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α-Amino bisphosphonate triazoles serve as GGDPS inhibitors. Bioorg Med Chem Lett 2024; 102:129659. [PMID: 38373465 PMCID: PMC10981527 DOI: 10.1016/j.bmcl.2024.129659] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2023] [Revised: 01/31/2024] [Accepted: 02/14/2024] [Indexed: 02/21/2024]
Abstract
Depletion of cellular levels of geranylgeranyl diphosphate by inhibition of the enzyme geranylgeranyl diphosphate synthase (GGDPS) is a potential strategy for disruption of protein transport by limiting the geranylgeranylation of the Rab proteins that regulate intracellular trafficking. As such, there is interest in the development of GGDPS inhibitors for the treatment of malignancies characterized by abnormal protein production, including multiple myeloma. Our previous work has explored the structure-function relationship of a series of isoprenoid triazole bisphosphonate-based GGDPS inhibitors, with modifications having impact on enzymatic, cellular and in vivo activities. We have synthesized a new series of α-amino bisphosphonates to understand the impact of modifying the alpha position with a moiety that is potentially linkable to other agents. Bioassays evaluating the enzymatic and cellular activities of these compounds demonstrate that incorporation of the α-amino group affords compounds with GGDPS inhibitory activity which is modulated by isoprenoid tail chain length and olefin stereochemistry. These studies provide further insight into the complexity of the structure-function relationship and will enable future efforts focused on tumor-specific drug delivery.
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2
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Diester Prodrugs of a Phosphonate Butyrophilin Ligand Display Improved Cell Potency, Plasma Stability, and Payload Internalization. J Med Chem 2023; 66:15309-15325. [PMID: 37934915 PMCID: PMC10683022 DOI: 10.1021/acs.jmedchem.3c01358] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Revised: 10/16/2023] [Accepted: 10/19/2023] [Indexed: 11/09/2023]
Abstract
Activation of Vγ9Vδ2 T cells with butyrophilin 3A1 (BTN3A1) agonists such as (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) has the potential to boost the immune response. Because HMBPP is highly charged and metabolically unstable, prodrugs may be needed to overcome these liabilities, but the prodrugs themselves may be limited by slow payload release or low plasma stability. To identify effective prodrug forms of a phosphonate agonist of BTN3A1, we have prepared a set of diesters bearing one aryl and one acyloxymethyl group. The compounds were evaluated for their ability to stimulate Vγ9Vδ2 T cell proliferation, increase production of interferon γ, resist plasma metabolism, and internalize into leukemia cells. These bioassays have revealed that varied aryl and acyloxymethyl groups can decouple plasma and cellular metabolism and have a significant impact on bioactivity (>200-fold range) and stability (>10 fold range), including some with subnanomolar potency. Our findings increase the understanding of the structure-activity relationships of mixed aryl/acyloxymethyl phosphonate prodrugs.
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3
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Cationic cascade cyclizations terminated by MOM ether derivatives of β-keto esters. Tetrahedron Lett 2023. [DOI: 10.1016/j.tetlet.2023.154450] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/30/2023]
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4
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Substitution of a triazole for the central olefin in biologically active stilbenes. Bioorg Med Chem Lett 2022; 75:128980. [PMID: 36096344 PMCID: PMC9563006 DOI: 10.1016/j.bmcl.2022.128980] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 08/29/2022] [Accepted: 09/05/2022] [Indexed: 11/24/2022]
Abstract
The stilbene moiety is commonly found in natural products and these compounds display an extraordinary range of biological activity. Efforts to derive useful drugs from stilbenes must address the potential liabilities of this structure, including a propensity for cis/trans isomerization. To identify olefin replacements that address this limitation while preserving biological activity we have prepared analogues of two bioactive stilbenes, a pawhuskin and a schweinfurthin, where a 1,2,3-triazole ring formally replaces the stilbene double bond. The new schweinfurthin analogue (23) has been tested for anti-proliferative activity against 60 cell lines, and shows a strong correlation of bioactivity when compared to the compound that inspired its synthesis (22).
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5
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Conjugate reduction of vinyl bisphosphonates. Tetrahedron Lett 2022; 106:154078. [PMID: 37521200 PMCID: PMC10373991 DOI: 10.1016/j.tetlet.2022.154078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Vinyl bisphosphonates can be readily prepared by condensation of an aromatic aldehyde with the tetraester of a methylenebisphosphonate, and reduction of the resulting olefin is an attractive strategy for the preparation of monoalkyl geminal bisphosphonates. Conjugate reduction through use of variations on the Stryker approach has proven to be an efficient method for that reduction, even in the presence of aromatic substituents that also could be reduced. Furthermore, remote olefins in an isoprenoid chain survive this conjugate reduction unaffected, allowing access to isoprenoid-substituted triazole bisphosphonates of interest as potential inhibitors of terpenoid biosynthesis.
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6
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Efficiency of bis-amidate phosphonate prodrugs. Bioorg Med Chem Lett 2022; 66:128724. [PMID: 35405283 DOI: 10.1016/j.bmcl.2022.128724] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Revised: 04/03/2022] [Accepted: 04/06/2022] [Indexed: 11/25/2022]
Abstract
Bis-amidate derivatives have been viewed as attractive phosphonate prodrug forms because of their straightforward synthesis, lack of phosphorus stereochemistry, plasma stability and nontoxic amino acid metabolites. However, the efficiency of bis-amidate prodrug forms is unclear, as prior studies on this class of prodrugs have not evaluated their activation kinetics. Here, we synthetized a small panel of bis-amidate prodrugs of butyrophilin ligands as potential immunotherapy agents. These compounds were examined relative to other prodrug forms delivering the same payload for their stability in plasma and cell lysate, their ability to stimulate T cell proliferation in human PBMCs, and their activation kinetics in a leukemia co-culture model of T cell cytokine production. The bis-amidate prodrugs demonstrate high plasma stability and improved cellular phosphoantigen activity relative to the free phosphonic acid. However, the efficiency of bis-amidate activation is low relative to other prodrugs that contain at least one ester such as aryl-amidate, aryl-acyloxyalkyl ester, and bis-acyloxyalkyl ester forms. Therefore, bis-amidate prodrugs do not drive rapid cellular payload accumulation and they would be more useful for payloads in which slower, sustained-release kinetics are preferred.
