There are eight known human herpes viruses, all capable of establishing life-long infection. The most recently discovered of these viruses, herpesvirus-8, is the cause of several AIDS-related cancers, including a form of skin cancer known as Kaposi’s sarcoma.
Herpesvirus-8 targets cells that line the surface of blood and lymphatic vessels. The virus reprograms these cells, giving them instructions to grow, form new vessels, and inflame surrounding tissues. These changes in the cells can lead to malignancies.
Dr. Jennifer Corcoran’s laboratory at Dalhousie Medical School has identified the gene in herpesvirus-8 that plays a key role in altering the healthy make-up of blood and lymph cells. It’s called Kaposin B.
“We’re looking at how viral genes, such as those found in herpesvirus-8, contribute to the development of cancer,” says Dr. Corcoran, assistant professor in the Departments of Microbiology & Immunology and Surgery.
“We’ve found that inside the cell, Kaposin B targets a control switch that’s normally only activated when the cell senses a threat, and then quickly turned off when the threat is averted,” explains Dr. Corcoran. "Kaposin B appears to jam this switch in the ‘on’ position, causing dramatic and sustained changes in cell behaviour.”
Hope for virus-caused cancers
It’s estimated that 15 to 20 per cent of cancers are caused by viruses. Dr. Corcoran’s discovery points to potential new treatments for these cancers. Some may even be able to be prevented.
“The research is telling us that Kaposin B is a very unique kind of viral cancer-causing gene, very different than others we have studied before,” says Dr. Corcoran. “Understanding how this gene works has already revealed some opportunities for using drugs to reverse its effects. And if we target the Kaposin B protein — or use molecules that target and limit the changes Kaposin B causes to the blood and lymphatic system — we could potentially limit cancer development.”
Inflammation has long been associated with the growth of cancer. The Dalhousie research team is hoping its work on the Kaposin B study will lead to better understanding of that link, too.
“By looking at the function of Kaposin B, we are also learning new molecular details about the relationship between inflammation and cancer,” says Dr. Corcoran. “Our findings may ultimately have implications for the treatment of other cancers that have a strong inflammatory component.”
Dr. Corcoran’s study was recently published in PLoS Pathogens, the leading journal in the field of infectious pathologies, including virus-induced cancer.
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