Cervical cancer and pre-cancer cervical growths require single HPV protein

September 17, 2012

(Medical Xpress)—Human papillomavirus (HPV) has long been implicated in cervical cancer, but details of how it happens have remained a mystery. Now researchers at the University of Wisconsin-Madison have found that a single HPV protein is required for cervical cancer and even pre-cancer growths in the cervix to survive.

In anticipation of a clinical trial in humans, the scientists and their collaborators are moving quickly to test if a gene-silencing technique could cripple the protein and eliminate and pre-cancerous growths in specially-bred mice.

The study, appearing online in , is the first to show that the protein works in living animals and in pre- as well as full-blown cervical cancer. 

Cervical cancer is relatively rare in the United States, thanks to the widespread use of as a . But pre-cancer in the , called cervical inter-epithelial neoplasias, or CINs, are common.

Low-grade CINs are typically left alone because most will shrink and pose no problem. But women with high-grade CINs have a 10 percent chance of getting cervical cancer, says Dr. Paul Lambert, senior author on the paper. In addition, surgical treatment of high-grade CINs carries a risk of excessive bleeding and even infertility.

Scientists know that two HPV cancer-causing proteins, or oncoproteins—E6 and E7—are always expressed in cervical cancer. Lambert and his team at UW's McArdle Laboratory of Cancer Research conducted experiments in cultured cell lines that suggested that the oncoproteins caused cervical cancer as well as anal and head and neck cancers. The researchers also learned that E7 had a much greater ability than E6 to cause cancer.

Other studies in different types of cancers suggested that when oncoproteins were involved, they needed to work together—blocking the expression of both often led to a more effective reduction of tumors than blocking either one alone.

But Lambert, a member of the UW Carbone Cancer Center, was intrigued with E7's power.

"In thinking of treatments, we wondered in this case if we could target just one oncoprotein, the most potent one, rather than two, which could be much more complicated," he says.

Dr. Sean Jabbar and Soyeong Park in the Lambert laboratory created and bred mice in which they could control the expression of both E7 and E6. They found that when he turned off E7 but left E6 on, the cervical cancers and CINs melted away.

"This told us that E7 should be an excellent therapeutic target for HPV-associated cancers, including pre-cancerous CINs," Lambert says.
        
If the gene-silencing experiments that are expected to take place soon prove effective, there's a good chance that the blocking approach could be used to control the disease without surgery.

Women in developing countries might benefit greatly, Lambert adds.

"Cervical cancer is prevalent around the world in places where screening does not exist and surgery is not available," he says.

Explore further: Researchers develop and test new anti-cancer vaccine

Related Stories

Researchers develop and test new anti-cancer vaccine

June 8, 2012
Researchers at Moffitt Cancer Center have developed and tested in mice a synthetic vaccine and found it effective in killing human papillomavirus-derived cancer, a virus linked to cervical cancers among others. The research ...

Most anal lesions don't cause cancer in men, research shows

March 23, 2012
(HealthDay) -- Anal human papillomavirus (HPV) infection and precancerous lesions are common among gay and bisexual men, but most of these cases will not progress to anal cancer, a new analysis of earlier research shows.

Recommended for you

Researchers discover a new target for 'triple-negative' breast cancer

November 20, 2017
So-called "triple-negative" breast cancer is a particularly aggressive and difficult-to-treat form. It accounts for only about 10 percent of breast cancer cases, but is responsible for about 25 percent of breast cancer fatalities.

Study reveals new mechanism used by cancer cells to disarm attacking immune cells

November 20, 2017
A new study by researchers at The Ohio State University Comprehensive Cancer Center - James Cancer Hospital and Solove Research Institute (OSUCCC - James) identifies a substance released by pancreatic cancer cells that protects ...

Clinical trial suggests new cell therapy for relapsed leukemia patients

November 20, 2017
A significant proportion of children and young adults with treatment-resistant B-cell leukemia who participated in a small study achieved remission with the help of a new form of gene therapy, according to researchers at ...

Cell-weighing method could help doctors choose cancer drugs

November 20, 2017
Doctors have many drugs available to treat multiple myeloma, a type of blood cancer. However, there is no way to predict, by genetic markers or other means, how a patient will respond to a particular drug. This can lead to ...

Lung cancer triggers pulmonary hypertension

November 17, 2017
Shortness of breath and respiratory distress often increase the suffering of advanced-stage lung cancer patients. These symptoms can be triggered by pulmonary hypertension, as scientists at the Max Planck Institute for Heart ...

Researchers discover an Achilles heel in a lethal leukemia

November 16, 2017
Researchers have discovered how a linkage between two proteins in acute myeloid leukemia enables cancer cells to resist chemotherapy and showed that disrupting the linkage could render the cells vulnerable to treatment. St. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.