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7
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Synthesis and Metabolism of BTN3A1 Ligands: Studies on Diene Modifications to the Phosphoantigen Scaffold. ACS Med Chem Lett 2022; 13:164-170. [PMID: 35178171 PMCID: PMC8842111 DOI: 10.1021/acsmedchemlett.1c00408] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/24/2022] [Indexed: 02/08/2023] Open
Abstract
Phosphoantigens (pAgs) are small organophosphorus compounds such as (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) that trigger an immune response. These molecules bind to butyrophilin 3A1 (part of the HMBPP receptor) and activate Vγ9Vδ2 T cells. To explore the structure-activity relationships underlying this process, we evaluated a series of novel diene analogs of HMBPP. Here we report that prodrug forms of [(1E)-4-methylpenta-1,3-dien-1-yl] phosphonic acid that lack the allylic alcohol of HMBPP but instead contained a diene scaffold exhibit mid-nanomolar potency for the activation of Vγ9Vδ2 T cells. The compounds also trigger the production of T-cell interferon γ upon exposure to loaded K562 cells. Although both the allylic alcohol and the diene scaffold boost pAg activity, the combination of the two decreases the activity and results in glutathione conjugation. Together, these data show that the diene scaffold results in intermediate pAgs that may have implications for the mechanisms regulating the HMBPP receptor.
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8
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Abstract
The natural schweinfurthins are stilbenes with significant antiproliferative activity and an uncertain mechanism of action. To obtain a fluorescent analogue with minimal deviation from the natural structure, a coumarin ring system was annulated to the D-ring, creating a new analogue of schweinfurthin F. This stilbene was prepared through a convergent synthesis, with a Horner-Wadsworth-Emmons condensation employed to form the central stilbene olefin. After preparation of a tricyclic phosphonate via a recent and more efficient modification of the classic Arbuzov reaction, condensation was attempted with an appropriately substituted bicyclic aldehyde but the coumarin system did not survive the reaction conditions. When olefin formation preceded generation of the coumarin, the stilbene formation proceeded smoothly and ultimately allowed access to the targeted coumarin-based schweinfurthin analogue. This analogue displayed the desired fluorescence properties along with significant biological activity in the National Cancer Institute's 60-cell line bioassay, and the pattern of this biological activity mirrored that of the natural product schweinfurthin F. This approach gives facile access to new fluorescent analogues of the natural schweinfurthins and should be applicable to other natural stilbenes as well.
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9
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Impact of α-modifications on the activity of triazole bisphosphonates as geranylgeranyl diphosphate synthase inhibitors. Bioorg Med Chem 2021; 44:116307. [PMID: 34298413 DOI: 10.1016/j.bmc.2021.116307] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Revised: 07/01/2021] [Accepted: 07/04/2021] [Indexed: 10/20/2022]
Abstract
Agents that inhibit the enzyme geranylgeranyl diphosphate synthase (GGDPS) have anti-cancer activity and our prior studies have investigated the structure-function relationship for a family of isoprenoid triazole bisphosphonates as GGDPS inhibitors. To further explore this structure-function relationship, a series of novel α-modified triazole phosphonates was prepared and evaluated for activity as GGDPS inhibitors in enzyme and cell-based assays. These studies revealed flexibility at the α position of the bisphosphonate derivatives with respect to being able to accommodate a variety of substituents without significantly affecting potency compared to the parent unsubstituted inhibitor. However, the monophosphonate derivatives lacked activity. These studies further our understanding of the structure-function relationship of the triazole-based GGDPS inhibitors and lay the foundation for future studies evaluating the impact of α-modifications on in vivo activity.
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10
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Incorporation of a FRET pair within a phosphonate diester. Bioorg Chem 2021; 114:105048. [PMID: 34126576 DOI: 10.1016/j.bioorg.2021.105048] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2021] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 10/21/2022]
Abstract
Cell-cleavable protecting groups are an effective tactic for construction of biological probes because such compounds can improve problems with instability, solubility, and cellular uptake. Incorporation of fluorescent groups in the protecting groups may afford useful probes of cellular functions, especially for payloads containing phosphonates that would be highly charged if not protected, but little is known about the steric or electronic factors that impede release of the payload. In this report we present a strategy for the synthesis of a coumarin fluorophore and a 4-((4-(dimethylamino)phenyl)diazenyl)benzoic acid (DABCYL) ester chromophore incorporated as a FRET pair within a single phosphonate. Such compounds were designed to deliver a BTN3A1 ligand payload to its intracellular receptor. Both final products and some synthetic intermediates were evaluated for their ability to undergo metabolic activation in γδ T cell functional assays, and for their photophysical properties by spectrophotometry. One phosphonate bearing a DABCYL acyloxyester and a novel tyramine-linked coumarin fluorophore exhibited strong, rapid, and potent cellular activity for γδ T cell stimulation and also showed FRET interactions. This strategy demonstrates that bioactivatable phosphonates containing FRET pairs can be utilized to develop probes to monitor cellular uptake of otherwise charged payloads.
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11
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Synthesis and Metabolism of BTN3A1 Ligands: Studies on Modifications of the Allylic Alcohol. ACS Med Chem Lett 2021; 12:136-142. [PMID: 33488975 DOI: 10.1021/acsmedchemlett.0c00586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Accepted: 11/30/2020] [Indexed: 12/26/2022] Open
Abstract
(E)-4-Hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) and its phosphonate analogs are potent phosphoantigens. HMBPP contains an (E)-allylic alcohol which interacts with the molecular target BTN3A1 giving an antigenic signal to activate Vγ9Vδ2 T cells. As probes of BTN3A1 function, we prepared prodrug derivatives of the HMBPP analog C-HMBP that lack the (E)-allylic alcohol or have modified it to an aldehyde or aldoxime and evaluated their biological activity. Removal of the alcohol completely abrogates phosphoantigenicity in these compounds while the aldoxime modification decreases potency relative to the (E)-allylic alcohol form. However, homoprenyl derivatives oxidized to an aldehyde stimulate Vγ9Vδ2 T cells at nanomolar concentrations. Selection of phosphonate protecting groups (i.e., prodrug forms) impacts the potency of phosphoantigen aldehydes, with mixed aryl acyloxyalkyl forms exhibiting superior activity relative to aryl amidate forms. The activity correlates with the cellular reduction of the aldehyde to the alcohol form. Thus, the functionality on this ligand framework can be altered concurrently with phosphonate protection to promote cellular transformation to highly potent phosphoantigens.
