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Thorat SS, Shimpi SP, Sambherao PI, Rama Krishna G, Kontham R. Regioselective Synthesis of Benzannulated [5,6]-Oxaspirolactones via Cu(II)-Catalyzed Cycloisomerization of 2-(5-Hydroxyalkynyl)benzoates. J Org Chem 2023. [PMID: 38010985 DOI: 10.1021/acs.joc.3c01751] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2023]
Abstract
Spiroketals and oxaspirolactones are widely found in biologically active natural products, serving as important structural motifs. In this study, we present a Cu(II)-catalyzed cascade cycloisomerization of 2-(5-hydroxyalkynyl)benzoates, enabling the regioselective synthesis of benzannulated [5,6]-oxaspirolactones containing an isochromen-1-one moiety. This strategy offers a rapid and efficient approach to access a diverse array of benzannulated [5,6]-oxaspirolactones. The methodology presented here showcases a broad substrate scope, delivering good yields and scalability up to gram scale. The structures of the oxaspirolactones were unequivocally confirmed through single-crystal X-ray analysis and by analogy using 1H and 13C{1H} NMR data.
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Affiliation(s)
- Sagar S Thorat
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Sagar P Shimpi
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Pooja I Sambherao
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Gamidi Rama Krishna
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Center for Materials Characterization, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
| | - Ravindar Kontham
- Organic Chemistry Division, CSIR-National Chemical Laboratory, Dr. Homi Bhabha Road, Pune 411008, India
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
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Burgers LD, Fürst R. Natural products as drugs and tools for influencing core processes of eukaryotic mRNA translation. Pharmacol Res 2021; 170:105535. [PMID: 34058326 DOI: 10.1016/j.phrs.2021.105535] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Revised: 03/02/2021] [Accepted: 03/02/2021] [Indexed: 12/19/2022]
Abstract
Eukaryotic protein synthesis is the highly conserved, complex mechanism of translating genetic information into proteins. Although this process is essential for cellular homoeostasis, dysregulations are associated with cellular malfunctions and diseases including cancer and diabetes. In the challenging and ongoing search for adequate treatment possibilities, natural products represent excellent research tools and drug leads for new interactions with the translational machinery and for influencing mRNA translation. In this review, bacterial-, marine- and plant-derived natural compounds that interact with different steps of mRNA translation, comprising ribosomal assembly, translation initiation and elongation, are highlighted. Thereby, the exact binding and interacting partners are unveiled in order to accurately understand the mode of action of each natural product. The pharmacological relevance of these compounds is furthermore assessed by evaluating the observed biological activities in the light of translational inhibition and by enlightening potential obstacles and undesired side-effects, e.g. in clinical trials. As many of the natural products presented here possess the potential to serve as drug leads for synthetic derivatives, structural motifs, which are indispensable for both mode of action and biological activities, are discussed. Evaluating the natural products emphasises the strong diversity of their points of attack. Especially the fact that selected binding partners can be set in direct relation to different diseases emphasises the indispensability of natural products in the field of drug development. Discovery of new, unique and unusual interacting partners again renders them promising tools for future research in the field of eukaryotic mRNA translation.
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Affiliation(s)
- Luisa D Burgers
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany
| | - Robert Fürst
- Institute of Pharmaceutical Biology, Faculty of Biochemistry, Chemistry and Pharmacy, Goethe University, Frankfurt, Germany; LOEWE Center for Translational Biodiversity Genomics (LOEWE-TBG), Frankfurt, Germany
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3
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Abstract
Inhibiting eukaryotic protein translation with small molecules is emerging as a powerful therapeutic strategy. The advantage of targeting cellular translational machinery is that it is required for the highly proliferative state of many neoplastic cells, replication of certain viruses, and ultimately the expression of a wide variety of protein targets. Although, this approach has been exploited to develop clinical agents, such as homoharringtonine (HHT, 1), used to treat chronic myeloid leukemia (CML), inhibiting components of the translational machinery is often associated with cytotoxic phenotypes. However, recent studies have demonstrated that certain small molecules can inhibit the translation of specific subsets of proteins, leading to lower cytotoxicity, and opening-up therapeutic opportunities for translation inhibitors to be deployed in indications beyond oncology and infectious disease. This review summarizes efforts to develop inhibitors of the eukaryotic translational machinery as therapeutic agents and highlights emerging opportunities for translation inhibitors in the future.
