Enhanced RNA binding of dimerized aminoglycosides

Michael, Katja; Wang, Hai; Tor, Yitzhak

doi:10.1016/s0968-0896(99)00071-1

Cited by 124 publications

(122 citation statements)

References 30 publications

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“…16,17 The amino groups of neomycin (1) were protected as tert-butylcarbamates to give 2. 16 The 5′-OH was converted into 2,4,6-triisopropylbenzenesulfonyl ester, 16 which was treated with aminoethanethiol 17 to give 3. Pyrene carboxylic acid was activated as hydroxysuccinimide ester and coupled with 3 as previously described.…”

Section: Tfn and Tft Synthesismentioning

confidence: 99%

“…After protection of all amino groups of the neomycin, nucleophilic displacement at the 5′-OH of 2 (Fig. 1D) as previously described 16,17 introduced a short linker with a terminal primary amino group in 3. Earlier studies 18 had shown that, among several pyrene derivatives, pyrenecarboxylic acid when conjugated to paromomycin and tobramycin exhibited the least nonspecific binding to RNA.…”

Section: In Vitro Rna Binding Assaymentioning

confidence: 99%

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Identification of Tau Stem Loop RNA Stabilizers

Donahue¹,

Ni²,

Rozners³

et al. 2007

SLAS Discovery

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Alternative splicing of tau exon 10 produces tau isoforms with either 3 (3R) or 4 (4R) repeated microtubule-binding domains. Increased ratios of 4R to 3R tau expression, above the physiological 1:1, leads to neurofibrillary tangles and causes neurodegenerative disease. An RNA stem loop structure plays a significant role in determining the ratio, with decreasing stability correlating with an increase in 4R tau mRNA expression. Recent studies have shown that aminoglycosides are able to bind and stabilize the tau stem loop in vitro, suggesting that other druglike small molecules could be identified and that such molecules might lead to decreased exon 10 splicing in vivo. The authors have developed a fluorescent high-throughput fluorescent binding assay and screened a library of ∼110,000 compounds to identify candidate drugs that will bind the tau stem loop in vitro. In addition, they have developed a fluorescent-based RNA probe to assay the stabilizing effects of candiate drugs on the tau stem loop RNA. These assays should be applicable to the general problem of identifying small molecules that interact with mRNA secondary structures. (Journal of Biomolecular Screening 2007:789-799)

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Section: Tfn and Tft Synthesismentioning

confidence: 99%

Section: In Vitro Rna Binding Assaymentioning

confidence: 99%

Identification of Tau Stem Loop RNA Stabilizers

Donahue¹,

Ni²,

Rozners³

et al. 2007

SLAS Discovery

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“…This allowed tobramycin to be displayed in multiple orientations on the beads for the potential discovery of new RNA-binding motifs. For the first attachment strategy (Scheme 1), tobramycin 1 was modified to add an aminoterminal linker at the 6Љ position by following reported procedures (21)(22)(23). The resulting Boc-protected tobramycin derivative 2 was coupled to carboxyl-terminated magnetic beads by using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide according to the protocol provided by the supplier.…”

Section: Resultsmentioning

confidence: 99%

Evaluation of RNA-binding specificity of aminoglycosides with DNA microarrays

Liang¹,

Greenberg²,

Hammond

et al. 2006

Proc. Natl. Acad. Sci. U.S.A.

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We have developed methods for using DNA array technology to probe the entire transcriptome to determine the RNA-binding specificity of ligands. Two methods were investigated. In the first method, the RNA-binding aminoglycoside antibiotic tobramycin was covalently linked to magnetic beads. The beads were bound to human liver mRNA and washed, and specifically bound RNA was eluted, amplified, and analyzed with DNA array technology. A small number of genes were found to bind specifically to the tobramycin beads. In the second method, the aminoglycoside ligand was added directly to the array hybridization reaction, and the signal was compared with a control experiment in the absence of ligand. The aminoglycosides were found to interfere with a small percentage of all hybridization events. These methods differ from traditional DNA array experiments in that the readout is a direct measure of the interaction between mRNA and a ligand, rather than an indirect measure of effect on expression. We expect that the results will lead to the discovery of new aminoglycosidebinding RNA motifs and may also have relevance toward understanding and overcoming the side effects observed with these antibiotics in the clinic. aminoglycoside-RNA interactionsA minoglycosides are among the most commonly used broadspectrum antibiotics in the clinic. Since the initial discovery of streptomycin in 1944, a series of aminoglycoside antibiotics, including kanamycin, neomycin B, gentamicin, and tobramycin have been successfully introduced as treatments for serious systemic infections and have been used for a variety of topical applications.The origin of the bactericidal activity of aminoglycosides has been extensively investigated and is due to binding to the bacterial ribosome (1). Aminoglycosides bind specifically to the 16S rRNA, near the mRNA decoding site. This binding decreases the fidelity of protein translation by lowering the energetic cost of a conformational transition in the ribosome that is required for the discrimination between near-cognate and cognate tRNAs (2-4). Interference with translation causes the production of erroneous proteins, and accumulation of mutant membrane proteins compromises the integrity of the bacterial envelope, which then allows the uptake of more aminoglycosides, resulting in further misreading and, eventually, cell lysis (5). Other aminoglycosides, such as apramycin and spectinomycin, act in a different mode by inhibiting the translocation process (6, 7).Under physiological conditions, aminoglycosides are cationic. The importance of electrostatic interactions in specific binding between aminoglycosides and their anionic RNA targets has been well established (8,9). Binding of aminoglycosides to nonribosomal RNAs may contribute to their potential therapeutic applications but also to the side effects that are observed for this class of compounds. Serious side effects, including ototoxicity and nephrotoxicity, have been reported and have limited the clinical use of aminoglycosides.Methods, such as surface plasm...

