Scientists at UCLA's Jonsson Comprehensive Cancer Center have published the first study that explains how viruses reprogram the cells they invade to promote their continued growth within an organism. This knowledge could have implications in cancer treatments based on similarities between viruses and cancer cell mechanisms, and even lead to drugs that could inhibit the virus that causes the common cold.
Led by Ming Thai, post-doctoral scholar and Heather Christofk, assistant professor of molecular & medical pharmacology, the study was published online ahead of print in the journal Cell Metabolism.
A cell's metabolism is basically the workings of its insides; that is the group of physical and chemical processes that feed and maintain the cell, allow it to reproduce, and eventually decide when it will die off and be replaced by its daughter cells. When a virus infects a cell, it triggers changes in the cell's metabolism, essentially reprogramming the cell in such a way that it promotes maintenance and reproduction of the virus. Although it has been known known that viruses reprogram cells, the molecular mechanisms that a virus uses to accomplish this have remained unknown until this study.
It also has been discovered that when normal cells become cancer cells, they are reprogrammed to act in some ways very similar to how virus-infected cells do. This means that the cells change their metabolism to support the maintenance and reproduction, and thus the spread, of cancer cells.
"In our laboratory, we've always been interested in how cancer cells acquire metabolic changes compared to normal cells," Christofk said. "We decided to look at viruses and how they change the metabolism of cells they invade, because we thought they might be using mechanisms similar to those in cancer cells, and that there might be some crossover in the way the mechanisms work."
"We hoped that by finding out how viruses reprogram cell metabolism we could learn more about how cancer cells do it," Christofk added.
In their research, Drs. Thai and Christofk and colleagues discovered that an adenovirus (the type of virus that causes the common cold) reprograms the cell it invades to be able to take on more glucose, an important nutrient for cells and viruses. The virus also reprograms the cell to increase its use of the glucose to create energy and biomass (grow larger). These metabolic alterations enable the virus to begin replicating inside the cell. Thus, Thai and Christofk have elucidated how a virus reprograms cells to its own benefit.
"With this knowledge we hope to begin designing drugs that can inhibit the increased glucose uptake in these cells," said Thai. "This could lead to drugs that stop the growth of viral infections, the most common being like cold or flu, but also meningitis or some types of pneumonia. Then it might be possible to use the same type of drug to stop the growth of cancer cells."
This research was supported by the National Institutes of Health, the Searle Scholars Program, and the UCLA Broad Stem Cell Research Center - Concern Foundation Research Award.