Antisense RNA gene therapy for studying and modulating biological processes

Abstract

Agents that produce their effects through an antisense mechanism offer the possibility of developing highly specific alternatives to traditional pharmacological antagonists, thereby providing a novel class of therapeutic agents, ones which act at the level of gene expression. Among the antisense compounds, antisense RNA produced intracellularly by an expression vector has been used extensively in the past several years. This review considers the advantages of the antisense RNA approach over the use of antisense oligodeoxynucleotides, the different means by which one may deliver and produce antisense RNA inside cells, and the experimental criteria one should use to ascertain whether the antisense RNA is acting through a true antisense mechanism. Its major emphasis is on exploring the potential therapeutic use of antisense RNA in several areas of medicine. For example, in the field of oncology antisense RNA has been used to inhibit several different target proteins, such as growth factors, growth factor receptors, proteins responsible for the invasive potential of tumor cells and proteins directly involved in cell cycle progression. In particular, a detailed discussion is presented on the possibility of selectively inhibiting the growth of tumor cells by using antisense RNA expression vectors directed to the individual calmodulin transcripts. Detailed consideration is also provided on the development and potential therapeutic applications of antisense RNA vectors targeted to the D2 dopamine receptor subtype. Studies are also summarized in which antisense RNA has been used to develop more effective therapies for infections with certain viruses such as the human immunodeficiency virus and the virus of hepatitis B, and data are reviewed suggesting new approaches to reduce elevated blood pressure using antisense RNA directed to proteins and receptors from the renin-angiotensin system. Finally, we outline some of the problems which the studies so far have yielded and some outstanding questions which remain to be answered in order to develop further antisense RNA vectors as therapeutic agents.

DNA targeting of rhinal cortex D2 receptor protein reversibly blocks learning of cues that predict reward

“…In the mouse, bilateral intrastriatal injections of a DNA antisense expression construct targeting the D2 receptor were followed by changes in D2-mediated behaviors, including catalepsy and climbing, lasting several weeks. D2 receptor ligand binding was altered in parallel with the behavioral results (25,26). The specificity and long duration of effects observed when using this technique suggested it might be a particularly attractive approach to apply to learning experiments in primates.…”

“…Given these experimental requirements, we adapted a molecular approach that has been successfully used to decrease ligand binding by the murine D2 receptor (24)(25)(26). In the mouse, bilateral intrastriatal injections of a DNA antisense expression construct targeting the D2 receptor were followed by changes in D2-mediated behaviors, including catalepsy and climbing, lasting several weeks.…”

“…First, the D2 receptor shows a distinctive distribution with increased density in the deep layers of rhinal cortex, suggesting that this receptor subtype might have a special role in this tissue, whereas the D1 receptor had a more diffuse, and, at peak, less dense, distribution (20,21). Second, and very important for us, was that the D2 receptor-targeted DNA treatment had a pronounced enough effect on the D2 receptors in a murine model to be followed by large effects on motor behavior (24)(25)(26), leading us to believe that the D2-targeting material might be effective in the monkey also. Since our study was undertaken, new information has come to light also showing that the D2 receptor may play an important role in regulating associative learning (30).…”

Viral vector producing antisense RNA restores myotonic dystrophy myoblast functions

“…[18][19][20][21] The antisense RNA technology utilizes ribonucleic acids that, like antisense oligonucleotides, bind by complementary interactions with a specific target mRNA (in this case forming RNA:RNA hybrids) and subsequently either block one of the several steps involved in the translation of a targeted protein or induced destruction of the target RNA most likely by activating an endonuclease activity following deamination of dsRNA by an adenosine deaminase. 22,23 Expression vectors producing antisense RNA have major advantages over the oligonucleotides in that, since vectors can synthesize the antisense RNA continuously inside the cell after a single administration, it would have a longer duration of action.…”

Thérapies antisens dirigées contre le récepteur de l’IGF-I

“…Brièvement, l'ARN antisens complé-mentaire de l'ARNm, en formant un ARN double brin, bloque physiquement la machinerie ribosomale, tandis que les oligonucléotides antisens induisent, la plupart du temps, une ribonucléase spécifique, la RNase H, qui reconnaît l'hybride ARNm/oligonucléotide et dégrade le brin ribonucléique (pour revue, [7,8] [23,24] [9, 10, 12-14, 17, 19, 20]. Les oligonucléotides antisens ont le même effet, ceci grâce à l'induction d'une ribonucléase spécifique, la RNase H [6,10,15,27].…”