DNC News

Evening primrose oil, breast cancer and herceptin

November 4, 2005

Subject: A recent study suggests that evening primrose oil taken as a supplement may increase the effectiveness of the chemotherapy drug herceptin used to treat breast cancer.

The following story showed up in a number of British newspapers a few days ago:

“Primrose oil may help fight cancer

A substance found in evening primrose oil may prove to be a powerful new weapon against aggressive breast cancer.

In laboratory tests it not only suppressed an important breast cancer gene but also amplified the effects of a drug used in advanced stages of the disease.

Evening primrose oil is commonly used to alleviate menstural symptoms.

These new findings suggest one of its active ingredients may also combat some of the most serious cases of breast cancer. A compound in evening primrose oil called gamma-linolenic acid (GLA) was found to inhibit the action of a gene responsible for about 30% of breast cancers. Patients with the mutant Her-2/neu oncogene have aggressive tumors and a poor outlook.

GLA reduced the levels of protein made by the gene which promotes tumor growth.

It also caused a 30 to 40-fold increase in the response of breast cancer cells to Herceptin, a drug given to women once the disease has metastasized, or spread to other parts of the body.

GLA increased apoptosis, cell suicide, in cancers cells also exposed to Herceptin.

Research leader Ruth Lupu, from Northwestern University , in Evanston , Illinois , said: ‘In our tests, treating the cancer cell lines with both GLA and Herceptin led to a synergistic increase in apoptosis and reduced cancer growth.'”

You've got to love a study like this. Evening primrose oil is a popular supplement in wide use by a large number of people for lots of years. The chance of it causing unwanted side effects is very low. Having a Her-2/neu positive breast tumor is not considered good news on a breast tumor biopsy. One wants to go all out and do everything possible in these situations. That we might increase the beneficial effects of Herceptin in treating these women is incredible news. Will this research work as well in people as it did in the laboratory? Only time will tell, but in the meantime there is no reason to start taking advantage of this knowledge. At this point it makes sense for any woman taking Herceptin to also take evening primrose oil.

The study:

J Natl Cancer Inst. 2005 Nov 2;97(21):1611-5.

Effect of gamma-linolenic acid on the transcriptional activity of the Her-2/neu (erbB-2) oncogene.

Menendez JA, Vellon L, Colomer R, Lupu R.

Department of Medicine, Evanston Northwestern Healthcare Research Institute, Evanston , IL 60201 , USA . jmenendez@enh.org

The omega-6 polyunsaturated fatty acid gamma-linolenic acid (GLA; 18:3n-6), which is found in several plant oils and is used as an herbal medicine, has antitumor activity in vitro. We examined the effect of GLA on the expression of the Her-2/neu (erbB-2) oncogene, which is involved in development of numerous types of human cancer. Flow cytometric and immunoblotting analyses demonstrated that GLA treatment substantially reduced Her-2/neu protein levels in the Her-2/neu-overexpressing cell lines BT-474, SK-Br3, and MDA-MB-453 (breast cancer), SK-OV3 (ovarian cancer), and NCI-N87 (gastrointestinal tumor derived). GLA exposure led to a dramatic decrease in Her-2/neu promoter activity and a concomitant increase in the levels of polyomavirus enhancer activator 3 (PEA3), a transcriptional repressor of Her-2/neu, in these cell lines. In transient transfection experiments, a Her-2/neu promoter bearing a PEA3 site-mutated sequence was not subject to negative regulation by GLA in Her-2/neu-overexpressing cell lines. Concurrent treatments of Her-2/neu-overexpressing cancer cells with GLA and the anti-Her-2/neu antibody trastuzumab led to synergistic increases in apoptosis and reduced growth and colony formation.

PMID: 16264182 [PubMed - in process]