Achilles heel in a protein that shields tumour cells from cell death have been identified by scientists.
They believe that this weakness can be exploited to target and kill the very tumour cells that the protein usually protects.
Akt is a signalling protein, called a kinase, that is hyperactive in the majority of human cancers.
"Akt is perhaps the most frequently activated oncoprotein (cancer-promoting protein) in human cancer," said Nissim Hay, professor of biochemistry and molecular genetics at the UIC College of Medicine.
"One of Akt's major functions in tumour cells is promoting cell survival.
"Tumor cells with hyperactive Akt are not only resistant to the external stresses that can induce cell death but also to chemotherapy," Hay added.
During the study, the researchers were able to exploit Akt hyperactivity against the tumour cell.
"We found that cells with hyperactive Akt have increased intracellular levels of reactive oxygen species (ROS) and at the same time impaired ability to scavenge ROS," Hay said.
"These ROS are highly reactive byproducts of metabolism that can damage the cell. Cells usually respond to high levels of ROS by undergoing cell suicide, or apoptosis.
"And, to our surprise, we found that although Akt can protect cancer cells from many of the external signals that would ordinarily induce cell death, including many chemotherapy drugs, it cannot protect from ROS inducers," said Hay.
The researchers found that when the cancer cells were treated with chemicals that raised ROS levels, the cells died.
The new study "provides a proof of the principle that Akt's Achilles heel - a consequence of its role in metabolism - can be exploited in at least these two ways to selectively target and kill cancer cells," Hay said.
The new study is published in journal Cancer Cell.