The research, published in Carcinogenesis, tested the effects of omega-3 fatty acids in a laboratory setting using in vitro samples of cancerous cells. The team focused their study on one specific type of cancer called squamous-cell carcinoma (SCC) - which is responsible for the majority of skin cancer. However, SCC can also occur in the lining of the digestive tract, lungs, and other areas of the body.
Led by Dr Zacharoula Nikolakopoulou at Queen Mary, University of London, UK, the research team found that omega-3 fatty acids - particuarly EPA - selectively blocks the growth and induces cell death in early and late-stage SCC oral and skin cancers.
Nikolakopoulo and colleagues noted that the in vitro tests showed the omega-3 fatty acids caused this cell death at levels that did not affect normal cells.
"As the doses needed to kill the cancer cells do not affect normal cells, especially with one particular fatty acid we used called eicosapentaenoic acid (EPA), there is potential for using omega-3 fatty acids in the prevention and treatment of skin and oral cancers," she said.
"It may be that those at an increased risk of such cancers - or their recurrence - could benefit from increased omega-3 fatty acids."
"Moreover, as the skin and oral cancers are often easily accessible, there is the potential to deliver targeted doses locally via aerosols or gels," suggested Nikolakopoulo. "However further research is needed to define the appropriate therapeutic doses."
The team noted that SCC is one of the major forms of skin cancer, while oral squamous cell carcinomas (OSCC) are the sixth most common cancer worldwide. OSCC in particular are difficult and very expensive to treat, the team noted.
In the new study, Nikolakopoulo and her colleagues grew cell cultures in the lab from several different cells lines - to which they added fatty acids. Cell lines included both malignant oral and skin SCCs, along with pre-malignant cells and normal skin and oral cells.
Both docosahexaenoic acid (DHA) and EPA forms of omega-3 fatty acids were found to be effective in reducing growth of the SCC cell lines, however the team revealed that even a low dose of EPA in particular blocked the growth of cancer cells with a combination of cell cycle arrest and apoptosis
"Surprisingly, we discovered this was partly due to an over-stimulation of a key growth factor (epidermal growth factor) which triggered cell death," explained Professor Parkinson, Head of the Oral Cancer Research Group at Queen Mary's, and senior author of the new study.
"This is a novel mechanism of action of these fatty acids," he said.
Published online ahead of print, doi: 10.1093/carcin/bgt257
"Omega-3 polyunsaturated fatty acids selectively inhibit growth in neoplastic oral keratinocytes by differentially activating ERK1/2"
Authors: Zacharoula Nikolakopoulou, Georgios Nteliopoulos, Adina Teodora Michael-Titus, Eric Kenneth Parkinson