Cell cycle re-entry following chemically-induced cell cycle synchronization leads to elevated p53 and p21 protein levels

Oncogene. 1997 Nov 27;15(22):2749-53. doi: 10.1038/sj.onc.1201441.


Mimosine (MIM) and aphidicolin (APH) are two agents frequently used in tissue culture-based experiments to achieve cell synchronization at late G1 and S phases. Following MIM or APH treatment of human cancer cell lines, a reversible growth arrest in late G1 and S phases of the cell cycle was correlated with moderate increases in p53 and p21 protein levels. Both p53-dependent and -independent increases in p21 were observed following treatment with either agent. However, a striking increase in p21 protein levels and a continuous elevation in both p53 and p21 protein levels were observed over 48 h after cells re-entered the cell cycle following the chemically-induced synchronization. In addition, the increase in p21 protein levels typically seen following treatment of cells with DNA damaging agents, was enhanced when cells were treated with genotoxic agents following MIM or APH synchronization. These findings suggest that caution should be exercised when interpreting results from experiments using cell synchronization agents, in particular, studies designed to investigate p53- and p21-regulatory pathways.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Aphidicolin / pharmacology
  • Carcinoma, Large Cell / drug therapy
  • Carcinoma, Large Cell / genetics
  • Cell Cycle / drug effects*
  • Cell Cycle / genetics
  • Colorectal Neoplasms / drug therapy
  • Colorectal Neoplasms / metabolism
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins / drug effects
  • Cyclins / metabolism*
  • Doxorubicin / pharmacology
  • Enzyme Inhibitors / pharmacology
  • Flow Cytometry
  • Humans
  • Malondialdehyde / pharmacology
  • Mimosine / pharmacology
  • Tumor Cells, Cultured
  • Tumor Suppressor Protein p53 / drug effects
  • Tumor Suppressor Protein p53 / metabolism*


  • CDKN1A protein, human
  • Cyclin-Dependent Kinase Inhibitor p21
  • Cyclins
  • Enzyme Inhibitors
  • Tumor Suppressor Protein p53
  • Aphidicolin
  • Malondialdehyde
  • Mimosine
  • Doxorubicin