Environmental Factor, September 2011, National Institute of Environmental Health Sciences
Study suggests nutritional supplements could one day prevent skin cancer
By Ian Thomas
Yu-Ying He is an assistant professor in the Department of Medicine at the University of Chicago. (Photo courtesy of Yu-Ying He)
Trempus is an alumna of North Carolina State University who works in the NIEHS Laboratory of Respiratory Biology. (Photo courtesy of Steve McCaw)
A new study(http://www.ncbi.nlm.nih.gov/pubmed?term=PTEN%20positively%20regulates%20UVB) from scientists at NIEHS and the University of Chicago found that decreased levels of phosphatase and tensin homolog (PTEN), a known tumor suppressing protein, led to an increased risk for ultraviolet (UV)-induced, non-melanoma skin cancer in mice. As a result, researchers now believe that, in time, America's number one form of cancer could conceivably be prevented with basic nutritional supplements.
“Based on our previous studies at NIEHS, we knew going in that UV radiation impaired the expression of PTEN,” explained Yu-Ying He, Ph.D.(http://biomedsciences.uchicago.edu/page/yu-ying-he-phd) , the project's lead researcher and an NIEHS postdoc from 2001 to 2007. “Therefore, with this particular study, we set out to ask three questions. First, what is the function of PTEN in UV response? Next, what is the consequence for PTEN loss? Finally, what is the relevance of this interaction to tumor development and human skin cancer?”
PTEN promotes genomic stability and cellular repair. In this instance, He and her staff found that mediating PTEN levels in mice prior to UVB exposure severely hindered DNA repair in radiation-damaged cells.
“This study provides an important role for PTEN in the earliest stages of tumorigenesis,” said Carol Trempus, a co-author on the project and NIEHS biologist since 1992. “Given that mice deficient in PTEN exhibited accelerated UV-mediated tumor development compared to those with sufficient PTEN levels, this work gives important insights into the early events in UV carcinogenesis. At the same time, it also emphasizes that loss of PTEN may be a predisposing event in human skin tumor development.”
Last year, the American Association for Cancer Research estimated that over one million Americans were diagnosed with non-melanoma skin cancer. This comprised 40 percent of all newly diagnosed cases of cancer (see press release(http://www.aacr.org/newsroom/Pages/default.aspx#.Vdsls_lVhuC) ). With rates climbing, He is encouraged by her study's results.
“Ultimately, these findings define PTEN as a key genomic gatekeeper in skin cells,” she concluded. “If we can begin to identify nutritional and/or pharmacological agents that can effectively increase PTEN activity, this could open the door to many new approaches for prevention and treatment of skin cancer.”
This study is dedicated in memory of the late Colin Chignell, Ph.D., a dedicated researcher and NIEHS employee of 42 years. Prior to his passing in 2008, Chignell oversaw the Photosensitization Reactions Group in the NIEHS Laboratory of Pharmacology, where this project was initially begun.
Citation: Ming M, Feng L, Shea CR, Soltani K, Zhao B, Han W, Smart RC, Trempus CS, He YY(http://www.ncbi.nlm.nih.gov/pubmed?term=PTEN%20positively%20regulates%20UVB) . 2011. PTEN positively regulates UVB-induced DNA damage repair. Cancer Res 71(15):5287-5295.
(Ian Thomas is a public affairs specialist in the NIEHS Office of Communications and Public Liaison.)