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12
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Amides as bioisosteres of triazole-based geranylgeranyl diphosphate synthase inhibitors. Bioorg Med Chem 2020; 28:115604. [PMID: 32690260 DOI: 10.1016/j.bmc.2020.115604] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/21/2020] [Accepted: 06/22/2020] [Indexed: 12/14/2022]
Abstract
Geranylgeranyl diphosphate synthase (GGDPS) inhibitors are of potential therapeutic interest as a consequence of their activity against the bone marrow cancer multiple myeloma. A series of bisphosphonates linked to an isoprenoid tail through an amide linkage has been prepared and tested for the ability to inhibit GGDPS in enzyme and cell-based assays. The amides were designed as analogues to triazole-based GGDPS inhibitors. Several of the new compounds show GGDPS inhibitory activity in both enzyme and cell assays, with potency dependent on chain length and olefin stereochemistry.
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13
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Novel benzimidazole phosphonates as potential inhibitors of protein prenylation. Bioorg Med Chem Lett 2019; 29:126757. [PMID: 31699606 DOI: 10.1016/j.bmcl.2019.126757] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 10/11/2019] [Accepted: 10/13/2019] [Indexed: 10/25/2022]
Abstract
Benzimidazole carboxyphosphonates and bisphosphonates have been prepared and evaluated for their activity as inhibitors of protein prenylation or isoprenoid biosynthesis. The nature of the phosphonate head group was found to dictate enzyme specificity. The lead carboxyphosphonate inhibits geranylgeranyl transferase II while its corresponding bisphosphonate analogue potently inhibits farnesyl diphosphate synthase. The most active inhibitors effectively disrupted protein prenylation in human multiple myeloma cells.
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14
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A luciferase lysis assay reveals in vivo malignant cell sensitization by phosphoantigen prodrugs. Biochem Pharmacol 2019; 170:113668. [PMID: 31628909 DOI: 10.1016/j.bcp.2019.113668] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Accepted: 10/11/2019] [Indexed: 02/07/2023]
Abstract
Human Vγ9Vδ2 T cells respond to small phosphorus-containing compounds, often called phosphoantigens, which are now known to be intracellular ligands of the immune receptor butyrophilin 3A1 (BTN3A1). In order to compare the efficiency of butyrophilin ligands, we developed a luciferase-based lysis assay that measures the direct cytolysis by Vγ9Vδ2 T cells of luciferase-expressing K562 leukemia cells sensitized by phosphoantigen prodrugs. Our results show that the luciferase-based lysis assay allows in vitro and in vivo assessment of phosphoantigen activity in a way that does not require the extensive processing of flow cytometry or ELISA based approaches. In cellular assays, the structure activity relationships of phosphoantigen prodrugs correlate with ELISA-based activation assays, though phosphoantigen induced target cell lysis occurs at lower concentrations relative to T cell interferon γ production measured by ELISA. In mice dosed with phosphoantigens, a racemic aryl phosphonamidate prodrug, methyl 2-[[[(E)-5-hydroxy-4-methyl-pent-3-enyl]-(1-naphthyloxy)phosphoryl]amino]acetate (1-Nap/GlyOMe C-HMBP, 5), sensitized subcutaneous K562 tumors within minutes, and this effect was maintained at least four hours after treatment. In vivo activity of compound 5 was stronger than that of an equivalent dose of zoledronate. This luciferase lysis assay can be used for evaluation of phosphoantigens due to its time efficiency, high sensitivity, and in vivo compatibility and demonstrates rapid in vitro and in vivo sensitization of tumor cells by phosphoantigen prodrugs.
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15
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Synthesis and Bioactivity of the Alanyl Phosphonamidate Stereoisomers Derived from a Butyrophilin Ligand. ACS Med Chem Lett 2019; 10:1284-1289. [PMID: 31531198 DOI: 10.1021/acsmedchemlett.9b00153] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Accepted: 08/06/2019] [Indexed: 02/07/2023] Open
Abstract
Aryloxy phosphonamidate derivatives of a butyrophilin 3A1 ligand are stimulants of Vγ9 Vδ2 T cells. However, when bonded to an aryl ester and an amine, the phosphorus is stereogenic, and past compounds were studied as racemates. To determine the impact of stereochemistry on the activity, we now have prepared phosphonate derivatives of l- and d-alanine ethyl ester, separated the diastereomers, and evaluated their biological activity as single stereoisomers. The results demonstrate that phosphonamidates substituted with l-alanine stimulate Vγ9 Vδ2 T cells at lower concentrations than the racemic glycine counterpart, while those derived from d-alanine require higher concentrations. All four diastereomers are more active than charged phosphoantigens such as HMBPP. Surprisingly, only a 2-fold difference was observed between the l-alanine phosphorus isomers, with the R P isomer more potent. This suggests that the small phosphoantigen scaffold reduces but does not eliminate dependence upon phosphorus stereochemistry for cellular activity.
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16
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Cover Feature: Stability and Efficiency of Mixed Aryl Phosphonate Prodrugs (ChemMedChem 17/2019). ChemMedChem 2019. [DOI: 10.1002/cmdc.201900491] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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17
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ω-Hydroxy isoprenoid bisphosphonates as linkable GGDPS inhibitors. Bioorg Med Chem Lett 2019; 29:126633. [PMID: 31474482 DOI: 10.1016/j.bmcl.2019.126633] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 08/20/2019] [Indexed: 02/08/2023]
Abstract
The enzyme geranylgeranyl diphosphate synthase (GGDPS) is a potential therapeutic target for multiple myeloma. Malignant plasma cells produce and secrete large amounts of monoclonal protein, and inhibition of GGDPS results in disruption of protein geranylgeranylation which in turn impairs intracellular protein trafficking. Our previous work has demonstrated that some isoprenoid triazole bisphosphonates are potent and selective inhibitors of GGDPS. To explore the possibility of selective delivery of such compounds to plasma cells, new analogues with an ω-hydroxy group have been synthesized and examined for their enzymatic and cellular activity. These studies demonstrate that incorporation of the ω-hydroxy group minimally impairs GGDPS inhibitory activity. Furthermore conjugation of one of the novel ω-hydroxy GGDPS inhibitors to hyaluronic acid resulted in enhanced cellular activity. These results will allow future studies to focus on the in vivo biodistribution of HA-conjugated GGDPS inhibitors.
