Health Scan: A team of Weizmann researchers learn to 'put the brakes' on cancer

The Weizmann Institute has discovered genes that slow cell division and may be able to prevent cancer.

By JUDY SIEGEL-ITZKOVICH
cancer gene 88 (photo credit: )
cancer gene 88
(photo credit: )
A group of genes that slows cell division and thus may be able to prevent cancer has been discovered by researchers at the Weizmann Institute. Cancer cells differ from normal cells in, among other things, the way they divide. When a normal cell responds to a signal telling it to divide, it also begins to activate a "braking system" that eventually returns the cell to a resting state. When that braking system is faulty, uncontrolled cell division (also known as cancer) can result. Weizmann scientists studied this system, and identified a number of the genes involved. According to the study's findings, which appeared recently in Nature Genetics , aberrations in the activities of these genes are tied to certain types of cancer, as well as to the aggressiveness of the disease. These insights may lead to the development of ways to "replace the brakes" on dividing cells and halt the progression of cancer. First, the scientists mapped the genes activated in normal cells on receiving the instruction to divide. The "divide!" signal comes in the form of a chemical called a growth factor, which initiates a chain of events inside the cell. The genes activated in this sequence produce proteins, some of which cause cell division, and others that put the brakes on that division. To find which genes were responsible for which action, the scientists needed to sift through a huge quantity of data. To cope with this task, a team of Weizmann researchers from diverse fields pooled their knowledge: Prof. Yosef Yarden of the biological regulation department, Prof. Eytan Domany of the physics of complex systems department, Prof. Uri Alon of the molecular cell biology department and Dr. Eran Segal of the computer science and applied mathematics department. Working with them were Prof. Gideon Rechavi of Sheba Medical Center and researchers from the M.D. Anderson Cancer Center in Houston, Texas, headed by Prof. Gordon Mills. This collaboration yielded some startling results: The researchers found that following receipt of the growth-factor signal, cell activity takes place in discrete waves, in which genes are turned on and off for different periods of time. In the first wave, the activity of a few genes rises for about 30 minutes. These are the genes that actually cause cells to divide. In contrast, the next four waves, coming from 40 to 240 minutes after the signal, are comprised primarily of gene activity halting cell division. The scientists then focused on identifying the genes in these later waves and confirming that they do indeed slow cell division. Through their wide-ranging study, they found 50 genes that interfere with the genetic activities of the first wave. This braking system works by producing proteins that attach to the cell-division genes, hindering them. Yet another protein they identified works, instead, by dismantling messenger RNA carrying instructions for making cell division proteins from the genes to the cell's protein-production machinery. In tests conducted on tissues from ovarian cancer patients, the scientists found a correlation between levels of activity in the "braking" genes, rates of survival, and the aggressiveness of the disease. These findings point the way toward the development of a personal genetic profile that might pinpoint the defects responsible for each cancer and help doctors tailor a treatment to each patient. Such a genetic profile could also help predict the individual progression of disease. In the future, identification of the exact factors causing uncontrolled cell division in different cancers might lead to the development of effective treatments for preventing or halting such cancer growth. LOSE SLEEP OVER IT If you suffer from sleep apnea or emphysema and are overweight, beware: Your risk of dying before the age of 62 is much higher than if your weight is normal and you have no chronic obstructive pulmonary disease. This is the conclusion of research conducted on nearly 11,000 Israeli men at the Technion-Israel Institute of Technology. An article just published in the Journal of Sleep Research by Prof. Peretz Lavie, Paul Herer and Lena Lavie of the Technion's sleep apnea research lab reports that 331 of the men died during the period of study between 1991 and 2001. Although it has been known that sleep apnea - frequent halting of breathing during sleep - was a risk factor for premature death, it had not been shown that this higher risk was connected to being overweight and other chronic conditions. The authors thus advise people who snore (a possible sign of sleep apnea), suffer episodes of apnea or have emphysema and are overweight to go for diagnosis and treatment at a sleep lab. Sleep apnea diagnosis, Lavie and colleagues wrote, should be widespread to identify high-risk patients at the youngest age possible. RED-AND-WHITE TO THE RESCUE Two rescue helicopters will soon be added to Magen David Adom's fleet of ambulances and mobile intensive care units. This has been made possible by an agreement between the first-aid, blood supply and rescue organization and Lahak, a private company that will purchase and maintain the red-and-white helicopters and train and employ the pilots. In the early 1970s, there was an attempt to supply MDA with light helicopters, when a friends' organization donated one. But because of high maintenance costs, it was transferred to the Israel Air Force, where it joined the Alouette helicopter fleet. MDA director-general Eli Bin has aimed since taking office at renewing the "dream" of a rescue helicopter service, which is practical in a small country. Helicopters, he said, will increase the survival rate of patients, especially road accident victims, because of the speed in bringing them to a medical facility. Today, only the busy Israel Air Force can supply helicopters for such a purpose, and it has complained many times that it's not its job to evacuate wounded and sick civilians, and that its rescue helicopters should be only for soldiers. After complicated negotiations, MDA has agreed to supply paramedics and communications services. Paramedics who previously served in Air Force rescue units will be specially trained for the MDA helicopters, and in how to use the advanced medical equipment that will be installed inside.