Integrating fragment-based screening with targeted protein degradation and genetic rescue to explore eIF4E function.

Eukaryotic initiation factor 4E (eIF4E) serves as a regulatory hub for oncogene-driven protein synthesis and is considered a promising anticancer target. Here we screen a fragment library against eIF4E and identify a ligand-binding site with previously unknown function. Follow-up structure-based design yields a low nM tool compound (4, K = 0.

HSF1 Pathway Inhibitor Clinical Candidate (CCT361814/NXP800) Developed from a Phenotypic Screen as a Potential Treatment for Refractory Ovarian Cancer and Other Malignancies.

CCT251236 , a potent chemical probe, was previously developed from a cell-based phenotypic high-throughput screen (HTS) to discover inhibitors of transcription mediated by HSF1, a transcription factor that supports malignancy. Owing to its activity against models of refractory human ovarian cancer, was progressed into lead optimization. The reduction of P-glycoprotein efflux became a focus of early compound optimization; central ring halogen substitution was demonstrated by matched molecular pair analysis to be an effective strategy to mitigate this liability.

Solution structure of the Hop TPR2A domain and investigation of target druggability by NMR, biochemical and in silico approaches.

Heat shock protein 90 (Hsp90) is a molecular chaperone that plays an important role in tumour biology by promoting the stabilisation and activity of oncogenic 'client' proteins. Inhibition of Hsp90 by small-molecule drugs, acting via its ATP hydrolysis site, has shown promise as a molecularly targeted cancer therapy. Owing to the importance of Hop and other tetratricopeptide repeat (TPR)-containing cochaperones in regulating Hsp90 activity, the Hsp90-TPR domain interface is an alternative site for inhibitors, which could result in effects distinct from ATP site binders.

Correction to: An in vitro and in vivo study of the combination of the heat shock protein inhibitor 17-allylamino-17-demethoxygeldanamycin and carboplatin in human ovarian cancer models.

The corresponding author of this article has informed us of concerns about the immunoblots in Fig. 2 which were carried out in the collaborating laboratory of Professor Ann Jackman.

Demonstrating In-Cell Target Engagement Using a Pirin Protein Degradation Probe (CCT367766).

Demonstrating intracellular protein target engagement is an essential step in the development and progression of new chemical probes and potential small molecule therapeutics. However, this can be particularly challenging for poorly studied and noncatalytic proteins, as robust proximal biomarkers are rarely known. To confirm that our recently discovered chemical probe 1 (CCT251236) binds the putative transcription factor regulator pirin in living cells, we developed a heterobifunctional protein degradation probe.

Discovery of 4,6-disubstituted pyrimidines as potent inhibitors of the heat shock factor 1 (HSF1) stress pathway and CDK9.

Heat shock factor 1 (HSF1) is a transcription factor that plays key roles in cancer, including providing a mechanism for cell survival under proteotoxic stress. Therefore, inhibition of the HSF1-stress pathway represents an exciting new opportunity in cancer treatment. We employed an unbiased phenotypic screen to discover inhibitors of the HSF1-stress pathway.

Fused imidazoles as potential chemical scaffolds for inhibition of heat shock protein 70 and induction of apoptosis. Synthesis and biological evaluation of phenanthro[9,10-d]imidazoles and imidazo[4,5-f][1,10]phenanthrolines.

The imidazole ring is widespread in biologically active compounds, and hence imidazole-containing scaffolds are useful starting points for drug discovery programmes. We report the synthesis of a series of novel imidazole-containing compounds fused with either phenanthrene or phenanthroline, which show enhanced growth inhibitory potency against human colon, breast and melanoma cancer cell lines, as well as evidence of inhibition of the molecular chaperone heat shock protein 70 (Hsp70) pathway in cells, as shown by depletion of downstream oncogenic client proteins of the Hsp90 chaperone pathway, and induction of apoptosis.

Co-crystalization and in vitro biological characterization of 5-aryl-4-(5-substituted-2-4-dihydroxyphenyl)-1,2,3-thiadiazole Hsp90 inhibitors.

A potential therapeutic strategy for targeting cancer that has gained much interest is the inhibition of the ATP binding and ATPase activity of the molecular chaperone Hsp90. We have determined the structure of the human Hsp90α N-terminal domain in complex with a series of 5-aryl-4-(5-substituted-2-4-dihydroxyphenyl)-1,2,3-thiadiazoles. The structures provide the molecular details for the activity of these inhibitors.

Effects of HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) on NEU/HER2 overexpressing mammary tumours in MMTV-NEU-NT mice monitored by Magnetic Resonance Spectroscopy.

Background: The importance of ERBB2/NEU/HER2 in the response of breast tumours to the heat shock protein 90 (HSP90) inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG; tanespimycin) has been demonstrated in the clinic. ERBB2 is an oncoprotein client that is highly dependent on HSP90. This and other oncogenic client proteins (e.

Targeting the Hsp90 molecular chaperone with novel macrolactams. Synthesis, structural, binding, and cellular studies.

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.

Modulation of melanoma cell phospholipid metabolism in response to heat shock protein 90 inhibition.

Molecular chaperone heat shock protein 90 (Hsp90) inhibitors are promising targeted cancer therapeutic drugs, with the advantage that they deplete multiple oncogenic client proteins and modulate all the classical hallmarks of cancer. They are now in clinical trial and show potential for activity in melanoma and other malignancies. Here we explore the metabolic response to Hsp90 inhibition in human melanoma cells using magnetic resonance spectroscopy.

MGMT-independent temozolomide resistance in pediatric glioblastoma cells associated with a PI3-kinase-mediated HOX/stem cell gene signature.

