Scientists have recently discovered the mechanisms that allow a type of herpesvirus to cause abnormal cell growth and ultimately, cancer. Researchers from the University of North Carolina Lineberger Comprehensive Cancer Center detail the processes in their new paper, published in Proceedings of the National Academy of Sciences.
A virus called Kaposi sarcoma-associated herpesvirus is a form of herpes known for leading to cancer. Patients with immune system disorders, including HIV infection, are especially at risk of developing Kaposi sarcoma. Kaposi sarcoma is a rare type of cancer that causes lesions to grow in soft tissue. Currently, the only possible treatments are chemotherapy and surgery, depending on the affected areas.
In past research, scientists found that Kaposi sarcoma-associated herpesvirus can produce proteins that prevent the host cells from dying. Normally, an unhealthy cell can trigger a process called apoptosis in which the cell essentially kills itself to prevent further damage. This type of herpesvirus prevents apoptosis and also halts the signals that generally alert the immune system to a threat.
In this new study, the researchers discovered that the Kaposi sarcoma-associated herpesvirus makes a protein called vPK. This protein mimics the shape and chemistry of a normal cell protein called S6KB1. The protein S6KB1 is normally used to signal cells to grow and reproduce. By producing vPK, the virus can tap into the S6KB1 signal pathway and cause the host cells to produce more proteins and begin dividing. Unlike S6KB1, vPK doesn’t respond to the normal “checks” that prevent abnormal cell activity and growth. This means that vPK can continue to act, unregulated, and cause cells to divide when they normally wouldn’t. Unregulated cell division is one the major steps in the development of cancer.
This new research provides insight on how a herpesvirus can lead to cancerous cell growth by mimicking normal cell proteins. The authors of the study are hopeful that their findings may lead to treatments for Kaposi sarcoma and other virus-caused cancers.
Aadra Prashant Bhatt et al. A viral kinase mimics S6 kinase to enhance cell proliferation. Proceedings of the National Academy of Sciences (2016).