By Candice Baker
October 20, 2009
UC Irvine researchers have discovered that a certain protein is the growth trigger of a cancer-causing toxin that profoundly affects people who live in developing and newly industrialized nations.
Aflatoxin, produced by mold that contaminates stored nuts and grains, and other such toxins might be responsible for liver cancers that lead to an estimated 10% of deaths in places like China, Vietnam and South Africa.
Regulation in such countries is either shoddy or absent, the researchers said, which leads to chronic exposure to large amounts of aflatoxin, sometimes hundreds of times higher than safe levels.
“It’s shocking how profoundly these molds can affect public health,” Sheryl Tsai, UCI molecular biology and biochemistry, chemistry, and pharmaceutical sciences associate professor, said in a news release.
She is the lead author of a study appearing Thursday in the journal “Nature” that reports the finding.
The toxin colonizes on nuts and grains either before the harvest or while they are stored, researchers said. Within the United States, the FDA says it is an “unavoidable” food contaminant, but sets maximum allowable limits in the food supply.
The toxin affects people’s immunity and metabolism, and can cause severe malnutrition and cancer by impacting a cancer-preventing gene.
Tsai worked with a graduate student, Tyler Korman, and undergraduate Oliver Kamari-Bidkorpeh, along with Johns Hopkins University researchers, to find that the protein PT is needed for aflatoxin to grow in the mold.
In the past, no one knew what triggered the toxin’s formation, so the mold itself was destroyed — an expensive process.
“The protein PT is the key to making the poison,” Tsai said. “With this knowledge, perhaps we could kill the PT with drugs, inhibiting the mold’s ability to make aflatoxin.”
Researchers hope the protein can be destroyed through chemoprevention.