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Affiliation(s)
- Angela Fan
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
| | - Phillip P Sharp
- Department of Discovery Chemistry, Merck & Co., Inc., South San Francisco, California 94080, United States
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Borade BR, Dixit R, Kontham R. Total Synthesis of Beshanzuenone D and Its Epimers and Abiespiroside A. Org Lett 2020; 22:8561-8565. [DOI: 10.1021/acs.orglett.0c03157] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Balasaheb R. Borade
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Ruchi Dixit
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
| | - Ravindar Kontham
- Academy of Scientific and Innovative Research (AcSIR), Ghaziabad-201002, India
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Shen L, Pelletier J. Selective targeting of the DEAD-box RNA helicase eukaryotic initiation factor (eIF) 4A by natural products. Nat Prod Rep 2019; 37:609-616. [PMID: 31782447 DOI: 10.1039/c9np00052f] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Covering: up to 2019Pharmacological targeting of eukaryotic mRNA translation initiation is a promising approach for cancer therapy, since several signaling pathways that are commonly deregulated during tumor progression converge on this process. The DEAD-box helicase, eukaryotic initiation factor (eIF) 4A, is essential for translation initiation and facilitates the loading of the 43S pre-initiation complex onto mRNAs. Hippuristanol, rocaglates, and pateamine A are natural products that each target eIF4A by interfering with the helicase's RNA-binding activity in distinct manners. They exert a selective change in gene expression that results in potent anti-tumorigenic activity in pre-clinical studies. This review will provide an update on the molecular mechanisms of action of these natural products.
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Affiliation(s)
- Leo Shen
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.
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Chu J, Pelletier J. Therapeutic Opportunities in Eukaryotic Translation. Cold Spring Harb Perspect Biol 2018; 10:cshperspect.a032995. [PMID: 29440069 DOI: 10.1101/cshperspect.a032995] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ability to block biological processes with selective small molecules provides advantages distinct from most other experimental approaches. These include rapid time to onset, swift reversibility, ability to probe activities in manners that cannot be accessed by genetic means, and the potential to be further developed as therapeutic agents. Small molecule inhibitors can also be used to alter expression and activity without affecting the stoichiometry of interacting partners. These tenets have been especially evident in the field of translation. Small molecule inhibitors were instrumental in enabling investigators to capture short-lived complexes and characterize specific steps of protein synthesis. In addition, several drugs that are the mainstay of modern antimicrobial drug therapy are potent inhibitors of prokaryotic translation. Currently, there is much interest in targeting eukaryotic translation as decades of research have revealed that deregulated protein synthesis in cancer cells represents a targetable vulnerability. In addition to being potential therapeutics, small molecules that manipulate translation have also been shown to influence cognitive processes such as memory. In this review, we focus on small molecule modulators that target the eukaryotic translation initiation apparatus and provide an update on their potential application to the treatment of disease.
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Affiliation(s)
- Jennifer Chu
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Department of Oncology, McGill University, Montreal, Quebec H3G 1Y6, Canada.,Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Quebec H3G 1Y6, Canada
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Ito M, Tanaka T, Cary DR, Iwatani-Yoshihara M, Kamada Y, Kawamoto T, Aparicio S, Nakanishi A, Imaeda Y. Discovery of Novel 1,4-Diacylpiperazines as Selective and Cell-Active eIF4A3 Inhibitors. J Med Chem 2017; 60:3335-3351. [PMID: 28358513 DOI: 10.1021/acs.jmedchem.6b01904] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Eukaryotic initiation factor 4A3 (eIF4A3), a member of the DEAD-box RNA helicase family, is one of the core components of the exon junction complex (EJC). The EJC is known to be involved in a variety of RNA metabolic processes typified by nonsense-mediated RNA decay (NMD). In order to identify molecular probes to investigate the functions and therapeutic relevance of eIF4A3, a search for selective eIF4A3 inhibitors was conducted. Through the chemical optimization of 1,4-diacylpiperazine derivatives identified via high-throughput screening (HTS), we discovered the first reported selective eIF4A3 inhibitor 53a exhibiting cellular NMD inhibitory activity. A surface plasmon resonance (SPR) biosensing assay ascertained the direct binding of 53a and its analog 52a to eIF4A3 and revealed that the binding occurs at a non-ATP binding site. Compounds 52a and 53a represent novel molecular probes for further study of eIF4A3, the EJC, and NMD.
