Several treatments have been developed that involve genetic material but are typically not considered gene therapy. Some of these methods alter DNA for a slightly different use than gene therapy. Others do not alter genes themselves, but they change whether or how a gene’s instructions are carried out to make proteins.
Cell-based gene therapy
CAR T cell therapy (or chimeric antigen receptor T cell therapy) is an example of cell-based gene therapy. This type of treatment combines the technologies of gene therapy and cell therapy. Cell therapy introduces cells to the body that have a particular function to help treat a disease. In cell-based gene therapy, the cells have been genetically altered to give them the special function. CAR T cell therapy introduces a gene to a person’s T cells, which are a type of immune cell. This gene provides instructions for making a protein, called the chimeric antigen receptor (CAR), that attaches to cancer cells. The modified immune cells can specifically attack cancer cells.
Several techniques, called RNA therapies, use pieces of RNA, which is a type of genetic material similar to DNA, to help treat a disorder. In many of these techniques, the pieces of RNA interact with a molecule called messenger RNA (or mRNA for short). In cells, mRNA uses the information in genes to create a blueprint for making proteins. By interacting with mRNA, these therapies influence how much protein is produced from a gene, which can compensate for the effects of a genetic alteration. Examples of these RNA therapies include antisense oligonucleotide (ASO), small interfering RNA (siRNA), and microRNA (miRNA) therapies. An RNA therapy called RNA aptamer therapy introduces small pieces of RNA that attach directly to proteins to alter their function.
Another gene-related therapy, called epigenetic therapy, affects epigenetic changes in cells. Epigenetic changes are specific modifications (often called “tags”) attached to DNA that control whether genes are turned on or off. Abnormal patterns of epigenetic modifications alter gene activity and, subsequently, protein production. Epigenetic therapies are used to correct epigenetic errors that underlie genetic disorders.
Scientific journal articles for further reading
Kim YK. RNA Therapy: Current Status and Future Potential. Chonnam Med J. 2020 May;56(2):87-93. doi: 10.4068/cmj.2020.56.2.87. Epub 2020 May 25. PubMed: 32509554. Free full-text article from PubMed Central: PMC7250668.
Lu Y, Chan YT, Tan HY, Li S, Wang N, Feng Y. Epigenetic regulation in human cancer: the potential role of epi-drug in cancer therapy. Mol Cancer. 2020 Apr 27;19(1):79. doi: 10.1186/s12943-020-01197-3. 32340605. Free full-text article from PubMed Central: PMC7184703.