Grape seed extract kills head and neck cancer cells, leaves healthy cells unharmed

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Nearly 12,000 people will die of head and neck cancer in the United States this year and worldwide cases will exceed half a million.

A study published this week in the journal Carcinogenesis shows that in both cell lines and mouse models, grape seed extract (GSE) kills head and neck squamous cell carcinoma cells, while leaving healthy cells unharmed.

“It’s a rather dramatic effect,” says Rajesh Agarwal, PhD, investigator at the University of Colorado Cancer Center and professor at the Skaggs School of Pharmaceutical Sciences.

Note: Here's more from Wkipedia:

Human case reports and results from laboratory and animal studies provide preliminary evidence that grape seed extract may affect heart diseases such as high blood pressure and high cholesterol.[1] By limiting lipid oxidation, phenolics in grape seeds may reduce risk of heart disease, such as by inhibiting platelet aggregation and reducing inflammation.[2] While such studies are promising, more research including long-term studies in humans is needed to confirm initial findings.

A polyphenol contained in grape seeds is resveratrol, which may interfere with cancer cell growth and proliferation, as well as induce apoptosis, among other potential chemopreventive effects.[3][4]

Preliminary research shows that grape seed extract may have other possible anti-disease properties, such as in laboratory models of
• wound healing —- grape seed proanthocyanidins induced vascular endothelial growth factor and accelerated healing of injured skin in mice[5]
• tooth decay -- seed phenolics may inhibit oral sugar metabolism and retard growth of certain bacteria that cause dental caries[6]
• osteoporosis -- grape seed extracts enhanced bone density and strength in experimental animals[7]
• skin cancer -- grape seed proanthocyanidins decreased tumor numbers and reduced the malignancy of papillomas[8]
• ultraviolet damage to skin -— dietary proanthocyanidins may protect against carcinogenesis and provide supplementation for sunscreen protection[9]
• anti-viral[10][11]

and from the National Center for Complementary and Alternative Medicine

• Studies have found that some compounds of grape seed extract may be effective in relieving symptoms of chronic venous insufficiency (when veins have problems sending blood from the legs back to the heart) and reducing edema (swelling) after an injury or surgery.
• Small randomized trials have found beneficial effects of grape seed extract for diabetic retinopathy (an eye problem caused by diabetes) and for vascular fragility (weakness in small blood vessels). Larger trials are needed to confirm these findings.
• Grape seed extract contains antioxidants, which help prevent cell damage caused by free radicals (highly reactive molecules that can damage cell function). Preliminary studies have shown some beneficial antioxidant effects; however, more research is needed.
• A study funded by the National Cancer Institute (NCI) found that grape seed extract did not reduce the hardening of breast tissue that can occur after radiation therapy for breast cancer.
• NCI is also funding studies to evaluate whether grape seed extract is effective in preventing breast cancer in postmenopausal women and prostate cancer.
• NCCAM is studying whether the action of grape seed extract and its components may benefit the heart or help prevent cognitive decline, Alzheimer's disease, and other brain disorders. Another study is investigating the effects of grape seed extract on colon cancer.

Specifically, the paper shows that grape seed extract both damages cancer cells’ DNA (via increased reactive oxygen species) and stops the pathways that allow repair (as seen by decreased levels of the DNA repair molecules Brca1 and Rad51 and DNA repair foci).

“Yet we saw absolutely no toxicity to the mice, themselves,” Agarwal says.

Again, the grape seed extract killed the cancer cells but not the healthy cells.

“I think the whole point is that cancer cells have a lot of defective pathways and they are very vulnerable if you target those pathways. The same is not true of healthy cells,” Agarwal says.

The Agarwal Lab hopes to move in the direction of clinical trials of grape seed extract, potentially as an addition to second-line therapies that target head and neck squamous cell carcinoma that has failed a first treatment.