Strawberry Extract Halts Progression of Breast Cancer Cells

Highlights:

• Strawberry extract can inhibit the spread of laboratory-grown breast cancer cells to healthy tissue in mice.
• The extract decreased cell viability, blocked the cycle leading to cell division and inhibited migration.
• Scientists do point out that the results from animal testing do not apply to humans until tested.

Berries, especially strawberries, have numerous bioactive compounds that help deal with diseases and promote overall health. Strawberries are also called superfoods because of their antioxidant value.

A recent study done in mice shows that polyphenol-rich strawberry extract (PRSE), obtained from the "Alba" variety, reduces the highly aggressive and invasive basal-like breast cancer cell line A17.

Strawberry Effect

Strawberries are a rich source of folate, vitamin C and several phytochemicals. The high levels of antioxidant compounds, most of which are phenolic compounds such as anthocyanins, flavonols, flavanols, condensed tannins, hydroxybenzoic and hydroxycinnamic acid derivatives, have the ability to lower the severity of diseases.

'Alba', a variety of strawberry was extracted and presents high levels of Vitamin C (0.57 mg/g) and phytochemical compounds.

Bioactive compounds in strawberries prevents cancer progression but involves different mechanisms, which have not yet been fully elucidated.

"We have shown for the first time that strawberry extract, rich in phenolic compounds, inhibits the proliferation of breast cancer cells in in vitro and in vivo models," said Maurizio Battino, co-author of the paper and a principal investigator at the Marche Polytechnic University (Italy) and the European University of the Atlantic in Santander (Spain).

Tumor growth, recurrence and metastasis formation are dependent on certain cells called cancer initiating cells (CICs) or cancer stem cells (CSCs). They are self-renewing cells. A17 cells are a highly tumorigenic and display properties of CICs and basal-like breast cancer.

For the study, the in vitro model used A17 tumour cell line. These were treated with different concentrations (between 0.5 and 5 mg/ml) of extract of the Alba variety of strawberry, for periods of 24, 48 and 72 hours.

Previous investigations have shown that the intake of 500 g of strawberries (between 10 and 15 strawberries) per day offers antioxidant and anti-inflammatory benefits and reduces blood cholesterol levels. But the group of phytochemicals responsible for cancer prevention was unknown.

The results of the study demonstrated that strawberry extract reduced the expression of several genes involved in the processes of invasion and metastasis, such as Csf1, Mcam, Nr4a3 and Set.

Htatip2, a gene that is thought to suppress metastasis to the lymphatic ganglion in breast cancer patients was stimulated after the ingestion of the extract.

Testing the Extract

The effect of Alba strawberry extract was tested in female laboratory mice. They were divided into two groups: one was given a standard diet, while the other group was given a diet; 15% of which was strawberry extract. Breast cancer was induced in the mice after a month using A17 breast cancer cells.

The tumors were monitored twice weekly and after 5 weeks, the tumors were extracted and analysed to evaluate their weight and volume.

The study found that supplementing the daily diet with strawberry extract stopped the propagation of cancer cells to adjacent the healthy tissue. "We also saw a significant reduction in the weight and volume of the tumor," Battino stresses.

"The majority of diseases, including cancer, are complex, and involve complex interactions between cellular and molecular systems that determine the development of the disease."

The authors also added, "these results are without a doubt valid for understanding potential effects of strawberries on breast cancer and the molecular mechanisms involved, but they must be complemented with clinical and epidemiological studies to verify whether humans experience the same positive effects as we have observed in mice."

 The effect of the extract is significantly higher in breast cancer A17cell lines, suggesting a therapeutic window for PRSE in vivo. 

The concentration of phenolic compounds can vary greatly between varieties of strawberry. Apart from strawberries, a balanced diet with fruits and vegetables, and a healthy active lifestyle also have the potential to protect against cancer.

Reference:

1. Polyphenol-rich strawberry extract (PRSE) shows in vitro and in vivo biological activity against invasive breast cancer cells - (https://www.ncbi.nlm.nih.gov/pubmed/27498973)

Source: Medindia