Rescue of mutants of the tumor suppressor p53 in cancer cells by a designed peptide

Abstract

We designed a series of nine-residue peptides that bound to a defined site on the tumor suppressor p53 and stabilized it against denaturation. To test whether the peptides could act as chaperones and rescue the tumor-suppressing function of oncogenic mutants of p53 in living cells, we treated human tumor cells with the fluorescein-labeled peptide Fl-CDB3 (fluorescent derivative of CDB3). Before treatment, the mutant p53 in the cell was predominantly denatured. Fl-CDB3 was taken up into the cytoplasm and nucleus and induced a substantial up-regulation of wild-type p53 protein and representative mutants. The mutants, His-273 and His-175 p53, adopted the active conformation, with a dramatic decrease in the fraction of denatured protein. In all cases, there was p53-dependent induction of expression of the p53 target genes mdm2, gadd45, and p21, accompanied by p53-dependent partial restoration of apoptosis. Fl-CDB3 sensitized cancer cells that carried wild-type p53 to p53-dependent ␥-radiation-induced apoptosis. Although Fl-CDB3 did not elicit a full biological response, it did bind to and rescue p53 in cells and so can serve as a lead for the development of novel drugs for anticancer therapy.

Mutant p53 drives multinucleation and invasion through a process that is suppressed by ANKRD11

“…This unique property of ANKRD11 is similar to that reported for the small molecules and peptides, PRIMA-1 (Bykov et al, 2002) and CDB-3 (Friedler et al, 2002;Issaeva et al, 2003), which reportedly restore a native conformation to mutant p53. We also show that expression of the ANKRD11 ankyrin domain is sufficient to dissociate the p53-R175H Á p63 and p53-R175H Á p73 complexes (Figure 7).…”

Reactivation of mutant p53: molecular mechanisms and therapeutic potential

“…Whereas CP-31398 confers protection from unfolding at physiological temperature, PRIMA-1 converts already unfolded p53 into an active form independently of protein synthesis (Bykov et al, 2002a). Furthermore, PRIMA-1 does not activate wild-type p53, in contrast to both CP-31398 (see above) and CDB3 (Issaeva et al, 2003), and causes a decrease in the overall level of p53 in cells.…”

“…CDB3 can enter cells and bind p53 in the context of cellular proteins. It restores the PAb1620 þ conformation and transcriptional activity of two hot-spot p53 mutants, R273H and R175H, in human tumor cells (Issaeva et al, 2003). Interestingly, CDB3 induces accumulation of both wild-type and mutant p53 in cells.…”

PRIMA-1MET synergizes with cisplatin to induce tumor cell apoptosis

“…Therefore, it is conceivable that reconstitution of wild-type p53 function could render tumor cells more responsive to chemotherapy. In recent years, a number of molecules that can reactivate mutant p53 have been identified, including short peptides (Selivanova et al, 1997;Issaeva et al, 2003), glycerol (Ohnishi et al, 1999(Ohnishi et al, , 2002, ellipticine derivatives (Sugikawa et al, 1999), CP-31398 (Foster et al, 1999), WR1065 (North et al, 2002), and PRIMA-1 (Bykov et al, 2002b). This raises the possibility of combining mutant p53-reactivating molecules with chemotherapeutic drugs as a novel strategy to treat cancer.…”