Dataset Information

Targeting Hsp27/eIF4E interaction with phenazine compound: a promising alternative for castration-resistant prostate cancer treatment.

ABSTRACT: The actual strategy to improve current therapies in advanced prostate cancer involves targeting genes activated by androgen withdrawal, either to delay or prevent the emergence of the castration-refractory phenotype. However, these genes are often implicated in several physiological processes, and long-term inhibition of survival proteins might be accompanied with cytotoxic effects. To avoid this problem, an alternative therapeutic strategy relies on the identification and use of compounds that disrupt specific protein-protein interactions involved in androgen withdrawal. Specifically, the interaction of the chaperone protein Hsp27 with the initiation factor eIF4E leads to the protection of protein synthesis initiation process and enhances cell survival during cell stress induced by castration or chemotherapy. Thus, in this work we aimed at i) identifying the interaction site of the Hsp27/eIF4E complex and ii) interfere with the relevant protein/protein association mechanism involved in castration-resistant progression of prostate cancer. By a combination of experimental and modeling techniques, we proved that eIF4E interacts with the C-terminal part of Hsp27, preferentially when Hsp27 is phosphorylated. We also observed that the loss of this interaction increased cell chemo-and hormone-sensitivity. In order to find a potential inhibitor of Hsp27/eIF4E interaction, BRET assays in combination with molecular simulations identified the phenazine derivative 14 as the compound able to efficiently interfere with this protein/protein interaction, thereby inhibiting cell viability and increasing cell death in chemo- and castration-resistant prostate cancer models in vitro and in vivo.

SUBMITTER: Ziouziou H

PROVIDER: S-EPMC5652782 | biostudies-literature | 2017 Sep

REPOSITORIES: biostudies-literature

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Targeting Hsp27/eIF4E interaction with phenazine compound: a promising alternative for castration-resistant prostate cancer treatment.

Ziouziou Hajer H Andrieu Claudia C Laurini Erik E Karaki Sara S Fermeglia Maurizio M Oueslati Ridha R Taieb David D Camplo Michel M Siri Olivier O Pricl Sabrina S Katsogiannou Maria M Rocchi Palma P

Oncotarget 20170824 44

The actual strategy to improve current therapies in advanced prostate cancer involves targeting genes activated by androgen withdrawal, either to delay or prevent the emergence of the castration-refractory phenotype. However, these genes are often implicated in several physiological processes, and long-term inhibition of survival proteins might be accompanied with cytotoxic effects. To avoid this problem, an alternative therapeutic strategy relies on the identification and use of compounds that ...[more]

PMID: 29100389

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Project description:Recurrent, metastatic prostate cancer continues to be a leading cause of cancer-death in men. The androgen receptor (AR) is a modular, ligand-inducible transcription factor that regulates the expression of genes that can drive the progression of this disease, and as a consequence, this receptor is a key therapeutic target for controlling prostate cancer. The current drugs designed to directly inhibit the AR are called anti-androgens, and all act by competing with androgens for binding to the androgen/ligand binding site. Unfortunately, with the inevitable progression of the cancer to castration resistance, many of these drugs become ineffective. However, there are numerous other regulatory sites on this protein that have not been exploited therapeutically. The regulation of AR activity involves a cascade of complex interactions with numerous chaperones, co-factors and co-regulatory proteins, leading ultimately to direct binding of AR dimers to specific DNA androgen response elements within the promoter and enhancers of androgen-regulated genes. As part of the family of nuclear receptors, the AR is organized into modular structural and functional domains with specialized roles in facilitating their inter-molecular interactions. These regions of the AR present attractive, yet largely unexploited, drug target sites for reducing or eliminating androgen signaling in prostate cancers. The design of small molecule inhibitors targeting these specific AR domains is only now being realized and is the culmination of decades of work, including crystallographic and biochemistry approaches to map the shape and accessibility of the AR surfaces and cavities. Here, we review the structure of the AR protein and describe recent advancements in inhibiting its activity with small molecules specifically designed to target areas distinct from the receptor's androgen binding site. It is anticipated that these new classes of anti-AR drugs will provide an additional arsenal to treat castration-resistant prostate cancer.

Project description:Although alternative anti-androgen therapy (switching to secondary anti-androgens) is no longer recommended in the clinical guidelines of prostate cancer in light of the new hormonal and cytotoxic agents available, this therapy has proven beneficial for some patients with castration-resistant prostate cancer (CRPC). The objective of this study was to identify favorable subgroups for alternative anti-androgen therapy among CRPC patients. Eighty-eight consecutive CRPC patients treated with alternative anti-androgen therapy were included in this study. All patients were treated with bicalutamide in the initial maximum androgen blockade (MAB) and switched to flutamide in the subsequent alternative anti-androgen therapy, combined with a luteinizing hormone-releasing hormone analogue. Several clinical and pathological factors for predicting the prostate-specific antigen (PSA) decline and PSA progression-free survival (PSA-PFS) of alternative anti-androgen therapy were investigated. Of all patients, 45 (51.1%) patients showed ?50% PSA decline. The median PSA-PFS was 7.5 months [95% confidence interval (CI), 5.7-10.3]. Notably, 15 (17.0%) patients had a PSA-PFS over 2 years. A multivariate analysis showed that ?3 bone metastatic lesions and a duration <12 months of initial MAB were significant factors shortening the duration of PSA-PFS, with hazard ratios of 2.11 (95% CI, 1.23-3.62; P=0.007) and 2.08 (95% CI, 1.20-3.57; P=0.008), respectively. Patients without any of these factors had a median PSA-PFS of 22.8 months (95% CI, 6.7-48.8). The overall survival in patients with a ?7.5-month PSA-PFS receiving alternative anti-androgen therapy was significantly longer than that of patients with a <7.5-month PSA-PFS (109.1 vs. 40.8 months; P<0.001). In conclusion, a longer duration of initial MAB and the absence of severe bone metastasis may predict a favorable response to alternative anti-androgen therapies in CRPC patients. Alternative anti-androgen therapy may still be beneficial for these patients, but this needs to be investigated further.

Dataset Information

Targeting Hsp27/eIF4E interaction with phenazine compound: a promising alternative for castration-resistant prostate cancer treatment.

Publications

Targeting Hsp27/eIF4E interaction with phenazine compound: a promising alternative for castration-resistant prostate cancer treatment.

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