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Affiliation(s)
- Masahiro Ito
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Toshio Tanaka
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Douglas R Cary
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Misa Iwatani-Yoshihara
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yusuke Kamada
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Tomohiro Kawamoto
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Samuel Aparicio
- Department of Molecular Oncology, BC Cancer Agency , 675 W. 10th Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Atsushi Nakanishi
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yasuhiro Imaeda
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited , 26-1, Muraoka-Higashi 2-Chome, Fujisawa, Kanagawa 251-8555, Japan
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Ito M, Iwatani M, Kamada Y, Sogabe S, Nakao S, Tanaka T, Kawamoto T, Aparicio S, Nakanishi A, Imaeda Y. Discovery of selective ATP-competitive eIF4A3 inhibitors. Bioorg Med Chem 2017; 25:2200-2209. [PMID: 28283335 DOI: 10.1016/j.bmc.2017.02.035] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 02/15/2017] [Accepted: 02/16/2017] [Indexed: 12/24/2022]
Abstract
Eukaryotic initiation factor 4A3 (eIF4A3), an ATP-dependent RNA helicase, is a core component of exon junction complex (EJC). EJC has a variety of roles in RNA metabolism such as translation, surveillance, and localization of spliced RNA. It is worthwhile to identify selective eIF4A3 inhibitors with a view to investigating the functions of eIF4A3 and EJC further to clarify the roles of the ATPase and helicase activities in cells. Our chemical optimization of hit compound 2 culminated in the discovery of ATP-competitive eIF4A3 inhibitor 18 with submicromolar ATPase inhibitory activity and excellent selectivity over other helicases. Hence, compound 18 could be a valuable chemical probe to elucidate the detailed functions of eIF4A3 and EJC.
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Affiliation(s)
- Masahiro Ito
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan.
| | - Misa Iwatani
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yusuke Kamada
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Satoshi Sogabe
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Shoichi Nakao
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Toshio Tanaka
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Tomohiro Kawamoto
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Samuel Aparicio
- Department of Molecular Oncology, BC Cancer Agency, 675 W10th Avenue, Vancouver, BC V5Z 1L3, Canada
| | - Atsushi Nakanishi
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan
| | - Yasuhiro Imaeda
- Pharmaceutical Research Division, Takeda Pharmaceutical Company Limited, 26-1, Muraoka-Higashi 2-chome, Fujisawa, Kanagawa 251-8555, Japan.
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9
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Cencic R, Pelletier J. Hippuristanol - A potent steroid inhibitor of eukaryotic initiation factor 4A. ACTA ACUST UNITED AC 2016; 4:e1137381. [PMID: 27335721 DOI: 10.1080/21690731.2015.1137381] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2015] [Revised: 12/08/2015] [Accepted: 12/24/2015] [Indexed: 01/02/2023]
Abstract
Protein synthesis and its regulatory signaling pathways play essential roles in the initiation and maintenance of the cancer phenotype. Insight obtained over the last 3 decades on the mechanisms regulating translation in normal and transformed cells have revealed that perturbed control in cancer cells may offer an Achilles' heel for the development of novel anti-neoplastic agents. Several small molecule inhibitors have been identified and characterized that target translation initiation - more specifically, the rate-limiting step where ribosomes are recruited to mRNA templates. Among these, hippuristanol, a polyhydroxysteroid from the gorgonian Isis hippuris has been found to inhibit translation initiation by blocking the activity of eukaryotic initiation factor (eIF) 4A, an essential RNA helicase involved in this process. Herein, we highlight the biological properties of this compound, its potential development as an anti-cancer agent, and its use to validate eIF4A as an anti-neoplastic target.
