Breast Cancer: Omega-3 Protection Mechanism Discovered
Breast cancer: here’s how fish oil protects against this, unfortunately, common disease
The molecular mechanism by which Omega 3 DHA (docosahexaenoic acid) inhibits the growth and spread of breast cancer cells has been discovered. Thanks to a study conducted on human cells, researchers at the UT Health Science Center in San Antonio (USA) revealed that this nutrient blocks the expression of the small molecule miR-21, involved in tumor growth as well as metastasis formation. The research was published in the journal Carcinogenesis1.
Omega-3, valuable allies against cancer
The potential of Omega-3 for cancer treatment (prevention, therapy, growth inhibition, spread) has been highlighted by many studies. For example, it has been found that a diet rich in these nutrients reduces cancer incidence. In combination with traditional therapies, Omega-3s help to:
- increase the effectiveness of therapies;
- reduce treatment toxicity;
- limit tumor growth;
- counteract metastasis formation.
The crucial point seems to be the balance between Omega-3 and Omega-6, other important fatty acids: the more the ratio of their concentrations favors Omega-3, the greater their protective effect against cancer. Among the mechanisms underlying Omega-3’s action against cancer is the increased sensitivity of tumor cells to free radicals, toxic molecules generated by some chemotherapies and radiotherapy. Moreover, it has been shown that Omega-3s impair the ability of cancer cells to adhere to and pass through membranes, essential functions for metastasis formation.
Breast cancer: a special case
Omega-3s have proven effective against the following tumor types:
In the case of breast cancer, it has been shown that an Omega-3 deficiency increases the likelihood of metastasis development, while a diet rich in these fatty acids can reduce tumor size. However, few studies have shed light on the molecular mechanisms triggered by these nutrients in tumor cells. Some researchers hypothesized that targets of these fatty acids include molecules regulating gene expression: so-called micro-RNAs. This hypothesis was confirmed by scholars at the UT Health Science Center, who demonstrated that DHA inhibits the expression of the micro-RNA miR-21 in breast cancer cells. In their study, the researchers explained that breast cancer growth and metastasis formation are associated with increased miR-21 levels. miR-21 in turn acts on a series of molecules known for their involvement in tumor formation, stimulating the activity of the CSF-1 gene, a powerful activator of cancer proliferation and metastasis formation. DHA reduces miR-21 levels and blocks CSF-1 activity. The results obtained by administering DHA to cells were confirmed by feeding mice with fish oil, a known source of Omega-3. In this case as well, a reduction in both miR-21 and CSF-1 levels was observed. Based on these results, the researchers concluded that the effectiveness of fish oil and the DHA it contains works through blocking miR-21, which leads to reduced CSF-1 expression.
Source:
1. Mandal CC, Ghosh-Choudhury T, Dey N, Ghosh Choudhury G, Ghosh-Choudhury N, “miR-21 is Targeted By Omega-3 Polyunsaturated Fatty Acid to Regulate Breast Tumor CSF-1 Expression”, Carcinogenesis. 2012 Jun 7.