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18
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Abstract
A set of phosphonate prodrugs of a butyrophilin ligand was synthesized and evaluated for plasma stability and cellular activity. The mixed aryl acyloxy esters were prepared either via a standard sequence through the phosphonic acid chloride, or through the more recently reported, and more facile, triflate activation. In the best of cases, this class of prodrugs shows cellular potency similar to that of bis-acyloxyalkyl phosphonate prodrugs and plasma stability similar to that of aryl phosphonamidates. For example, {[((3E)-5-hydroxy-4-methylpent-3-en-1-yl) (naphthalen-2-yloxy)phosphoryl]oxy}methyl 2,2-dimethylpropanoate can activate BTN3A1 in K562 cells after just 15 minutes of exposure (at an EC50 value of 31 nm) and is only partially metabolized (60 % remaining) after 20 hours in human plasma. Other related novel analogues showed similar potency/stability profiles. Therefore, mixed aryl acyloxyalkyl phosphonate prodrugs are an exciting new strategy for the delivery of phosphonate-containing drugs.
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19
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Loop-mediated isothermal amplification for paratyphoid fever - a proof-of-principle analysis. Lett Appl Microbiol 2019; 68:509-513. [PMID: 30761564 DOI: 10.1111/lam.13130] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Revised: 02/08/2019] [Accepted: 02/11/2019] [Indexed: 11/26/2022]
Abstract
In-house loop-mediated isothermal amplification (LAMP) procedures for the detection of paratyphoid fever-associated bacteria on serovar level were evaluated. Therefore, LAMP primers for Salmonella genus, for two LAMP schemes for S. Paratyphi A, for S. Paratyphi B and for S. Paratyphi C were tested with DNA from culture isolates from strain collections and spiked blood cultures against published PCR protocols targeting the same micro-organisms. Sensitivity and specificity for DNA from culture isolates verified by LAMP ranged from 80·0 to 100·0% and 96·1 to 100·0% vs 65 to 100% and 98·7 to 100% for the PCR approaches. For the spiked blood culture materials, sensitivity and specificity for LAMP ranged from 87·5 to 100·0% and 96·7 to 100·0% vs from 60 to 100% and 98·2 to 100% for PCR. In conclusion, LAMP for paratyphoid fever shows comparable performance characteristics as PCR. Due to its easy application, the procedure is well suited for surveillance purposes in resource-limited settings. SIGNIFICANCE AND IMPACT OF THE STUDY: The use of easy-to-apply, point-of-care-testing-like loop-mediated isothermal amplification (LAMP) for the diagnosis of paratyphoid fever is evaluated. This approach can contribute to low-threshold availability of surveillance options for resource limited settings. Easy-to-teach and easy-to-apply LAMP schemes with similar performance characteristics as PCR are provided. The described test evaluation is of particular use for surveillance and public health experts.
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Phosphonamidate Prodrugs of a Butyrophilin Ligand Display Plasma Stability and Potent Vγ9 Vδ2 T Cell Stimulation. J Med Chem 2018; 61:8658-8669. [PMID: 30199251 PMCID: PMC6703555 DOI: 10.1021/acs.jmedchem.8b00655] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Small organophosphorus compounds stimulate Vγ9 Vδ2 T cells if they serve as ligands of butyrophilin 3A1. Because the most potent natural ligand is ( E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP), which is the last intermediate in bacterial biosynthesis of isoprenoids that is not found in mammalian metabolism, activation of these T cells represents an important component of the immune response to bacterial infections. To identify butyrophilin ligands that may have greater plasma stability, and clinical potential, we have prepared a set of aryl phosphonamidate derivatives (9a-i) of the natural ligand. Testing of these new compounds in assays of T cell response has revealed that this strategy can provide compounds with high potency for expansion of Vγ9 Vδ2 T cells (9f, EC50 = 340 pM) and interferon γ production in response to loaded K562 cells (9e, EC50 = 62 nM). Importantly, all compounds of this class display extended plasma stability ( t1/2 > 24 h). These findings increase our understanding of metabolism of butyrophilin ligands and the structure-activity relationships of phosphonamidate prodrugs.
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22
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Chemo-enzymatic synthesis of the exocyclic olefin isomer of thymidine monophosphate. Bioorg Med Chem 2018; 26:2365-2371. [PMID: 29606487 DOI: 10.1016/j.bmc.2018.03.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2018] [Revised: 03/15/2018] [Accepted: 03/21/2018] [Indexed: 12/19/2022]
Abstract
Exocyclic olefin variants of thymidylate (dTMP) recently have been proposed as reaction intermediates for the thymidyl biosynthesis enzymes found in many pathogenic organisms, yet synthetic reports on these materials are lacking. Here we report two strategies to prepare the exocyclic olefin isomer of dTMP, which is a putative reaction intermediate in pathogenic thymidylate biosynthesis and a novel nucleotide analog. Our most effective strategy involves preserving the existing glyosidic bond of thymidine and manipulating the base to generate the exocyclic methylene moiety. We also report a successful enzymatic deoxyribosylation of a non-aromatic nucleobase isomer of thymine, which provides an additional strategy to access nucleotide analogs with disrupted ring conjugation or with reduced heterocyclic bases. The strategies reported here are straightforward and extendable towards the synthesis of various pyrimidine nucleotide analogs, which could lead to compounds of value in studies of enzyme reaction mechanisms or serve as templates for rational drug design.
