A National Taiwan University (NTU) research team yesterday published research into an intercellular mechanism they say is behind the aging process and the proliferation of tumor cells, which scientists said offers possibilities for cancer treatment and reinvigorating people in poor health.
The project, funded by the Ministry of Science and Technology, is the first to establish that the aging process is caused by changes within an area of the nucleus known as the telomere.
Project leader Teng Shu-chun (鄧述諄) said that aging occurs when a chromosome stops growing after the Cdc13 protein is dephosphorylated by protein phosphatase 2 (PPA2), an enzyme, in a pre-chromosomal replication stage
After chromosomes have finished replicating, the Cdc13 is dephosphorylated, which weakens its binding affinity with PPA2, causing PPA2 to leave the telomere, Teng said.
This causes the telomere to become shorter, signifying the aging of cells, he said.
He said that his team experimented on Saccharomyces cerevisiae, a species of yeast whose conserved pathway of cells is similar to that of human cells.
Teng said that the scientists built on their findings of 2006, when they discovered that Cdc13 induces telomerase to bind with it after undergoing phosphorylation.
This process triggers the replication of DNA in telomeres and causes telomeres to grow longer, he said, adding that cancer cells sometimes rely on this process to proliferate, with the phenomenon also commonly observed in stem cells and germ cells.
“When there is no need for telomeres in a cell to grow longer, but that continues to happen, it wastes the cell’s energy and could obstruct its functions,” he said.
He said that there are many factors that cause telomeres in cancer cells to grow, and that the team’s findings concern just one of them.
As telomere replication is essential for cancer cells to proliferate, inhibiting the binding process between telomerase and the Cdc13 protein with anticancer drugs is a feasible way to tackle cancer, Teng said.
“In a nutshell, last time [in 2006], we discovered the extension of telomeres. This time, we discovered when chromosomes should hit the brakes and just rest,” Teng said.
Teng said that while telomerase has been dubbed the “enzyme of eternal youth” by some scientists, it probably would not help prevent aging in people, as extending chromosomes in healthy cells is not an effective way to retain their youth.
However, theoretically, enhancing the reaction between telomerase and Cdc13 would improve the health of ill people and rejuvenate them, which is a field of research worth exploring, he said.