Breast cancer, protective mechanism activated by Omega-3s discovered
Breast cancer: here's how fish oil protects against this, unfortunately, common disease
The molecular mechanism by whichOmega 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 (United States) have unveiled that this nutrient blocks the expression of the small molecule miR-21, which is involved in tumor growth as well as metastasis formation. The research was published in the pages of the journal Carcinogenesis1.
Omega-3s, valuable allies against cancer
The potential of Omega-3s for cancer treatment (prevention, therapy, growth inhibition, spread) has been highlighted by many studies. For example, a diet rich in these nutrients has been found to reduce the occurrence of cancer. In combination with traditional therapies, Omega-3s allow:
- Increase the effectiveness of the therapies themselves;
- Reduce the toxicity of treatments;
- Limit tumor growth;
- Counteract the formation of metastasis.
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 is unbalanced in favor of Omega-3, the greater their protective effect against cancer. Among the mechanisms underlying the action of Omega-3s against cancer is the increased sensitivity of cancer cells to the action of free radicals, toxic molecules generated by some chemotherapeutics and radiotherapy. In addition, Omega-3s have been shown to impair the ability of cancer cells to adhere to and cross membranes, functions that are essential for metastasis formation.
Breast cancer: a special case
Omega-3s have been shown to be effective toward the following forms of cancer:
In the case of breast cancer, Omega-3 deficiency has been shown to increase the likelihood of developing metastases, while a diet rich in these fatty acids can reduce their size. Few studies have, however, been able to shed light on the molecular mechanisms triggered by these nutrients in cancer cells. Some researchers have hypothesized that among the targets of these fatty acids are molecules that regulate gene expression: so-called micro-RNAs. The hypothesis was confirmed by UT Health Science Center scholars, who showed that DHA inhibits the expression of the micro-RNA miR-21 in breast cancer cells. In their study, the researchers explained that growth and metastasis formation from breast cancer is associated with increased miR-21 concentrations. This in turn acts on a number of molecules known to be involved in tumor formation, going so far as to stimulate the activity of the CSF-1 gene, a potent 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. Again, a reduction in both miR-21 and CSF-1 levels was observed. Based on these results, the researchers concluded that the efficacy of fish oil and the DHA it contains comes 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.
