Could sea snails be the key to curing cancer?

Australian researchers have discovered natural cancer fighters in the molecules of sea snail eggs

karaThe discovery is all the more significant as the active molecules from the egg masses of sea cone snails were found to kill both normal cancer cells and drug-resistant cells within 48 hours. Kara Perrow, a lecturer and cancer researcher at the University of Wollongong, told us the next steps in this research and what inspired her to look to sea snails for a cancer cure.

ResearchGate: Can you explain the significance of your findings?

Kara Perrow: The development of multi-drug resistance is the most significant clinical problem facing the chemotherapeutic treatment of cancer today. It is responsible for local reoccurrence and relapse in a large number of cases, affecting patients with blood cancers and solid tumors, including breast, ovarian, lung, and gastrointestinal cancers. Any discovery we make in this space could change the way we treat chemo-resistant cancer in the future and ultimately increase patient survival.

RG: What caused you to look into potential cancer-fighting capacities in sea snails?

Perrow: Over 50 percent of drugs used for the treatment of cancer and more than 75 percent of the drugs used for treating infectious diseases are derived from natural products. The marine environment is virtually an untapped resource and holds great promise for us to discover novel molecules with anti-cancer activities.

RG: Could you summarize the method you used to reach your findings?

Perrow: The compounds were originally isolated from the egg masses of the sea snail. Our compounds were screened against cancer cells that were either sensitive or resistant to commonly used chemotherapeutic drugs and the number of live and dead cells in the population quantified after 48 hours. Our molecules, called N-alkylisatins, killed 100 percent of drug resistant cancer cells in just 48 hours. In comparison, a chemotherapy drug commonly used to treat breast cancer only killed 10 percent of cells in the same time period. We have identified that the mechanism by which these compounds kill cancer cells is by disrupting the cells' skeleton.

RG: Why do these snails have these cancer-fighting chemical compounds? Is it likely that other breeds of sea snails could have similar compounds?

Perrow: Many marine invertebrates, including sea snails, deposit their egg masses on the floor of the ocean, making them vulnerable to predation and microbial infection. To help counter this threat, they have evolved a form of chemical protection for their embryos which not only displays anti-bacterial and anti-microbial properties, but anti-cancer properties as well. Other sea snails have also been reported to contain the same or similar compounds that also display anti-cancer activity.


Sea snails
Sea snails from Australia's east coast (photo credit Kara Perrow)

RG: Do these snails get cancer themselves? 

Perrow: Not to my knowledge for this particular mollusk, but two different types of cancer have been reported to occur in marine mollusks, a transmissible form of leukemia and cancer of the gonads.

RG: What is the next step in this research?

Perrow: We currently optimizing the formulation by packing these molecules into small, lipid-based particles, so that they are suitable for injecting into humans and testing in preclinical models. We need to prove safety and efficacy in these models before progressing to humans. In the future, these compounds could be used in three ways: as a form of chemotherapy when all standard chemotherapies fail, as a new drug to replace existing chemotherapies, or in combination with currently used chemotherapies to reduce the chances of multi-drug resistance (MDR) arising.

Further testing in our laboratory will help us decide where in the treatment schedule patients are most likely to benefit from this new drug.

RG: If the cancer-fighting capacities of these chemical compounds is proven successful in human tests, would it be possible to produce these drugs on a large scale?

Perrow: Absolutely – we are already routinely synthetically manufacturing these compounds in the laboratory very cheaply. We no longer need to source the compounds from the sea snail.

Image credit Ian Armstrong.