Grape Seed Extract for Colorectal Cancer
Compounds selectively target advanced disease in lab study (Jan. 16)
A study conducted at the University of Colorado Cancer Center has shown that grape seed extract (GSE) inhibits the growth and survival of advanced colorectal cancer cells while leaving healthy cells alone. The new findings were published in Cancer Letters.
“We’ve known for quite a while that the bioactive compounds in grape seed extract selectively target many types of cancer cells,” said doctoral candidate Molly Derry. “This study shows that many of the same mutations that allow colorectal cancer cells to metastasize and survive traditional therapies make them especially sensitive to treatment with GSE.”
Derry noted that this is an especially important finding in light of increasing rates of colorectal cancer — partly due to increasingly high-fat diets and sedentary lifestyles — and low screening rates. An estimated 60% of patients diagnosed with colorectal cancer have already reached an advanced stage of disease.
“Finding a way to selectively target advanced colorectal cancer cells could have major clinical importance,” Derry said.
The researchers conducted experiments on colorectal cancer cell lines representing various stages of the disease. While it generally takes more chemotherapy to kill a stage IV cancer cell than a stage II cancer cell, Derry found that the reverse was true with GSE.
“It required less than half the concentration of GSE to suppress cell growth and to kill 50% of stage IV cells than it did to achieve similar results in the stage II cells,” she said.
The investigators also discovered a likely mechanism behind GSE’s preferential targeting of advanced colorectal cancer cells: when the cells were treated with antioxidants, the GSE-induced cell death was reversed. Therefore, Derry and her colleagues consider it likely that GSE targets colorectal cancer cells by inducing oxidative stress, which leads to apoptosis.
“A colorectal cancer cell can have upwards of 11,000 genetic mutations — differences from the DNA in healthy cells,” Derry said. “Traditional chemotherapies may target only a specific mutation, and as cancer progresses more mutations occur. These changes can result in cancer that is resistant to chemotherapy. In contrast, the many bioactive compounds of GSE are able to target multiple mutations. The more mutations a cancer presents, the more effective GSE is in targeting them.”
Source: University of Colorado Cancer Center; January 16, 2013.