PPM1B depletion in U2OS cells supresses cell growth through RB1-E2F1 pathway and stimulates bleomycin-induced cell death

Rachel Elizabeth Miller, Nathalie Uwamahoro, Jeong Hyeon Park*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)


PPM1B is a metal-dependent serine/threonine protein phosphatase, with a similar structure and function to the well-known oncogene in breast cancer, PPM1D (WIP1). However, clinical significance of PPM1B as a pharmacological target in cancer therapy has not been explored. To test if PPM1B can be a drug target in the cellular proliferation and death pathway, the lentiviral PPM1B shRNA was stably expressed in cancer cell lines and its regulatory function in the RB1-E2F1 pathway was examined. We found that PPM1B depletion suppressed cellular proliferation of U2OS cells, accompanied by hyper-phosphorylation of RB1 and up-regulation of E2F1 target genes, p27 and caspase 7. Notably, PPM1B depletion significantly sensitised U2OS cells to bleomycin-induced cell death at a minimal effective concentration. Our results suggest that PPM1B plays a negative role in the activation of the p38-RB1-E2F1 pathway and that targeting PPM1B could be useful in certain types of cancer by stimulating chemotherapy-induced cell death.

Original languageEnglish
Pages (from-to)391-397
Number of pages7
JournalBiochemical and Biophysical Research Communications
Issue number2
Publication statusPublished - 2 Jun 2018
Externally publishedYes


  • Apoptosis
  • E2F1
  • PPM1B
  • RB1
  • p38

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