Article

Allele-Specific p53 Mutant Reactivation

The Cancer Institute of New Jersey, New Brunswick, NJ 08903, USA.
Cancer cell (Impact Factor: 23.52). 05/2012; 21(5):614-25. DOI: 10.1016/j.ccr.2012.03.042
Source: PubMed

ABSTRACT

Rescuing the function of mutant p53 protein is an attractive cancer therapeutic strategy. Using the National Cancer Institute's anticancer drug screen data, we identified two compounds from the thiosemicarbazone family that manifest increased growth inhibitory activity in mutant p53 cells, particularly for the p53(R175) mutant. Mechanistic studies reveal that NSC319726 restores WT structure and function to the p53(R175) mutant. This compound kills p53(R172H) knockin mice with extensive apoptosis and inhibits xenograft tumor growth in a 175-allele-specific mutant p53-dependent manner. This activity depends upon the zinc ion chelating properties of the compound as well as redox changes. These data identify NSC319726 as a p53(R175) mutant reactivator and as a lead compound for p53-targeted drug development.

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Available from: Alexei Vazquez, Jul 21, 2014
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    • "It would appear reasonable to conclude that similar extrusion and misfolding would proceed with other zinc metalloproteins. In a related study, it was noted that thiosemicarbazones such as NSC319726 (Fig. 2) could be used as a delivery vehicle for zinc ions to assist in a zinc templated refolding of mutant metalloproteins in TOV112D (Yu et al. 2012). As follows from the above, the thiosemicarbazones are implicated in zinc transport. "
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    ABSTRACT: Zinc is the second most abundant transition metal in the human body, between 3 and 10 % of human genes encoding for zinc binding proteins. We have investigated the interplay of reactive oxygen species and zinc homeostasis on the cytotoxicity of the thiosemicarbazone chelators against the MCF-7 cell line. The cytotoxicity of thiosemicarbazone chelators against MCF-7 can be improved through supplementation of ionic zinc provided the zinc ion is at a level exceeding the thiosemicarbazone concentration. Elimination of the entire cell population can be accomplished with this regime, unlike the plateau of cytotoxicity observed on thiosemicarbazone monotherapy. The cytotoxic effects of copper complexes of the thiosemicarbazone are not enhanced by zinc supplementation, displacement of copper from the complex being disfavoured. Treatment of MCF-7 with uncomplexed thiosemicarbazone initiates post G1 blockade alongside the induction of apoptosis, cell death being abrogated through subsequent supplementation with zinc ion after drug removal. This would implicate a metal depletion mechanism in the cytotoxic effect of the un-coordinated thiosemicarbazone. The metal complexes of the species, however, fail to initiate similar G1 blockade and apparently exert their cytotoxic effect through generation of reactive oxygen species, suggesting that multiple mechanisms of cytotoxicity can be associated with the thiosemicarbazones dependant on the level of metal ion association.
    Full-text · Article · Dec 2015 · Biology of Metals
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    • "Among the various approaches, targeting the p53 for improved and efficient anticancer therapies is the restoration of wild-type p53 function in tumors that have lost p53 tumor suppressor activity [17]. Several small-molecule screening studies have led to the identification of compounds such as the PRIMA-1 [18], MIRA-1 [19], CP-31398 [20], STIMA-1 [21], SCH529074 [22], NSC319726 [23] and others [24] [25] with the ability to reactivate the mutant p53 protein and confer biological functions such as the activation of the target gene expression. A common property of many of these compounds is they possess chemically active, highly electrophilic double bonds that participate in reactions of nucleophilic addition and in a cellular milieu; as such, they are capable of inducing oxidative stress and redox imbalance in human cells (Fig. 1A). "
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    ABSTRACT: Small molecules that can restore biological function to the p53 mutants found in human cancers have been highly sought to increase the anticancer efficacy. In efforts to generate hybrid anticancer drugs that can impact two or more targets simultaneously, we designed and developed piperlongumine (PL) derivatives with an aryl group inserted at the C-7 position. This insertion bestowed a combretastatin A4 (CA4, an established microtubule disruptor) like structure while retaining the piperlongumine configuration. The new compounds exhibited potent antiproliferative activities against eight cancer cell lines, in particular, were more cytotoxic against the SKBR-3 breast cancer cells which harbor a R175H mutation in p53 suppressor. KSS-9, a representative aryl PL chosen for further studies induced abundant ROS generation and protein glutathionylation. KSS-9 strongly disrupted the tubulin polymerization in vitro, destabilized the microtubules in cells and induced a potent G2/M cell cycle block. More interestingly, KSS-9 showed the ability to reactivate the p53 mutation and restore biological activity to the R175H mutant protein present in SKBR3 cells. Several procedures, including immunocytochemistry using conformation-specific antibodies for p53, immunoprecipitation combined with western blotting, electrophoretic shift mobility shift assays showed a reciprocal loss of mutant protein and generation of wild-type like protein. p53 reactivation was accompanied by the induction of the target genes, MDM2, p21cip1 and PUMA. Mechanistically, the redox-perturbation in cancer cells by the hybrid drug appears to underlie the p53 reactivation process. This anticancer drug approach merits further development.
    Full-text · Article · Nov 2015 · European Journal of Medicinal Chemistry
    • "Recently, two compounds, NSC319726 (Yu et al., 2012) and stictic acid (Wassman et al., 2013), were reported as mutant Figure 6. Binding of CTM to the Hsp40 Protein Is Required for the CTM-Mediated Reactivation of Mutant p53 R175H (A) Hsp40 expression is increased and its binding capacity to mutant p53 is enhanced upon CTM treatment in CAL-33 (R175H) cells. "
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    ABSTRACT: TP53 is the most frequently mutated gene in human cancer, and small-molecule reactivation of mutant p53 function represents an important anticancer strategy. A cell-based, high-throughput small-molecule screen identified chetomin (CTM) as a mutant p53 R175H reactivator. CTM enabled p53 to transactivate target genes, restored MDM2 negative regulation, and selectively inhibited the growth of cancer cells harboring mutant p53 R175H in vitro and in vivo. We found that CTM binds to Hsp40 and increases the binding capacity of Hsp40 to the p53 R175H mutant protein, causing a potential conformational change to a wild-type-like p53. Thus, CTM acts as a specific reactivator of the p53 R175H mutant form through Hsp40. These results provide new insights into the mechanism of reactivation of this specific p53 mutant. Copyright © 2015 Elsevier Ltd. All rights reserved.
    No preview · Article · Aug 2015 · Chemistry & biology
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