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“…Milli-Q water was directly obtained from a Milli-Q system equipped with a 5000-Da ultrafiltration cartridge. Boc-protected amino derivative of neomycin (5) 52 and trityl-and pmethoxybenzyl-protected amino derivative of neamine (8) 24 were synthesized according to procedures described elsewhere.…”

Section: Methodsmentioning

confidence: 99%

Conjugation of a Ru(II) Arene Complex to Neomycin or to Guanidinoneomycin Leads to Compounds with Differential Cytotoxicities and Accumulation between Cancer and Normal Cells

et al. 2013

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&These two authors contributed equally to this work. ABSTRACTA straightforward methodology for the synthesis of conjugates between a cytotoxic organometallic ruthenium(II) complex and amino-and guanidinoglycosides, as potential RNA-targeted anticancer compounds, is described. Under microwave irradiation, the imidazole ligand incorporated on the aminoglycoside moiety (neamine or neomycin) was found to replace one triphenylphosphine ligand from the ruthenium precursor [(η 6 -p-cym)RuCl(PPh 3 ) 2 ] + , allowing the assembly of the target conjugates. The guanidinylated analogue was easily prepared from the neomycin-ruthenium conjugate by reaction with N,N'-di-Boc-N"-triflylguanidine, a powerful guanidinylating reagent that was compatible with the integrity of the metal complex. All conjugates were purified by semi-preparative HPLC and characterized by ESI and MALDI-TOF MS and NMR spectroscopy. The cytotoxicity of the compounds was tested in and DU-145 (prostate) human cancer cells, as well as in the normal HEK293 (Human Embryonic Kidney) cell line, revealing a dependence on the nature of the glycoside moiety and the type of cell (cancer or healthy). Indeed, neomycin-ruthenium conjugate (2) displayed moderate anti-proliferative activity in both cancer cell lines (IC 50 ≈ 80 µM), whereas that of the neamine conjugate (4) was inactive (IC 50 ≈ 200 µM).However, the guanidinylated analogue of the neomycin-ruthenium conjugate (3) required much lower concentrations than the parent conjugate for equal effect (IC 50 = 7.17 µM in DU-145 and IC 50 = 11.33 µM in MCF-7). Although the same ranking in anti-proliferative activity was found in the non-tumorigenic cell line (3 >> 2 > 4), IC 50 values indicate that aminoglycoside-containing conjugates are about 2-fold more cytotoxic in normal cells (e.g. IC 50 = 49.4 µM for 2) than in cancer cells, whereas an opposite tendency was found with the guanidinylated conjugate, since its cytotoxicity in the normal cell line (IC 50 = 12.75 µM for 3) was similar or even lower than that found in MCF-7 and DU-145 cancer cell lines, respectively. Cell uptake studies performed by ICP-MS with conjugates 2 and 3 revealed that guanidinylation of the neomycin moiety had a positive effect on accumulation (about 3-fold higher in DU-145 and 4-fold higher in HEK293), which correlates well with the higher anti-proliferative activity of 3.Interestingly, despite the slightly higher accumulation in the normal cell than in the cancer cell line (about 1.4-fold), guanidinoneomycin-ruthenium conjugate (3) was more cytotoxic to cancer cells (about 1.8-fold), whereas the opposite tendency applied for neomycin-ruthenium conjugate (2). Such differences in cytotoxic activity and cellular 3 accumulation between cancer and normal cells open the way to the creation of more selective, less toxic anticancer metallodrugs by conjugating cytotoxic metal-based complexes such as ruthenium(II) arene derivatives to guanidinoglycosides.

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Enhanced RNA binding of dimerized aminoglycosides

Cited by 124 publications

References 30 publications

Identification of Tau Stem Loop RNA Stabilizers

Identification of Tau Stem Loop RNA Stabilizers

Evaluation of RNA-binding specificity of aminoglycosides with DNA microarrays

Conjugation of a Ru(II) Arene Complex to Neomycin or to Guanidinoneomycin Leads to Compounds with Differential Cytotoxicities and Accumulation between Cancer and Normal Cells

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