p53 Is Not Directly Relevant to the Response of Polo-like Kinase 1 Inhibitors

Cell Cycle. 2012 Feb 1;11(3):543-53. doi: 10.4161/cc.11.3.19076. Epub 2012 Feb 1.


Polo-like kinase 1 (Plk1) is elementary for cell proliferation and its deregulation is involved in tumorigenesis. Plk1 has been established as one of the most attractive targets for molecular cancer therapy. In fact, multiple small molecule inhibitors targeting either the kinase domain or the Polo-box binding domain (PBD) of Plk1 have been identified and intensively investigated. Intriguingly, Plk1 depletion affects more cancer cells than normal cells. It is also reported that the cytotoxicity induced by Plk1 inhibition is elevated in cancer cells with defective p53. The data lead to the hypothesis that p53 might be a predictive marker for the response of Plk1 inhibition. In this study, we demonstrate that there is no obvious different cytotoxic response between cancer cells with and without functional p53, including the isogenic colon cancer cell lines HCT116p53(+/+) and HCT116p53(-/-), breast cancer cell line MCF7, lung cancer cell line A549 and cervical carcinoma cell line HeLa, after treatment with either siRNA against Plk1, the kinase domain inhibitors BI 2536 and BI 6727 or the PBD inhibitor Poloxin. We suggest that the p53 status is not a predictor for the response of Plk1 inhibition, at least not directly. Yet, the long-term outcomes of losing p53, such as genome instability, could be associated with the cytotoxicity of Plk1 inhibition. Further studies are required to investigate whether other circumstances of cancer cells, such as DNA replication/damage stress, mitotic stress, and metabolic stress, which make possibly the survival of cancer cells more dependent on Plk1 function, are responsible for the sensitivity of Plk1 inhibition.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Benzoates / pharmacology
  • Cell Cycle Proteins / antagonists & inhibitors*
  • Cell Cycle Proteins / genetics
  • Cell Cycle Proteins / metabolism
  • Cell Line, Tumor
  • Cell Proliferation / drug effects
  • Genomic Instability
  • HCT116 Cells
  • HeLa Cells
  • Humans
  • Protein Kinase Inhibitors / pharmacology*
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors*
  • Protein-Serine-Threonine Kinases / genetics
  • Protein-Serine-Threonine Kinases / metabolism
  • Proto-Oncogene Proteins / antagonists & inhibitors*
  • Proto-Oncogene Proteins / genetics
  • Proto-Oncogene Proteins / metabolism
  • Quinones / pharmacology
  • RNA Interference
  • RNA, Small Interfering / metabolism
  • Tumor Suppressor Protein p53 / genetics
  • Tumor Suppressor Protein p53 / metabolism*


  • Benzoates
  • Cell Cycle Proteins
  • Protein Kinase Inhibitors
  • Proto-Oncogene Proteins
  • Quinones
  • RNA, Small Interfering
  • Tumor Suppressor Protein p53
  • poloxin
  • Protein-Serine-Threonine Kinases
  • polo-like kinase 1