Scientists have unlocked the genetic sequence of the enzyme that controls whether cells reproduce or die-and is vital to the growth and spread of cancer.
The enzyme, telomerase, is responsible for nine out of ten types of cancerous tumors. Telomerase adds sequences of DNA to the end of chromosomes, called telomeres. These telomeres get shorter each time a cell divides, as a kind of natural clock, getting shorter each time a cell reproduces. When the telomere gets so short that it can no longer be divided, the cell dies. When the telomerase is overactive, cells continue to divide at advanced rates, which cause them to become cancerous.
For years, telomerase has been targeted by researchers searching for a way to stop the rapid reproduction of cancer cells. But the lack of understanding about the structure of its building block, TERT, (telomerase reverse transcriptase protein) has impeded researcher's efforts, until now.
"Studies of telomerase have been extremely difficult due to the size and complexity of the enzyme," said Emmanuel Skordalakes, structural biologist at Philadelphia's Wistar Institute and lead researcher of the study. Skordalakes and his team tried to cultivate a useable sample of TERT in hundreds of organisms before finding the key protein molecule in the red flour beetle.
"Telomerase is an ideal target for chemotherapy because it is active in all human tumors," said Skordalakes. "That means that a drug that deactivates telomerase would likely work against all cancers."
Although the 3-D modeling of the TERT protein is being hailed as a major breakthrough within the scientific community, some are cautioning against unrealistic expectations.
"People have been beating their heads against a wall for quite a while," acknowledges Elizabeth H. Blackburn, a biology and psychology professor at the University of California, and one of the original discoverers of telomerase. However, she is quick to point out that "the subtle details matter."
"This is a beetle. It's not a human."
Now that the basic component of telomerase has been modeled, researchers will be able to probe it for a way to develop a treatment to not only deactivate telomerase in cancerous cells, but a way to turn it on in normal cells-which could potentially undo the natural aging process.
Source
