title: Stimulation of hepatoma cell invasiveness and metastatic potential by proteins secreted from irradiated nonparenchymal cells.
abstract: OBJECTIVE
  To determine whether factors secreted by irradiated liver nonparenchymal cells (NPCs) may influence invasiveness and/or metastatic potential of hepatocellular carcinoma (HCC) cells and to elucidate a possible mechanism for such effect.
  
  
  METHODS
  Primary rat NPCs were cultured and divided into irradiated (10-Gy X-ray) and nonirradiated groups. Forty-eight hours after irradiation, conditioned medium from irradiated (SR) or nonirradiated (SnonR) cultures were collected and added to sublethally irradiated cultures of the hepatoma McA-RH7777 cell line. Then, hepatoma cells were continuously passaged for eight generations (RH10Gy-SR and RH10Gy-SnonR). The invasiveness and metastatic potential of McA-RH7777, RH10Gy-SnonR, and RH10Gy-SR cells were evaluated using an in vitro gelatinous protein (Matrigel) invasion and an in vivo metastasis assay. In addition, SR and SnonR were tested using rat cytokine antibody arrays and enzyme-linked immunosorbent assay (ELISA).
  
  
  RESULTS
  In vitro gelatinous protein invasion assay indicated that the numbers of invading cells was significantly higher in RH10Gy-SR (40 ± 4.74) than in RH10Gy-SnonR (30.6 ± 3.85) cells, and lowest in McA-RH7777 (11.4 ± 3.56) cells. The same pattern was observed in vivo in a lung metastasis assay, as evaluated by number of metastatic lung nodules seen with RH10Gy-SR (28.83 ± 5.38), RH10Gy-SnonR (22.17 ± 4.26), and McA-RH7777 (8.3 ± 3.8) cells. Rat cytokine antibody arrays and ELISA demonstrated that metastasis-promoting cytokines (tumor necrosis factor-α and interleukin-6), circulating growth factors (vascular endothelial growth factor and epidermal growth factor), and metalloproteinases (MMP-2 and MMP-9) were upregulated in SR compared with SnonR.
  
  
  CONCLUSIONS
  Radiation can increase invasiveness and metastatic potential of sublethally irradiated hepatoma cells, and soluble mediators released from irradiated NPCs promote this potential. Increased secretion of metastasis-related cytokines and factors from NPCs after irradiation may be a possible mechanism for the radiation-induced invasiveness and metastatic potential of HCC.
authors.affiliation: Department of Radiation Oncology, Zhongshan Hospital, Fudan University, Shanghai, China.
authors.forename: Le-Yuan
authors.initials: LY
authors.lastname: Zhou
authors.forename: Zhi-Ming
authors.initials: ZM
authors.lastname: Wang
authors.forename: Ya-Bo
authors.initials: YB
authors.lastname: Gao
authors.forename: Ling-Yan
authors.initials: LY
authors.lastname: Wang
authors.forename: Zhao-Chong
authors.initials: ZC
authors.lastname: Zeng
mesh_terms: D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000473:pathology* / Q000556:secondary*; D018929:Cell Culture Techniques; D003094:Collagen; D016207:Cytokines / Q000378:metabolism*; D004338:Drug Combinations; D004815:Epidermal Growth Factor / Q000378:metabolism; D022781:Hepatocytes / Q000378:metabolism / Q000528:radiation effects*; D015850:Interleukin-6 / Q000378:metabolism; D007797:Laminin; D008113:Liver Neoplasms / Q000473:pathology*; D008175:Lung Neoplasms / Q000556:secondary*; D020778:Matrix Metalloproteinase 2 / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009361:Neoplasm Invasiveness; D011509:Proteoglycans; D051381:Rats; D017207:Rats, Sprague-Dawley; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism
chemical_list: D016207:Cytokines; D004338:Drug Combinations; D015850:Interleukin-6; D007797:Laminin; D011509:Proteoglycans; D014409:Tumor Necrosis Factor-alpha; D042461:Vascular Endothelial Growth Factor A; C059485:matrigel; D004815:Epidermal Growth Factor; D003094:Collagen; D020778:Matrix Metalloproteinase 2; D020780:Matrix Metalloproteinase 9