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pentose phosphate pathway

Orange lichens are source for potential anticancer drug

An orange pigment found in lichens and rhubarb called parietin may have potential as an anti-cancer drug, scientists at Winship Cancer Institute of Emory University have discovered.

The results were published in Nature Cell Biology on October 19.

Caloplaca_Fenwick

Parietin, shown to have anticancer activity in the laboratory, is a dominant pigment in Caloplaca lichens. Note: this study did not assess the effects of eating lichens or rhubarb. Photo courtesy of www.aphotofungi.com

Parietin, also known as physcion, could slow the growth of and kill human leukemia cells obtained directly from patients, without obvious toxicity to human blood cells, the authors report. The pigment could also inhibit the growth of human cancer cell lines, derived from lung and head and neck tumors, when grafted into mice.

A team of researchers led by Jing Chen, PhD, discovered the properties of parietin because they were looking for inhibitors for the metabolic enzyme 6PGD (6-phosphogluconate dehydrogenase). 6PGD is part of the pentose phosphate pathway, which supplies cellular building blocks for rapid growth. Researchers have already found 6PGD enzyme activity increased in several types of cancer cells.

“This is part of the Warburg effect, the distortion of cancer cells’ metabolism,” says Chen, professor of hematology and medical oncology at Emory University School of Medicine and Winship Cancer Institute. “We found that 6PGD is an important metabolic branch point in several types of cancer cells.” Read more

Posted on by Quinn Eastman in Cancer Leave a comment