Recent cloning of a gene could be a first step toward slowing or stopping the growth of tumor cells, according to scientists at Baylor University in Houston, Texas. The scientists have cloned a gene that can slow down the growth of young, active cells. Using these same methods, the investigators hope that other regulatory genes, such as those that code for tumor suppression, can be isolated and used as therapies for controlling cell growth and tumor activity.
Dr. James Smith, a National Institute on Aging (NIA) grantee and researcher at Baylor University, who cloned the gene, will have his work published in Experimental Cell Research. He explains the chain reaction-type mechanism that occurs when his cloned gene, SDI1, interacts with the tumor suppressor protein, p53, and cyclin dependent kinases (CDK's), which can activate the cell growth cycle. This same gene, given different names, was also cloned by two other research groups, one at Baylor, the other at Johns Hopkins University, in Baltimore, Maryland.
"In normal cells, p53 causes high levels of expression of the SDI1 gene which binds to and inactivates CDKs. Without CDK function, cells cannot duplicate. When p53 is not functional, SDI1 levels drop and CDKs function to promote cell duplication. Without regulation, cell growth becomes uncontrolled and can lead to tumor formation," says Dr. Smith.
Dr. Smith's work in the cellular biology of aging points to hope for a better understanding of how cellular activity changes as we age, from active to less active. If the gene Dr. Smith has isolated can be controlled, cell activity and division could be better regulated in an aging human body.
Drs. Steve Elledge and Wade Harper, also of Baylor College of Medicine and NIA grantees, cloned the same gene as Dr. Smith using a different approach and a different organism. They came up with similar results which have just been published in Cell. Dr. Elledge says, "This research goes right to the heart of cellular growth control ... and gives us another protein that might be manipulated for therapeutic purposes."
Yet a third scientist, Dr. Bert Vogelstein at Johns Hopkins University, cloned the same gene, and he believes that, " an important step has been made in the understanding of human cancer." With this third confirmation of the suppressor gene finding, it is clear that this research is an important and hopeful breakthrough in the fields of aging and cancer.
NIA scientists are available to explain these latest findings and give a broad perspective on the research.
The National Institute on Aging is the major federal funding agency of cellular aging research. Please call (301)496-1752 for further information and to arrange interviews.