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Quantitative determination of a potent geranylgeranyl diphosphate synthase inhibitor using LC-MS/MS: Derivatization and application. J Pharm Biomed Anal 2018; 153:22-28. [PMID: 29455093 DOI: 10.1016/j.jpba.2018.02.010] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2017] [Revised: 01/30/2018] [Accepted: 02/04/2018] [Indexed: 02/01/2023]
Abstract
An isomeric mixture of homogeranyl/homoneryl triazole bisphosphonates (VSW1198) has previously been shown to be a potent inhibitor of geranylgeranyl diphosphate (GGDP) synthase (GGDPS) and of therapeutic interest for the treatment of multiple myeloma. We have developed and validated a selective and sensitive liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) method for the simultaneous quantitation of both the E- and Z- isomers of VSW1198 in cell culture media, mouse plasma and tissues. VSW1198 and internal standard are extracted from the bio-matrices by solid-phase extraction, followed by derivatization using trimethylsilyldiazomethane. The chromatographic separation of analytes was achieved on a Phenomenex Gemini NX column (150 mm * 2.0 mm, 5 μ) with gradient elution using 0.1% acetic acid and methanol/acetonitrile (1:1) as the mobile phase at a flow rate of 0.2 mL/min. Derivatized analytes were ionized with an electrospray ionization source in positive multiple reaction monitoring (MRM) mode and quantitated using MS/MS. The MS/MS response was linear over the concentration range from 0.38-1500 and 0.13-500 ng/mL for the E- and Z-isomers, respectively. The within- and between-day precision (relative standard deviation, % RSD) and accuracy were within the acceptable limits per FDA guidelines. The validated method was used for quantitative determination of the compounds in preclinical studies focused on the development of VSW1198 as a novel anti-cancer agent.
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α-Methylation enhances the potency of isoprenoid triazole bisphosphonates as geranylgeranyl diphosphate synthase inhibitors. Bioorg Med Chem 2018; 26:376-385. [PMID: 29248353 PMCID: PMC5752576 DOI: 10.1016/j.bmc.2017.10.023] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2017] [Revised: 10/12/2017] [Accepted: 10/18/2017] [Indexed: 12/19/2022]
Abstract
Disruption of protein geranylgeranylation via inhibition of geranylgeranyl diphosphate synthase (GGDPS) represents a novel therapeutic strategy for a variety of malignancies, especially those characterized by excessive protein secretion such as multiple myeloma. Our work has demonstrated that some isoprenoid triazole bisphosphonates are potent and selective inhibitors of GGDPS. Here we present the synthesis and biological evaluation of a new series of isoprenoid triazoles modified by incorporation of a methyl group at the α-carbon. These studies reveal that incorporation of an α-methyl substituent enhances the potency of these compounds as GGDPS inhibitors, and, in the case of the homogeranyl/homoneryl series, abrogates the effects of olefin stereochemistry on inhibitory activity. The incorporation of the methyl group allowed preparation of a POM-prodrug, which displayed a 10-fold increase in cellular activity compared to the corresponding salt. These studies form the basis for future preclinical studies investigating the anti-myeloma activity of these novel α-methyl triazole bisphosphonates.
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Synthesis of amide isosteres of schweinfurthin-based stilbenes. Bioorg Med Chem 2017; 25:5483-5489. [PMID: 28866376 PMCID: PMC5763908 DOI: 10.1016/j.bmc.2017.08.016] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 08/03/2017] [Accepted: 08/08/2017] [Indexed: 02/08/2023]
Abstract
The schweinfurthins are plant-derived stilbenes with an intriguing profile of anti-cancer activity. To obtain analogues of the schweinfurthins that might preserve the biological activity but have greater water solubility, a formal replacement of the central olefin with an amide has been explored. Two pairs of amides have been prepared, each containing the same hexahydroxanthene "left half" joined through an amide linkage to two different "right halves." In each series, the amide has been inserted in both possible orientations, placing the carbonyl group on the tricyclic ABC ring system and the amine on the D-ring, or placing the amine on the hexahydroxanthene and the carbonyl group on the D-ring. The four new schweinfurthin analogues have been tested in the NCI 60 cell line screen, and in both cases the more active isomer carried the carbonyl group on the C-ring.
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Mixed Aryl Phosphonate Prodrugs of a Butyrophilin Ligand. ACS Med Chem Lett 2017; 8:914-918. [PMID: 28947936 DOI: 10.1021/acsmedchemlett.7b00245] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Accepted: 08/09/2017] [Indexed: 02/08/2023] Open
Abstract
Studies of aryl phosphonate derivatives of a butyrophilin 3A1 ligand have resulted in identification of a potent stimulant of Vγ9 Vδ2 T cells. This compound, a mixed ester bearing one pivaloyloxymethyl substituent and one 1-naphthyl ester displayed an EC50 of 0.79 nM as a stimulant of T cell proliferation, and a 9.0 nM EC50 in an assay designed to measure interferon gamma production. In both assays, this is the most potent butyrophilin ligand prodrug yet reported, and thus it should be a valuable tool for studies of T cell function. Furthermore, mixed aryl/acyloxyalkyl esters may represent a new class of phosphonate prodrugs with high efficacy.
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Selective opioid growth factor receptor antagonists based on a stilbene isostere. Bioorg Med Chem 2017; 25:4464-4474. [PMID: 28693915 PMCID: PMC5567982 DOI: 10.1016/j.bmc.2017.06.035] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Revised: 06/13/2017] [Accepted: 06/21/2017] [Indexed: 02/01/2023]
Abstract
As part of an ongoing drug development effort aimed at selective opioid receptor ligands based on the pawhuskin natural products we have synthesized a small set of amide isosteres. These amides were centered on lead compounds which are selective antagonists for the delta and kappa opioid receptors. The amide isomers revealed here show dramatically different activity from the parent stilbene compounds. Three of the isomers synthesized showed antagonist activity for the opioid growth factor (OGF)/opioid growth factor receptor (OGFR) axis which is involved in cellular and organ growth control. This cellular signaling mechanism is targeted by "low-dose" naltrexone therapy which is being tested clinically for multiple sclerosis, Crohn's disease, cancer, and wound healing disorders. The compounds described here are the first selective small molecule ligands for the OGF/OGFR system and will serve as important leads and probes for further study.
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Bishomoisoprenoid triazole bisphosphonates as inhibitors of geranylgeranyl diphosphate synthase. Bioorg Med Chem 2017; 25:2437-2444. [PMID: 28302510 PMCID: PMC5450914 DOI: 10.1016/j.bmc.2017.02.066] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2017] [Revised: 02/22/2017] [Accepted: 02/27/2017] [Indexed: 11/23/2022]
Abstract
Protein geranylgeranylation reactions are dependent on the availability of geranylgeranyl diphosphate (GGDP), which serves as the isoprenoid donor. Inhibition of GGDP synthase (GGDPS) is of interest from a drug development perspective as GGDPS inhibition results in impaired protein geranylgeranylation, which in multiple myeloma, disrupts monoclonal protein trafficking and induces apoptosis. We have recently reported a series of isoprenoid triazole bisphosphonates and have demonstrated that a 3:1 mixture of homogeranyl and homoneryl isomers potently, and in a synergistic manner, inhibits GGDPS. We now present the synthesis and biological evaluation of a novel series of bishomoisoprenoid triazoles which furthers our understanding of the structure-function relationship of this class. These studies demonstrate the importance of chain length and olefin stereochemistry on inhibitory activity.
