“Missing Link” between pond scum and humans discovered, holds promise for cancer research
As written by Ryan W. Miller of USA Today:
Researchers discovered a “missing link” within plants between humans and simple pond scum that could provide insight into how some organisms live for thousands of years, according to a study published Monday. The enzyme telomerase can slow aging within cells by lengthening telomeres, a sort of cap at the end of chromosomes that protects DNA and the chromosomes’ stability. For the first time, scientists have identified the RNA component of telomerase enzymes from land plants, which study author Dorothy Shippen described as an “intermediate structure” between humans’ and pond scum’s telomerase. “Our discovery of this key component of the telomerase enzyme in the plant kingdom provides an evolutionary bridge, and a novel path forward, for understanding how humans keep their DNA safe and enable cells to divide indefinitely,” said Shippen, a professor at Texas A&M University. The study could one day provide insight into how to treat human diseases caused by cell proliferation, such as cancer, she said. “The ability to control where and when cells divide – it’s a fundamental question,” Shippen said.
The study was published Monday in the peer-reviewed Proceedings of the National Academy of Sciences. Telomerase allows for immortality on a cellular level, said study author Julian Chen, an Arizona State University professor. As cells age, their telomeres shorten, and chromosomes in turn stop the cell from dividing further, Chen said. Telomerase stops this process and can reverse the cell aging by lengthening the telomeres, he said. On the level of an entire organism, the aging process is much more complex, and the length of telomeres does not necessarily correlate with life span, Chen said. Plants have an incredible plasticity, Shippen said, and it’s possible that studying how telomerase lengthens their telomeres could provide scientists clues to manipulating human telomerase. “Some of these mechanisms might be different from human mechanisms,” Chen said, “but we might be able to apply the plant-specific mechanism in a different way to recognize human telomerase. “One practical application would be cancer treatment. Cancer cells have plenty of telomerase, which allows them to live and grow much longer than normal cells in our body, Chen said. Studying plant telomerase might lead researchers to a way to stop human telomerase in cancer cells and allow the telomeres to shorten, killing off the cancer cells. These sorts of applications are years off, the study authors said, but they hope the research in plants will have some human applications. “All of this information will be useful in future to design and engineer a way to facilitate anti-aging therapy,” Chen said.
“The jury is still out,” Shippen said on whether the research could expand to anti-aging in an entire organism, but “I think telomerase has a place.” For years, scientists weren’t able to locate the RNA component of telomerase enzymes from land plants. Shippen said that component has been divergent and prone to change over the years. The next steps in research will involve better understanding the entire telomerase enzyme in plants, Shippen said.The RNA component the researchers found is “like a scaffold, it’s the framework,” Shippen said. “There are other things that hang off the sides … we want to understand how those parts control the enzyme.” Then researchers can look for human counterparts, she said. Elizabeth Blackburn won a Nobel prize in 2009, along with Carol Greider and Jack Szostak, for their work that discovered how telomerase and telomeres protect chromosomes. Blackburn praised the new study. “Excitingly, this paper reports how plants fill in the missing links of telomerase RNA’s eventful evolutionary history … from our simplest forebears,” Blackburn told CNN. “This fundamental new understanding may pave the way to new routes to optimizing telomere maintenance for human health.”