Ant toxin provides new approach to cancer therapy

In a development that promises a new approach to cancer therapy, researchers from The University of Technology Sydney have developed an immunotoxin which effectively targets malignant cells with a new toxin found in an Australian ant.

The immunotoxin, which incorporates a major component from the venom of the jumper ant Myrmecia pilosula, is four times more potent than an immunotoxin derived from bee venom, which the team investigated in an earlier research project.

In the earlier research, the team, headed by Professor Robert Raison of the Cell and Molecular Biology Department, isolated melittin, a toxic protein in bee venom. They fused the gene encoding the toxin protein with the gene encoding the binding site of an antibody molecule in order to produce a new protein with strong anti-cancer properties, especially effective against the human leukaemia known as multiple myeloma.

"This new protein had the targetting potential of the antibody molecule at one end and the toxin at the other. It's a bit like a guided missile," Prof. Raison said.

He believes the team's current research involving the venom of the jumper ant represents a new approach in the development of immunotoxins for cancer chemotherapy.

Previous attempts at linking toxins to antibodies have worked well in the laboratory but in clinical trials have demonstrated some undesirable side effects.

"We believe these side effects are a consequence of the high potency of the toxins used, so we decided on a different approach, targeting less potent toxins that act on the cell membrane rather than within the cell itself," said Prof. Raison.

"We've developed a sound immunotoxin incorporating pilosulin and, in laboratory comparisons between pilosulin and melittin, we've shown that the ant venom component is far more effective than the bee venom component when used in an immunotoxin against cancer cells."

Item provided courtesy of The University of Technology Sydney