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Phosphinophosphonates and Their Tris-pivaloyloxymethyl Prodrugs Reveal a Negatively Cooperative Butyrophilin Activation Mechanism. J Med Chem 2017; 60:2373-2382. [PMID: 28218845 DOI: 10.1021/acs.jmedchem.6b00965] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Butyrophilin 3A1 (BTN3A1) binds small phosphorus-containing molecules, which initiates transmembrane signaling and activates butyrophilin-responsive cells. We synthesized several phosphinophosphonates and their corresponding tris-pivaloyloxymethyl (tris-POM) prodrugs and examined their effects on BTN3A1. An analog of (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) bound to BTN3A1 with intermediate affinity, which was enthalpy-driven. Docking studies revealed binding to the basic surface pocket and interactions between the allylic hydroxyl group and the BTN3A1 backbone. The phosphinophosphonate stimulated proliferation of Vγ9Vδ2 T cells with moderate activity (EC50 = 26 μM). Cellular potency was enhanced >600-fold in the tris-POM prodrug (EC50 = 0.041 μM). The novel prodrug also induced T cell mediated leukemia cell lysis. Analysis of dose-response data reveals HMBPP-induced Hill coefficients of 0.69 for target cell lysis and 0.68 in interferon secretion. Together, tris-POM prodrugs enhance the cellular activity of phosphinophosphonates, reveal structure-activity relationships of butyrophilin ligands, and support a negatively cooperative model of cellular butyrophilin activation.
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Olefin Isomers of a Triazole Bisphosphonate Synergistically Inhibit Geranylgeranyl Diphosphate Synthase. Mol Pharmacol 2017; 91:229-236. [PMID: 28057800 DOI: 10.1124/mol.116.107326] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2016] [Accepted: 12/28/2016] [Indexed: 11/22/2022] Open
Abstract
The isoprenoid donor for protein geranylgeranylation reactions, geranylgeranyl diphosphate (GGDP), is the product of the enzyme GGDP synthase (GGDPS) that condenses farnesyl diphosphate (FDP) and isopentenyl pyrophosphate. GGDPS inhibition is of interest from a therapeutic perspective for multiple myeloma because we have shown that targeting Rab GTPase geranylgeranylation impairs monoclonal protein trafficking, leading to endoplasmic reticulum stress and apoptosis. We reported a series of triazole bisphosphonate GGDPS inhibitors, of which the most potent was a 3:1 mixture of homogeranyl (HG) and homoneryl (HN) isomers. Here we determined the activity of the individual olefin isomers. Enzymatic and cellular assays revealed that although HN is approximately threefold more potent than HG, HN is not more potent than the original mixture. Studies in which cells were treated with varying concentrations of each isomer alone and in different combinations revealed that the two isomers potentiate the induced-inhibition of protein geranylgeranylation when used in a 3:1 HG:HN combination. A synergistic interaction was observed between the two isomers in the GGDPS enzyme assay. These results suggested that the two isomers bind simultaneously to the enzyme but within different domains. Computational modeling studies revealed that HN is preferred at the FDP site, that HG is preferred at the GGDP site, and that both isomers may bind to the enzyme simultaneously. These studies are the first to report a set of olefin isomers that synergistically inhibit GGDPS, thus establishing a new paradigm for the future development of GGDPS inhibitors.
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Abstract
Isoprenoid-substituted bisphosphonates are known to serve as inhibitors of the enzyme geranylgeranyl diphosphate synthase, and their activity can be highly sensitive to olefin stereochemistry. A mixture of homogeranyl and homoneryl triazole bisphosphonates has previously demonstrated potent activity, and thus stereocontrolled syntheses of the individual isomers have been developed.
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Abstract
Through treatment with NaI and trifluoroacetic anhydride, which presumably forms trifluoroacetyl iodide in situ, epoxides can be converted to olefins. This reaction now has been shown to tolerate remote olefins without loss of their individual stereochemistry. A reaction sequence involving regiospecific epoxidation of an isoprenoid alcohol, conversion of the alcohol to an azide, and cycloaddition with an acetylene, followed by conversion of the epoxide back to the original olefin, has allowed stereocontrolled preparation of triazole bisphosphonates with a farnesyl or a geranylgeranyl substituent. This strategy may be applicable selective protection of an alkene in other polyolefins, including substrates for metathesis reactions.
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Corrigendum to "A selective delta opioid receptor antagonist based on a stilbene core" [Bioorg. Med. Chem. Lett. 25 (2015) 5532-5535]. Bioorg Med Chem Lett 2016; 26:1645. [PMID: 28750745 DOI: 10.1016/j.bmcl.2016.02.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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34
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Selective Prenylation of Protected Phenols for Synthesis of Pawhuskin A Analogues. J Org Chem 2016; 81:1585-92. [DOI: 10.1021/acs.joc.5b02756] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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Potent Triazole Bisphosphonate Inhibitor of Geranylgeranyl Diphosphate Synthase. ACS Med Chem Lett 2015; 6:1195-8. [PMID: 26713103 DOI: 10.1021/acsmedchemlett.5b00334] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Accepted: 10/28/2015] [Indexed: 02/08/2023] Open
Abstract
Studies of triazole bisphosphonates have resulted in identification of a potent inhibitor of geranylgeranyl diphosphate synthase (IC50 = 45 nM) with very good selectivity for this enzyme over farnesyl diphosphate synthase (IC50 = 28 μM). This compound also potently disrupts geranylgeranylation and induces cytotoxicity in human myeloma cells at submicromolar levels, suggesting that it may serve as a lead compound for treatment of malignancies characterized by excessive protein secretion.
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A selective delta opioid receptor antagonist based on a stilbene core. Bioorg Med Chem Lett 2015; 25:5532-5. [PMID: 26525865 DOI: 10.1016/j.bmcl.2015.10.059] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Revised: 10/16/2015] [Accepted: 10/20/2015] [Indexed: 10/22/2022]
Abstract
Studies of directed ortho metalation reactions on an aromatic substrate with multiple potential directing groups have identified conditions that favor either of two regioisomers. One of these regioisomers has been converted to an analogue of the stilbene pawhuskin A, and been shown to have high selectivity as an antagonist of the delta opioid receptor. Docking studies have suggested that this compound can adopt a conformation similar to naltrindole, a known delta antagonist.
