Cancer researchers ?nd progress in glowing mice

UNC researchers are continuing to seek innovative ways to fight cancer — this time, with glow-in-the-dark mice.

Professor of Medicine Dr. Norman Sharpless’ latest experiment involved genetically engineering mice to measure an organic response to aging and cancerous cells.

Sharpless, along with a team of researchers at the UNC Lineberger Comprehensive Cancer Center, said with this new process, researchers can detect cancerous tumors at much earlier stages and also specifically pinpoint when cells begin aging.

He said with more work, the results of the research might be applicable to humans as well.

According to his report, originally published in Cell magazine Jan. 17, the team used mice to measure the expression of the p16 gene, which activates a process called cellular senescence.

“In terms of cellular biology, (senescence) is what happens to certain damaged cells when they stop dividing forever,” he said.

Sharpless said the p16 gene has been known as a link to senescence for more than five decades but has only recently been the subject of research.

He said it is a process that occurs as a result of aging or cancer.

“We are hard wired to not let cells go wild — and p16 is a part of that,” said Dr. Shelton Earp, director of cancer cell biology at the Lineberger Center.

Earp said even though p16 is supposed to stop cells from dividing, by the time doctors are able to see the tumor, the cell has lost the gene.

The report explained how the team was able to link the p16 gene in the mice to a firefly allele, thereby activating a glowing response when the p16 gene was activated when it was time for the cells to stop dividing.

Sharpless said the mice were anesthetized, and while they were asleep, they were given an injection that caused them to glow.

The report documented the mice’s responses for more than 100 weeks.

It showed how as the mice aged or developed tumors, they would glow brighter.

His team used a special camera so they could measure how brightly the mice were glowing, which told them how many cells were undergoing cellular senescence.

“It is very useful for seeing tumor developments about 100 days before using any other means,” Sharpless said, adding that now they are able to detect tumors as small as one millimeter in mice.

Before, they could not be seen until they were one centimeter.

Sharpless said the process could measure senescence in human cells as well.

“We can’t make humans glow obviously, but we can take a tube of blood from people and measure p16 in their T-cells,” he said.

Earp said the findings could lead to new experiments such as testing the p16 levels of elderly bone marrow transplant candidates to see if their marrow would be sufficient.

He also said studying cancer in its earliest stages would allow them to better understand which preventative measures work.

“That’s what our job is — to create knowledge that is ahead of everyone else that benefits cancer patients and their families.”

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