The sansalvamide A (San A) scaffold is a promising structure for the development of novel cancer therapeutics. We have used the San A scaffold to produce 7 compounds that are cytotoxic to pancreatic and colon cancer cell lines at nanomolar concentrations. The San A derivatives are of particular interest because they do not share structural homology with other classes of marketed cancer therapeutics, they appear to inhibit an established target (Hsp90) at a novel site, and they are significantly more potent than the drugs currently available for the treatment of colon and pancreatic cancer. Known Hsp90 inhibitors interact with the N-terminal domain whereas our compounds are unique in that they target the C-terminal domain and block the binding of inositol hexakisphosphate kinase 2 (IP6K2). It is the overall goal of this project to develop a novel chemotherapeutic agent based on the San A scaffold. It is our hypothesis that analogs of San A with even greater potency and selectively can be synthesized by modifying key structural features identified in our preliminary studies.
The specific aims are to: a) Identify the binding site at the C-terminus of Hsp90 and design a potent second-generation lead candidate compound, b) Identify the key cellular targets and their role in San A's cytotoxic effect, and c) Identify the key cellular targets and their role in San A's cytotoxic effect.

Public Health Relevance

Cancers have continued to evolve new mechanisms of action that make them resistant to most known chemotherapeutic agents. Consequently, there remains a serious and immediate need for the development of antitumor agents that target drug-resistant cancers. The goal of this project involves using conformational based design to synthesize potent new anticancer agents that act via binding to the C-terminus of Hsp90 thus inhibiting the binding of inositol hexakisphosphate kinase 2 (IP6K2). Current lead compounds show promise for binding to this novel site and show potent cytotoxicity (nanomolar) as well as differential selectivity for cancer over normal cells. Through the proposed structural studies of our lead compounds with their biological targets combined with synthesis and in vivo studies, we anticipate generating a new class of therapeutic agents that may be useful in treating cancers.

Agency
National Institute of Health (NIH)
Institute
National Cancer Institute (NCI)
Type
Research Project (R01)
Project #
4R01CA137873-03
Application #
8192947
Study Section
Synthetic and Biological Chemistry B Study Section (SBCB)
Program Officer
Lees, Robert G
Project Start
2009-05-24
Project End
2012-04-30
Budget Start
2011-05-01
Budget End
2012-04-30
Support Year
3
Fiscal Year
2011
Total Cost
$305,938
Indirect Cost
Name
San Diego State University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
073371346
City
San Diego
State
CA
Country
United States
Zip Code
92182
Wang, Yao; Koay, Yen Chin; McAlpine, Shelli R (2017) How Selective are Hsp90 Inhibitors for Cancer Cells over Normal Cells? ChemMedChem 12:353-357
McConnell, Jeanette R; Alexander, Leslie A; McAlpine, Shelli R (2014) A heat shock protein 90 inhibitor that modulates the immunophilins and regulates hormone receptors without inducing the heat shock response. Bioorg Med Chem Lett 24:661-6
Ramsey, Deborah M; McAlpine, Shelli R (2013) Halting metastasis through CXCR4 inhibition. Bioorg Med Chem Lett 23:20-5
Kim, Seong Jong; McAlpine, Shelli R (2013) Solid phase versus solution phase synthesis of heterocyclic macrocycles. Molecules 18:1111-21
McConnell, Jeanette R; McAlpine, Shelli R (2013) Heat shock proteins 27, 40, and 70 as combinational and dual therapeutic cancer targets. Bioorg Med Chem Lett 23:1923-8
Kim, Seong Jong; Ramsey, Deborah M; Boyer, Cyrille et al. (2013) Effectively delivering a unique hsp90 inhibitor using star polymers. ACS Med Chem Lett 4:
McConnell, Jeanette R; Rananaware, Dimple P; Ramsey, Deborah M et al. (2013) A potential rhodium cancer therapy: studies of a cytotoxic organorhodium(I) complex that binds DNA. Bioorg Med Chem Lett 23:2527-31
Ramsey, Deborah M; Amirul Islam, Md; Turnbull, Lynne et al. (2013) Psammaplysin F: a unique inhibitor of bacterial chromosomal partitioning. Bioorg Med Chem Lett 23:4862-6
Kim, Seong Jong; Lin, Chun Chieh; Pan, Chung-Mao et al. (2013) A structure-activity relationship study on multi-heterocyclic molecules: two linked thiazoles are required for cytotoxic activity. Medchemcomm 4:406-410
Singh, Erinprit K; Ramsey, Deborah M; McAlpine, Shelli R (2012) Total synthesis of trans,trans-Sanguinamide B and conformational isomers. Org Lett 14:1198-201

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