With more than 80,000 new cases diagnosed in Australia alone every year, cancer is now the leading cause of death in the Western world. But armed with hope and a naturally occurring sugar, a Monash researcher is waging war against the disease that claims so many lives.

By Corey Nassau

Cancer is now the leading cause of death in Western countries.

Dr Tracey Brown requires no encouragement to share her excitement for the molecule that has top billing on her laboratory door.

According to Dr Brown, a research fellow at Monash's Laboratory for Hyaluronan Research, the naturally occurring poly-saccharide found in the human body and known as Hyaluronan, or HA, is a wondrous molecule that is showing promise as the next breakthrough in cancer treatments.

Research already completed by the laboratory on mice has demonstrated that using HA can increase the action and efficacy of currently used chemotherapeutic drugs as well as reduce their side-effects.

"Chemotherapy is limited as it lacks a targeting system and has a high toxicity," Dr Brown said. "For the patient, this often translates into nausea and vomiting, hair loss and reductions in red and white cell counts."

To combat this shortfall, Dr Brown and her research team are utilising HA as a drug sensitiser and delivery vehicle to more accurately target cancerous tumours while making the cancer more susceptible to the anti-cancer drug. The results continue to be extremely encouraging.

Dr Tracey Brown says Hyaluronan is showing great promise as the next breakthrough in cancer treatments. The molecule, which occurs naturally in the human body, increases the action and efficiency of anti-cancer drugs as well as reducing their side effects.

"When we combine HA with anti-cancer drugs, we actually lower toxicity, the animals live longer, they put on weight throughout the therapy, and we reduce the spread of cancer to secondary sites such as the lymph nodes," Dr Brown said. "In some cases, the tumours actually die and start dropping off the mice."

Dr Brown first became interested in Hyaluronan while studying the molecule for her PhD, and only later became interested in its potential uses for treating cancer.

Hyaluronan is found naturally throughout the human body and has many physiological functions. According to Dr Brown, its primary function is to keep the body hydrated.

"It has an amazing capacity to absorb water, and because it is so thick it also acts like a shock absorber in joints," she said. "To obtain it through commercial sources, it is usually made from bacterial fermentation, but is also found in rooster combs.

"We started thinking about Hyaluronan as a sensitising drug delivery vehicle because it has amazing physical chemical characteristics. At very low concentrations, it forms a three-dimensional meshwork filter that enables it to entrain small molecules within the big, viscous meshwork of the HA molecule."

According to Dr Brown, HA has double appeal as a drug enhancer. Firstly, numerous cancers have an over-expression of proteins on the surface of their cells - the receptors - which means HA can target the anti-cancer drugs to the receptors.

Secondly, it appears that HA alters the membrane of the cancer cells so they become more susceptible to the anti-cancer drug.

Dr Brown and her team realised that if these receptors only recognised HA and the HA was combined with an anti-cancer drug, they could target the cancer cell more efficiently.

The Monash research team is conducting human clinical trials for breast and colon cancer.

"The HA acts like a transport, carrying the drug with it through the blood stream until it recognises the receptor on the cancer cell and hits it like a missile," she said. "As it does this, it is internalised and drags more drug into the cell with it, resulting in increased cancer kill.

"We've done a lot of toxicology over the past year where we've shown that HA by itself is non-toxic and has no side-effects, so the therapy should reduce presently experienced side-effects instead of introducing new ones."

Following the success of their animal model, the team received approval to conduct two sets of human clinical trials for breast and colon cancer at Royal Melbourne Hospital and Hammersmith Hospital in London.

The project, under way for more than four years now, is being funded by Perth-based biotechnology company Meditech Research and has won the support of one of Australia's leading oncologists, Professor Richard Fox.

A better quality of life

"As a scientist, the ultimate end-point is to get your therapy into humans, and we are now at this very exciting stage. If you'd asked me a year ago if we'd be able to get this far, I wouldn't have been able to answer," Dr Brown said.

"But if we can relate the results that we've achieved in mice to humans, cancer patients will put on weight during therapy, they may not experience nausea and vomiting, they will have prolonged survival due to the cancer not spreading as rapidly, and the tumours will be smaller. Ultimately they will have a better quality of life."

		The Graduate Diploma in the Biotechnologies of Life is being offered for the first time in 2001. For more information, contact Ms Fran Spain at frances.spain@med.monash.edu.au or on +61 3 9905 2719.