Researchers at the Mayo Clinic and Harvard Medical School have discovered that a protein thought to ward against the development of cancer can actually cause tumors to spread.
The study revolves around FOXO3a, a transcription factor that acts to regulate gene expression. For years, researchers had believed that activating FOXO3a would help fight cancer growth, which naturally becomes active when cancer cells are deprived of nutrients. But the current research indicates that as cancer cells starve the protein “flips” molecular switches that enable the cancer cells to invade surrounding healthy tissues.
The results of the study, which was funded in part by the Florida Department of Health and the National Institutes of Health, were published in the Sept. 3 issue of Molecular and Cellular Biology, and demonstrate a growing recognition among scientists that proteins can act in different ways – and play multiple roles – in the process of tumor progression. Other studies have also revealed that proteins thought to be protective against the development and growth of tumors can actually promote cancer cell division and reproduction, based on the type of cancer and the biological context. Similarly, studies have also shown that certain proteins thought to encourage cancer growth and proliferation can, under specific circumstances, act to inhibit tumor cell invasion.
In the case of FOXO3a, researchers believe that when a cancer cell is starved of the nutrients it requires for sustenance and growth, it “flips” a switch on the transcripting protein, which instructs cells to migrate to areas of the body that are able to supply the necessary nutrients for cell division and proliferation.
These findings show potential promise for the treatment of several cancers, including mesothelioma, a rare cancer that affects the mesothelium, the protective, lubricating membrane that surrounds the body’s internal organs.
Mesothelioma occurs as a result of exposure to asbestos, a silica-based mineral which was widely used in the manufacture of multiple construction, automotive, and mechanical products, and was used heavily in naval shipyards. Cheap and readily available, asbestos was used in literally millions of products, and was commonly used in homes, office buildings, and government buildings, as well as automotive products and components, ship’s coatings, and HVAC units and ductwork. Amid worries of health risks, the use of asbestos in the manufacturing and building industries was banned by federal legislation in the late 1970s. Warehoused asbestos products were used until the 1980s.
Although asbestos is harmless in its pristine state, as it ages it becomes friable, breaking apart easily into tiny flakes that can float for long distances. Once airborne, these fibers can be ingested or inhaled. In the body, these tiny fibers embed themselves deeply into the mesothelium, where they cause abnormal growth of cells and eventual tumor development. Today, veterans are at particular risk, as asbestos is still used extensively overseas. When buildings are demolished, they release these tiny fibers into the air. Men and women involved in home renovation projects, as well as those in buildings being renovated, can be exposed to the dangers of asbestos inhalation or ingestion. Even duct and furnace or boiler cleaning or servicing can release asbestos fibers into the air.
It can be decades before the symptoms of mesothelioma cancer become evident, and these symptoms may include persistent cough, chest or abdominal pain or bloating, and difficulty breathing. Mesothelioma diagnosis involves a thorough physical exam and health history, as well as chest X-rays and other procedures, like thoracentesis.
Mesothelioma prognosis is poor, with no known cure. Most treatments are designed to improve or lessen symptoms that accompany the condition.
Individuals interested in learning more about pleural
mesothelioma, its causes, and current research regarding treatment of the
condition can contact University of Wisconsin professor Dr. H.
Ian Robins, an oncologist who specializes in the treatment of mesothelioma
and other cancers. Dr. Robins is also a principal investigator on various cooperative
group protocols, including the North American Brain Tumor Consortium (NABTC),
Eastern Cooperative Oncology Group (ECOG) and Radiation Therapy Oncology Group
(RTOG).
