100 percent survival rate of cancer – sounds like a miracle.
This is what researchers at Griffith University in Australia have accomplished in cervical cancer in mice experiments. By using the CRISPR-Cas9 gene-editing system, they successfully cured cervical cancer in mice, which brings us one step closer to a cure for cancer in humans.
HPV and cervical cancer
You must have heard of HPV, whole name human papillomavirus, at some point of your life. Some of your friends or yourself may have got the HPV vaccine which can help prevent cervical diseases.
HPV infects people by integrating two particular genes called E6 and E7 into the human genome, which then go on to drive and sustain the cancer. Infections by HPV are the cause of almost all cases of cervical cancer. The purpose of HPV vaccines is to prevent HPV infection, thus prevent cervical cancer.
CRISPR, or clustered regularly interspaced short palindromic repeats, is a family of DNA sequences found within the genomes of prokaryotic organisms, like bacteria and archaea.
CRISPR-Cas9 stands for CRISPR-associated protein 9, an enzyme that can recognize and cleave specific strands of DNA that are complementary to the CRISPR sequence. In this way, CRISPR-Cas9 can edit genes within organisms.
Since HPV integrates the cancer-causing genes, or oncogenes into cells, CRISPR can target on the oncogenes. And because the oncogenes only appear in cancerous cells, the attack on these cells won’t have any effect on healthy cells.
Target the oncogenes
In most CRISPR experiments, the tool hunts down a specific section of DNA, for example, the one that causes cancer. It snips the section of DNA out and replaces it with something benign.
In this case, however, the research team instead added extra info that garbles the gene.
Imagine the DNA section as a string of letters. Only in the right order can the letters combine and make a meaningful word, which can then be recognized and made products, in this case cancer. If adding extra letters into the sequence, the word becomes meaningless, making it unable to produce cancer, so the disease can be treated.
Outcome of the experiment
The results are quite impressive: the tumors in the treated mice completely disappeared, and the animals had a 100% survival rate. No signs of side effects like inflammation was reported.
This means that complete cure of cervical cancer, or even all kinds of cancers, is possible.
The researchers say that there may be other oncogenes that were not targeted, which remain to be discovered by further research.
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 the lead researcher Nigel McMillan. “Other cancers can be treated once we know the right genes.”