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Affiliation(s)
- Regina Cencic
- Department of Biochemistry, McGill University , Montreal, Québec, Canada
| | - Jerry Pelletier
- Department of Biochemistry, McGill University, Montreal, Québec, Canada; The Rosalind and Morris Goodman Cancer Research Center, McGill University, Montreal, Québec, Canada; Department of Oncology, McGill University, Montreal, Québec, Canada
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Synthesis of the antiproliferative agent hippuristanol and its analogues from hydrocortisone via Hg(II)-catalyzed spiroketalization: structure-activity relationship. J Med Chem 2014; 57:2511-23. [PMID: 24588834 DOI: 10.1021/jm401799j] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
An efficient synthesis of hippuristanol (1), a marine-derived highly potent antiproliferative steroidal natural product, and nine closely related analogues has been accomplished from the commercially available hydrocortisone utilizing Hg(II)-catalyzed spiroketalization of 3-alkyne-1,7-diol motif as a key strategy. This practical synthetic sequence furnished 1 in 11% overall yield from hydrocortisone in 15 linear steps. Modifications to the parent molecule 1 encompassed changing the functional groups on rings A and E. Each analogue was screened for their effects on inhibition of cap-dependent translation, and the assay results were used to establish structure-activity relationships. These results suggest that the stereochemistry and all substituents of spiroketal portion (rings E and F) and C3-α and C11-β hydroxyl functional groups on rings A and C, respectively, are critical for the inhibitory activity of natural product 1.
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Cencic R, Robert F, Galicia-Vázquez G, Malina A, Ravindar K, Somaiah R, Pierre P, Tanaka J, Deslongchamps P, Pelletier J. Modifying chemotherapy response by targeted inhibition of eukaryotic initiation factor 4A. Blood Cancer J 2013; 3:e128. [PMID: 23872707 PMCID: PMC3730203 DOI: 10.1038/bcj.2013.25] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2013] [Revised: 06/13/2013] [Accepted: 06/18/2013] [Indexed: 12/21/2022] Open
Abstract
Translation is regulated predominantly at the initiation phase by several signal transduction pathways that are often usurped in human cancers, including the PI3K/Akt/mTOR axis. mTOR exerts unique administration over translation by regulating assembly of eukaryotic initiation factor (eIF) 4F, a heterotrimeric complex responsible for recruiting 40S ribosomes (and associated factors) to mRNA 5′ cap structures. Hence, there is much interest in targeted therapies that block eIF4F activity to assess the consequences on tumor cell growth and chemotherapy response. We report here that hippuristanol (Hipp), a translation initiation inhibitor that selectively inhibits the eIF4F RNA helicase subunit, eIF4A, resensitizes Eμ-Myc lymphomas to DNA damaging agents, including those that overexpress eIF4E—a modifier of rapamycin responsiveness. As Mcl-1 levels are significantly affected by Hipp, combining its use with the Bcl-2 family inhibitor, ABT-737, leads to a potent synergistic response in triggering cell death in mouse and human lymphoma and leukemia cells. Suppression of eIF4AI using RNA interference also synergized with ABT-737 in murine lymphomas, highlighting eIF4AI as a therapeutic target for modulating tumor cell response to chemotherapy.
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Affiliation(s)
- R Cencic
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada
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Cencic R, Pelletier J. Throwing a monkey wrench in the motor: targeting DExH/D box proteins with small molecule inhibitors. BIOCHIMICA ET BIOPHYSICA ACTA-GENE REGULATORY MECHANISMS 2013; 1829:894-903. [PMID: 23385390 DOI: 10.1016/j.bbagrm.2013.01.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2012] [Revised: 01/21/2013] [Accepted: 01/24/2013] [Indexed: 01/04/2023]
Abstract
DExH/D box proteins are molecular motors that utilize the energy derived from NTP hydrolysis to perform work - from helicases that remodel RNA to RNPases that alter RNA-protein complexes. Members of this class of proteins are uniquely placed along the RNA information highway to regulate the flow of genetic information. They have been implicated in a number of nodal points encompassing nuclear, cytoplasmic, and organellar RNA-based processes. The identification and characterization of three unique natural products that selectively inhibit the activity of eukaryotic initiation factor (eIF)4A (DDX2) has provided proof-of-principle that the activity of DExH/D box family members can be selectively targeted. Extending these achievements to other DExH/D box proteins is an important future challenge for drugging this family of proteins. This article is part of a Special Issue entitled: The Biology of RNA helicases - Modulation for life.
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Affiliation(s)
- Regina Cencic
- Department of Biochemistry, McGill University, Montreal, Quebec, Canada.
