Therapeutic Inhibitor for Epstein-Barr Virus (EBV)-associated Cancers

EBV is a ubiquitous human herpes virus, which spreads through saliva. EBV infects over 90% of the human population and can establish life-long persistence in the host. Most people get EBV when they are young, but they will not experience any symptoms until they get older.

There are about 200,000 EBV-associated cancer new cases per year. Nasopharyngeal cancer (NPC) is one of EBV associated cancers which is endemic in a few areas including Southern China, Southeast Asia, North Africa and the Arctic. The highest NPC incidence rate is found in Southern China including Hong Kong. The association of NPC and EBV is nearly 100% in endemic areas. Unfortunately, more than 80% of the new NPC cases are diagnosed in stage III or IV, while the survival rate of stage IV NPC is only 38%. Early detection and treatment would help to increase survival rate.

This invention is a new EBV-specific targeted agent which selectively kills cancer cells without affecting any normal cells. The uptake of this drug can also be traced by the fluorescent signal that can be used for cancer cells imaging.

Currently, there is no single agent that can both image and kill NPC cancer cells at the same time.

Epstein–Barr nuclear antigen 1 (EBNA1) is the only viral protein expressed in all EBV-infected cells. This invention is an EBNA1 targeting bio-probe that can effectively target EBNA1 to disrupt its cancerous activities and inhibit cancer cell growth.

In addition, it can also emit fluorescent signals to show the presence of EBV-infected cells, and this can be used for imaging the EBV-associated cancers. The invention is the first known agent with a dual function that can accurately trace and image for the EBV-associated cancers while being a pinpointed therapeutic intervention at the same time. 

Other than providing a fast, simple and accurate detection for EBV-associated cancers, this invention shows a high efficacy at a low dose (less than 4mol/kg, ~92% cancer inhibition) toward cancer treatment.

This invention shed light to develop a new generation medical reagent that has both imaging function and anti-cancer activity. The specificity of this technology provides a crucial means in the accurate detection of EBV-associated cancers. More importantly, its anti-tumour ability provides inhibition in the cancer cells and thus reduces potential metastasis.

People in NPC-endemic areas could benefit from this world’s first agent with dual functions that can detect EBV-infected cells and inhibit cancer cells. It can be used to trace the presence of residual cancer cells after treatments.

This invention could also replace or minimize the use of the radio- and chemo-therapies for NPC which could greatly improve the survival of patients with advanced diseases, as well as their quality of life.