title: Human multi-drug resistant hepatocellular carcinoma induced in nude mice by B-ultrasonographically-directed orthotopic implantation: a new experimental model.
abstract: BACKGROUND
  Present studies on the reversal of multi-drug resistance (MDR) are almost entirely limited to in vitro systems, and are seldom carried out in vivo. In order to study MDR under the in vivo situation, a MDR cell strain was used to establish a model in nude mice via orthotopic implantation directed by B-ultrasonography. This model is expected to provide a good platform for evaluating strategies to reverse the phenomenon of primary hepatocellular carcinoma (HCC) MDR.
  
  
  METHODS
  An orthotopic MDR1 hepatoma was obtained by injecting the cell lines HepG2 and HepG2/ADM subserosally into the liver of nude mice (10 control and 20 MDR mice). The injections were made under B-ultrasonographic direction. Ultrasonography and laparotomy were used to assess tumor growth, and the long chain PCR technique was applied to sequence the MDR1 gene from multi-drug resistant human HCC cells, HepG2/ADM, and corresponding implanted tumor tissues. Furthermore, MDR1 mRNA and P-gp protein expression were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR), Western blotting, and immunohistochemical methods.
  
  
  RESULTS
  The success rates of tumor implantation and induction of MDR were 100% (30/30) and 95% (19/20), respectively. The 3.8kbp MDR1 gene band was detected from the HepG2/ADM cell line and the corresponding implanted tumor tissues, and the MDR1 gene sequence coincided with that reported in GenBank. The expressions of MDR1 mRNA and P-gp protein in MDR mice were significantly higher than those in the control group. There was a significant difference in P-gp protein expression between MDR and control mice.
  
  
  CONCLUSIONS
  A MDR model has been successfully established in nude mice via orthotopic implantation of multi-drug resistant human HCC cells directed by ultrasonography.
authors: Hepatic Surgery Center, Affiliated Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China. dinglei1005@yahoo.com.cn
authors: Lei
authors: L
authors: Ding
authors: Xiao-Ping
authors: XP
authors: Chen
authors: Zhi-Wei
authors: ZW
authors: Zhang
authors: Kai
authors: K
authors: Jing
authors: Wan-Guang
authors: WG
authors: Zhang
mesh_terms: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000096:biosynthesis / Q000235:genetics; D000818:Animals; D001483:Base Sequence; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology*; D045744:Cell Line, Tumor; D004195:Disease Models, Animal; D018432:Drug Resistance, Multiple; D015972:Gene Expression Regulation, Neoplastic; D008099:Liver / Q000378:metabolism; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology*; D051379:Mice; D008807:Mice, Inbred BALB C; D008819:Mice, Nude; D008969:Molecular Sequence Data; D009368:Neoplasm Transplantation; D014463:Ultrasonography
chemical_list: D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1