SEARCH · PubMed Health

Results for “Antisense oligonucleotides”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources

PubMed1993

Inhibition of mouse hepatitis virus multiplication by antisense oligonucleotide, antisense RNA, sense RNA and ribozyme.

Antisense nucleic acids against specific sequences of mouse hepatitis virus (MHV)-RNAs were tested for their inhibitory effects on viral multiplication in mouse DBT cells. An antisense oligonucleotide containing a sequence complementary to leader RNA was synthesized and shown to induce a significant inhibitory effect on the multiplication of MHV-JHM. A vector which expressed the antisense or sense mRNA7 of MHV was transfected into DBT cells. A decreased multiplication of MHV was observed in both cell lines. The transfected cell line which expressed ribozyme against the 5'-end of the MHV genome was established. The rate of inhibition of MHV-multiplication and the quantity of synthesized virus-specific mRNAs in this transfected cell line were the same for both antisense and sense RNA. These results show that antisense nucleic acids might be eligible for use as antiviral agents against MHV multiplication.

Animals↗

PubMed2001

A dynamical systems model to simulate the perturbation kinetics of gene expression by antisense oligonucleotides.

Antisense oligonucleotides owe their efficacy to an ability to induce RNase H-dependent suppression of RNA translation, for sufficient time to allow physiological proteolysis. The magnitude and time delay preceding the protein nadir concentration determine the extent and timing of maximum antisense oligonucleotide activity. Antisense oligonucleotide degradation underlies reversal of RNA downregulation. The kinetics of protein downregulation is therefore determined by the complex interaction of both ligand chemistry (nuclease stability, affinity and RNase H activation), and gene expression kinetics. Optimization of antisense oligonucleotide efficacy and experimental design requires understanding of these interactions. The kinetics of protein and RNA downregulation have therefore been simulated by analysing a two-compartment kinetic model incorporating RNase H-dependent transcript degradation. The system of nonlinear differential equations describing this model was solved numerically using Runge-Kutte integration. The timecourse solutions corresponding to the four state variables (RNA, protein, antisense/RNA heteroduplex and antisense oligonucleotide), were determined simultaneously. This allowed systematic in silico examination of the consequences of altering variables such as oligonucleotide concentration, affinity, and stability, or the scheduling of multiple transfections on RNA and protein perturbations. By providing a tool for examining antisense oligonucleotide action theoretically, this heuristic model should facilitate both the rational design and interpretation of antisense experiments.

Animals↗

PubMed2001

Encapsulation of DNA in negatively charged liposomes and inhibition of bacterial gene expression with fluid liposome-encapsulated antisense oligonucleotides.

Antisense therapy for the treatment of bacterial infections is a very attractive alternative to overcome drug resistance problems. However, the penetration of antisense oligonucleotides into bacterial cells is a major huddle that has delayed research and application in this field. In the first part of this study, we defined efficient conditions to encapsulate plasmid DNA and antisense oligonucleotides in a fluid negatively charged liposome. Subsequently, we evaluated the potential of liposome-encapsulated antisense oligonucleotides to penetrate the bacterial outer membrane and to inhibit gene expression in bacteria. It was found that 48.9+/-12% and 43.5+/-4% of the purified plasmid DNA and antisense oligonucleotides were respectively encapsulated in the liposomes. Using fluorescence-activated cell sorting analysis, it was shown, after subtraction of the fluorescence values due to the aggregation phenomenon measured at 4 degrees C, that about 57% of bacterial cells had integrated the encapsulated antisense oligonucleotides whereas values for free antisenses were negligible. The uptake of the encapsulated anti-lacZ antisense oligonucleotides resulted in a 42% reduction of beta-galactosidase compared to 9% and 6% for the encapsulated mismatch antisense oligonucleotides and the free antisense oligonucleotides respectively. This work shows that it is possible to encapsulate relatively large quantities of negatively charged molecules in negative fluid liposomes and suggests that fluid liposomes could be used to deliver nucleic acids in bacteria to inhibit essential bacterial genes.

DNA↗

PubMed2001

Rational selection and quantitative evaluation of antisense oligonucleotides.

