Safety of intracoronary administration of c-myc antisense oligomers after percutaneous transluminal coronary angioplasty (PTCA)

Antisense molecules: A new class of drugs

An improved understanding of disease pathogenesis leads to identification of novel therapeutic targets. From a pharmacologic point of view, these can be addressed by small chemical compounds, so-called biologicals (eg, mAbs and recombinant proteins), or by a rather new class of molecule based on the antisense concept. Recently, a new wave of clinical studies exploring antisense strategies is evolving. In addition to cancer, they include predominantly trials on infectious and noninfectious diseases, such as chronic inflammatory and metabolic conditions. This article, based on a systematic PubMed literature search, highlights recent developments in this emerging field.

Transfection of NF-κB decoy oligodeoxynucleotide suppresses pulmonary metastasis by murine osteosarcoma

Nuclear factor-kappa B (NF-κB) has a pivotal role in the progression and distant metastasis of cancers, including malignant bone tumors. To inhibit NF-κB activation, a new molecular therapy using synthetic double-stranded oligodeoxynucleotide (ODN) as a 'decoy' cis element against NF-κB has been developed. To determine whether pulmonary metastasis of osteosarcoma is reduced by inhibiting the action of NF-κB, NF-κB decoy ODN was transfected into the nuclei of murine osteosarcoma cells with high pulmonary metastatic potential, the LM8 cell line, using a three-dimensional alginate spheroid culture model. An in vitro study demonstrated the successful transfection of LM8 cells cultured in alginate beads by 'naked' NF-κB decoy ODN and that the activation of NF-κB signaling was significantly suppressed. Tumor growth was not affected by transfection of NF-κB decoy ODN, however, the expression of vascular endothelial growth factor (VEGF) and intercellular adhesion molecule 1 (ICAM-1) mRNA was markedly decreased. Furthermore, the transfection of 'naked' NF-κB decoy ODN effectively suppressed pulmonary metastasis in an in vivo alginate bead transplantation model. Our results suggest that NF-κB has a central and specific role in the regulation of tumor metastasis and could be a molecular target for development of anti-metastatic treatments for osteosarcoma.

Progress in the development of nucleic acid therapeutics

Abnormal gene expression is a hallmark of many diseases. Gene-specific downregulation of aberrant genes could be useful therapeutically and potentially less toxic than conventional therapies due its specificity. Over the years, many strategies have been proposed for silencing gene expression in a gene-specific manner. Three major approaches are antisense oligonucleotides (AS-ONs), ribozymes/DNAzymes, and RNA interference (RNAi). In this brief review, we will discuss the successes and shortcomings of these three gene-silencing methods, and the approaches being taken to improve the effectiveness of antisense molecules. We will also provide an overview of some of the clinical applications of antisense therapy.

Molecular therapy to inhibit NFkappaB activation by transcription factor decoy oligonucleotides

Molecular therapy is emerging as a potential strategy for the treatment of various diseases for which few known effective therapies exist. One strategy for combating disease processes has been to target the transcriptional process. Two approaches have been used to accomplish this: the use of antisense complimentary to the mRNA of interest and the use of ribozymes, a unique class of RNA molecules that not only store information but also process catalytic activity. Ribozymes are known to catalytically cleave specific target RNA, leading to its degradation, whereas antisense molecules inhibit translation by binding to mRNA sequences on a stoichiometric basis. More recently, small interfering RNA has been shown to inhibit target gene expression. The application of oligonuclotide technology, such as antisense, to regulate the transcription of disease-related genes in vivo has important therapeutic potential. Transfection of cis-element double-stranded oligodeoxynucleotides has been reported as a powerful tool in a new class of anti-gene strategies for molecular therapy.

Prevention and regression of atopic dermatitis by ointment containing NF-kB decoy oligodeoxynucleotides in NC/Nga atopic mouse model

Atopic dermatitis, a chronic inflammatory skin disease characterized by relapsing eczema and intense prurigo, requires effective and safe pharmacological therapy. In this study, we examined the efficacy of ointment containing NF-kB decoy oligodeoxynucleotides (ODN) on atopic dermatitis lesions in NC/Nga mice, which are characterized by the spontaneous onset of atopic dermatitis in conventional conditions. Topical administration of NF-kB decoy ODN twice a month resulted in a significant reduction in clinical skin condition score and marked improvement of histological findings. Reduction of the atopic skin condition by NF-kB decoy ODN was accompanied by a significant decrease in migration of mast cells into the dermis and an increase in apoptotic cells. Here, we demonstrated the successful treatment of atopic dermatitis with ointment containing NF-kB decoy ODN in a mouse model, promising new therapy for atopic dermatitis.

Nucleic-acid therapeutics: basic principles and recent applications

The sequencing of the human genome and the elucidation of many molecular pathways that are important in disease have provided unprecedented opportunities for the development of new therapeutics. The types of molecule in development are increasingly varied, and include antisense oligonucleotides and ribozymes. Antisense technology and catalytic nucleic-acid enzymes are important tools for blocking the expression of abnormal genes. One FDA-approved antisense drug is already in the clinic for the treatment of cytomegalovirus retinitis, and other nucleic-acid therapies are undergoing clinical trials. This article reviews different strategies for modulating gene expression, and discusses the successes and problems that are associated with this type of therapy.

Molecular strategy using cis-element 'decoy' of E2F binding site inhibits neointimal formation in porcine balloon-injured coronary artery model

Transcription factor E2F plays a pivotal role in the transactivation of cell cycle regulatory genes, leading to vascular lesion formation. Double-stranded DNA with high affinity for E2F as 'decoy' cis elements may block the activation of genes mediating the cell cycle, resulting in an effective therapeutic agent for treating intimal hyperplasia. In this study, we tested the feasibility of E2F decoy therapy to treat neointimal formation in a porcine coronary artery balloon injury model. An angioplasty catheter was inserted in the left anterior descending coronary artery of pigs to cause vascular injury. Initially, we tested the feasibility of transfection of FITC-labeled E2F decoy ODN using a hydrogel balloon catheter. Fluorescence due to E2F decoy ODN could be detected throughout the medial layer. Therefore, we transfected E2F decoy ODN into the balloon-injured artery using hydrogel catheter. Of importance, intravascular ultrasound (IVUS) and histological evaluation demonstrated that plaque area in the balloon-injured artery was significantly reduced by E2F decoy ODN compared with mismatched decoy ODN at 1 month after a single transfection (P < 0.01). In contrast, luminal and total vessel areas were significantly increased in vessels treated with E2F decoy ODN as compared with mismatched decoy. Endothelial function after angioplasty was not affected by E2F decoy transfection. Finally, we tested the acute toxicity of E2F decoy ODN in monkeys, and no apparent side-effects were detected. Here, we report the successful in vivo transfer of E2F decoy ODN using a hydrogel catheter to inhibit vascular lesion formation in balloon-injured porcine coronary artery without any apparent side-effects.