In a breakthrough study, a cell biologist in the Johns Hopkins University School of Medicine has shown how genetically removing the protein tail of a tumour suppressor can activate its ability to fight cancer.
Usually, the tumour-suppressor called PTEN lingers around in the cellular broth instead of muscling its way out to the cells' membranes and foiling cancer growth.
Advertisement"It was curious that when we removed its tail, the protein suddenly was unhindered and moved out to the membrane and became active," said Meghdad Rahdar, a graduate student in pharmacology.
According to Dr. Peter Devreotes, professor and director of cell biology at Johns Hopkins, the discovery represents a potential new approach to cancer therapy.
"A long-term goal is to find a drug that does the equivalent of our bit of genetic engineering," he said.
The flexible tail of the protein contains a cluster of four amino acids - the building blocks of proteins - that regulate PTEN.
These amino acids, when chemically modified, act to "glue" the tail back to the body of PTEN and prevent the attachment of PTEN to the membrane.
By genetically removing PTEN's tail, or manipulating the cluster of four amino acids so that they cannot be modified, the researchers forced PTEN to move to the cell membrane.
That's where PTEN it goes about its tumor-suppressing business of degrading a molecular signal called PIP3 that causes errant cell growth.
"As far as I know, I haven't seen anyone activate a tumor suppressor, but we seem to have done it genetically," said Rahdar.
Scientists said that manipulating such unbinding of PTEN with drugs is a viable alternative to guard against cell overgrowth, the hallmark of cancer.
The study was published in a recent issue of the Proceedings of the National Academy of Sciences.
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