title: Iodine-125 induces apoptosis via regulating p53, microvessel density, and vascular endothelial growth factor in colorectal cancer.
abstract: BACKGROUND
  Iodine interstitial brachytherapy has been widely reported for treating colorectal cancer (CRC). However, the inhibitory molecular mechanism of iodine-125 (I-125) on CRC has not been reported.
  
  
  METHODS
  To illustrate the inhibitory mechanism of iodine-125 (I-125) on CRC, we established the animal models of CRC via the injection of HCT-8 cells into nude mice. Subsequently, the I-125 granules were implanted into the tumor of the animal model at different dosages. Proliferating cell nuclear antigen and terminal transferase dUTP nick end labeling were used to detect the apoptosis of the tumor cells. Immunohistochemistry SP staining was used to measure the expression of p53 protein. The protein levels were examined with western blot and ELISA. Meanwhile, microvessel density (MVD) was counted by endothelial cells immunostained by anti-CD34 antibody.
  
  
  RESULTS
  The results showed that I-125 protests against CRC via increasing the protein level of p53 and decreasing the level of vascular endothelial growth factor (VEGF), leading to the decrease of MVD in CRC (P <0.0001). An effective inhibition dosage of I-125 ranged from 0.4 to 0.8 mCi.
  
  
  CONCLUSIONS
  The inhibitory mechanisms of iodine on CRC acted through an increase in the level of p53 and a decrease in the level of VEGF, resulting in a decrease of MVD.
authors.forename: Zhenhuan
authors.initials: Z
authors.lastname: Ma
authors.affiliation: Department of General Surgery, the Second People's Hospital of Yunnan, Kunming 650021, China. yyyunnan@163.com.
authors.forename: Yong
authors.initials: Y
authors.lastname: Yang
authors.forename: Guokai
authors.initials: G
authors.lastname: Yang
authors.forename: Jia
authors.initials: J
authors.lastname: Wan
authors.forename: Guojian
authors.initials: G
authors.lastname: Li
authors.forename: Ping
authors.initials: P
authors.lastname: Lu
authors.forename: Lingjuan
authors.initials: L
authors.lastname: Du
mesh_terms: D000818:Animals; D017209:Apoptosis; D014408:Biomarkers, Tumor / Q000378:metabolism; D015153:Blotting, Western; D001918:Brachytherapy; D049109:Cell Proliferation; D015179:Colorectal Neoplasms / Q000378:metabolism / Q000473:pathology* / Q000532:radiotherapy; D005434:Flow Cytometry; D006801:Humans; D007457:Iodine Radioisotopes / Q000627:therapeutic use*; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D055806:Microvessels / Q000378:metabolism / Q000473:pathology; D009389:Neovascularization, Pathologic; D014407:Tumor Cells, Cultured; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism*; D023041:Xenograft Model Antitumor Assays
chemical_list: D014408:Biomarkers, Tumor; D007457:Iodine Radioisotopes; D016159:Tumor Suppressor Protein p53; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse