CRISPR-Mediated Drug-Target Validation Reveals Selective Pharmacological Inhibition of the RNA Helicase, eIF4A

Chu, Jennifer; Galicia-Vázquez, Gabriela; Cencic, Regina; Mills, John R.; Katigbak, Alexandra; Porco, John A.

doi:10.1016/j.celrep.2016.05.005

Cited by 86 publications

(110 citation statements)

References 27 publications

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“…The specificity of Rocaglates for inhibition of eIF4AI was confirmed by genetic complementation and crispr/cas9 gene editing, using an eIF4A mutant with impaired rocaglate binding, while retaining its functionality[84]. Silvestrol, one of the most studied rocaglates, reduces translation initiation, especially of mRNAs with a complex 5′UTR[22], and was originally thought to sequester eIF4A from the eIF4F complex by its increased RNA affinity[23, 83].…”

Section: Targeting Oncogenic Translation With Dead/h Box Rna Helicmentioning

confidence: 99%

Targeting RNA helicases in cancer: The translation trap

Voss

Diest

Raman

2017

Biochimica et Biophysica Acta (BBA) - Reviews on Cancer

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Cancer cells are reliant on the cellular translational machinery for both global elevation of protein synthesis and the translation of specific mRNAs that promote tumor cell survival. Targeting translational control in cancer is therefore increasingly recognized as a promising therapeutic strategy. In this regard, DEAD/H box RNA helicases are a very interesting group of proteins, with several family members regulating mRNA translation in cancer cells. In this review, we delineate the mechanisms by which DEAD/H box proteins modulate oncogenic translation and how inhibition of these RNA helicases can be exploited for anti-cancer therapeutics.

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Section: Targeting Oncogenic Translation With Dead/h Box Rna Helicmentioning

confidence: 99%

Targeting RNA helicases in cancer: The translation trap

Voss

Diest

Raman

2017

Biochimica et Biophysica Acta (BBA) - Reviews on Cancer

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“…It belongs to the flavaglines, which have a cyclopenta [b] benzofuran skeleton in common (Pan et al, 2014). Recently, a CRISPR/ Cas-based genetic proof of silvestrol's target specificity for the DEADbox RNA helicase eIF4A was provided (Chu et al, 2016). This enzyme is required to unwind stable RNA secondary structures in 5′ UTRs of capped mRNAs to create a binding platform for the 43S preinitiation complex which then scans the 5′ UTR for the start codon to initiate protein synthesis (Hinnebusch et al, 2016).…”

Section: Introductionmentioning

confidence: 99%

Broad-spectrum antiviral activity of the eIF4A inhibitor silvestrol against corona- and picornaviruses

et al. 2018

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Coronaviruses (CoV) and picornaviruses are plus-strand RNA viruses that use 5' cap-dependent and cap-independent strategies, respectively, for viral mRNA translation initiation. Here, we analyzed the effects of the plant compound silvestrol, a specific inhibitor of the DEAD-box RNA helicase eIF4A, on viral translation using a dual luciferase assay and virus-infected primary cells. Silvestrol was recently shown to have potent antiviral activity in Ebola virus-infected human macrophages. We found that silvestrol is also a potent inhibitor of cap-dependent viral mRNA translation in CoV-infected human embryonic lung fibroblast (MRC-5) cells. EC values of 1.3 nM and 3 nM silvestrol were determined for MERS-CoV and HCoV-229E, respectively. For the highly pathogenic MERS-CoV, the potent antiviral activities of silvestrol were also confirmed using peripheral blood mononuclear cells (PBMCs) as a second type of human primary cells. Silvestrol strongly inhibits the expression of CoV structural and nonstructural proteins (N, nsp8) and the formation of viral replication/transcription complexes. Furthermore, potential antiviral effects against human rhinovirus (HRV) A1 and poliovirus type 1 (PV), representing different species in the genus Enterovirus (family Picornaviridae), were investigated. The two viruses employ an internal ribosomal entry site (IRES)-mediated translation initiation mechanism. For PV, which is known to require the activity of eIF4A, an EC value of 20 nM silvestrol was determined in MRC-5 cells. The higher EC value of 100 nM measured for HRV A1 indicates a less critical role of eIF4A activity in HRV A1 IRES-mediated translation initiation. Taken together, the data reveal a broad-spectrum antiviral activity of silvestrol in infected primary cells by inhibiting eIF4A-dependent viral mRNA translation.

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“…In this study, we screened a diversity-oriented synthetic library, including a subset of natural-product-inspired compounds, to identify novel probes with antifungal activity against C. auris. Among 2,454 compounds screened, the majority of bioactive hits were natural and synthetic variants of the natural-product chemotypes known as rocaglates, which are well-described inhibitors of translation initiation in mammalian cells and Saccharomyces cerevisiae (25). We established that the rocaglates inhibit translation initiation in C. auris, leading to activation of a cell death program with phenotypic characteristics shared with apoptosis in metazoans.…”

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confidence: 99%

Translation Inhibition by Rocaglates Activates a Species-Specific Cell Death Program in the Emerging Fungal Pathogen Candida auris

Iyer

Whitesell

Porco

et al. 2020

mBio

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Fungal infections are a major contributor to infectious disease-related deaths worldwide. Recently, global emergence of the fungal pathogen Candida auris has caused considerable concern because most C. auris isolates are resistant to fluconazole, the most commonly administered antifungal, and some isolates are resistant to drugs from all three major antifungal classes. To identify novel agents with bioactivity against C. auris, we screened 2,454 compounds from a diversity-oriented synthesis collection. Of the five hits identified, most shared a common rocaglate core structure and displayed fungicidal activity against C. auris. These rocaglate hits inhibited translation in C. auris but not in its pathogenic relative Candida albicans. Species specificity was contingent on variation at a single amino acid residue in Tif1, a fungal member of the eukaryotic initiation factor 4A (eIF4A) family of translation initiation factors known to be targeted by rocaglates. Rocaglate-mediated inhibition of translation in C. auris activated a cell death program characterized by loss of mitochondrial membrane potential, increased caspase-like activity, and disrupted vacuolar homeostasis. In a rocaglate-sensitized C. albicans mutant engineered to express translation initiation factor 1 (Tif1) with the variant amino acid that we had identified in C. auris, translation was inhibited but no programmed cell death phenotypes were observed. This surprising finding suggests divergence between these related fungal pathogens in their pathways of cellular responses to translation inhibition. From a therapeutic perspective, the chemical biology that we have uncovered reveals species-specific vulnerability in C. auris and identifies a promising target for development of new, mechanistically distinct antifungals in the battle against this emerging pathogen. IMPORTANCE Emergence of the fungal pathogen Candida auris has ignited intrigue and alarm within the medical community and the public at large. This pathogen is unusually resistant to antifungals, threatening to overwhelm current management options. By screening a library of structurally diverse molecules, we found that C. auris is surprisingly sensitive to translation inhibition by a class of compounds known as rocaglates (also known as flavaglines). Despite the high level of conservation across fungi in their protein synthesis machinery, these compounds inhibited translation initiation and activated a cell death program in C. auris but not in its relative Candida albicans. Our findings highlight a surprising divergence across the cell death programs operating in Candida species and underscore the need to understand the specific biology of a pathogen in attempting to develop more-effective treatments against it.

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CRISPR-Mediated Drug-Target Validation Reveals Selective Pharmacological Inhibition of the RNA Helicase, eIF4A

Cited by 86 publications

References 27 publications

Targeting RNA helicases in cancer: The translation trap

Targeting RNA helicases in cancer: The translation trap

Broad-spectrum antiviral activity of the eIF4A inhibitor silvestrol against corona- and picornaviruses

Translation Inhibition by Rocaglates Activates a Species-Specific Cell Death Program in the Emerging Fungal Pathogen Candida auris

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