. Mice were monitored for tumor growth and survival after radiotherapy. MiR-210 expression in tumor tissues was assessed by real-time Reverse transcription-Polymerase Chain Reaction (RT-PCR). Protein expression of HIF-1α and miR-210 targeted genes in human hepatoma xenograft was assessed by Western blot. Tumors were analyzed for proliferation, apoptosis, and angiogenesis biomarkers by immunohistochemistry staining.
  
  
  RESULTS
  Tumor growth was delayed in miR-210 downregulated xenograft. Knockdown of miR-210 increased protein expression of miR-210 targeted genes, but decreased HIF-1α protein in hepatoma xenograft. Knockdown of miR-210 in combination with radiotherapy is more effective than radiotherapy alone or miR-210 knockdown therapy alone in suppressing tumor growth and extending survival duration. Combined therapy decreased Ki-67-positive cells and CD31-positive cells and increased TUNEL-positive cells in tumor xenograft.
  
  
  CONCLUSIONS
  Knockdown of miR-210 in combination with radiotherapy showed an enhanced anti-tumor effect on human hepatoma xenograft. Our experiments demonstrated specific inhibition of miR-210 expression might be a means to enhance the effectiveness of radiotherapy to human hepatoma.
authors.affiliation: Department of Radiobiology, School of Radiological Medicine and Protection, Soochow University, No, 199 Renai Road, Suzhou 215123, China. yangwei1976@suda.edu.cn
authors.forename: Wei
authors.initials: W
authors.lastname: Yang
authors.forename: Jing
authors.initials: J
authors.lastname: Wei
authors.forename: Ting
authors.initials: T
authors.lastname: Sun
authors.forename: Fenju
authors.initials: F
authors.lastname: Liu
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006528:Carcinoma, Hepatocellular / Q000235:genetics* / Q000532:radiotherapy*; D045744:Cell Line, Tumor; D003131:Combined Modality Therapy; D055785:Gene Knockdown Techniques; D006801:Humans; D008113:Liver Neoplasms / Q000235:genetics* / Q000532:radiotherapy*; D051379:Mice; D008819:Mice, Nude; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000235:genetics*; D011836:Radiation Tolerance / Q000235:genetics; D011839:Radiation, Ionizing; D011878:Radiotherapy; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D023041:Xenograft Model Antitumor Assays
chemical_list: C543800:MIRN210 microRNA, human; D035683:MicroRNAs