Sensitivity to temozolomide is restricted to a subset of glioblastoma patients, with the major determinant of resistance being a lack of promoter methylation of the gene encoding the repair protein DNA methyltransferase MGMT, although other mechanisms are thought to be active. There are, however, limited preclinical data in model systems derived from pediatric glioma patients. We screened a series of cell lines for temozolomide efficacy in vitro, and investigated the differential mechanisms of resistance involved.

Inhibition of Hsp90 with resorcylic acid macrolactones: synthesis and binding studies.

A series of resorcylic acid macrolactones, analogues of the natural product radicicol has 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 acylation of an ortho-toluic acid dianion, esterification, followed by a ring-closing metathesis to form the macrocycle. Subsequent manipulation of the protected hydroxymethyl side chain allows access to a range of new analogues following deprotection of the two phenolic groups.

Mechanistic evaluation of the novel HSP90 inhibitor NVP-AUY922 in adult and pediatric glioblastoma.

The dismal prognosis of glioblastoma (GB) indicates the urgent need for new therapies for these tumors. Heat shock protein 90 (HSP90) inhibitors induce the proteasome-mediated degradation of many oncogenic client proteins involved in all of the hallmark characteristics of cancer. Here, we explored the mechanistic potential of the potent synthetic diarylisoxazole amide resorcinol HSP90 inhibitor, NVP-AUY922, in adult and pediatric GB.

Targeting the Hsp90 chaperone: synthesis of novel resorcylic acid macrolactone inhibitors of Hsp90.

A series of benzo-macrolactones has been prepared by chemical synthesis, and evaluated as inhibitors of heat shock protein 90 (Hsp90), an emerging attractive target for novel cancer therapeutic agents. A new synthesis of these resorcylic acid macrolactone analogues of the natural product radicicol is described in which the key steps are the acylation and ring opening of a homophthalic anhydride to give an isocoumarin, followed by a ring-closing metathesis to form the macrocycle. The methodology has been extended to a novel series of macrolactones incorporating a 1,2,3-triazole ring.

EGFRvIII deletion mutations in pediatric high-grade glioma and response to targeted therapy in pediatric glioma cell lines.

Purpose: The epidermal growth factor receptor (EGFR) is amplified and overexpressed in adult glioblastoma, with response to targeted inhibition dependent on the underlying biology of the disease. EGFR has thus far been considered to play a less important role in pediatric glioma, although extensive data are lacking. We have sought to clarify the role of EGFR in pediatric high-grade glioma (HGG).

Combining hit identification strategies: fragment-based and in silico approaches to orally active 2-aminothieno[2,3-d]pyrimidine inhibitors of the Hsp90 molecular chaperone.

Inhibitors of the Hsp90 molecular chaperone are showing considerable promise as potential molecular therapeutic agents for the treatment of cancer. Here we describe novel 2-aminothieno[2,3-d]pyrimidine ATP competitive Hsp90 inhibitors, which were designed by combining structural elements of distinct low affinity hits generated from fragment-based and in silico screening exercises in concert with structural information from X-ray protein crystallography. Examples from this series have high affinity (IC50 = 50-100 nM) for Hsp90 as measured in a fluorescence polarization (FP) competitive binding assay and are active in human cancer cell lines where they inhibit cell proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72.

Acquired resistance to 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin) in glioblastoma cells.

Heat shock protein 90 (HSP90) inhibitors, such as 17-allylamino-17-demethoxygeldanamycin (17-AAG, tanespimycin), which is currently in phase II/phase III clinical trials, are promising new anticancer agents. Here, we explored acquired resistance to HSP90 inhibitors in glioblastoma (GB), a primary brain tumor with poor prognosis. GB cells were exposed continuously to increased 17-AAG concentrations.

NVP-AUY922: a novel heat shock protein 90 inhibitor active against xenograft tumor growth, angiogenesis, and metastasis.

We describe the biological properties of NVP-AUY922, a novel resorcinylic isoxazole amide heat shock protein 90 (HSP90) inhibitor. NVP-AUY922 potently inhibits HSP90 (K(d) = 1.7 nmol/L) and proliferation of human tumor cells with GI(50) values of approximately 2 to 40 nmol/L, inducing G(1)-G(2) arrest and apoptosis.

Silencing of HSP90 cochaperone AHA1 expression decreases client protein activation and increases cellular sensitivity to the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin.

AHA1 (activator of HSP90 ATPase) is a cochaperone of the ATP-dependent molecular chaperone, HSP90, which is involved in the maturation, stabilization/degradation, and function of oncogenic proteins. HSP90 operates in a multimeric complex driven by the binding and hydrolysis of ATP. Treatment of cells with the HSP90 inhibitor 17-allylamino-17-demethoxygeldanamycin (17-AAG) results in the degradation of client proteins via the ubiquitin-proteasome pathway.

An in vitro and in vivo study of the combination of the heat shock protein inhibitor 17-allylamino-17-demethoxygeldanamycin and carboplatin in human ovarian cancer models.

Purpose: 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.

Experimental Design: 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.

4,5-diarylisoxazole Hsp90 chaperone inhibitors: potential therapeutic agents for the treatment of cancer.

Inhibitors of the Hsp90 molecular chaperone are showing considerable promise as potential chemotherapeutic agents for cancer. Here, we describe the structure-based design, synthesis, structure-activity relationships and pharmacokinetics of potent small-molecule inhibitors of Hsp90 based on the 4,5-diarylisoxazole scaffold. Analogues from this series have high affinity for Hsp90, as measured in a fluorescence polarization (FP) competitive binding assay, and are active in cancer cell lines where they inhibit proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72.