Antisense oligonucleotides are an attractive therapeutic option to modulate specific gene expression. However, not all antisense oligonucleotides are effective in inhibiting gene expression, and currently very few methods exist for selecting the few effective ones from all candidate oligonucleotides. The lack of quantitative methods to rapidly assess the efficacy of antisense oligonucleotides also contributes to the difficulty of discovering potent and specific antisense oligonucleotides. We have previously reported the development of a prediction algorithm for identifying high affinity antisense oligonucleotides based on mRNA-oligonucleotide hybridization. In this study, we report the antisense activity of these rationally selected oligonucleotides against three model target mRNAs (human lactate dehydrogenase A and B and rat gp130) in cell culture. The effectiveness of oligonucleotides was evaluated by a kinetic PCR technique, which allows quantitative evaluation of mRNA levels and thus provides a measure of antisense-mediated decreases in target mRNA, as occurs through RNase H recruitment. Antisense oligonucleotides that were predicted to have high affinity for their target proved effective in almost all cases, including tests against three different targets in two cell types with phosphodiester and phosphorothioate oligonucleotide chemistries. This approach may aid the development of antisense oligonucleotides for a variety of applications.

Animals↗

PubMed1998

Do overexpressed oncoproteins cause malignant growth of cancer cells?--Studied by antisense oligonucleotides.

Antisense oligonucleotides were used to demonstrate the importance of insulin-like growth factor II and alpha-fetoprotein for the growth of hepatoma cell lines. The level of insulin-like growth factor II was found to correlate positively with cell proliferative activity, whereas alpha-fetoprotein was not. We have developed an in vitro system for the screening of antisense oligonucleotides effective for inhibiting target protein production. Using this system, the effectiveness of antisense oligonucleotides can be determined even when a specific antibody or activity assay method is not available. These approaches will be useful for verifying the physiological role of other oncoproteins or proteins in living cells, and antisense oligonucleotides may be developed as new therapeutic agents.

Cell Division↗

PubMed2003

Structural modifications of antisense oligonucleotides.

Antisense oligonucleotides are efficient tools for the inhibition of gene expression in a sequence specific way. Natural oligonucleotides are decomposed rapidly in biological systems, which strongly restrict their application. In contrast, artificial oligonucleotides are designed to be more stable against degradation than the target mRNA, which results in a catalytic effect of the drug. Modification of the phosphate linkage has been the first successful strategy for antisense drug developments and Fomivirsene the first antisense drug in therapy. The launch of Fomivirsene has resulted in a revolutionary spin off to antisense research leading to a second generation of antisense oligonucleotides, which are stable against oligonucleotide cleaving enzymes. Among these, oligonucleotides bearing an alkoxy substituent in position 2' were the most successful ones. The third generation of antisense oligonucleotides contains structure elements, which enhance the antisense action. Zwitterionic oligonucleotides show remarkable results, first, because the stability against ribozymes is largely increased, and secondly, because the electrostatic repulsion between the anionic sense and the zwitterionic antisense cords is minimized. Promising new target molecules in antisense research are oligonucleotide chimäres, which enhance the antisense action (chimäres with intercalators, chelators or polyamines) or enable an application as sequence specific detectors (chimäres with biotin, fluorescein or radioligands).

Animals↗

PubMed1996

Towards genomic drug therapy with antisense oligonucleotides.

Antisense oligonucleotides represent a novel class of potential drugs for highly selective blocking of genes. The basic concept of antisense strategy is simple: an antisense molecule recognizes a complementary mRNA (or DNA) by sequence-specific base pairing, and hence prevents translation (or transcription), resulting in a selective inhibition of protein synthesis. Because of these properties, antisense oligonucleotides have great potential as therapeutic agents in several human diseases, such as viral diseases, malignancies and dominant hereditary diseases. However, technical difficulties have slowed down their use as drugs: structural modifications are needed to increase the stability and potency of synthetic oligonucleotides, specific delivery systems are required to facilitate their entry into target cells, and more information is needed to their mechanism of action. Much of the current research on antisense oligonucleotides takes place at the interface of chemistry and biomedical sciences, a multidisciplinary field where finding a common language is sometimes difficult. The aim of this review is to present an overview of the antisense strategy in terms which should be understandable for chemists, biologists and physicians.

Animals↗

PubMed2000

The disposition (ADME) of antisense oligonucleotides.

Antisense oligonucleotides hold great promise as novel therapeutic agents designed to specifically and selectively inhibit the production of various disease-related gene products. For efficacy to occur, the therapeutic entity must reach the site of action in amounts sufficient to produce the desired therapeutic effect. Pharmacokinetics is defined as the study of the time course of the absorption, distribution, metabolism and elimination (ADME) of drugs. An understanding of the pharmacokinetics of antisense oligonucleotides and, in particular, the mechanisms by which oligonucleotides accumulate in tissues and in cells are critical to understanding the limitations of this technology and ultimately the development of effective antisense therapeutics. This review summarizes the known observations on the pharmacokinetics of antisense oligonucleotides with particular attention to contributions (non-clinical and clinical) published during the interval 1997 to 2000. Principles underlying the ADME of oligonucleotides are presented at the beginning of each section.

