PHILADELPHIA Researchers have found a new oncogenic signaling pathway by which the environmental toxin arsenic may lead to adverse health effects, including bladder cancer. These study results are published in Cancer Research, a journal of the American Association for Cancer Research.
"In a collaborative investigation we found that arsenic, at environmentally relevant levels, is capable of activating the Hedgehog pathway and may represent a novel pathway of arsenic-associated diseases, such as bladder cancer," said Margaret R. Karagas, Ph.D., professor in the Department of Community and Family Medicine at Dartmouth Medical School.
"We provide important insight into the etiology of arsenic-induced disease, potentially relevant to the millions of people worldwide who are exposed to arsenic," she said.
Arsenic is a well-known environmental toxin and carcinogen. Studies to date have shown that individuals who live in arsenic contaminated areas of the world exhibit an elevated cancer rate. In many regions of the world, notably Taiwan, Bangladesh and Argentina, high levels of arsenic are detected in drinking water, according to Karagas. Here in the United States, Karagas said that arsenic concentrations above the current maximum contaminant level of 10 μg/L are often found in private, unregulated drinking water systems.
While the correlation between exposure to arsenic resulting in human tumors such as those derived from bladder, lung and skin is well established, the molecular mechanisms driving this connection is unclear.
Karagas and colleagues examined the hypothesis that the secreted protein called Hedgehog, a key oncogenic signaling pathway, might be activated by arsenic. Activation might underlie the mechanism by which arsenic acts as a co-carcinogen.
Using experimental data from cell cultures and results of epidemiologic studies, the researchers found that arsenic activates the Hedgehog
|Contact: Tara Yates|
American Association for Cancer Research