Attenuation of Tumorigenicity in Neurofibromatosis 1 Using Splice-Switching Oligonucleotides
Abstract
Rationale: Neurofibromatosis type 1 (NF-1) is one of the most common monogenic disorders and involves mutations of the neurofibromin (nf1) gene. An estimated 1 in 2,500 children worldwide are affected and consequently predisposed to the development of tumors of the nervous system, with a 15% greater chance of developing malignancies compared to the general population. The regulation and function of the nf1 gene is very complex and is not well understood. This is, in part, because of the large number of exons in the gene and how their arrangement can be modified to form several different versions of the neurofibromin protein, referred to as isoforms. Recent studies reveal that mutations that change the way these exons are spliced together are associated with the development of brain tumors. Thus, therapies that can counteract changes in splicing caused by mutations are likely to be effective as treatment for a number of NF-1 tumors. Researchers who study other diseases that result from splicing defects, such as spinal muscular atrophy and Duchenne muscular dystrophy, have begun to explore the use of splice-switching oligonucleotides (SSOs) as a therapeutic strategy with some success. In fact, two SSO drugs have already been expeditiously approved by the Food and Drug Administration for use in clinical trials for these diseases. However, therapeutics to modulate nf1 splicing have not been explored. Objective: We are proposing to test whether SSOs, when applied to specific cells, can be used to change levels of nf1 isoforms. This will help establish a basic understanding of how SSOs should be designed for NF-1 and how they can be used in studies. We are also proposing to test whether SSOs can be used to correct abnormal levels of nf1 isoforms in cells with a mutation in the nf1 gene and whether this will also reduce the tumor-producing potential of these cells. Impact: Our proposed research will provide a strong rationale to pursue development of SSO therapy targeting patient-specific mutations in these and other splicing sites within the nf1 gene. The studies we have proposed will also establish SSOs as a tool that can be used in future research to understand how splicing mutations affect the development of tumors and nontumor manifestations of NF1, including cognitive and bone disorders. Such understanding will not only reveal the potential for SSO-based therapies for nontumor manifestations, but also likely reveal other targets within the cell for the development of new drugs or repurposing of existing drugs. By the latter, we are referring to drugs that are being used to treat other conditions, but may be effective for also treating NF-1, if the above-mentioned studies reveal similarities in disease mechanisms. Therapies that correct genetic defects have traditionally been difficult to develop, as many of these approaches create permanent changes to the gene and/or use viruses to deliver the therapy. Such approaches have often failed to produce the expected efficacy, had serious side effects, and raised ethical concerns regarding the modification of genes. In contrast, SSOs do not alter the gene. They also can be easily and relatively cheaply customized to be specific for a particular patient’s mutation, allowing the creation of personalized treatments. SSOs can be delivered to most cells of the body without the need for complicated delivery techniques. They have low toxicity and side effects and can be modified to last a shorter or longer time in the body as needed. In this proposal, we have intentionally chosen to use swine cells to study SSOs. If we successfully demonstrate that SSOs are a viable treatment strategy for NF-1, we can then rapidly advance to studying SSOs in NF-1 swine models that we recently developed. Given the biological similarities between swine and humans, the studies will allow us to advance the development of SSO as a therapy in a manner that is more translatable to
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Oct 29, 2018
- Source ID
- W81XWH1810633
Entities
People
- Dhanansayan Shanmuganayagam
Organizations
- United States Army
- University of Wisconsin–Madison