Vitamin C helps brain tumour therapy

Sydney:  Feeding brain cancer cells with vitamin C softens them up for radiation therapy and hastens their death.

Patries Herst from the University of Otago, with Melanie McConnell investigated how combining high dose vitamin C with radiation affected the survival of cancer cells isolated from brain tumours, and compared this with the survival of normal cells.

They found that a high dose of vitamin C by itself caused DNA damage and cell death which was much more pronounced, especially before radiation, the journal Free Radical Biology and Medicine reports.

Herst says brain cancer patients have a poor prognosis because these tumours are aggressive and very resistant to radiation therapy.

"We found that high dose vitamin C makes it easier to kill these cells by radiation therapy," says Herst, according to an Otago statement.

She says there has long been a debate about the use of high dose vitamin C in the treatment of cancer. High dose vitamin C specifically kills a range of cancer cells in the lab and in animal models.

"If carefully designed clinical trials show that combining high dose vitamin C with radiation therapy improves patient survival, there may be merit in combining both treatments for radiation-resistant cancers, such as glioblastoma multiforme," says Herst.

Scientists identify bacteria that causes colon cancer

Washington: Scientists have identified a molecule produced by common gut bacterium that activates signalling pathways lined with colon cancer cells.

'We wanted to investigate how colon cells respond to normal gut bacteria that can damage DNA, like E. faecalis,' said Mark Huycke of the Department of Veterans Affairs Medical Centre in Oklahoma.

'We found that superoxide from E. faecalis led to strong signalling in immune cells called macrophages (a type of white blood cell that ingests foreign material). It also altered the way some cells in the gut grew and divided and even increased the productivity of genes that are associated with cancer.'

E faecalis is a normal gut bacterium. Unlike most gut bacteria, it can survive using two different types of metabolism: respiration and fermentation, reports Eurekalert.

When the bacteria use fermentation (without use of oxygen) they release by-products, one them being an oxygen molecule called superoxide, which can damage DNA and may play a role in the formation of colon tumours.

The team found that 42 genes in epithelial cells lining the gut are involved in the regulation of cell cycle, cell death and signalling based on the unique metabolism of E. faecalis.

This suggests that cells of the lining of colon are rapidly affected when E. faecalis switches to fermentation. It also indicates that E. faecalis may have developed novel mechanisms to encourage colon cells to turn cancerous.

Intestinal cancers occur almost exclusively in the colon where billions of bacteria are in contact with the gut surface. For years scientists have tried to identify links between gut bacteria and people who are at risk of colon cancer. This has been made difficult by the enormous complexity of the microbial communities in the intestine.

'Our findings are among the first to explore mechanisms by which normal gut bacteria damage DNA and alter gene regulation in the colon that might lead to cancer,' said Huycke.

These findings are scheduled for publication in the October issue of the Journal of Medical Microbiology.


Source: IANS