Mutant p53-R273H mediates cancer cell survival and anoikis resistance through AKT-dependent suppression of BCL2-modifying factor (BMF)

Cell Death Dis. 2015 Jul 16;6(7):e1826. doi: 10.1038/cddis.2015.191.

Abstract

p53 is the most frequently mutated tumor-suppressor gene in human cancers. Unlike other tumor-suppressor genes, p53 mutations mainly occur as missense mutations within the DNA-binding domain, leading to the expression of full-length mutant p53 protein. Mutant p53 proteins not only lose their tumor-suppressor function, but may also gain new oncogenic functions and promote tumorigenesis. Here, we showed that silencing of endogenous p53-R273H contact mutant, but not p53-R175H conformational mutant, reduced AKT phosphorylation, induced BCL2-modifying factor (BMF) expression, sensitized BIM dissociation from BCL-XL and induced mitochondria-dependent apoptosis in cancer cells. Importantly, cancer cells harboring endogenous p53-R273H mutant were also found to be inherently resistant to anoikis and lack BMF induction following culture in suspension. Underlying these activities is the ability of p53-R273H mutant to suppress BMF expression that is dependent on constitutively active PI3K/AKT signaling. Collectively, these findings suggest that p53-R273H can specifically drive AKT signaling and suppress BMF expression, resulting in enhanced cell survivability and anoikis resistance. These findings open the possibility that blocking of PI3K/AKT will have therapeutic benefit in mutant p53-R273H expressing cancers.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adaptor Proteins, Signal Transducing / biosynthesis*
  • Adaptor Proteins, Signal Transducing / genetics
  • Anoikis / genetics*
  • Apoptosis / genetics
  • Carcinogenesis / genetics*
  • Cell Survival / genetics
  • Drug Resistance, Neoplasm / genetics
  • Gene Expression Regulation, Neoplastic
  • Humans
  • MCF-7 Cells
  • Mutation, Missense
  • Neoplasms / genetics*
  • Neoplasms / pathology
  • Oncogene Protein v-akt / genetics
  • Phosphatidylinositol 3-Kinases / genetics
  • Proto-Oncogene Proteins c-bcl-2 / genetics
  • Signal Transduction
  • Tumor Suppressor Protein p53 / genetics*

Substances

  • Adaptor Proteins, Signal Transducing
  • BMF protein, human
  • Proto-Oncogene Proteins c-bcl-2
  • TP53 protein, human
  • Tumor Suppressor Protein p53
  • Phosphatidylinositol 3-Kinases
  • Oncogene Protein v-akt