Pleckstrin homology domain-containing protein PHLDB3 supports cancer growth via a negative feedback loop involving p53

Nat Commun. 2016 Dec 23:7:13755. doi: 10.1038/ncomms13755.

Abstract

The tumour suppressor p53 transactivates the expression of its target genes to exert its functions. Here, we identify a pleckstrin homology domain-containing protein (PHLDB3)-encoding gene as a p53 target. PHLDB3 overexpression increases proliferation and restrains apoptosis of wild-type p53-harboring cancer cells by reducing p53 protein levels. PHLDB3 binds to MDM2 (mouse double minute 2 homolog) and facilitates MDM2-mediated ubiquitination and degradation of p53. Knockdown of PHLDB3 more efficiently inhibits the growth of mouse xenograft tumours derived from human colon cancer HCT116 cells that contain wild type p53 compared with p53-deficient HCT116 cells, and also sensitizes tumour cells to doxorubicin and 5-Fluorouracil. Analysis of cancer genomic databases reveals that PHLDB3 is amplified and/or highly expressed in numerous human cancers. Altogether, these results demonstrate that PHLDB3 promotes tumour growth by inactivating p53 in a negative feedback fashion and suggest PHLDB3 as a potential therapeutic target in various human cancers.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Antineoplastic Agents / pharmacology
  • Apoptosis / drug effects
  • Apoptosis / genetics
  • Base Sequence
  • Cell Proliferation / drug effects
  • Feedback, Physiological* / drug effects
  • Gene Expression Regulation, Neoplastic / drug effects
  • Gene Knockdown Techniques
  • HCT116 Cells
  • Humans
  • Intracellular Signaling Peptides and Proteins / chemistry
  • Intracellular Signaling Peptides and Proteins / genetics
  • Intracellular Signaling Peptides and Proteins / metabolism*
  • Mutation / genetics
  • Neoplasm Proteins / chemistry*
  • Neoplasm Proteins / genetics
  • Neoplasm Proteins / metabolism*
  • Neoplasms / genetics
  • Neoplasms / pathology*
  • Pleckstrin Homology Domains*
  • Protein Binding / drug effects
  • Proteolysis / drug effects
  • Proto-Oncogene Proteins c-mdm2 / metabolism
  • Tumor Suppressor Protein p53 / metabolism*
  • Ubiquitination / drug effects

Substances

  • Antineoplastic Agents
  • Intracellular Signaling Peptides and Proteins
  • Neoplasm Proteins
  • PHLDB3 protein, human
  • Tumor Suppressor Protein p53
  • Proto-Oncogene Proteins c-mdm2