Health Scan: Chance discovery can stop cancer in its tracks

New approach shown to inhibit malignant cells without affecting normal ones, and without severe side effects.

By JUDY SIEGEL-ITZKOVICH
cancer cell 88 (photo credit: )
cancer cell 88
(photo credit: )
Sometimes, research in one field can lead to discoveries in an entirely different one. An example is work carried out at The Hebrew University's Faculty of Agricultural, Food and Environmental Quality new drug treatment for halting the growth and spread of cancer cells. The approach has been shown to inhibit malignant cells without affecting normal ones, and without the severe side effects of traditional treatments. researchers isolated the malignant tumor from its nutritional and oxygen supplies, thereby halting its growth and stopping metastases from spreading to other parts of the body. The team - headed by Prof. Oded Shoseyov and including Dr. Levava Roiz, Dr. Patricia Smirnoff and Dr. Betty Schwartz - published their discoveries in the American Cancer Society's journal Cancer. The HU researchers' approach is based on the actions of actibind, a protein produced by the black mold Aspergillus niger, a well-known microorganism used in biotech and food technology. In plants, actibind binds actin, a major component of the intracellular structure in plants, interfering with the plants' pollen tubes and halting cell growth. While the researchers were initially interested in the activity of actibind in connection with a horticultural project aimed at improving the quality of peaches and nectarines, an actibind-like protein, RNaseT2, was also found to bind actin in human and animal migrating cells, such as the cells responsible for new blood vessel formation (angiogenesis) in tumors. By blocking the blood supply to the tumors, actibind halted the ability of malignant cells to move through the blood stream to form new metastases. A further benefit is that actibind is not toxic to normal cells. In lab experiments using cell cultures that originated from human colon cancer, breast cancer and melanoma, increasing the level of actibind was found to reduce the ability of these cells to form tumorogenic colonies. Further experimentation with a variety of animal models showed that increased actibind inhibited the growth of colon cancer-derived tumors, metastases and blood-vessel formation. The results shown in working with actibind led to a further development in the researchers' project: During the completion of the Human Genome project, the gene encoding for RNaseT2 - the human actibind-like protein - was found on chromosome #6. The researches used genetic engineering procedures to produce a recombinant RNaseT2 protein that showed an impressive anti-cancer potential. These results have raised broad interest in international scientific meetings and in business circles, as actibind and the human RNaseT2 represent the basis for a new class of drugs that could be used as a front-line therapy in the fight against cancer. A BRAND NEW RULING ON SECONDHAND SMOKE The High Court has set an international precedent in enforcing regulations that protect people from exposure to sidestream (secondhand) tobacco smoke. It is believed to be the first high legal application of the provisions of the Framework Convention on Tobacco Control (FCTC) of the World Health Organization. Supreme Court Justice Elyakim Rubinstein allowed the appeal of Irit Shemesh, a pregnant woman who was exposed to secondhand smoke in a Jerusalem restaurant. He argued that, in addition to criminal enforcement, there should be a mechanism of civil enforcement by a "caring citizen" who sues for compensation from those who manage or own a public place but make no effort to enforce laws barring smoking there. Shemesh was represented by Amos Hausner, the country's leading anti-tobacco activist and chairman of the Israel Council for the Prevention of Smoking. The local Small Claims Court had awarded Shemesh only a nominal compensation by the restaurant's owners, and the District Court did not intervene. But Rubinstein granted the right to appeal and raised the compensation tenfold, to NIS 1,000 plus legal fees and expenses, totalling NIS 2,500. All signatories that ratified the FCTC, including Israel, have agreed that secondhand smoke causes "death, disability and illness," said Rubinstein, and these countries assumed responsibility for the protection of their inhabitants. He also cited Jewish sources and rulings on the dangers of smoking - and secondhand smoke in particular. This ruling attracted wide public opinion in the country to the problem of second hand smoke and to the FCTC, which is now cited as a legal source for court rulings. Meanwhile, US Surgeon-General Dr. Richard Carmona has issued a report on secondhand smoke that clearly blames this phenomenon for disease and death in non-smokers. The New York Times wrote in a recent editorial that the report "should demolish any lingering contentions that inhaling the fumes from smokers is simply a nuisance that should be tolerated, not a health hazard that needs to be eliminated entirely. The report persuasively argues that inhaling secondhand smoke can cause both immediate and long-term harm to the millions of Americans, young and old, who are still regularly exposed to it despite crackdowns in many states and localities." Although the strength of the evidence varies from one disease to another, the report says smoke inhaled by adult nonsmokers increases their risk of heart disease by 25 to 30 percent and lung cancer by 20% to 30%. It is even more dangerous to children and babies because it is a known cause of sudden infant death syndrome, respiratory problems and ear infections. The report concludes that less-than-vigorous measures such as separating smokers from nonsmokers, cleaning the air and ventilating buildings are not enough. "The only sure way to protect nonsmokers from the dangerous chemicals in secondhand smoke is to eliminate all smoking indoors," the editorial concluded.