Absorption↗

PubMed2001

Topical and transdermal delivery of antisense oligonucleotides.

Antisense oligonucleotides have great potential as therapeutic agents. As a result, a variety of chemistries have been developed to improve the efficacy of these molecules without compromising their specificity. Because the skin is such a large organ with extensive accessibility, it is a natural target for drug delivery. It is, however, an effective barrier, so physical and chemical methods to improve drug penetration have been developed. These enhancement techniques can be combined with modified oligonucleotide chemistries to provide sufficient levels of antisense activity either within the skin or systemically. This review will describe in vitro and in vivo experiments that demonstrate the potential of antisense oligonucleotides to treat both dermal and systemic disorders.

Administration, Cutaneous↗

PubMed2003

Cellular uptake and intracellular fate of antisense oligonucleotides.

Antisense oligonucleotides and short interfering RNAs are routinely used for gene function analysis and are being developed for clinical applications. The mechanism underlying internalization of free oligonucleotides into cells is poorly understood and inefficient in most cases. Antisense oligonucleotide delivery into ex vivo cells is routinely improved by the addition of cationic lipids. New chemical modifications and vectors allowing improved cellular delivery in vivo are being developed.

Animals↗

PubMed1998

Inhibition of endogenous expression of connective tissue growth factor by its antisense oligonucleotide and antisense RNA suppresses proliferation and migration of vascular endothelial cells.

Previously, we cloned an mRNA predominantly expressed in hypertrophic chondrocytes by differential display-PCR from a human chondrosarcoma-derived chondrocytic cell line (HCS-2/8) that is identical to that of connective tissue growth factor (CTGF). In the present study, we investigated the roles of CTGF in the proliferation and migration of vascular endothelial cells using its antisense oligonucleotide and antisense RNA, because angiogenesis into the hypertrophic zone of cartilage occurs at the final step of endochondral ossification. Immunohistochemical and immunofluorescence techniques revealed that not only hypertrophic chondrocytes but also endothelial cells in the cost-chondral junctions of mouse ribs were stained with an anti-CTGF antibody in vivo. Northern blot analysis revealed that CTGF was strongly expressed in chondrocytic cells as well as bovine aorta endothelial (BAE) cells in culture, but not in other types of cells such as osteoblastic cells. Its expression in BAE cells was greater in the growing phase than in the confluent phase. When one-half of a monolayer of a confluent culture of BAE cells had been peeled off, only the cells proliferating and extending into the vacant area were stained with the anti-CTGF antibody. The addition of an antisense oligonucleotide inhibited the proliferation and extension of the BAE cells into the vacant area. The antisense oligonucleotide also inhibited the proliferation of BAE cells in the rapidly proliferating phase. In a Boyden chamber assay, pretreatment with the antisense oligonucleotide markedly inhibited the migration of BAE cells. Furthermore, the abilities to proliferate and migrate of BAE cells, which were stably transfected with expression vectors that generate the antisense RNA of CTGF cDNA, were markedly lower than those of the control. These findings suggest that endogenous CTGF expression is involved in the proliferation and migration of BAE cells.

Animals↗

PubMed1992

Therapeutic implications of antisense oligonucleotides.

Antisense oligonucleotides and their derivatives have been shown to be specific inhibitors of gene expression. They are considered a very promising new generation of drugs, potentially useful in most human diseases, including cancers and viral infections. The elegance of the antisense oligonucleotides lies in their ability to bind, via standard Watson-Crick base pairing, a complementary region within a target mRNA. Although easily synthesized, therapeutic applications have been restricted by a number of difficulties including: stability, pharmacokinetic behavior (both a cellular and at systemic level), and the high cost of industrial production. The object of this review is to briefly describe the major properties of antisense oligonucleotides, the modalities currently under investigation to circumvent the difficulties in their use, and the up-to-date experimental applications, including findings from our own laboratory. As very few oligonucleotides need to be synthesized in order to obtain an active compound, compared with an average of 10,000 new standard compounds, prospects are extremely exciting and worthy of maximum attention.

Autoimmune Diseases↗

PubMed2005

Molecular and cellular barriers limiting the effectiveness of antisense oligonucleotides.

