High affinity interaction of the p53 peptide-analogue with human Mdm2 and Mdmx

Czarna, Anna; Popowicz, Grzegorz M.; Pęcak, Aleksandra; Wolf, Siglinde; Dubin, Grzegorz; Holak, Tad A.

doi:10.4161/cc.8.8.8185

Cited by 100 publications

(115 citation statements)

References 35 publications

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“…The dissociation constants of the labeled peptide were determined by direct titration on a microtiter plate reader ( Fig. 2A) to be 12.5 AE 0.3 nM (MDM4) and 5.7 AE 1.2 nM (MDM2), consistent with literature values (27). The stoichiometry of binding of the labeled peptide to MDM4 was found by analytical ultracentrifugation experiments to be 1∶1 (Fig.…”

Section: Resultssupporting

confidence: 66%

Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2

Vogel

Bauer

Joerger

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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The proteins MDM2 and MDM4 are key negative regulators of the tumor suppressor protein p53, which are frequently upregulated in cancer cells. They inhibit the transactivation activity of p53 by binding separately or in concert to its transactivation domain. MDM2 is also a ubiquitin ligase that leads to the degradation of p53. Accordingly, MDM2 and MDM4 are important targets for drugs to inhibit their binding to p53. We found from in silico screening and confirmed by experiment that lithocholic acid (LCA) binds to the p53 binding sites of both MDM2 and MDM4 with a fivefold preference for MDM4. LCA is an endogenous steroidal bile acid, variously reported to have both carcinogenic and apoptotic activities. The comparison of LCA effects on apoptosis in HCT116 p53 þ∕þ vs. p53 −∕− cells shows a predominantly p53-mediated induction of caspase-3/7. The dissociation constants are in the μM region, but only modest inhibition of binding of MDM2 and MDM4 is required to negate their upregulation because they have to compete with transcriptional coactivator p300 for binding to p53. Binding was weakened by structural changes in LCA, and so it may be a natural ligand of MDM2 and MDM4, raising the possibility that MDM proteins may be sensors for specific steroids.HDMX | virtual screening | natural product | cancer pathways | bile acid sensor T he tumor-suppressor protein p53 plays a pivotal role in cancer (1, 2). Often, its function is severely impaired by upregulation of its two key negative regulators, MDM2 and MDM4 (1-3). The N-terminal domains of MDM2 and MDM4 are structurally very similar and both bind to the same sequence in the intrinsically disordered N terminus of p53 (2, 4, 5). The binding cavities within MDM4 and MDM2 are important targets for drug therapy that releases them from p53 (6-10). Nutlins (11), for example, are potent MDM2 inhibitors and are potential therapeutics (12, 13) as well as being invaluable research tools for probing p53 pathways (12,14), as are spiro-oxindoles, which were found by in silico methods (15,16). MDM4 has a different specificity for small molecules, binding nutlins, for example, less tightly. Accordingly, MDM4-selective and dual MDM4/MDM2 inhibitors are also being sought (7,17,18). We searched for MDM4 inhibitors by structure-based in silico screening of binding (6, 19) and identified LCA as an endogenous inhibitor of both MDM4 and MDM2. LCA is a secondary bile acid formed by bacteria in the gut from its precursor chenodeoxycholic acid (CDCA, Fig S1). It has been variously reported to show both carcinogenic and apoptotic activities (20,21). LCA is a rare example of a toxic endobiotic that is efficiently detoxicated by conjugation with taurine or glycine, sulfation at C-3 by the sulfotransferase SULT2A1, or metabolism through cytochrome P450 CYP3A enzymes (20). It induces its own metabolism by activating nuclear receptors like the vitamin D receptor (22) (VDR) and the farnesoid X receptor (23) (FXR). Thereby, it inhibits the synthesis of bile acids and promotes the transcription of gene...

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Section: Resultssupporting

confidence: 66%

Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2

Vogel

Bauer

Joerger

et al. 2012

Proc. Natl. Acad. Sci. U.S.A.

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“…Several peptides, small molecules and peptidomimetics have been identified as inhibitors of this interaction between p53 and MDM2/ MDMX. 17,24,[28][29][30][31][32][33][34][35][36][37] The crystal structure of nutlin complexed to MDM2, PDB code 1RV1, 28 has been resolved at 2.3 Å. It shows (Fig.…”

Section: Resultsmentioning

confidence: 99%

Differential binding of p53 and nutlin to MDM2 and MDMX: Computational studies

Joseph

Madhumalar²,

Brown³

et al. 2010

Cell Cycle

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“…4A), inhibitors that were specifically designed or screened for MDM2 binding are generally much weaker inhibitors of p53-MDMX interaction (Popowicz et al 2008). More recent studies have elucidated the binding modes of p53-derived peptides (Czarna et al 2009;Pazgier et al 2009) and a chlorinated peptidomimetic (Kallen et al 2009) that bind to both MDM2 and MDMX with low nanomolar affinities, two to three orders of magnitude tighter than the native p53 peptide. This wealth of novel structural information, which also offers insights into the conformational plasticity within the binding pocket of MDMX, is an excellent starting point for the development of cross-selective MDM2/MDMX inhibitors for use in cancer therapy.…”

Section: Targeting the P53 Pathway: Mdm2 Mdmx Sirtuins And Beyondmentioning

confidence: 99%

The Tumor Suppressor p53: From Structures to Drug Discovery

Joerger

Fersht²

2010

Cold Spring Harbor Perspectives in Biology

291

280

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Even 30 years after its discovery, the tumor suppressor protein p53 is still somewhat of an enigma. p53's intimate and multifaceted role in the cell cycle is mirrored in its equally complex structural biology that is being unraveled only slowly. Here, we discuss key structural aspects of p53 function and its inactivation by oncogenic mutations. Concerted action of folded and intrinsically disordered domains of the highly dynamic p53 protein provides binding promiscuity and specificity, allowing p53 to process a myriad of cellular signals to maintain the integrity of the human genome. Importantly, progress in elucidating the structural biology of p53 and its partner proteins has opened various avenues for structure-guided rescue of p53 function in tumors. These emerging anticancer strategies include targeting mutant-specific lesions on the surface of destabilized cancer mutants with small molecules and selective inhibition of p53's degradative pathways.

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High affinity interaction of the p53 peptide-analogue with human Mdm2 and Mdmx

Cited by 100 publications

References 35 publications

Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2

Lithocholic acid is an endogenous inhibitor of MDM4 and MDM2

Differential binding of p53 and nutlin to MDM2 and MDMX: Computational studies

The Tumor Suppressor p53: From Structures to Drug Discovery

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