More than 20 percent of human cancers - as well as a number of other diseases - are linked to chronic viral infections.

Researchers have now identified a new innate immunity pathway that protects mammals from viral oncogenesis, the process by which viruses cause normal cells to become cancerous. The findings were published recently in Proceedings of the National Academy of Sciences.

This study revealed that the autophagy-related protein beclin can help break down the key oncogenic viral protein associated with Kaposi's sarcoma, a type of cancer most commonly found in people with HIV infection or transplant-related suppression of their immune systems.

Autophagy is a cellular "housekeeping" process in which the body's cells destroy damaged proteins and organelles. The present study revealed that, in addition to mediating autophagy, beclin 2 is also involved in a novel immune pathway that suppresses viral infection and virus-caused cancer.

More specifically, researchers found that increased beclin 2 expression accelerated degradation of viral GPCR and decreased pro-tumorigenic signaling, whereas decreased beclin 2 expression led to sustained levels of viral GPCR and enhanced pro-tumorigenic signaling. This response is part of an endolysolomal trafficking process in which microbes and their constituent proteins are delivered to enzyme-filled cellular components called lysosomes.

http://www.utsouthwestern.edu/newsroom/news-releases/year-2016/march/utsw-identified-immunity-pathway.html