A gene called SIR2 is thought to control this process. Now, researchers at Harvard Medical School and UC Davis have discovered four cousins of the SIR2 gene that also extend lifespan, suggesting that the whole family of SIR2 genes is involved in controlling lifespan. The research indicates potential targets for developing drugs to lengthen life and prevent or treat aging-related diseases. The findings are reported July 28 in the advance online edition of Science. This discovery comes on the heels of the Harvard group's discovery of a molecule in red wine that extends the lifespan of every organism so far tested.
"We think these new Sir2 genes are as important as any longevity genes discovered so far," said molecular biologist David Sinclair, director of the Paul F. Glenn Laboratories for Aging Research at Harvard Medical School and co-author of the new study. "There is a growing realization from the aging field that we might finally understand how to control certain aspects of the aging process and one day have drugs that can fight some of the disabilities the process causes."
Sinclair's research group previously reported in the journal Nature the first genetic link between environmental stresses and longer life. Triggered by low salt, heat, or extreme calorie restriction, a yeast "master longevity regulator" called PNC1 stimulated Sir2 activity. This new work, led by Harvard graduate student Dudley Lamming, demonstrates that PNC1 regulates the whole SIR2 family of genes, suggesting that a human PNC1 gene might protect against diseases of aging such as cancer, heart disease and diabetes.
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"There's no reason to believe that this is the only compound in broccoli that has an anti-cancer effect," said Steven Clinton, a study co-author and an associate professor of hematology and oncology at Ohio State. "There are at least a dozen interesting compounds in the vegetable.
"We're now studying more of those compounds to determine if they work together or independently, and what kind of effects they have on cancer cells," he added.
Broccoli isn't the only cruciferous veggie with health benefits, the researchers say. The plant's kin, which include cabbage, cauliflower, Brussels sprouts and kale, may all contain similar disease-fighting phytochemicals.
It's too early to suggest just how much broccoli or other cruciferous vegetables should be eaten to stave off or slow down the progression of bladder cancer. Still, they are an important part of the diet.
"Cruciferous veggies have an effect on other types of cancer, too," Schwartz said. "We already know that they contain compounds that help detoxify carcinogens. We're thinking more along the lines of progression and proliferation, such as once cancer starts, is there a way to slow it down?"
He and Clinton conducted the study with Ohio State colleagues Robin Rosselot, a graduate student in food science and technology and Qingguo Tian, a research associate also in food science and technology.
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