- The major focus of this laboratory is control of gene expression by antisense oligonucleotides and RNA.
Antisense oligonucleotides represent a new class of compounds that are emerging as highly specific therapeutics. They interact with mRNA in a sequence specific fashion downregulating the expression of the gene from which the RNA has been transcribed. In a novel approach, we have used oligonucleotides to modulate gene expression by modifying alternative splicing of targeted pre-mRNA. The importance of this approach is underscored by recent findings that up to 70% of all human genes are alternatively spliced. Thus, sequence specific modification of splicing by splice switching oligonucleotides (SSO) promises to be useful in a broad range of therapeutic indications with thousands of genes as potential targets. This notion is illustrated by the work in this laboratory, which showed that modification of alternative splicing of Bcl-x, a gene over-expressed in prostate cancer cells, leads to cell apoptosis and may provide gene specific treatment for prostate and other cancers. Furthermore, by targeting the SSOs against aberrant splice sites generated by genetic mutations we were able to reverse aberrant and restore correct splicing and therefore increase the levels of correctly spliced pre-mRNAs in cellular models of ß-thalassemia, cystic fibrosis and Duchenne muscular dystrophy. The work on thalassemia and muscular dystrophy progressed to animal models of these disorders and to ex vivo treatment of erythroid cells from thalassemia patients. As an extension of the above work, we developed methods that take advantage of lentiviruses as vectors to provide gene therapy alternatives to oligonucleotide treatment. These methods have been successfully applied to thalassemic mutants. (See Figure)
Members of the laboratory become knowledgeable in RNA processing and splicing and macromolecular drug d elivery and oligonucleotide technology. They acquire expertise in a variety of techniques such as site specific mutagenesis, PCR and RT-PCR, transient and stable gene expression in cultured cells, delivery of antisense oligonucleotides and vectors for intracellular activity in cell culture and in animal models.