Can animals without cancer be hope for cure?
Many animal species on earth get cancer just like humans. But there are some mysterious animal species that are using surprising ways to fight cancer. Elephants have trillions of more cells than humans and live longer lives.
But the incidence of cancer is much lower than in humans. This example demonstrates that cancer prevalence is not correlated with body size, as explained by Peto’s paradox, named after Richard Peto. Only five percent of the elephant population dies from cancer. Considering that one in five people die of cancer, this rate is extremely low.
Why don’t elephants get cancer?
Last month, the elephant genome was found to contain an abundance of cancer-fighting genes. The tumor suppressor gene p53 is found in many animals. While humans only have one in their genome, twenty p53s were detected in elephants.
New target in cancer therapy: P53 gene activation
Vincent Lynch of the University of Chicago explains the two functions of this gene: First, it prevents the cell from multiplying, giving time to repair itself. If the cell is impossible to heal, p53 forces the cell to self-destruct. This process is called apoptosis. He adds that theoretically, he could produce drugs for cancer patients that would mimic the process in elephants. A drug called Nutlin is currently in the testing phase. The drug protects the p53 protein, allowing it to continue its work.
The secret of polar whales is still unknown
Polar whales have a lower cancer rate than elephants. In addition to being the largest living creature, it is surprising that they did not get cancer in their 200-year lifespan. When the scientists scanned the arctic whales’ genes, they found mutations that prevented their DNA from being damaged. This, in turn, lowers the whales’ risk of developing cancer. Vera Gorbunova of the University of Rochester, who works with polar whale cells in her lab, has yet to find a way to infect whales with cancer. “It’s much harder to make arctic whale cells cancerous than it is to make human cells,” Gorbunava said. We don’t know why,” she says.
How the p53 gene was found to be inactive in cancer cells!
It is not yet known which gene protects arctic whales from cancer. João Pedro de Magalhães of the University of Liverpool says we can transfer arctic whale genes to mice to find out which gene is beneficial. “By working with mice, we can find out which genes fight disease and lead to a long life,” says Magalhães.
What is the function of hyaluronic acid?
Another hope for future cancer treatment is hairless mole rats. With a lifespan of 30 years, which is quite long for such a small animal, hairless mole rats have a natural defense mechanism against cancer. As a result of years of studies, no hairless mole rat has developed tumors.
In 2013, Gorbunova and colleagues found that hairless mole rats produce a special molecule that protects them from getting tumors. This substance called Hyaluronic acid, which is dense and sugary, is located between the cells. Even if the cells mutate, the acid acts as a sticky, protective glass between the cells, preventing them from further dividing. According to Gorbunova, the treatment method based on this process can be applied within five years. “While humans also produce hyaluronic acid, the hairless mole we produce is quite different from that of rats,” Gorbunova said. Mice produce acid more intensely and in large quantities. We are looking for ways to use this molecule in humans,” she says.
Can the same method be used in humans?
While all these developments may seem promising, it is too soon to give up hope of a complete prevention of cancer. The question is whether these treatment methods are suitable for humans. Because hairless mole rats are different from humans, it is unknown how extra hyaluronic acid will affect the human body. Cancer expert David Vail of the University of Wisconsin-Madison says:
“There may be a reason why we have less hyaluronic acid in our bodies. Higher levels of acid can poison our body.” The same goes for genetic manipulation. A cancer-fighting gene in hairless mole rats could cause an entirely new disease in humans. Adds Vail: We don’t know what humans will lose until we try genetic manipulation. What seems magical in one species may not be compatible with another.’
This is not a theoretical problem, because we know that similar examples have happened before. In a 2002 study, mice were transferred multiple p53 genes. Although they gained resistance to cancer, they began to age very quickly and could not reproduce at a young age.
Some of his internal organs were also greatly reduced. This unexpected result could only be explained by giving the mice extra p53. In the same study that continued in 2007, this time mice were added a p53 and they were allowed to live longer lives without side effects.
But Lynch isn’t sure what the consequences of passing the extra gene to humans will be. Lynch thinks that if these genes were useful, they would already have appeared in humans who have evolved over hundreds of thousands of years. (BBC)