n the worm.
Life span is influenced by cells in the reproductive system and sensory neurons in the brain.
In the study, the team mutated a tumor suppressor gene called gld-1 in the worms, causing cells in the animals' gonads to divide rapidly and form germ-line tumors. These tumor cells, when left undisturbed, break out of the gonad and fill the body, killing the worm at around 9 days old age.
They then studied the effects of a few different 'longevity' genes in the tumor-affected animals, to assess the influence on lifespan and tumor growth. All of the longevity mutations tested increased the worms' lifespan in spite of them having cancer.
It is a long known fact that insulin boosts growth of tumor in rats. When the insulin levels are reduced in rats by making them diabetic, the tumor growth also slows down.
"The study is another example of the intimate tie-in between insulin and tumorigenesis," says David Kritchevsky from the Wistar Institute in Philadelphia, Pennsylvania, who studies the effects of diet on cancer.
“In the worms, lowering insulin levels seems to slow cell division and increase apoptosis - the process by which some cells are able to commit suicide — with a particular impact on tumor cells.”
The results indicate that tumor cells are generally more susceptible to the effects of longevity-causing mutations than normal cells. Thus, investigating these long-life mechanisms might provide better ways to fight cancer. Drugs created this way might even have the side effect of extending life further than the normal span for those without cancer.
This study is a significant start in this direction: the short lifespan of the worms makes for a quick study of old age. More human-like models will need to be studied to unravel what is really going on say other experts.
Biologist Siegfried Hekimi of McGill University in Montreal, who studies C. elegans, warns that the laboraPage: 1 2 3 Related medicine news :1
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