Use of G-actin for improving transfection of a...

Chemistry: molecular biology and microbiology – Process of mutation – cell fusion – or genetic modification – Introduction of a polynucleotide molecule into or...

Reexamination Certificate

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C435S456000, C435S458000, C435S325000, C424S001130, C514S002600, C514S04400A

Reexamination Certificate

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06528312

ABSTRACT:

The present invention relates to the use of a nuclease inhibitor or of interleukin-10 (IL-10) for the preparation of a therapeutic composition for improving transfection of a polynucleotide into a cell, and to compositions comprising a mixture of polynucleotide and nuclease inhibitor and/or interleukin-10. Such a composition is useful in gene therapy, vaccination, and any therapeutic situation in which a gene-based product is administered to cells in vivo.
Gene therapy has generally been conceived as principally applicable to heritable deficiency diseases (cystic fibrosis, dystrophies, haemophilias, etc.) where permanent cure may be effected by introducing a functional gene. However, a much larger group of diseases, notably acquired diseases (cancer, AIDS, multiple sclerosis, etc.) might be treatable by transiently engineering host cells to produce beneficial proteins.
Applications are, for example, the treatment of muscular dystrophies or of cystic fibrosis. The genes of Duchenne/Becker muscular dystrophy and cystic fibrosis have been identified and encode polypeptides termed dystrophin and cystic fibrosis transmembrane conductance regulator (CFTR), respectively. Direct expression of these genes within, respectively, the muscle or lung cells of patients should contribute to a significant amelioration of the symptoms by expression of the functional polypeptide in targeted tissues. Moreover, studies in cystic fibrosis have suggested that one would need to achieve expression of the CFTR gene product in only about 5% of lung epithelial cells in order to significantly improve the pulmonary symptoms.
Another application of gene therapy is vaccination. In this regard, the immunogenic product encoded by the polynucleotide introduced in cells of a vertebrate may be expressed and secreted or be presented by said cells in the context of the major histocompatibility antigens, thereby eliciting an immune response against the expressed immunogen. Functional polynucleotides can be introduced into cells by a variety of techniques resulting in either transient expression of the gene of interest, referred to as transient transfection, or permanent transformation of the host cells resulting from incorporation of the polynucleotide into the host genome.
Successful gene therapy depends on the efficient delivery to and expression of genetic information within the cells of a living organism. Most delivery mechanisms used to date involve viral vectors, especially adeno- and retroviral vectors. Viruses have developed diverse and highly sophisticated mechanisms to achieve this goal including crossing of the cellular membrane, escape from lysosomal degradation, delivery of their genome to the nucleus. Consequently, viruses have been used in many gene delivery applications in vaccination or gene therapy applied to humans. The use of viruses suffers from a number of disadvantages: retroviral vectors cannot accommodate large-sized DNA (for example, the dystrophin gene which is around 13 Kb), the retroviral genome is integrated into host cell DNA and may thus cause genetic changes in the recipient cell and infectious viral particles could disseminate in the organism or in the environment and adenoviral vectors can induce a strong immune response in treated patients (Mc Coy et al., Human Gene Therapy 6 (1995), 1553-1560; Yang et al., Immunity 1 (1996), 433-442). Nevertheless, despite these drawbacks, viral vectors are currently the most useful delivery systems because of their efficiency. Non-viral delivery systems have been developed which are based on receptor-mediated mechanisms (Perales et al., Eur. J. Biochem. 