| A Novel Endocrine-Disrupting Agent in Corn with Mitogenic Activity in Human Breast and Prostatic Cancer Cells Barry Markaverich,1,2 Shaila Mani,2 Mary Ann Alejandro,1,2 Andrea Mitchell,2 David Markaverich,1,2 Trellis Brown,1,2 Claudia Velez-Trippe,1,2 Chris Murchison,1 Bert O'Malley,2 and Robert Faith1 1Center for Comparative Medicine and 2Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA Abstract
Housing adult rats on ground corncob bedding impedes male and female mating behavior and causes acyclicity in females. The suppressive effects on ovarian cyclicity are mimicked by a mitogenic agent purified from the ground corncob bedding material (corn mitogen ; CM) , which stimulates the proliferation of estrogen receptor (ER) -positive (MCF-7 cells) and ER-negative (MDA-MD-231 cells) breast cancer cells. Purified CM does not compete for [3H]estradiol binding to ER or nuclear type II sites, and its effects on MCF-7 breast cancer cell proliferation are not blocked by the antiestrogen ICI-182,780. These results suggest that the active component is unlikely to be a phytoestrogen, bioflavonoid, mycotoxin, or other known endocrine-disrupting agent that modifies cell growth via ER or type II [3H]estradiol binding sites. CM also stimulates the proliferation of PC-3 human prostatic cancer cells in vitro, and the growth rate of PC-3 cell xenografts is accelerated in nude male mice housed on ground corncob as opposed to pure cellulose bedding. Consequently, this endocrine-disrupting agent in ground corncob bedding may influence behavioral and physiologic reproductive response profiles and malignant cell proliferation in experimental animals. Fresh corn (kernels and cob) or corn tortillas also contain CM, indicating that human exposure is likely ; consequently, CM and/or related mitogens in corn products may influence human health and development. Key words: breast cancer, corncob bedding, corn mitogen, endocrine disruptor, estrogen receptor. Environ Health Perspect 110:169-177 (2002) . [Online 17 January 2002] http://ehpnet1.niehs.nih.gov/docs/2002/110p169-177markaverich/ abstract.html Address correspondence to B. Markaverich, Department of Molecular and Cellular Biology, Baylor College of Medicine, One Baylor Plaza, Houston, TX 77030 USA. Telephone: (713) 798-6497. Fax (713) 798-6588. E-mail: barrym@bcm.tmc.edu This research was supported by grants awarded to B. Markaverich from the National Institutes of Health (National Cancer Institute ; CA-35480) , the National Institute of Environmental Health Sciences and the Office of Research on Women's Health (ES-09664) , the American Institute for Cancer Research (AICR-98A007) , and the State of Texas Applied Technology Program (ATP grant 004949-027) . Received 17 January 2001 ; accepted 18 July 2001.
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