Chronic Cadmium Exposure Increases Breast Cancer Cell Aggression
(ChemotherapyAdvisor) – The metastatic phenotype of breast cancer cells increases with chronic exposure to small concentrations of cadmium, a heavy metal commonly found in cosmetics, food, water, and air particles, according to a study presented on April 23 at the annual meeting of the American Society for Biochemistry and Molecular Biology, held in conjunction with the Experimental Biology 2012 conference in San Diego.
Since environmental factors such as heavy-metal exposure are believed to contribute to the development and progression of breast cancer, researchers from Dominican University of California in San Rafael sought to understand the effects of chronic cadmium exposure on breast cancer progression. Heavy metals such as cadmium can act as endocrine disruptors and mimic estrogen, thereby disrupting hormone dependent pathways.
“The relationship between cancer and chronic exposures at low levels is important to understand because most people are not exposed to high levels of heavy metals, unless they work in manufacturing plants that deal with such metals,” said Maggie C. Louie.
Preliminary data show an increase in the ability of breast cancer cells to migrate and invade through the extracellular matrix with prolonged cadmium exposure. MCF-7 cells chronically exposed to cadmium (MCF7-CdC) expressed higher levels of SDF-1, a protein associated with tumor invasion and metastasis. Additionally, matrix metalloproteinase-9 (MMP-9) activity was significantly higher in MCF7-CdC cells.
“Many of us are exposed to very low levels of cadmium from the environment on a daily basis, and our research shows that even small concentrations of this metal at prolonged exposures can cause breast cancer cell growth,” Louie said.
How specific proteins, including SDF-1, contribute to the aggressive characteristics of the cadmium-exposed cells requires further research, and understanding their role in cadmium-induced carcinogenesis will provide further insights to how heavy metals contribute to breast cancer progression.
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