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ABSTRACT: The early clinical hypothesis for inhibiting HSP90 in cancers was based on the dependence of certain key client proteins in malignant cells--including a host of well-characterized oncoproteins--on the activity of HSP90 for their function and stability. The additional concept has been established that cancer cells have heightened dependence on the efficient maintenance of intracellular proteomic homeostasis, central components of which are HSP90 and other heat shock proteins. We evaluate the evidence that inhibiting HSP90 in cancer exploits both of these biological vulnerabilities very effectively, we review the current status of the discovery and development of HSP90 inhibitors and we identify routes to improve their clinical efficacy, based on emerging knowledge.
Drug discovery today 03/2012; 17(5-6):242-52. · 6.63 Impact Factor
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James E H Day, Swee Y Sharp,
Martin G Rowlands,
Wynne Aherne,
Angela Hayes,
Florence I Raynaud,
William Lewis,
S Mark Roe,
Chrisostomos Prodromou,
Laurence H Pearl,
Paul Workman,
Christopher J Moody
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ABSTRACT: A series of resorcylic acid macrolactams, nitrogen analogues of the naturally occurring macrolactone radicicol, have been prepared by chemical synthesis and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. The synthesis involves, as key steps, ring opening of an isocoumarin intermediate, followed by a ring-closing metathesis reaction to form the macrocycle. Subsequent manipulation of the ester group into a range of amides allows access to a range of new macrolactams following deprotection of the two phenolic groups. These new resorcylic acid lactams exhibit metabolic stability greater than that of related lactone counterparts, while co-crystallization of three macrolactams with the N-terminal domain ATP site of Hsp90 confirms that they bind in a similar way to the natural product radicicol and to our previous synthetic lactone analogues. Interestingly, however, in the case of the N-benzylamide, additional binding to a hydrophobic pocket of the protein was observed. In biological assays, the new macrocyclic lactams exhibit a biological profile equivalent or superior to that of the related lactones and show the established molecular signature of Hsp90 inhibitors in human colon cancer cells.
ACS Chemical Biology 09/2011; 6(12):1339-47. · 6.45 Impact Factor
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Elodie E Noel,
Marc Yeste-Velasco,
Xueying Mao,
Jackie Perry,
Sakunthala C Kudahetti,
Ningfeng F Li, Swee Sharp,
Tracy Chaplin,
Liyan Xue,
Alan McIntyre,
Ling Shan,
Thomas Powles,
R Tim D Oliver,
Bryan D Young,
Janet Shipley,
Daniel M Berney,
Simon P Joel,
Yong-Jie Lu
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ABSTRACT: Development of chemoresistance limits the clinical efficiency of platinum-based therapy. Although many resistance mechanisms have been demonstrated, genetic/molecular alterations responsible for drug resistance in the majority of clinical cases have not been identified. We analyzed three pairs of testicular germ cell tumor cell lines using Affymetrix expression microarrays and revealed a limited number of differentially expressed genes across the cell lines when comparing the parental and resistant cells. Among them, CCND1 was the most significantly differentially expressed gene. Analysis of testicular germ cell tumor clinical samples by quantitative reverse transcription PCR analysis revealed that overall expression of CCND1 was significantly higher in resistant cases compared with sensitive samples (P < 0.0001). We also found that CCND1 was dramatically overexpressed both in induced and intrinsically resistant samples of ovarian and prostate cancer. Finally combined CCND1 knockdown using small-interfering RNA and cisplatin treatment inhibited cell growth in vitro significantly more effectively than any of these single treatments. Therefore, deregulation of CCND1 may be a major cause of cisplatin resistance in testicular germ cell tumors and may also be implicated in ovarian and prostate cancers. CCND1 could be potentially used as a marker for treatment stratification and as a molecular target to improve the treatment of platinum-resistant tumors.
American Journal Of Pathology 06/2010; 176(6):2607-15. · 4.89 Impact Factor
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Udai Banerji,
Nivedita Sain, Swee Y Sharp,
Melanie Valenti,
Yasmin Asad,
Ruth Ruddle,
Florence Raynaud,
Michael Walton,
Suzanne A Eccles,
Ian Judson,
Ann L Jackman,
Paul Workman
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ABSTRACT: To study the interactions of the heat shock protein 90 (HSP90) inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) and carboplatin in vitro and in vivo.