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Abstract
RNA helicases unwind their RNA substrates in an ATP-dependent reaction, and are central to all cellular processes involving RNA. They have important roles in viral life cycles, where RNA helicases are either virus-encoded or recruited from the host. Vertebrate RNA helicases sense viral infections, and trigger the innate antiviral immune response. RNA helicases have been implicated in protozoic, bacterial and fungal infections. They are also linked to neurological disorders, cancer, and aging processes. Genome-wide studies continue to identify helicase genes that change their expression patterns after infection or disease outbreak, but the mechanism of RNA helicase action has been defined for only a few diseases. RNA helicases are prognostic and diagnostic markers and suitable drug targets, predominantly for antiviral and anti-cancer therapies. This review summarizes the current knowledge on RNA helicases in infection and disease, and their growing potential as drug targets.
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Affiliation(s)
- Lenz Steimer
- University of Muenster, Institute for Physical Chemistry, Muenster, Germany
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Abstract
Protein synthesis is a complex, tightly regulated process in eukaryotic cells and its deregulation is a hallmark of many cancers. Translational control occurs primarily at the rate-limiting initiation step, where ribosomal subunits are recruited to template mRNAs through the concerted action of several eukaryotic initiation factors (eIFs). One factor that interacts with both the mRNA and ribosomes, and appears limiting for translation is eIF4F, a complex composed of the cap-binding protein, eIF4E; the scaffold protein, eIF4G; and the ATP-dependent DEAD-box helicase, eIF4A. eIF4E appears to play an important role in tumor initiation and progression since its overexpression can cooperate with oncogenes to accelerate transformation in cell lines and animal models, and its levels are elevated in many human cancers. This, therefore, represents a vulnerability for transformed cells, and presents an opportunity for therapeutic intervention. In this review, we discuss approaches for targeting eIF4F activity.
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Abstract
A defining feature of many cancers is deregulated translational control. Typically, this occurs at the level of recruitment of the 40S ribosomes to the 5'-cap of cellular messenger RNAs (mRNAs), the rate-limiting step of protein synthesis, which is controlled by the heterotrimeric eukaryotic initiation complex eIF4F. Thus, eIF4F in particular, and translation initiation in general, represent an exploitable vulnerability and unique opportunity for therapeutic intervention in many transformed cells. In this article, we discuss the development, mode of action and biological activity of a number of small-molecule inhibitors that interrupt PI3K/mTOR signaling control of eIF4F assembly, as well as compounds that more directly block eIF4F activity.
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Affiliation(s)
- Abba Malina
- Department of Biochemistry and McGill University, Montréal, Québec H3G 1Y6, Canada
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Heasley B. Chemical synthesis of the cardiotonic steroid glycosides and related natural products. Chemistry 2012; 18:3092-120. [PMID: 22354477 DOI: 10.1002/chem.201103733] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The active components from the extracts of Digitalis, cardiotonic steroid glycosides, have been ingested by humans for more than 200 years as a medicinal therapy for heart failure and abnormal heart rhythms. The positive inotropic activity of the cardiotonic steroids that mediates clinically useful physiological effects in patients has been attributed largely to a high affinity inhibitory interaction with the extracellular surface of the membrane-bound sodium pump (Na(+)/K(+)-ATPase). However, previously unrecognized intracellular signaling pathways continue to be uncovered. This Review examines both partial and de novo synthetic approaches to the medicinally important and structurally captivating cardenolide and bufadienolide steroid families, with an emphasis on the stereocontrolled construction of the pharmacophoric aglycone (genin) framework.
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Affiliation(s)
- Brian Heasley
- Scynexis, Inc. P. O. Box 12878, Research Triangle Park, NC 27709-2878, USA.
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Dang Y, Schneider-Poetsch T, Eyler DE, Jewett JC, Bhat S, Rawal VH, Green R, Liu JO. Inhibition of eukaryotic translation elongation by the antitumor natural product Mycalamide B. RNA (NEW YORK, N.Y.) 2011; 17:1578-88. [PMID: 21693620 PMCID: PMC3153980 DOI: 10.1261/rna.2624511] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2011] [Accepted: 05/19/2011] [Indexed: 05/24/2023]
Abstract
Mycalamide B (MycB) is a marine sponge-derived natural product with potent antitumor activity. Although it has been shown to inhibit protein synthesis, the molecular mechanism of action by MycB remains incompletely understood. We verified the inhibition of translation elongation by in vitro HCV IRES dual luciferase assays, ribosome assembly, and in vivo [(35)S]methinione labeling experiments. Similar to cycloheximide (CHX), MycB inhibits translation elongation through blockade of eEF2-mediated translocation without affecting the eEF1A-mediated loading of tRNA onto the ribosome, AUG recognition, or dipeptide synthesis. Using chemical footprinting, we identified the MycB binding site proximal to the C3993 28S rRNA residue on the large ribosomal subunit. However, there are also subtle, but significant differences in the detailed mechanisms of action of MycB and CHX. First, MycB arrests the ribosome on the mRNA one codon ahead of CHX. Second, MycB specifically blocked tRNA binding to the E-site of the large ribosomal subunit. Moreover, they display different polysome profiles in vivo. Together, these observations shed new light on the mechanism of inhibition of translation elongation by MycB.
