4′,6′-Methano carbocyclic thymidine: A conformationally constrained building block for oligonucleotides

Altmann, Karl‐Heinz; Kesselring, Rudolf; Francotte, Eric; Rihs, Grety

doi:10.1016/0040-4039(94)85212-x

Cited by 136 publications

(65 citation statements)

References 21 publications

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“…Several analogs containing bi-and tricyclic carbohydrate moieties have displayed enhanced duplex stability (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) and most notably so locked nucleic acids (LNA) (Fig. 1).…”

mentioning

confidence: 99%

Potent and nontoxic antisense oligonucleotides containing locked nucleic acids

Wahlestedt

Salmi

Good

et al. 2000

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

568

416

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Insufficient efficacy and͞or specificity of antisense oligonucleotides limit their in vivo usefulness. We demonstrate here that a highaffinity DNA analog, locked nucleic acid (LNA), confers several desired properties to antisense agents. Unlike DNA, LNA͞DNA copolymers were not degraded readily in blood serum and cell extracts. However, like DNA, the LNA͞DNA copolymers were capable of activating RNase H, an important antisense mechanism of action. In contrast to phosphorothioate-containing oligonucleotides, isosequential LNA analogs did not cause detectable toxic reactions in rat brain. LNA͞DNA copolymers exhibited potent antisense activity on assay systems as disparate as a G-protein-coupled receptor in living rat brain and an Escherichia coli reporter gene. LNA-containing oligonucleotides will likely be useful for many antisense applications.A ntisense oligonucleotides designed according to straightforward base-pairing rules have been useful in functional genomics efforts, and there also has been recent clinical progress in developing antisense drugs (1-5). The key objective in the field, however, remains the identification of oligonucleotide analogs that provide the possibility to achieve high in vivo efficacy in the absence of significant toxicity (1-3).To date, all human antisense studies, as well as the vast majority of studies on other species, have relied on the use of phosphorothioate DNA analogs (where one nonbridging phosphate oxygen has been replaced). Although phosphorothioates are markedly more resistant to degrading enzymes than DNA, their DNA-binding capacity (relating to potency when used as antisense agents) is low, and they are well known to cause nonspecific protein binding, largely because of their polyanionic nature. The latter phenomenon contributes to a toxicity profile that limits many applications (6, 7). For example, when injected into the brain, phosphorothioates can cause severe tissue damage, especially with repeated or prolonged administration schedules (7,8). Such phosphorothioate-induced toxic reactions are thought to be reduced but not absent in second-generation antisense agents, like mixed backbone oligonucleotides (containing phosphorothioates in combination with oligodeoxyribonucleotides or oligoribonucleotides) (9).Interestingly, conformational restriction has been successfully applied in recent years to the design of high-affinity oligonucleotides. Several analogs containing bi-and tricyclic carbohydrate moieties have displayed enhanced duplex stability (10-20) and most notably so locked nucleic acids (LNA) (Fig. 1). LNA induces unprecedented increases in the thermal stability (melting temperature, T m ) of duplexes toward complementary DNA and RNA (⌬T m ͞LNA monomer ϭ ϩ 3 to ϩ 11°C compared with the corresponding DNA reference). By virtue of their bicyclic structure, the furanose ring of the LNA monomers is locked in a 3Ј-endo conformation, thus structurally mimicking the standard RNA monomers. Moreover, LNA͞LNA duplex formation has been shown to constitute the most stable...

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mentioning

confidence: 99%

Potent and nontoxic antisense oligonucleotides containing locked nucleic acids

Wahlestedt

Salmi

Good

et al. 2000

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

568

416

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“…12.3.1.2 2 0 -Deoxyribonucleoside Analogues With the advent of the antisense field, there was a need to increase the thermodynamic stability of DNA/RNA heteroduplexes by chemical modification of the DNA strand. The desired modification involved the use of conformationally locked nucleosides to facilitate the preorganization of the annealed strands into an A-type conformation where all the sugars are puckered N. The first synthesis of a locked N, 2 0 -deoxynucleoside intended for this use was that of the thymidine analogue 17 reported by Altmann et al [17] (Scheme 12.2). Starting from enantiomerically enriched cyclopentenol 8, a hydroxyl-directed Simmons-Smith cyclopropanation provided the desired bicyclo[3.1.0]hexane 9 as a single diastereoisomer.…”

Section: Synthesis Of Locked Nucleosidesmentioning

confidence: 99%

“…Unfortunately, during early attempts to make modified ODNs containing locked, 2 0 -exo (N) bicyclo[3.1.0]hexane units some serious difficulties were reported with the phosphoramidite approach [17]. These difficulties were not encountered with the hydrogen phosphonate protocol during the synthesis of a phosphorothioate 15-mer ODN containing 10 modified 2 0 -exo N-thymidine units [20].…”

Section: Synthesis Of Oligodeoxynucleotides (Odns) Containing Locked mentioning

confidence: 99%

The Properties of Locked Methanocarba Nucleosides in Biochemistry, Biotechnology, and Medicinal Chemistry

Márquez

2008

Modified Nucleosides

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“…Almost two decades ago, Altmann et al [8] and Marquez and co-workers [9] independently showed that the bicyclo-[3.1.0]hexyl scaffold can serve as an effective structural mimic of the C3'-endo sugar pucker. The appended cyclopropyl ring essentially "locks" the conformation of the cyclopentane ring without the need for an electron-withdrawing group at the 2'-position (Scheme 1).…”

Section: Introductionmentioning

confidence: 99%