Scientists looking for ways to stop human cancer cells in their tracks have isolated the protein that can turn off the production of these deadly cells.
Dr. Thomas Cech, Nobel laureate and investigator with the Howard Hughes Medical Institute in Boulder, Colorado, has lead a team of scientists, including researchers at Geron Corp., in finding telomerase, a protein that leads a dual existence and holds in its grasp the power to extend cell life - or end it. Their findings were published in Friday�s edition of the journal Science.
"We refer to it as a clock; you have only so many hours programmed [into each cell]. If you can [manipulate] the telomerase, you can rewind the clock," explained Kevin Kaster, Geron vice president of intellectual properties.
As part of the work, Geron developed a proprietary way to manipulate and engineer the protein to turn it into a minifactory for making exact copies of itself. "We want to do a number of things with the protein that the body doesn�t do, so we need a lot more of the protein than the body can produce," Kaster said.
Telomerase�s role in normal germline cells is to ensure that the full complement of genetic information gets programmed into every new cell. Once finished, telomerase turns off, and cell division begins. During cell division, threads of telomeres, brief gene-free DNA sequences found on the ends of chromosomes, act as a limited buffer for the chromosome strands. A tiny portion of the telomere is lost in each cell division, so it becomes shorter. Eventually, the length runs out and cell division stops.
But in a cancer cell, telomerase is always on, so cells divide without limit. Once a chromosome strand runs through its telomeres, it begins losing genetic material as the division cuts into the DNA strand. This results in cell mutations, and once these build up, cells die.
By isolating telomerase and replicating it in a laboratory, scientists can study its behavior and reaction to drugs that can, for example, turn off the protein in cancer cells and cause them to stop dividing. It can also have other implications.
"Perhaps there�s a way to turn telomerase back on to lengthen the telomeres and lengthen a normal cell�s life," said Kaster.
This could help researchers treat the diseases of aging such as heart ailments. Kaster envisions taking cells from a young person�s heart, storing them, treating them and then reintroducing them into the older person�s heart to rejunvenate the organ. "But this is very speculative for now," Kaster warned.