The combination of 17-AAG and carboplatin on the growth inhibition of A2780, SKOV-3, IGROV-1 and HX62 human ovarian cancer cells was studied in vitro by MTT assays. The effect of the sequence of administration of both drugs was further investigated in A2780 cells by sulforhodamine B assays. The ability of 17-AAG to deplete HSP90 client proteins either alone or in combination with carboplatin was evaluated by western blotting. Tumor concentrations of 17-AAG and carboplatin alone or in combination in vivo were determined by validated liquid chromatography with ultraviolet detection and atomic absorption spectroscopy methods. The growth inhibitory effects of 17-AAG, carboplatin and the combination were studied in the A2780 xenograft model.
The combination index (CI) at fu(0.5) for 17-AAG plus carboplatin was 0.97 (+/-0.12 SD) when A2780 cells were exposed to carboplatin followed by 17-AAG indicating additivity. The addition of carboplatin did not alter the ability of 17-AAG to cause C-RAF, CDK4 and p-AKT depletion or HSP70 induction. Tumor 17-AAG and carboplatin concentrations were not significantly different in the single agent and combination arms. Tumor weights relative to controls on day 6 (T/C) were 67% for the carboplatin, 64% for the 17-AAG and 22% for the combination.
In the specified sequences of drug exposure, 17-AAG and carboplatin have additive growth inhibitory effects in vitro and beneficial effects were seen with the combination in vivo. These findings form the basis for the possible evaluation of 17-AAG and carboplatin in a clinical trial.
Cancer Chemotherapy and Pharmacology 02/2008; 62(5):769-78. · 2.83 Impact Factor
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Alison Maloney,
Paul A Clarke,
Soren Naaby-Hansen,
Rob Stein,
Jens-Oliver Koopman,
Akunna Akpan,
Alice Yang,
Marketa Zvelebil,
Rainer Cramer,
Lindsay Stimson, [......],
Udai Banerji,
Ian Judson, Swee Sharp,
Marissa Powers,
Emmanuel deBilly,
Joanne Salmons,
Michael Walton,
Al Burlingame,
Michael Waterfield,
Paul Workman
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ABSTRACT: The promising antitumor activity of 17-allylamino-17-demethoxygeldanamycin (17AAG) results from inhibition of the molecular chaperone heat shock protein 90 (HSP90) and subsequent degradation of multiple oncogenic client proteins. Gene expression microarray and proteomic analysis were used to profile molecular changes in the A2780 human ovarian cancer cell line treated with 17AAG. Comparison of results with an inactive analogue and an alternative HSP90 inhibitor radicicol indicated that increased expression of HSP72, HSC70, HSP27, HSP47, and HSP90beta at the mRNA level were on-target effects of 17AAG. HSP27 protein levels were increased in tumor biopsies following treatment of patients with 17AAG. A group of MYC-regulated mRNAs was decreased by 17AAG. Of particular interest and novelty were changes in expression of chromatin-associated proteins. Expression of the heterochromatin protein 1 was increased, and expression of the histone acetyltransferase 1 and the histone arginine methyltransferase PRMT5 was decreased by 17AAG. PRMT5 was shown to be a novel HSP90-binding partner and potential client protein. Cellular protein acetylation was reduced by 17AAG, which was shown to have an antagonistic interaction on cell proliferation with the histone deacetylase inhibitor trichostatin A. This mRNA and protein expression analysis has provided new insights into the complex molecular pharmacology of 17AAG and suggested new genes and proteins that may be involved in response to the drug or be potential biomarkers of drug action.
