Our lab has shown that the S100B protein binds to wild-type p53 in primary malignant melanoma, dissociates the p53 tetramer, and down-regulates p53-dependent tumor suppression;therefore, it is important to develop inhibitors of the S100B-p53 interaction to restore wild-type p53 activity in this cancer. As a proof of principle, we have also demonstrated that inhibiting S100B with small interfering antisense RNA (siRNASIOOB) restores wild-type p53 tumor suppressor activity in primary malignant melanoma. Accordingly, we hypothesize that low molecular weight compounds can be rationally designed to bind the well-defined p53 binding site on S100B with high affinity and inhibit the S100B-p53 interaction. This hypothesis will be tested further in the proposed study, via discovery and synthesis of such molecules with the following specific aims.
In Aim 1, computer aided drug design (CADD), combined with high- throughput/automated NMR, thermodynamic binding and p53 functional assays will be used to discover lead compounds that bind S100B and inhibit the S100B-p53 interaction.
In Aim 2, 3D structures of S100B-drug complexes will be determined using NMR spectroscopy and/or X-ray crystallography. Such structure determinations are already underway.
In Aim 3, optimization of lead compounds that inhibit the S100B-p53 interaction will be performed via chemical modifications. Organic syntheses will be guided by 3D structural data (from Aim 2) and CADD lead optimization approaches. Testing of new analogues will be performed using existing thermodynamic binding and biological assays (as in Aim 1). With this strategy, it is our aim to discover/synthesize new compounds that bind S100B and restore p53 activity in malignant melanoma. In the future, the most promising compounds will be examined for efficacy in treating melanoma in animal models. Inhibitors such as these will likely have therapeutic value for treatment of other cancers that have elevated S100B levels and wild-type p53 such as astrocytomas, renal tumors and malignant mature T-cells in leukemia patients.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
5R01CA107331-04
Application #
7621011
Study Section
Macromolecular Structure and Function B Study Section (MSFB)
Program Officer
Lees, Robert G
Project Start
2006-07-01
Project End
2011-04-30
Budget Start
2009-06-04
Budget End
2010-04-30
Support Year
4
Fiscal Year
2009
Total Cost
$497,921
Indirect Cost
Name
University of Maryland Baltimore
Department
Biochemistry
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
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Melville, Zephan; Hernández-Ochoa, Erick O; Pratt, Stephen J P et al. (2017) The Activation of Protein Kinase A by the Calcium-Binding Protein S100A1 Is Independent of Cyclic AMP. Biochemistry 56:2328-2337
Cavalier, Michael C; Melville, Zephan; Aligholizadeh, Ehson et al. (2016) Novel protein-inhibitor interactions in site 3 of Ca(2+)-bound S100B as discovered by X-ray crystallography. Acta Crystallogr D Struct Biol 72:753-60
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Cavalier, Michael C; Ansari, Mohd Imran; Pierce, Adam D et al. (2016) Small Molecule Inhibitors of Ca(2+)-S100B Reveal Two Protein Conformations. J Med Chem 59:592-608
Faller, Christina E; Raman, E Prabhu; MacKerell Jr, Alexander D et al. (2015) Site Identification by Ligand Competitive Saturation (SILCS) simulations for fragment-based drug design. Methods Mol Biol 1289:75-87
Yu, Wenbo; Lakkaraju, Sirish Kaushik; Raman, E Prabhu et al. (2015) Pharmacophore modeling using site-identification by ligand competitive saturation (SILCS) with multiple probe molecules. J Chem Inf Model 55:407-20
He, Xinhua; Lakkaraju, Sirish K; Hanscom, Marie et al. (2015) Acyl-2-aminobenzimidazoles: a novel class of neuroprotective agents targeting mGluR5. Bioorg Med Chem 23:2211-20
Lakkaraju, Sirish Kaushik; Yu, Wenbo; Raman, E Prabhu et al. (2015) Mapping functional group free energy patterns at protein occluded sites: nuclear receptors and G-protein coupled receptors. J Chem Inf Model 55:700-8

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