Nitrophenols isolated from diesel exhaust particles promote the growth of MCF-7 breast adenocarcinoma cells.

Abstract

Diesel exhaust particles (DEPs) cause many adverse health problems, and reports indicate increased risk of breast cancer in men and women through exposure to gasoline and vehicle exhaust. However, DEPs include vast numbers of compounds, and the specific compound(s) responsible for these actions are not clear. We recently isolated two nitrophenols from DEPs-3-methyl-4-nitrophenol (4-nitro-m-cresol; PNMC) and 4-nitro-3-phenylphenol (PNMPP)-and showed that they had estrogenic and anti-androgenic activities. Here, we tried to clarify the involvement of these two nitrophenols in promoting the growth of the MCF-7 breast cancer cell line. First, comet assay was used to detect the genotoxicity of PNMC and PNMPP in a CHO cell line. At all doses tested, PNMC and PNMPP showed negative genotoxicity, indicating that they had no tumor initiating activity. Next, the estrogen-responsive breast cancer cell line MCF-7 was used to assess cell proliferation. Proliferation of MCF-7 cells was stimulated by PNMC, PNMPP, and estradiol-17beta and the anti-estrogens 4-hydroxytamoxifen and ICI 182,780 inhibited the proliferation. To further investigate transcriptional activity through the estrogen receptor, MCF-7 cells were transfected with a receptor gene that allowed expression of luciferase enzyme under the control of the estrogen regulatory element. PNMC and PNMPP induced luciferase activity in a dose-dependent manner at submicromolar concentrations. ICI 182,780 inhibited the luciferase activity induced by PNMC and PNMPP. These results clearly indicate that PNMC and PNMPP do not show genotoxicity but act as tumor promoters in an estrogen receptor alpha-predominant breast cancer cell line.

• Authors: Chie Furuta, Akira K Suzuki, Gen Watanabe, Chunmei Li, Shinji Taneda, Kazuyoshi Taya
• Journal: Toxicology and applied pharmacology (Toxicol Appl Pharmacol) Vol. 230 Issue 3 Pg. 320-6 (Aug 01 2008) ISSN: 0041-008X [Print] United States
• PMID: 18439640 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• 4-nitro-3-phenylphenol
• Biphenyl Compounds
• Cresols
• Nitrophenols
• Receptors, Estrogen
• Vehicle Emissions
• 4-nitro-3-cresol

Topics

• Animals
• Biphenyl Compounds (toxicity)
• Breast Neoplasms (pathology)
• CHO Cells
• Cell Line, Tumor
• Cell Proliferation (drug effects)
• Comet Assay
• Cresols (toxicity)
• Cricetinae
• Cricetulus
• Female
• Humans
• Nitrophenols (toxicity)
• Receptors, Estrogen (genetics)
• Response Elements
• Vehicle Emissions (analysis)