Dca is not wonder drug

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Wonder Drug

November 22, 2010 - News Release

A University of Guelph study has found that a prescription drug thought to have

anti-cancer properties when used off-label may not only be less effective than

claimed but may actually protect some kinds of cancers.

" Sodium dichloroacetate is not very effective at killing some kinds of cancer

cells and, in fact, it has the opposite effect and could even make things

worse, " said Coomber, a professor in the Department of Biomedical

Sciences in Guelph's Ontario Veterinary College.

This research was published recently in the journal Cancer Letters.

Developed three decades ago to treat a rare serious metabolic disorder in

children, sodium dichloroacetate (DCA) has been touted as a safe, inexpensive

anti-cancer drug.

In patients with this metabolic disorder, DCA " resets " malfunctioning

mitochondria to restore the body's normal energy pathway. Mitochondria are

cellular " power plants " that convert glucose into energy. Normally, they also

generate oxygen radicals used in further metabolism but that are also toxic to

cells. Mitochondria also help trigger cell death, a normal part of tissue growth

and health.

Scientists believe that, when oxygen is present, DCA forces cancer cells to use

the mitochondrial pathway, producing oxygen radicals that kill the cancer cells

while leaving normal cells unharmed. Studies of brain tumours have found that

DCA selectively kills cancer cells without damaging normal tissue.

But that's not what Coomber found with colorectal cancer. Along with her team —

research associate Siranoush Shahrzad, graduate students Lacombe and Una

Adamic, and technician Kanwal Minhas — she looked at ischemic regions of

tumours, or areas with low oxygen and nutrients due to abnormal blood flow. They

had expected that, under fluctuating oxygen levels, DCA treatment would force

cancer cells to use the mitochondrial pathway, generate oxygen radicals and die.

In normal culture, DCA killed some human colon cancer cells. But under low

oxygen, the same cancer cells were more likely to survive. In mice with human

colon cancer cells grown as tumours, DCA provided no therapeutic benefit; in

fact, some treated tumours grew better than untreated ones. Fewer cells in

ischemic regions died in DCA-treated tumours than in untreated ones.

" The bottom line is that cancer is not a single disease, so it's unrealistic to

expect a single drug to be a `magic bullet' that's effective against every type

of cancer, " Coomber said, adding that many factors influence how cancer cells

develop and behave.

" We are only beginning to tease these things out. DCA may well turn out to be an

effective treatment in some cases, but it's not necessarily safe in all cases.

There are people out there buying this drug off the Internet and self-medicating

— who knows what's going on in their tumour? They might actually be making it

worse. "

Her team now plans to study the pathways DCA uses to protect some cancer cells.

This research was funded by the Canadian Cancer Society's Research