Antisense oligonucleotides present a powerful means to inhibit expression of specific genes, but their effectiveness is limited by factors including cellular delivery, biochemical attack, and poor binding to target. We have developed a systems model of the processes required for an antisense oligonucleotide to enter, gain access to its target mRNA, and exert activity in a cell. The model accurately mimics observed trends in antisense effectiveness with the stability of the oligonucleotide backbone and with the affinity/kinetics of binding to the mRNA over the time course of inhibition. By varying the model parameters within the physically realizable range, we note that the major molecular and cellular barriers to antisense effectiveness are intracellular trafficking, oligonucleotide-mRNA binding rate, and nuclease degradation of oligonucleotides, with a weaker dependence on total cellular uptake than might be expected. Furthermore, the model may serve as a predictive tool to design and test strategies for the cellular use of antisense oligonucleotides. The use of integrated mathematical modeling can play a significant role in the development of antisense and related technologies.

Animals↗

PubMed1992

Liposomes as a drug delivery system for antisense oligonucleotides.

Antisense oligonucleotides seem to provide a promising new tool for the therapy of viral diseases and of cancer. However, before the therapeutic potential of antisense compounds can be fulfilled, it will be necessary to overcome significant problems relating to their inefficient uptake by cells and their rapid loss from the body. Phospholipid vesicles (liposomes) have been widely used as a drug delivery system for standard anticancer and anti-infectious drugs. In this article we examine the potential role of liposomes as a drug delivery system for antisense oligonucleotides.

Antineoplastic Agents↗

PubMed2000

Cellular delivery of antisense oligonucleotides.

Antisense oligonucleotides can be successfully employed to inhibit specifically gene expression. However, many oligonucleotide classes are polyanions and cannot passively transit the cell membrane. Thus, the use of naked oligonucleotides for antisense purposes poses some rather stringent challenges, and it is not a trivial task to appropriately interpret the data derived from experiments in which they have been used. Multiple methods have been developed to improve intracellular, and in particular, intranuclear oligonucleotide delivery, and in doing so, to maximize the performance of the antisense technologies that are currently available. This review discusses the use of cationic lipids, protein and peptide delivery agents, and several novel chemical and viral methods that have recently been explored as delivery vehicles, focussing not only on their strengths, but also on their limitations.

Animals↗

PubMed2001

Targeting the expression of anti-apoptotic proteins by antisense oligonucleotides.

Antisense oligonucleotide (ASO) biotechnology has been widely used to inhibit the expression of proteins involved in human disease. ASOs are designed to bind messenger RNA transcripts via Watson-Crick base-pairing and inhibit synthesis of targeted proteins. These proteins include protein kinases, growth factors, glutamate receptors, anti-apoptotic proteins, and proteins involved in genetic disorders. Non-mRNA targets such as the RNA component of the telomerase enzyme are also being explored. Pre-clinical and clinical trials using ASO biotechnology have progressed with standard ASOs such as phosphorothioates, but newer ASO analogs are rapidly being developed with the idea of enhancing specificity and biological activity. A current major research thrust is the design and testing of antisense oligonucleotides as anti-cancer drugs. The primary focus of this review is an analysis of recent uses of ASO biotechnology to inhibit anti-apoptotic gene expression in tumor cells.

Clinical Trials as Topic↗

PubMed1999

Preclinical and clinical pharmacology of antisense oligonucleotides.

Antisense oligonucleotides are short (typically 15-20 bases in length pieces of synthetically manufactured, chemically modified DNA or RNA. They are designed to interact by Watson-Crick base pairing with mRNA transcripts encoding proteins of interest, and by virtue of this interaction inhibit the expression of the protein encoded in the mRNA. Since their first proposed use in 1978, antisense oligonucleotides have become come widely used as tools to modulate gene expression in tissue culture. The great specificity that these compounds exhibited in vitro has also led them to be viewed as potentially therapeutically useful. This interest has resulted in the progression of (to date) a dozen compounds into human clinical trials for a variety of indications ranging from cancer to inflammatory diseases. Here, we will review some of the progress that has been made with antisense pharmacology, both in vitro and in vivo, as well as describe the current status of this class of compound in clinical trials.

Clinical Trials as Topic↗

PubMed1994

Inhibition of herpes simplex virus 1 reproduction with hydrophobized antisense oligonucleotides.

Antisense oligonucleotides were modified by their ends with hydrophobic substituents which permitted enhancing their activity. The effect of hydrophobized oligonucleotides on reproduction of Herpes Simplex Virus type 1 in Vero cells was studied. Two types of oligonucleotides were used: a 12-mer complementary to the splicing site 983-994 of early mRNA-5 of the virus and 19-mer complementary to the site of mRNA that encodes the virus DNA-polymerase. These oligonucleotides were modified by 5'-ends with n-undecyl or cholesteryl moieties and by 3'-ends with acridine or 1,7-heptanediol. In comparison with the unmodified oligonucleotides the hydrophobized ones were significantly more active and inhibited HSV-1 infection at micromolar concentrations.

Acridines↗