Antisense applications for biological control

Abstract

Although Nature's antisense approaches are clearly impressive, this Perspectives article focuses on the experimental uses of antisense reagents (ASRs) for control of biological processes. ASRs comprise antisense oligonucleotides (ASOs), and their catalytically active counterparts ribozymes and DNAzymes, as well as small interfering RNAs (siRNAs). ASOs and ribozymes/DNAzymes target RNA molecules on the basis of Watson-Crick base pairing in sequence-specific manner. ASOs generally result in destruction of the target RNA by RNase-H mediated mechanisms, although they may also sterically block translation, also resulting in loss of protein production. Ribozymes and DNAzymes cleave target RNAs after base pairing via their antisense flanking arms. siRNAs, which contain both sense and antisense regions from a target RNA, can mediate target RNA destruction via RNAi and the RISC, although they can also function at the transcriptional level. A considerable number of ASRs (mostly ASOs) have progressed into clinical trials, although most have relatively long histories in Phase I/II settings. Clinical trial results are surprisingly difficult to find, although few ASRs appear to have yet established efficacy in Phase III levels. Evolution of ASRs has included: (a) Modifications to ASOs to render them nuclease resistant, with analogous modifications to siRNAs being developed; and (b) Development of strategies to select optimal sites for targeting. Perhaps the biggest barrier to effective therapies with ASRs is the "Delivery Problem." Various liposomal vehicles have been used for systemic delivery with some success, and recent modifications appear to enhance systemic delivery, at least to liver. Various nanoparticle formulations are now being developed which may also enhance delivery. Going forward, topical applications of ASRs would seem to have the best chances for success. In summary, modifications to ASRs to enhance stability, improve targeting, and incremental improvements in delivery vehicles continue to make ASRs attractive as molecular therapeutics, but their advance toward the bedside has been agonizingly slow.

Sirt-1 Is Required for the Inhibition of Apoptosis and Inflammatory Responses in Human Tenocytes

“…Several ASO-based drugs have been developed as gene-silencing therapeutic agents for use in clinical trials and the treatment of diseases such as cancer (20,21). Thus far there have been no in vitro studies on the effects of ASO against Sirt-1 in the context of tendon biology.…”

Oligonukleotid Therapeutika – eine neu entstehende Substanzklasse

“…20 weitere ASO Moleküle in klinischen Phase-II-Prüfungen [3,22]. Zu den am weitesten in der klinischen Erprobung fortgeschrittenen ASO gehört ein gegen den "Transforming growth factor β 2" (TGF-β2) gerichtetes ASO.…”

“…Neben modernen Antikörpertherapien ist insbesondere die noch junge Substanzklasse der Oligonukleotid Therapeutika als ein prototypischer Vertreter dieser neuen molekular gezielten Therapieformen anzusehen [3,4]. Oligonukleotide sind kurzkettige DNA oder RNA Moleküle, die aus Einzel-oder Doppelsträngen von 10-50 Nukleotiden bestehen.…”

Transcriptomics and proteomics in studies of induced differentiation of leukemia cells

“…Подобные исследования обеспечивают наглядность эффекта тестируемой молекулы, однако характеризуются низкой продуктивностью; кроме того наблюдаемое уменьшение пролиферации и развитие апоптоза могут быть обусловлены неспецифическим ингибированием синтеза белка [13]. С другой стороны, в процессе дифференцировки происходит изменение содержания молекул мРНК и белков, одни из которых необходимы для формирования зрелого фенотипа, другие же могут служить регуляторными молекулами, направляющими клетку по пути пролиферации или дифференцировки.…”