CHICAGO, July 14 (Xinhua) -- A class of molecules formed when the body metabolizes omega-3 fatty acids could inhibit cancer's growth and spread, a study in mice by researchers at the University of Illinois (UI) found.

The molecules, called endocannabinoids, are made naturally by the body and have similar properties to cannabinoids found in marijuana, but without the psychotropic effects, the study shows.

In 2017, UI researchers identified a new group of omega-3 fatty-acid metabolites called endocannabinoid epoxides, or EDP-EAs. They found that these molecules had anti-inflammatory properties and targeted the same receptor in the body that cannabis does.

As cannabis has been proven to have some anti-cancer properties, the researchers investigated whether EDP-EAs also affect cancer cells.

In mice with tumors of osteosarcoma, a bone cancer that is notoriously painful and difficult to treat, EDP-EAs slowed the growth of tumors and blood vessels, inhibited the cancer cells from migrating and caused cancer cell death.

The researchers found that in higher concentrations, EDP-EAs did kill cancer cells, but not as effectively as other chemotherapeutic drugs on the market. Meanwhile, the compounds also combated the osteosarcoma in other ways: they slowed tumor growth by inhibiting new blood vessels from forming to supply the tumor with nutrients; prevented interactions between the cells; and most significantly, appeared to stop cancerous cells from migrating.

The researchers isolated the most potent of the molecules and are working to develop derivatives that bind better to the cannabinoid receptor, which is plentiful on the surface on cancer cells.

"Dietary consumption of omega-3 fatty acids can lead to the formation of these substances in the body and may have some beneficial effects," said study leader Aditi Das, a professor of comparative biosciences and an affiliate of biochemistry at UI. "If you have cancer, you want something concentrated and fast acting, that's where the endocannabinoid epoxide derivatives come into play. You could make a concentrated dose of the exact compound that's most effective against the cancer. You could also mix this with other drugs such as chemotherapies."

In the next step, the researchers plan to perform preclinical studies in dogs, since dogs develop osteosarcoma spontaneously, similarly to humans. They also plan to study the effects of EDP-EAs derived from omega-3 fatty acids in other cancer types.

The study has been published in the Journal of Medicinal Chemistry.