A team of University of Wisconsin researchers believes it may have discovered a class of drugs capable of destroying the Epstein-Barr virus, which is responsible for several types of cancer and mononucleosis.
The discovery reveals a possible new way of treating patients who are infected with diseases caused by a latent EBV infection, which is especially important in the cases of transplant patients and of patients who suffer from other immune-suppressive diseases, Oncology and Medicine professor Shannon Kenney said.
Unlike the form of EBV that actively generates an infection, the latent form of EBV, which resides in the body for life after the original infection, causes some cancer development.
Before now, no one had identified a drug treatment capable of preventing or treating this latent EBV infection that causes EBV-associated diseases, which include mild and severe mononucleosis, certain types of lymphoma, Hodgkin’s disease and a subset of stomach cancers, Kenney said.
“Even though it is just beginning to be studied, latent EBV may also be involved in auto-immune diseases, such as multiple sclerosis as well,” Kenney said.
Cells inhabited by latent EBV produce viral proteins capable of changing normal cells into cancer cells.
Since the key viral protein, EBNA-1, is the only requirement for lifelong persistence of EBV, the researchers’ goal was to uncover a drug which could inhibit protein production, Kenney said.
She said after they discovered EBNA-1 requires a certain protein to function, they realized many of the proteins could not survive a treatment consisting of certain inhibitors, which dramatically reduce the viral protein’s activity of by hindering the protein’s ability to synthesize and to translate.
While they have yet to test the drug on humans infected with EBV, the researchers have performed several experiments on animals to test the drug’s effectivity and have received positive results.
“Not only did the drug work to cure the cancers found in the animals, but it also killed the cells transformed by EBV,” Kenney said.
She added during the process, the drug was highly toxic to the viral proteins and in turn to the EBV-infected cells, yet no damaging effects to the normal surrounding cells were observed.
“The researchers have provided terrific evidence that proves the drug could become a form of effective treatment for specific cancer patients,” Academic Program Director of the UW Comprehensive Cancer Center George Wilding said.
Wilding said many steps still remain to capitalize on the breakthrough, such as the translation of the drug into clinics and the actual treatment of patients.
In testing human response to the drug, the researchers may have to design a study with multiple institutions to gather enough patients with EBV-infected cancers to produce sufficient data, Wilding said.
Kenney said while drug testing may soon occur on humans who are diagnosed with severe cases of mononucleosis, those with a mild form of the disease will not be treated with the drug until the drug’s ultimate toxicity is determined.