226 (1994), 255-266; Wagner et al., Advanced Drug Delivery Reviews 14 (1994), 113-135), on polymer-mediated transfection such as polyamidoamine (Haensler and Szoka, Bioconjugate Chem. 4 (1993), 372-379), dendritic polymer (WO 95/24221), polyethylene imine or polypropylene imine (WO 96/02655), polylysine (U.S. Pat. No. 5,595,897 or FR 2 719 316) or on lipid-mediated transfection (Feigner et al., Nature 337 (1989), 387-388) such as DOTMA (Feigner et al., Proc. Natl. Acad. Sci. USA 84 (1987), 7413-7417), DOGS or Transfectam™ (Behr et al., Proc. Natl. Acad. Sci. USA 86 (1989), 6982-6986), DMRIE or DORIE (Felgner et al., Methods 5 (1993), 67-75), DC-CHOL (Gao and Huang, BBRC 179 (1991), 280-285), DOTAP™ (McLachlan et al., Gene Therapy 2 (1995), 674-622) or Lipofectamine™. These systems present potential advantages with respect to large-scale production, safety, targeting of transfectable cells, low immunogenicity and the capacity to deliver large fragments of DNA. Nevertheless their efficiency in vivo is still limited.
Finally, in 1990, Wolff et al. (Science 247 (1990), 1465-1468) have shown that injection of naked RNA or DNA, without a special delivery system, directly into mouse skeletal muscle results in expression of reporter genes within the muscle cells. This technique for transfecting cells offers the advantage of simplicity and experiments have been conducted that support the usefulness of this system for the delivery to the lung (Tsan et al., Am. J. Physiol. 268 (1995), L1052-L1056; Meyer et al., Gene Therapy 2 (1995), 450-460), brain (Schwartz et al., Gene Therapy 3 (1996), 405-411), joints (Evans and Roddins, Gene therapy for arthritis; In Wolff (ed) Gene therapeutics: Methods and Applications of direct Gene Transfer. Birkhaiser. Boston (1990), 320-343), thyroid (Sikes et al., Human Gen. Ther. 5 (1994), 837-844), skin (Raz et al., Proc. Natl. Acad. Sci. USA 91 (1994), 9519-9523) and liver (Hickman et al., Hum. Gene Ther. 5 (1994),1477-1483). Nevertheless, Davis et al. (Human Gene Therapy 4 (1993), 151-159 and Human Mol. Genet. 4 (1993), 733-740) observed a large variability of expression due to nonuniform distribution of naked DNA injected into skeletal muscle in vivo. Only a small proportion of the muscle fibers (about 1-2%) are transfected and this level of gene transfer would be insufficient for the treatment of primary myopathies. The authors propose solutions in order to obtain an improvement of the efficiency of gene transfer (resulting in about 10% of transfected muscle fibers) by preinjecting muscles with a relatively large volume of hypertonic sucrose or with toxins, for example cardiotoxin isolated from snake, in order to stimulate regeneration of muscles. These methods, although promising, would not be applicable for human treatment.
Thus, the available delivery methods are not satisfactory in terms of safety or efficiency for their implementation in in vivo gene therapy.
Therefore, the technical problem underlying the present invention is the provision of improved methods and means for the delivery of nucleic acid molecules in gene therapy.
This technical problem is solved by the provision of the embodiments as defined in the claims.
Accordingly, the present invention relates to the use of a nuclease inhibitor for the preparation of a therapeutic composition for introducing a polynucleotide into a cell. It was surprisingly found that the addition of a nuclease inhibitor when transfecting a polynucleotide into vertebrate tissue leads to a dramatic improvement of the transfection efficiency. In particular, it was surprisingly found that if the polynucleotide is injected together with a nuclease inhibitor, e.g., into muscular tissue, the transfection is not only improved in the surrounding of the injection site but also in other areas of the muscle. Thus, the present invention preferably relates to the use of a nuclease inhibitor for the preparation of a pharmaceutical composition for an improved introduction of a polynucleotide into a cell. The term “improved introduction” in the scope of the present invention means, in this regard, a more efficient uptake of a polynucleotide by cells when a nuclease inhibitor is present compared to an introduction performed without a nuclease inhibitor. This can be determined by comparing the amount of the polynucleotide taken up without the use of a nuclease inhibitor and comparing this amount with the amount taken up by the cells when using a

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