Cancer Research 05/2007; 67(7):3239-53. · 7.86 Impact Factor
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ABSTRACT: The molecular chaperone heat shock protein 90 (HSP90) has emerged as an exciting molecular target for cancer therapy. It operates as part of a multichaperone complex and is essential for the conformation, stability, and function of several key oncogenic client proteins such as mutant p53, ERBB2, B-RAF, C-RAF, and CDK4. The HSP90-based chaperone machine is driven by the hydrolysis of ATP and ADP/ATP nucleotide exchange. Many of the inhibitors of HSP90 interrupt the intrinsic ATPase activity, causing degradation of the client proteins via the ubiquitin-proteasome pathway. The first-in-class HSP90 inhibitor in clinical trials is the geldanamycin analog, 17-allylamino, 17-demethoxygeldanamycin (17-AAG). The results that have emerged from these trials have been encouraging, with stable disease observed in two melanoma patients. Pharmacodynamic endpoints, such as induction of HSP70 and downregulation of C-RAF and CDK4 in peripheral blood mononuclear cells and tumor biopsies from treated patients, provided evidence of HSP90 inhibition at well-tolerated doses. The toxicity of 17-AAG has been mild. Several preclinical studies have shown that 17-AAG may enhance the efficacy of a variety of chemotherapeutic agents. Phase II clinical trials in various cancers have been initiated as well as Phase I trials of combined therapy with 17-AAG. However, there are several limitations with 17-AAG such as solubility, stability, and hepatotoxicity. Thus, it is not surprising that new HSP90 agents are under development against this novel target for cancer therapy and several show promise.
Advances in Cancer Research 02/2006; 95:323-48. · 4.46 Impact Factor
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ABSTRACT: High-throughput screening of chemical libraries and the subsequent rapid progress of hit compounds through an iterative developmental test cascade are essential parts of modern molecular mechanism-based drug discovery. These processes depend on the use of efficient assay technologies and equipment. Enzyme-linked immunosorbent assays have historically been carried out in 96-well microtitre plates. Improvements in reagents and assay technologies mean that solid-phase immunoassays can be adapted for higher throughput to play an important role in modern drug discovery. The molecular chaperone heat-shock protein (Hsp) 90 is an important anticancer drug target because it maintains the conformation, stability, and function of many important oncogenic client proteins, including those involved with signal transduction, cell proliferation, survival, differentiation, motility angiogenesis, and metastasis. Using the standard inhibitors of the adenosine triphosphatase (ATPase) activity of Hsp90, geldanamycin (GA) and 17-allylamino-17- demethoxygeldanamycin (17AAG), novel solid-phase immunoassays have been validated using a time-resolved fluorescence (TRF) end point. Their utility for confirming the mechanism of action of Hsp90 inhibition in secondary cell-based assays has been shown and applied to the novel Hsp90 inhibitor CCT018159. Adaptation of these assays for later studies using human tumour xenografts and samples obtained from a Phase 1 trial of 17AAG is also described. Finally, comparison is made between the use and applicability of this type of immunoassay and other techniques such as western blotting, immunohistochemistry, and flow cytometry analysis.
Assay and Drug Development Technologies 07/2005; 3(3):273-85. · 1.73 Impact Factor
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Lisa Wright,
Xavier Barril,
Brian Dymock,
Louisa Sheridan,
Allan Surgenor,
Mandy Beswick,
Martin Drysdale,
Adam Collier,
Andy Massey,
Nick Davies,
Alex Fink,
Christophe Fromont,
Wynne Aherne,
Kathy Boxall, Swee Sharp,
Paul Workman,
Roderick E Hubbard
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ABSTRACT: Inhibition of the ATPase activity of the chaperone protein HSP90 is a potential strategy for treatment of cancers. We have determined structures of the HSP90alpha N-terminal domain complexed with the purine-based inhibitor, PU3, and analogs with enhanced potency both in enzyme and cell-based assays. The compounds induce upregulation of HSP70 and downregulation of the known HSP90 client proteins Raf-1, CDK4, and ErbB2, confirming that the molecules inhibit cell growth by a mechanism dependent on HSP90 inhibition. We have also determined the first structure of the N-terminal domain of HSP90beta, complexed with PU3. The structures allow a detailed rationale to be developed for the observed affinity of the PU3 class of compounds for HSP90 and also provide a structural framework for design of compounds with improved binding affinity and drug-like properties.
Chemistry & Biology 07/2004; 11(6):775-85. · 5.83 Impact Factor
