Restoration of the growth suppression function of mutant p53 by a synthetic peptide derived from the p53 C-terminal domain

Abstract

We demonstrate here that synthetic 22-mer peptide 46, corresponding to the carboxy-terminal amino acid residues 361-382 of p53, can activate specific DNA binding of wild-type p53 in vitro and can restore the transcriptional transactivating function of at least some mutant p53 proteins in living cells. Introduction of peptide 46 in Saos-2 cells carrying a Tet-regulatable His-273 mutant p53 construct caused growth inhibition and apoptosis in the presence of mutant p53 but not in its absence, confirming that the effect of the peptide is mediated by reactivation of mutant p53. Moreover, peptide 46 caused apoptosis in mutant as well as wild-type p53-carrying human tumor cell lines of different origin, whereas p53 null tumor cells were not affected. These findings raise possibilities for developing drugs that restore the tumor suppressor function of mutant p53 proteins, thus selectively eliminating tumor cells.

Twenty years of p53 research: structural and functional aspects of the p53 protein

“…This extreme C-terminal domain (amino acids 363 ± 393) seems to act as a negative regulator of p53 sequence speci®c binding. This idea is further substantiated by the ®nding that binding of p53 to the anti-p53 monoclonal antibody PAb421 (which recognizes a C-terminal epitope) can activate speci®c DNA binding (Abarzua et al, 1996;Hupp and Lane, 1995;Selivanova et al, 1997Selivanova et al, , 1999Shaw et al, 1996).…”

Reactivation of mutant p53: molecular mechanisms and therapeutic potential

“…A synthetic peptide derived from the p53 C-terminal domain (peptide 46) was shown to restore the specific DNA binding and transcriptional transactivation function of several hot-spot mutant p53 proteins and rescue the function of endogenous mutant p53 proteins resulting in growth inhibition and cell death by apoptosis (Selivanova et al, 1997;Kim et al, 1999). The observation that C-terminal peptides can restore the DNA-binding activity to isolated core domain proteins indicated that it might directly affect the p53 domain where tumor-derived mutations are clustered.…”

“…The observation that C-terminal peptides can restore the DNA-binding activity to isolated core domain proteins indicated that it might directly affect the p53 domain where tumor-derived mutations are clustered. It was hypothesized that C-terminal peptides reactivate mutant p53 through stabilization of the core domain folding and/or establishment of novel DNA contacts (Abarzu´a et al, 1995;Selivanova et al, 1997Selivanova et al, , 1998Selivanova et al, , 1999. These findings provided proof-of-principle for functional restoration of tumor-derived mutant p53 proteins by small molecules.…”

p53-dependent apoptosis is regulated by a C-terminally alternatively spliced form of murine p53

“…Synthetic peptides corresponding to the p53 C-terminus were shown to restore the wild-type biological functions of a variety of mutant p53 proteins (Muller-Tiemann et al, 1998;Selivanova et al, 1997). Furthermore, p53 protein stabilization was also shown to be controlled by the C-terminus.…”