With the exception of the so-called cervical cancer vaccine, no shots have been approved specifically to prevent malignant tumors. But cervical cancer, which is caused by the sexually transmitted human papillomavirus (HPV), isn't the only tumor linked to a virus; another is cytomegalovirus (CMV), a usually harmless form of herpes that's the target of a possible therapeutic cancer vaccine for brain tumor patients.
As Scientific American reports this month, CMV has been found in the most common type of brain tumor, glioblastoma multiforme (GBM) — the cancer Massachusetts Democratic Sen. Edward Kennedy is battling. Duke University is recruiting 20 patients with these types of tumors for a combined phase 1/2 clinical trial (an early stage of testing that checks the safety and usefulness of a product) of an experimental vaccine treatment for these patients. It's also testing a similar version in another trial.
Duane Mitchell, the Duke University neuro-oncologist heading up the GBM vaccine treatment trials, is optimistic about them, telling Scientific American that creating a shot that goes after CMV "may be a radically new way to consider treating these tumors."
Pharma giant Novartis, meanwhile, is working on a CMV vaccine that would prevent infection with the virus. The company, headquartered in Basel, Switzerland, announced late last month that it expected to begin a phase 2 trial (which tests efficacy) of a preventive CMV vaccine this year. While CMV isn’t dangerous to most people, it infects 30,000 newborns in the U.S. annually, causing severe disability such as vision or hearing loss, seizures and cognitive problems in 8,000, according to the Centers for Disease Control and Prevention (CDC). It can also be deadly in people with weakened immune systems, such as AIDS patients.
Still, there are challenges. One researcher who tested a preventive CMV vaccine, University of Pennsylvania emeritus professor Stanley Plotkin, came up short when he found that it seemed to produce an immune response without actually preventing infection. "Is antibody sufficient, or do you need cellular immune responses? Or, are cellular immune responses sufficient and you don't need antibody? Those are unresolved issues," Plotkin told The Scientist in 2006, "that have somewhat hindered CMV vaccine development."
CMV: A virus in search of a vaccine
Protein in Common Virus
A protein found in the common human virus cytomegalovirus (CMV) appears to be a key factor in making brain tumors more aggressive and faster spreading (Cancer Research, Feb. 1, 2008).
The researchers, from the California Pacific Medical Center Research Institute in
"IE1 delivers a one-two punch to tumor cells. We detect the CMV IE1 protein in nearly all malignant brain tumors, and we find that it can make tumor cells more aggressive by affecting two major pathways," said Charles Cobbs, MD, the lead author of the study.
"First, it inhibits two key tumor suppressor proteins in the brain tumor cells; then it promotes the most important growth signaling pathway in the tumor itself. By modulating these cellular pathways, this viral protein makes the tumor cells more aggressive."
Dr. Cobbs first made the discovery that CMV was associated with malignant brain tumors in 2002. Now, by identifying the mechanism that helps CMV fuel tumors, the researchers say it could speed up the search for new treatments.
"This opens up the door to the possibility of treating the malignant brain tumors with an antiviral drug, a simple oral medication that could dramatically help patients fight off a previously fatal cancer" says Liliana Soroceanu, PhD, MD, a co-author of the study.
High grade glioma tumors are the most common form of brain cancer. They are difficult to treat because surgical cure is not an option, and radiation and chemotherapy have only limited success against them. As a result the tumors are typically fatal within a year, claiming some 20,000 lives in the
CMV is a common virus, causing a persistent infection in 50 to 80 percent of all Americans. Because it often produces few symptoms most people are unaware they are infected. In normal, healthy individuals CMV poses few risks, but it can pose serious health problems for people with compromised immune systems such as people with HIV/AIDS, organ transplant recipients, and pregnant women and their fetus.
Protein in Common Virus Linked to Aggressive Brain Tumors
| Source: California Pacific Medical Center | Released: Wed 30-Jan-2008, 13:40 ET Embargo expired: Fri 01-Feb-2008, 00:05 ET |
| Libraries Medical News | Keywords VIRUS, BRAIN TUMORS, CYTOMEGALOVIRUS, CMV, PROTEIN, RESEARCH, CANCER, TREATMENT, ANTI-VIRAL, CALIFORNIA PACIFIC MEDICAL CENTER, | |
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Description A protein found in the common human virus cytomegalovirus (CMV) appears to be a key factor in making brain tumors more aggressive and faster spreading. This opens the door to the possibility of treating the malignant brain tumors with antiviral drugs, simple oral medications that could dramatically help patients fight off a previously fatal cancer. | ||
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Newswise — A protein found in the common human virus cytomegalovirus (CMV) appears to be a key factor in making brain tumors more aggressive and faster spreading. That’s the finding of a new study in the journal Cancer Research.
The researchers, from the California Pacific Medical Center Research Institute, say the protein known as IE1 plays a number of roles, modifying brain cancer cells in a way that makes them grow more rapidly, and confirming a potential role for CMV in the malignant process of this cancer.
“IE1 delivers a one-two punch to tumor cells. We detect the CMV IE1 protein in nearly all malignant brain tumors, and we find that it can make tumor cells more aggressive by affecting two major pathways,” says Charles Cobbs, M.D, the lead author of the study. “First, it inhibits two key tumor suppressor proteins in the brain tumor cells; then it promotes the most important growth signaling pathway in the tumor itself. By modulating these cellular pathways, this viral protein makes the tumor cells more aggressive.”
Dr. Cobbs first made the discovery that CMV was associated with malignant brain tumors in 2002. Now, by identifying the mechanism that helps CMV fuel tumors, the researchers say it could speed up the search for new treatments.
“This opens up the door to the possibility of treating the malignant brain tumors with an antiviral drug, a simple oral medication that could dramatically help patients fight off a previously fatal cancer” says Liliana Soroceanu, Ph.D., M.D., a co-author of the study.
High grade glioma tumors are the most common form of brain cancer. They are difficult to treat because surgical cure is not an option, and radiation and chemotherapy have only limited success against them. As a result the tumors are typically fatal within a year, claiming some 20,000 lives in the U.S. every year.
CMV is a common virus, causing a persistent infection in 50- 80 percent of all Americans. Because it often produces few symptoms most people are unaware they are infected. In normal, healthy individuals CMV poses few risks, but it can pose serious health problems for people with compromised immune systems such as people with HIV/AIDS, organ transplant recipients, and pregnant women and their fetus.
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