CRISPR closes in on a cure for cervical cancer in mice
Researchers at Griffith University in Australia have used the CRISPR-Cas9 gene-editing system to effectively cure cervical cancer in mice. The team targeted specific cancer-causing genes, disrupting them so the tumors die, with a 100 percent survival rate of the animals. The study brings us one step closer to a cure for cancer in humans.
Infections by human papillomavirus (HPV) are the cause of almost all cases of cervical cancer. The virus integrates two particular genes called E6 and E7 into the human genome, which then go on to drive and sustain the cancer.
That makes these cancer-causing genes (or “oncogenes”) the perfect target for CRISPR – not only do they provide a weakness for tumors, but because they only appear in cancerous cells disrupting them shouldn’t have any effect on healthy cells.
So the team designed a way to target these oncogenes. In most CRISPR experiments, the tool hunts down a specific section of DNA – such as one that causes cancer – then snips it out and replaces it with something benign. In this case, the team instead added extra info that garbles the gene.
“The nanoparticles search out the cancer-causing gene in cancer cells and ‘edit it’ by introducing some extra DNA that causes the gene to be misread and stop being made,’’ says Nigel McMillan, lead researcher on the study. “This is like adding a few extra letters into a word, so the spell checker doesn’t recognize it ‘anyTTmore’. Because the cancer must have this gene to produce, once edited the cancer dies.”
To demonstrate the effectiveness of the treatment, the team tested it in live mice that bore human cervical cancer cells. They encapsulated the CRISPR machinery into “stealth” nanoparticles, then injected the mix into the mice.
The results are quite impressive: the tumors in the treated mice completely disappeared, and the animals had a 100-percent survival rate. The team also reported that the mice showed no signs of side effects, such as inflammation.
That said, the researchers did caution that there may be other gene changes that they haven’t noticed yet – after all, previous studies have found evidence of off-target mutations. While safety remains a topic of debate, it’s still a concern worth keeping an eye out for.
The team is hoping to have the treatment ready for human trials within the next five years. It might also be applicable to other types of cancer.
“This is the first cure for any cancer using this technology,’’ says McMillan. “Other cancers can be treated once we know the right genes.”
The team describes the work in the video below, and the research was published in the journal Molecular Therapy.
Source: Griffith University