A study has found that a class of molecules formed when the body metabolizes omega-3 fatty acids could inhibit the spreading and growth of cancer.
In a recent study conducted at the University of Illinois, researchers have found that in mices, the molecules called endocannabinoids, are made naturally by the body and have similar properties to cannabinoids found in marijuana - but without the psychotropic effects.
In mice with tumors of osteosarcoma - a bone cancer that is notoriously painful and difficult to treat - endocannabinoids slowed the growth of tumors and blood vessels, inhibited the cancer cells from migrating and caused cancer cell death.
"We have a built-in endocannabinoid system which is anti-inflammatory and pain-reducing. Now we see it is also anti-cancer, stopping the cells from proliferating or migrating," said a researcher Aditi Das.
"These molecules could address multiple problems: cancer, inflammation and pain," she added.
In 2017, the Illinois team 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.
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Since cannabis has been shown to have some anti-cancer properties, the researchers have investigated in the new study that whether EDP-EAs also affect cancer cells.
They also found that in mice with osteosarcoma tumors that metastasized to their lungs, there was an 80 percent increase in naturally occurring EDP-EAs in cancerous lung tissues over the lungs of healthy mice.
"The dramatic increase indicated that these molecules were doing something to cancer - but we didn't know if it was harmful or good, "she further said.
"We asked, are they trying to stop cancer, or facilitating it? So we studied the individual properties and saw that they are working against cancer in several ways," she further pointed it out.
The researchers found that in higher concentrations, EDP-EAs did kill cancer cells, but not as effective as other chemotherapeutic drugs on the market.
However, 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, they prevented interactions between the cells, and most significantly, they appeared to stop cancerous cells from migrating.
"The major cause of death from cancer is driven by the spread of tumor cells, which requires migration of cells," said another researcher Timothy Fan.
"As such, therapies that have the potential to impede cell migration also could be useful for slowing down or inhibiting metastases," she added.
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. However, if you have cancer, you want something concentrated and fast acting," Das said.
The endocannabinoid epoxide derivatives come into play - since one can make a concentrated dose of the exact compound that's most effective against cancer.
"You could also mix this with other drugs such as chemotherapies," Das added.
Next, 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.
"Particular cancers that might be most interesting to study would be solid tumors or carcinomas, which tend to spread and cause pain within the skeleton. Some of the most common tumors that behave this way are breast, prostate, and lung carcinomas, and we can certainly explore these tumors in the future," Fan added.
The study appeared in the Journal of Medicinal Chemistry.