Australian scientists are modifying bee venom to develop cancer treatments that may have fewer side effects than other drugs used to fight the disease.

A research project to utilise an active ingredient from bee venom as a potential cure for cancer has just been funded.

Part of the mellitin molecule

The venom in the bee sting contains a number of active ingredients, the main one being mellitin, a molecule that kills cells by slicing through cell walls.

"What we have done is to modify the structure of the mellitin molecule and remove the part that causes the allergic reaction while still maintaining its ability to kill cells," said Dr Jerome Werkmeister of the Commonwealth Science and Industry Research Organisation, CSIRO.

One problem the researchers have to tackle is targeting the cell-killing activity of mellitin to cancer cells only and not to normal healthy cells.

Antibody molecule

They plan to achieve this by attaching the modified mellitin to an antibody molecule that specifically recognises cancer cells. The combination of a toxin and an antibody is called an immunotoxin.

"Chemotherapy drugs are not specific; they attack normal cells thereby causing unwanted side effects such as hair loss, vomiting and weight loss.

"Such symptoms limit the amount of drug that can be administered and hence its effectiveness," says CSIRO's Dr Dean Hewish.

Dr Werkmeister points out that mellitin is far less toxic than the plant and bacterial toxins used in earlier work. New immunotoxin drugs produced from it may reduce potential side effects while still retaining the specific killing of target cancers.