title: Survival and malignant phenotype changes of human hepatoma SMMC-7721 cell line induced by cryopreservation at -50 °C.
abstract: OBJECTIVE
  To investigate the effect of cryopreservation at -50 °C on the human hepatoma SMMC-7721 cell line.
  
  
  METHODS
  With 15% DMSO as a cryoprotectant, the SMMC-7721 cells were cryopreserved at -50 °C, then thawed and recultured. The survival rate, mitotic index and LDH isoenzymes were compared between pre- and post-cryopreservation.
  
  
  RESULTS
  Thirteen hours after the thaw, the mitotic index of cryopreserved SMMC-7721 cells decreased by 1.09%. The mode scope of chromosome number (46-53) after cryopreservation tended to transfer to that of normal human cells, and the percentage of metaphases containing 46 chromosomes changed from 0% to 16%. LDH isoenzymes changed from H-like model (LDH3(29.3%) > LDH4 (26.8%) > LDH2 (25.3%) > LDH5 (14.9%) > LDH1 (3.6%) to M-like model (LDH4 (48.3%) > LDH5 (28.3%) > LDH3 (18.9%) > LDH2 (4.4%) > LDH1 (0%)). This suggests that the survival rate could reach over 95%.
  
  
  CONCLUSIONS
  Cryopreservation at -50 °C can be a convenient method for the cryopreservation of cell lines. However, cryopreservation at -50 °C is likely involved in the changes of the malignant phenotypes of the human hepatoma SMMC-7721 cell line, and may induce the differentiation of malignant cells.
authors.affiliation: Shi-Ming Jiang, Zhao-Hui Xu, Biology Department, Shandong Normal University, Jinan 250014, Shandong Province, China.
authors.forename: S M
authors.initials: SM
authors.lastname: Jiang
authors.affiliation: Shi-Ming Jiang, Zhao-Hui Xu, Biology Department, Shandong Normal University, Jinan 250014, Shandong Province, China.
authors.forename: Z H
authors.initials: ZH
authors.lastname: Xu
authors.affiliation: Shi-Ming Jiang, Zhao-Hui Xu, Biology Department, Shandong Normal University, Jinan 250014, Shandong Province, China.
authors.forename: Y
authors.initials: Y
authors.lastname: Zhang
authors.affiliation: Shi-Ming Jiang, Zhao-Hui Xu, Biology Department, Shandong Normal University, Jinan 250014, Shandong Province, China.
authors.forename: X M
authors.initials: XM
authors.lastname: Shi
keywords: Carcinoma, hepatocellular; Cryopreservation; Liver neoplasms; Phenotype; Tumor cells, cultured