Using a gene-editing method, investigators were able to delete certain genes in the human papillomavirus, prompting cancer-causing cells to self-destruct. The antiviral technique could be replicated to target other DNA-based viruses like hepatitis B and herpes simplex, researchers say.
In laboratory tests of HPV cells, Duke University scientists selectively destroyed two viral genes responsible for the growth and survival of cervical carcinoma cells using the genome editing tool called CRISPR. The target genes--E6 and E7, known as oncogenes--block the host's ability to squelch cancer cells.
"Because this approach is only going after viral genes, there should be no off-target effects on normal cells," said Bryan Cullen, senior study author and professor of molecular genetics and microbiology at Duke University School of Medicine, in a statement. "You can think of this as targeting a missile that will destroy a certain target. You put in a code that tells the missile exactly what to hit, and it will only hit that, and it won't hit anything else because it doesn't have the code for another target."
The researchers packaged the antiviral therapy--consisting of a short strip of RNA sequence, plus a Cas9 protein, designed to cut any DNA that could line up and bind to that RNA sequence--into a viral vector based on a disabled version of HIV.
The RNA/Cas9 combination therapy essentially turned off E6 and E7, which switched the cells' defense mechanisms back on and initiated cancer cell death. The findings appeared online Aug. 6 in the Journal of Virology.
Gene therapy has gone through its ups and downs over the years, but in recent years there has been renewed interest in the field.
Next, Cullen and his colleagues plan to test the approach in animals.
- read the press release
- see the study abstract