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Affiliation(s)
- Yongjun Dang
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Tilman Schneider-Poetsch
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Daniel E. Eyler
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - John C. Jewett
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
| | - Shridhar Bhat
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Viresh H. Rawal
- Department of Chemistry, The University of Chicago, Chicago, Illinois 60637, USA
| | - Rachel Green
- Department of Molecular Biology and Genetics, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
| | - Jun O. Liu
- Department of Pharmacology and Molecular Sciences, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
- Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland 21205, USA
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Ravindar K, Reddy MS, Lindqvist L, Pelletier J, Deslongchamps P. Synthesis of the antiproliferative agent hippuristanol and its analogues via Suárez cyclizations and Hg(II)-catalyzed spiroketalizations. J Org Chem 2011; 76:1269-84. [PMID: 21268618 DOI: 10.1021/jo102054r] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A full account of the synthesis of hippuristanol and its analogues is described. Hecogenin acetate was identified as a suitable and economical starting material for this work, and substrate-controlled stereoselection was obtained throughout the construction of the key spiroketal unit. Suárez cyclization was first used, but Hg(II)-catalyzed spiroketalization of the 3-alkyne-1,7-diol motif was finally identified as the most convenient strategy.
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Affiliation(s)
- Kontham Ravindar
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, Canada, J1K 2R1
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Blunt JW, Copp BR, Munro MHG, Northcote PT, Prinsep MR. Marine natural products. Nat Prod Rep 2010; 28:196-268. [PMID: 21152619 DOI: 10.1039/c005001f] [Citation(s) in RCA: 343] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- John W Blunt
- Department of Chemistry, University of Canterbury, Christchurch, New Zealand.
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Ravindar K, Reddy MS, Lindqvist L, Pelletier J, Deslongchamps P. Efficient Synthetic Approach to Potent Antiproliferative Agent Hippuristanol via Hg(II)-Catalyzed Spiroketalization. Org Lett 2010; 12:4420-3. [DOI: 10.1021/ol1019663] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Kontham Ravindar
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada, and Department of Biochemistry and Oncology, McIntyre Medical Sciences Building, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Maddi Sridhar Reddy
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada, and Department of Biochemistry and Oncology, McIntyre Medical Sciences Building, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Lisa Lindqvist
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada, and Department of Biochemistry and Oncology, McIntyre Medical Sciences Building, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Jerry Pelletier
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada, and Department of Biochemistry and Oncology, McIntyre Medical Sciences Building, McGill University, Montreal, QC H3G 1Y6, Canada
| | - Pierre Deslongchamps
- Département de Chimie, Université de Sherbrooke, Sherbrooke, QC, J1K 2R1, Canada, and Department of Biochemistry and Oncology, McIntyre Medical Sciences Building, McGill University, Montreal, QC H3G 1Y6, Canada
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Li W, Dang Y, Liu JO, Yu B. Structural and stereochemical requirements of the spiroketal group of hippuristanol for antiproliferative activity. Bioorg Med Chem Lett 2010; 20:3112-5. [PMID: 20409710 DOI: 10.1016/j.bmcl.2010.03.093] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 03/17/2010] [Accepted: 03/26/2010] [Indexed: 11/28/2022]
Abstract
Hippuristanol is a natural product that has recently been shown to inhibit eukaryotic translation initiation and tumor cell proliferation. To investigate the structure and activity relationship of hippuristanol, we synthesized a series of analogs by expanding the size of its F ring and determined their effects on the proliferation of cancer cell lines. All changes to the F-ring of hippuristanol resulted in 3-fold to >100-fold decrease in activity.
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Affiliation(s)
- Wei Li
- State Key Laboratory of Bio-organic and Natural Products Chemistry, Shanghai Institute of Organic Chemistry, Chinese Academy of Sciences, 200032 Shanghai, China
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