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Evaluation of a 7-Methoxycoumarin-3-carboxylic Acid Ester Derivative as a Fluorescent, Cell-Cleavable, Phosphonate Protecting Group. Chembiochem 2015; 17:52-5. [PMID: 26503489 DOI: 10.1002/cbic.201500484] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Indexed: 02/04/2023]
Abstract
Cell-cleavable protecting groups often enhance cellular delivery of species that are charged at physiological pH. Although several phosphonate protecting groups have achieved clinical success, it remains difficult to use these prodrugs in live cells to clarify biological mechanisms. Here, we present a strategy that uses a 7-methoxycoumarin-3-carboxylic acid ester as a fluorescent protecting group. This strategy was applied to synthesis of an (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) analogue to assess cellular uptake and human Vγ9Vδ2 T cell activation. The fluorescent ester displayed low cellular toxicity (IC50 >100 μm) and strong T cell activation (EC50 =0.018 μm) relative to the unprotected anion (EC50 =23 μm). The coumarin-derived analogue allowed no-wash analysis of biological deprotection, which revealed rapid internalization of the prodrug. These results demonstrate that fluorescent groups can be applied both as functional drug delivery tools and useful biological probes of drug uptake.
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3-Deoxyschweinfurthin B Lowers Cholesterol Levels by Decreasing Synthesis and Increasing Export in Cultured Cancer Cell Lines. Lipids 2015; 50:1195-207. [PMID: 26494560 DOI: 10.1007/s11745-015-4083-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Accepted: 10/02/2015] [Indexed: 01/12/2023]
Abstract
The schweinfurthins have potent antiproliferative activity in multiple glioblastoma multiforme (GBM) cell lines; however, the mechanism by which growth is impeded is not fully understood. Previously, we demonstrated that the schweinfurthins reduce the level of key isoprenoid intermediates in the cholesterol biosynthetic pathway. Herein, we describe the effects of the schweinfurthins on cholesterol homeostasis. Intracellular cholesterol levels are greatly reduced in cells incubated with 3-deoxyschweinfurthin B (3dSB), an analog of the natural product schweinfurthin B. Decreased cholesterol levels are due to decreased cholesterol synthesis and increased cholesterol efflux; both of these cellular actions can be influenced by liver X-receptor (LXR) activation. The effects of 3dSB on ATP-binding cassette transporter 1 levels and other LXR targets are similar to that of 25-hydroxycholesterol, an LXR agonist. Unlike 25-hydroxycholesterol, 3dSB does not act as a direct agonist for LXR α or β. These data suggest that cholesterol homeostasis plays a significant role in the growth inhibitory activity of the schweinfurthins and may elucidate a mechanism that can be targeted in human cancers such as GBM.
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Synthesis and Biological Evaluation of a Phosphonate Phosphoantigen Prodrug. PHOSPHORUS SULFUR 2015. [DOI: 10.1080/10426507.2014.974099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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40
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N-Oxide derivatives of 3-(3-pyridyl)-2-phosphonopropanoic acids as potential inhibitors of Rab geranylgeranylation. Bioorg Med Chem Lett 2015; 25:2331-4. [PMID: 25935643 DOI: 10.1016/j.bmcl.2015.04.021] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2015] [Revised: 04/06/2015] [Accepted: 04/08/2015] [Indexed: 10/23/2022]
Abstract
The N-oxide derivatives of [2-(3-pyridinyl)-1-hydroxyethylidene-1,1-phosphonocarboxylic acid (or PEHPC) and [2-(3-pyridinyl)-1-ethylidene-1,1-phosphonocarboxylic acid (or PEPC) have been prepared and evaluated for their activity against several enzymes which utilize isoprenoids. The parent pyridines are known inhibitors of GGTase II, but the N-oxide derivatives show no improvement in biological activity in assays with the isolated enzyme. However, the PEHPC N-oxide did induce significant accumulation of intracellular light chain in myeloma cells, consistent with inhibition of Rab geranylgeranylation.
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In vitro studies in a myelogenous leukemia cell line suggest an organized binding of geranylgeranyl diphosphate synthase inhibitors. Biochem Pharmacol 2015; 96:83-92. [PMID: 25952057 DOI: 10.1016/j.bcp.2015.04.009] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 04/16/2015] [Indexed: 10/23/2022]
Abstract
A small set of isoprenoid bisphosphonates ethers has been tested in the K562 chronic myelogenous leukemia cell line to determine their impact on isoprenoid biosynthesis. Five of these compounds inhibit geranylgeranyl diphosphate synthase (GGDPS) with IC50 values below 1 μM in enzyme assays, but in cells their apparent activity is more varied. In particular, the isomeric C-geranyl-O-prenyl and C-prenyl-O-geranyl bisphosphonates are quite different in their activity with the former consistently demonstrating greater impairment of geranylgeranylation in cells but the latter showing greater impact in the enzyme assays with GGDPS. Together, these findings suggest an organized binding of these inhibitors in the two hydrophobic channels of the geranylgeranyl diphosphate synthase enzyme.
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Abstract
A substantial portion of metabolism involves transformation of phosphate esters, including pathways leading to nucleotides and oligonucleotides, carbohydrates, isoprenoids and steroids, and phosphorylated proteins. Because the natural substrates bear one or more negative charges, drugs that target these enzymes generally must be charged as well, but small charged molecules can have difficulty traversing the cell membrane by means other than endocytosis. The resulting dichotomy has stimulated a great deal of effort to develop effective prodrugs, compounds that carry little or no charge to enable them to transit biological membranes, but able to release the parent drug once inside the target cell. This chapter presents recent studies on advances in prodrug forms, along with representative examples of their application to marketed and developmental drugs.
