New Weapon Discovered in Fight Against Cervical Cancer


2013-05-31 14:46

Researchers at the University of Leeds have discovered a new way to target and destroy a key protein associated with the development of cervical and other cancers, according to a new report published in PLOS One.

The key protein is called the E7 protein, and it is produced early in the lifecycle of the human papillomavirus (HPV). The E7 protein blocks the body's natural ability to fight against the uncontrolled division of cells that can lead to cancer.

However, the researchers have synthesized a molecule, called an RNA aptamer, which latches onto the cancer-causing protein and targets it for destruction; thus, significantly reducing its presence in cells derived from cervical cancers.

There are many different types of human papillomavirus, some of which are transmitted by sexual contact and linked not just with cervical cancer, but with head and neck cancer as well.

In the United Kingdom, where researchers made their discovery, an increasing number of young women are vaccinated against the virus. But most women in their mid-20s and older are not vaccinated – and many may already be HPV positive.

"We therefore need to maintain screening and to develop novel therapeutic strategies," said lead researcher Dr. Nicola Stonehouse.

"Currently, if you have advanced cervical cancer or head and neck cancer, both of which are associated with human papillomavirus, you really have little choice but surgery,” Stonehouse added. “If we can use this aptamer to target the carcinogenic protein, we might be talking about much less radical surgery in the future."

Aptamers are a topic of intense research interest and a relatively new tool for molecular biologists. Similar to antibodies, aptamers can recognize and target other molecules, as well as viruses and bacteria – but, unlike antibodies, aptamers can be artificially designed in the test tube while providing possible insertion into live cells.
The researchers from Leeds were originally looking for an aptamer for use as a research tool.

"We were not trying to develop a therapy. We wanted to create better ways of looking at the virus infection because the current tools that we have are very limited," Stonehouse said. "But what we found was that the aptamers caused the E7 protein to actually disappear. They seem to target it to be degraded. In a cell which is producing lots of E7 and is therefore dangerous, the level of E7 goes down if these RNA aptamers are there."

Although the new study is based on laboratory cell lines, instead of actual cancer cases, the discovery of a molecule that targets one of the key proteins involved in HPV-related cancers raises the possibility of less invasive treatments.

Moreover, the new aptamer may be used in the future to help stop residual cancerous material from multiplying after surgery – therefore, allowing less aggressive approaches to surgery.

Meanwhile, researchers are preparing for the challenge involved in effectively targeting the new aptamer at real cancers.

SOURCES: University of Leeds (2013, May 30). New weapon in fight against cervical cancer. 'An RNA aptamer provides a novel approach for the induction of apoptosis by targeting the HPV16 E7 oncoprotein,' PLOS ONE (2013) (DOI: 10.1371/journal.pone.0064781)