Fighting cancer with tobacco?

Researchers from La Trobe University have found that the natural defence mechanisms of a tobacco plant could be harnessed to kill cancer cells in the human body. The multidisciplinary collaboration utilised equipment at the Australian Synchrotron and is supported by Hexima, Balmoral and the Australian Research Council.

The scientists identified the small peptide molecule NaD1 in the flowers of an ornamental tobacco plant Nicotiana alata. The molecule forms a pincer-like structure that grips onto lipids present in the membrane of a fungal cell - or a cancer cell - and rips the membrane open, causing the cell to expel its contents and explode.

The flower of the ornamental tobacco plant and the structure of the molecule NaD1, which scientists say has the potential to treat cancer in humans. Credit: Fung Lay, La Trobe University.

“There is some irony in the fact that a powerful defence mechanism against cancer is found in the flower of a species of ornamental tobacco plant,” said lead investigator Dr Mark Hulett, “but this is a welcome discovery, whatever the origin.

“One of the biggest issues with current cancer therapies is that the effect of the treatment is indiscriminate. In contrast, we’ve found NaD1 can target cancerous cells and has little or no effect on those that are healthy.

“The next step is to undertake preclinical studies to determine what role NaD1 might be able to play in treating cancer. The preclinical work is being conducted by the Melbourne biotechnology company Hexima.”

Dr Hulett said scientists have known for some time about the molecules that form the first line of defence against microbial invasion in all plant and animal species, but until now, nobody has known how the molecules actually did their job. Along with Dr Marc Kvansakul and other La Trobe researchers, he used X-ray diffraction techniques at the Australian Synchrotron’s MX beamlines to determine the structure of NaD1 in the act of binding to a lipid molecule found in the cell membranes of fungi and mammals.

The synchrotron showed how 14 of the NaD1 molecules work together to surround each lipid molecule and disrupt the cell membrane, ultimately killing the target cell. Dr Hulett said the team has thus “discovered the workings of this universal defence process, which could also potentially be harnessed for the development of other therapeutic applications, including antibiotic treatment for microbial infections”.

The study has been published in the journal eLife