title: Primary study of leptin and human hepatocellular carcinoma in vitro.
abstract: OBJECTIVE
  To investigate the expression level and effects of leptin in human hepatocellular carcinoma cells in vitro and to explore the correlation between them.
  
  
  METHODS
  Human hepatocellular carcinoma cell line HepG2 was cultured in vitro, and (the expression level) mRNA of leptin and leptin receptors in HepG2 were assessed using reverse transcription polymerase chain reaction (RT-PCR). Effects of different concentrations of leptin (50 ng/mL, 100 ng/mL, 200 ng/mL) on HepG2 were detected with colorimetric assay by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) after incubation periods of 24 h, 48 h, and 72 h. Flow cytometry was performed to assess cell cycle progression of different concentrations of leptin as stated above after each 24 h incubation period.
  
  
  RESULTS
  mRNA of leptin and leptin receptors (including short and long isoforms) were expressed in HepG2. The 72 h incubation of leptin at different concentrations (50 ng/mL, 100 ng/mL, 200 ng/mL) promoted proliferation of HepG2 in a concentration- and time-dependent manner. The experimental group shows significant statistical differences when compared to the controlled group which contained 0 ng/mL of leptin. As the concentration of leptin increases, significant fewer cells were detected in G0-G1 phase and more cells in S and G2-M phases.
  
  
  CONCLUSIONS
  Leptin and leptin receptor are simultaneously expressed in human hepatocellular carcinoma cell line HepG2. Addition of leptin (0 ng/mL-200 ng/mL) in 72 h periods indicated there is a concentration- and time-dependent correlation in the stimulation of HepG2 cell proliferation. The effect of proliferation by leptin is due to promotion of DNA synthesis and enhancement of mitotic activity. The relationship between leptin and human hepatocellular carcinoma cells might indicate that adipokine could be associated with the progression of human hepatocellular carcinoma.
authors.affiliation: Department of Gastroenterology, Renmin Hospital of Wuhan University, No. 238 Jiefang Road, Wuchang District, Wuhan 430060, Hubei Province, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Zhou
authors.forename: Wei
authors.initials: W
authors.lastname: Lei
authors.forename: Lei
authors.initials: L
authors.lastname: Shen
authors.forename: He-Sheng
authors.initials: HS
authors.lastname: Luo
authors.forename: Zhi-Xiang
authors.initials: ZX
authors.lastname: Shen
mesh_terms: D006528:Carcinoma, Hepatocellular / Q000378:metabolism* / Q000473:pathology; D002453:Cell Cycle / Q000187:drug effects; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D004305:Dose-Response Relationship, Drug; D006801:Humans; D020738:Leptin / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology; D008113:Liver Neoplasms / Q000378:metabolism* / Q000473:pathology; D012333:RNA, Messenger / Q000378:metabolism; D054411:Receptors, Leptin / Q000235:genetics / Q000378:metabolism
chemical_list: D020738:Leptin; D012333:RNA, Messenger; D054411:Receptors, Leptin