November 6, 2014
Searching for cures for cancer in the deep-sea
The cure for cancer might be hidden in the deepest depths of the ocean, according to UOW chemist Dr Danielle Skropeta.
Dr Skropeta, who has dedicated her career to the discovery and development of new drugs inspired by nature, has recently published a review that found that 188 new chemicals have been discovered in the deep sea in the last five years alone and of these, more than 60 per cent are cytotoxic, meaning they can kill cancer cells in the dish.
From sea cucumbers that destroy multi-resistant ovarian cancer to microorganisms that work magic against breast cancer or a fungus that could be a match for leukaemia, Dr Skropeta said the ‘twilight zone’, which is too deep for the sunlight to reach at 200 metres and below, contains a flurry of untapped medicines.
“The common statement in the field is that we know far more about the moon than we know about the deep sea, and that is certainly true,” Dr Skropeta, from UOW’s School of Chemistry, said.
Access to the deep sea has only come about with the advent of scuba and with around 50 years of research under the belt compared to the thousands of years of knowledge of plants, there is still much to be learned about an environment that was once thought to be completely barren.
“Considering the deep sea is one of the most bio-diverse and species-rich habitats on the planet, rivalling coral reefs and rainforests, we are expecting to find many more new chemicals that could be used to treat cancer and other diseases.”
Dr Skropeta said in order to survive in the ‘twilight zone’, an environment with very high pressure, and very low temperature, oxygen and nutrients, deep sea marine organisms have had to evolve different biological systems to their land counterparts.
These biological systems contain a number of curious chemicals that are completely new to science. And chemists like Dr Skropeta are finding many of them are deadly to cancer.
Currently, there are six marine-derived drugs that have been approved for clinical use for cancer, pain, and HIV, with dozens more in different phases of clinical trials, hundreds in preclinical trials and thousands under development.
“What most people don’t know is that natural product-derived drugs account for 50 per cent of the drugs used for the treatment of cancer and more than 75 per cent of the drugs used for treating infectious diseases,” Dr Skropeta said.
Dr Skropeta, and her colleagues Associate Professor Andy Davis and Ms Alison Broad, have had several trips offshore over the past few years exploring various parts of the deep sea in the North West Shelf, off the coast of Western Australia.
By borrowing mini submarines and marine robots from the oil and gas industry, Dr Skropeta and her team have collected many deep sea organisms, which she is currently testing for bioactivity.
“To find out if there is any bioactive chemicals in the samples, we use organic solvents to extract the organic soluble material. Just like making a cup of tea,” Dr Skropeta explained.
“So you’ve got your cup, tea bag and hot water and you’re extracting out all the tannins and the caffeine. Using the same principal, we can extract the organic chemicals using an organic solvent rather than hot water. We then test the extracts for bioactivity and in the ones that are bioactive, we try to isolate the individual chemicals. In any one extract there could be anywhere between 100 and 1,000 natural chemicals.”
Dr Skropeta said her team is focused on finding new treatments for pancreatic and ovarian cancers in particular, which are notoriously difficult to treat.
“There is no good treatment available today for these cancers. The treatments have not changed in more than 40 years. We urgently need new drugs.”
With the vast oceans covering 70 per cent of the world's surface and 95 per cent of them being greater than 1,000 metres deep, there are still thousands of new species and chemicals just waiting to be found.
“It’s really important to explore the deep sea so that we don’t wipe out these species before we even know that they are there. They might hold the potential cure or treatment for cancer and other diseases,” Dr Skropeta said.
“Nature does it best and we’ve got a lot to learn.”
Media contact: Elise Pitt, Media & PR Officer, UOW, +61 2 4221 3079, +61 422 959 953, epitt@uow.edu.au.