Vitamin C fights Cancer, and How

WASHINGTON: Vitamin C can help to prevent cancer, but not the way that scientists thought, according to a study published Monday in the US.

Scientists have long thought that vitamin C and other antioxidants help to fight cancer growth by grabbing volatile oxygen free radical molecules and preventing them doing damage to DNA. But researchers at Johns Hopkins University in Baltimore found that antioxidants play a different role in the fight: they destabilize a tumor's ability to grow under oxygen-starved conditions.

The researchers happened on this new role by observing mice which had been implanted with one of two types of cancer which produce high levels of free radicals, which can be suppressed by feeding the mice supplements of antioxidants, such as vitamin C.

When the Hopkins team examined cancer cells from mice that had been implanted with cancer but not fed antioxidants, they noticed there was no significant DNA damage.

"If DNA damage was not in play as a cause of the cancer, then whatever the antioxidants were doing to help was also not related to DNA damage," said Ping Gao, one author of the study.

That conclusion led Gao and Dang to suspect that some other mechanism was involved, such as a protein known to be dependent on free radicals called HIF-1 (hypoxia-induced factor). The researchers found that HIF-1 was abundant in untreated cancer cells taken from the mice, but disappeared in vitamin C-treated cells.

"HIF-1 helps an oxygen-starved cell convert sugar to energy without using oxygen and also initiates the construction of new blood vessels to bring in a fresh oxygen supply," explained Chi Dang, who also worked on the research.

Source:Times of India, wednesday, sept 12,2007