Can Resveratrol Prevent or Help Treat Breast Cancer?

Breast cancer is still a leading cause of death for women, with more than 40,000 deaths a year from metastatic breast cancer alone. Conventional chemotherapy often causes severe adverse side effects, and many tumors are already resistant or develop resistance to chemotherapy drugs. Resveratrol may offer a safer option for breast cancer patients, depending on the type of breast cancer, and could also reduce the severe pain associated with advanced cancer.^20,143,192

How Does Resveratrol Work In Some Types of Breast Cancer?

Lab studies indicate that resveratrol inhibits the metabolism of estrogen and estrogen metabolites. When oxidized, these estrogenic hormones can react with DNA and create a risk for the formation of breast cancer cells.¹⁹³ However, early studies suggest that in certain breast cancer cell lines (T47D and MCF7) resveratrol’s estrogenic properties may stimulate cancer cell growth.¹⁹⁴ In breast adenocarcinoma cell lines resveratrol inhibited tumor growth factors, stopped the cells from growing, and induced cell death.¹⁹⁴

Animal studies show that resveratrol also blocks production and activation of inflammatory and other proteins known to play a role in breast cancer development and growth and increases the death of cancer cells.¹⁴⁸ Other research, in both the lab and on human breast cancer tumors made to grow on rats, demonstrates that resveratrol targets the mitochondria in breast cancer cells and increases the amount of calcium inside them, which in turn stimulates the release of enzymes that trigger cell death.¹⁴³

One of the ways resveratrol causes cancer cells to die in breast cancer associated with mutations of BRCA1 appears to be by promoting the SIRT1 gene activity that can counteract the pro-tumor effects of these mutations. BRCA genes are associated with DNA repair and tumor suppression. BRCA1 is most often found to be mutated in families with multiple cases of breast cancer amongst close relatives and greatly increases the risk of breast cancer. A common feature in BRCA1-associated breast cancers are low levels of SIRT1 and high levels of a protein called survivin, which promotes the growth of these tumors. Lab and animal studies show that resveratrol inhibits BRCA1 tumor growth by inhibiting expression of survivin—but seems to only do so when SIRT1 is present.¹⁹⁵

Research published at the end of 2010 indicates that resveratrol can inhibit high levels of formaldehyde produced by tumor cells in the body. Formaldehyde not only helps cancer tumors grow, it also causes pain—possibly by activating pain sensors that increase sensitivity and pain signals. Tests show that formaldehyde levels breast cancer patients are 2-8 times higher than normal (as measured in exhaled air).²⁰

Evidence of Benefit

Both lab and animal studies reveal that resveratrol significantly inhibits the growth of certain breast cancer cell types.¹⁹⁶ In study rats with breast cancer tumors, resveratrol doses of between 5-µg per 30 grams of body weight and 10- mg per kg of body weight given over periods of 3-18 weeks had the following effects:¹⁴⁸

• Increased time of tumor progression.
• Decreased occurrence or recurrence of tumors.
• Lower number of tumors.
• Inhibited tumor growth.

Some preclinical studies suggest that resveratrol’s powerful anti-inflammatory and gene regulating properties may help prevent some types of breast cancer tumors from developing, growing, and spreading.¹⁹⁷ Resveratrol has even been shown to delay development of HER-2 type breast cancers and inhibit metastatic tendencies of these tumors.¹⁹⁷ These cancers produce more of pro-tumor HER2 proteins because of a genetic mutation, are highly aggressive and generally nonresponsive to hormone therapies.¹⁹²

However, one earlier animal study published in 2002 showed that resveratrol failed to block the growth of another type of aggressive breast cancer (4T1 murine mammary cells).¹⁹⁷ In addition, there are conflicting study results regarding resveratrol’s ability to sensitize breast cancer cells to other conventional chemotherapy drugs. A recently published study showed that resveratrol inhibited the cancer-fighting effects of paclitaxel on MDA-MB-435s cancer cells in mice and on MDA-MB-231 and SKBR-3 breast cancer cell lines in the lab.¹⁹⁸

Resveratrol injected into lab rats treated to mimic bone cancer showed significant decreases in formaldehyde and pain levels. These results suggest that resveratrol can help relieve pain in breast cancer patients where the malignancy has spread to the bones, as well as inhibit growth in the cancer itself.²⁰