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Synthesis of isoprenoid bisphosphonate ethers through C-P bond formations: Potential inhibitors of geranylgeranyl diphosphate synthase. Beilstein J Org Chem 2014; 10:1645-50. [PMID: 25161722 PMCID: PMC4142842 DOI: 10.3762/bjoc.10.171] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2014] [Accepted: 06/25/2014] [Indexed: 12/03/2022] Open
Abstract
A set of bisphosphonate ethers has been prepared through sequential phosphonylation and alkylation of monophosphonate ethers. After formation of the corresponding phosphonic acid salts, these compounds were tested for their ability to inhibit the enzyme geranylgeranyl diphosphate synthase (GGDPS). Five of the new compounds show IC50 values of less than 1 μM against GGDPS with little to no activity against the related enzyme farnesyl diphosphate synthase (FDPS). The most active compound displayed an IC50 value of 82 nM when assayed with GGDPS, and no activity against FDPS even at a 10 μM concentration.
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Opportunities and challenges in development of phosphoantigens as Vγ9Vδ2 T cell agonists. Biochem Pharmacol 2014; 89:301-12. [DOI: 10.1016/j.bcp.2014.03.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 03/17/2014] [Accepted: 03/17/2014] [Indexed: 01/29/2023]
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Geranyl and neryl triazole bisphosphonates as inhibitors of geranylgeranyl diphosphate synthase. Bioorg Med Chem 2014; 22:2791-8. [PMID: 24726306 DOI: 10.1016/j.bmc.2014.03.014] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2014] [Revised: 02/26/2014] [Accepted: 03/08/2014] [Indexed: 10/25/2022]
Abstract
When inhibitors of enzymes that utilize isoprenoid pyrophosphates are based on the natural substrates, a significant challenge can be to achieve selective inhibition of a specific enzyme. One element in the design process is the stereochemistry of the isoprenoid olefins. We recently reported preparation of a series of isoprenoid triazoles as potential inhibitors of geranylgeranyl transferase II but these compounds were obtained as a mixture of olefin isomers. We now have accomplished the stereoselective synthesis of these triazoles through the use of epoxy azides for the cycloaddition reaction followed by regeneration of the desired olefin. Both geranyl and neryl derivatives have been prepared as single olefin isomers through parallel reaction sequences. The products were assayed against multiple enzymes as well as in cell culture studies and surprisingly a Z-olefin isomer was found to be a potent and selective inhibitor of geranylgeranyl diphosphate synthase.
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Synthesis and structure activity relationships of schweinfurthin indoles. Bioorg Med Chem 2014; 22:2542-52. [PMID: 24656801 DOI: 10.1016/j.bmc.2014.02.043] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Revised: 02/11/2014] [Accepted: 02/19/2014] [Indexed: 11/17/2022]
Abstract
As part of a program to explore the biological activity of analogues of the natural schweinfurthins, a set of compounds has been prepared where an indole system can be viewed as a substitution for the resorcinol substructure of the schweinfurthin's D-ring. Twelve of these schweinfurthin indoles have been prepared and evaluated in the 60 cell line screen of the National Cancer Institute. While a range of activity has been observed, it is now clear that schweinfurthin indoles can demonstrate the intriguing pattern of activity associated with the natural stilbenes. In the best cases, these indole analogues display both potency and differential activity across the various cell lines comparable to the best resorcinol analogues.
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Stilbenes as κ-selective, non-nitrogenous opioid receptor antagonists. JOURNAL OF NATURAL PRODUCTS 2014; 77:311-319. [PMID: 24456556 PMCID: PMC3993902 DOI: 10.1021/np4009046] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/25/2013] [Indexed: 06/03/2023]
Abstract
The natural stilbene pawhuskin A has been shown to function as an opioid receptor antagonist, with preferential binding to the κ receptor. This finding encouraged assembly of a set of analogues to probe the importance of key structural features. Assays on these compounds determined that one (compound 29) shows potent opioid receptor binding activity and significantly improved selectivity for the κ receptor. These studies begin to illuminate the structural features of these non-nitrogenous opioid receptor antagonists that are required for activity.
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Nerol: An alarm substance of the stingless bee,Trigona fulviventris (Hymenoptera: Apidae). J Chem Ecol 2014; 8:1167-81. [PMID: 24413960 DOI: 10.1007/bf00990750] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/1981] [Revised: 01/18/1982] [Indexed: 11/29/2022]
Abstract
Bees of the genusTrigona and subgenusTrigona possess volatile materials in their mandibular glands, used as alarm substances and as marking pheromones. Heads of workers ofTrigona fulviventris were analyzed by gas chromatography-mass spectrometry. The two major volatile components were nerol (∼ 50%), and octyl caproate (∼ 20%). Relative to other substances tested at a Costa Rican nest, treatments containing 20 μg of nerol attractedT. fulviventris, depressed numbers of bees leaving the nest by about 50%, and elicited wing vibration and biting. The responses were similar to those obtained with the contents of one worker head. Attraction and biting were also seen in response to captures of colony members by assassin bugs (Apiomerus pictipes) outside a nest entrance; one bee responded in about 15% of the captures. This alarm behavior, although weak, is of interest since it was thought thatT. fulviventris was unusual for its subgenus in its lack of nest defense behaviors.
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Abstract
To gain access to prenylated hexahydroxanthenes, tandem cascade cyclization-electrophilic aromatic substitution reactions have been studied on substrates bearing allylic and propargylic substituents. Both BF3·OEt2 and TMSOTf can be used to initiate this reaction sequence, resulting in different ratios of the C-2 and C-6 substitution products. Even though allylic transposition is observed in some cases, the results of a crossover experiment are consistent with an intramolecular reaction sequence. Taken together, these studies now allow preparation of either the C-2 or C-6 prenylated hexahydroxanthene products.
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Abstract
An interest in the schweinfurthins, natural stilbenes with significant antiproliferative activity, has prompted efforts to prepare a set of indole analogues. To approach the desired compounds through a Horner-Wadsworth-Emmons condensation, new indole derivatives bearing a phosphonomethyl substituent in the B-ring were required. The parent indole system with the necessary substitution pattern was obtained through Stobbe condensation and cyclization. A prenyl substituent was incorporated at the C3 position of a 4,6-disubstituted indole through a highly regioselective electrophilic aromatic substitution reaction, while metalation and alkylation provided the C2-prenylated indole. After introduction of the phosphonate group through classical reactions, the new indole phosphonates were found to undergo the desired condensation with nonracemic aldehydes representing the schweinfurthin left half. This approach provides facile access to new heteroaromatic analogues of the natural schweinfurthins and should be applicable to many other natural stilbenes as well.
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