title: Exposure to the polyester PET precursor--terephthalic acid induces and perpetuates DNA damage-harboring non-malignant human breast cells.
abstract: Identification of early perturbations induced in cells from non-cancerous breast tissue is critical for understanding possible breast cancer risk from chemical exposure. We have demonstrated previously that exposure to the ubiquitous xenoestrogens, bisphenol A (BPA) and methyl paraben, promotes the hallmarks of cancer in non-malignant human high-risk donor breast epithelial cells (HRBECs) isolated from several donors. Here we show that terephthalic acid (TPA), a major chemical precursor of polyethylene terephthalate (PET) containers used for the storage of food and beverages, increased the ERα: ERβ ratio in multiple HRBEC samples, suggesting an estrogenic effect. Although, like BPA and methyl paraben, TPA also promoted resistance to tamoxifen-induced apoptosis, unlike these chemicals instead of inducing an increased S-phase fraction, TPA treatment arrested cell proliferation. DNA-PK, ATM and members of the MRN complex, known to be involved in DNA damage sensor and effector proteins, were elevated indicating induction of DNA strand breaks. Early DNA damage checkpoint response, mediated through p53/p21, led to G1 arrest in TPA-exposed cells. Removal of TPA from the growth medium resulted in the rapid induction of BCL2, increasing the ratio of anti-: pro-apoptotic proteins, together with overexpression of Cyclin A/CDK2 proteins. Consequently, despite elevated p53(pSer15) and H2AX(pSer139), indicating sustained DNA damage, TPA exposed cells resumed robust growth rates seen prior to TPA exposure. The propensity for the perpetuation of DNA aberrations that activate DNA damage pathways in non-malignant breast cells justifies careful consideration of human exposure to TPA, particularly at vulnerable life stages.
authors.affiliation: California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA.
authors.forename: Maria Gloria
authors.initials: MG
authors.lastname: Luciani-Torres
authors.affiliation: California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA.
authors.forename: Dan H
authors.initials: DH
authors.lastname: Moore
authors.affiliation: California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA dairkes@cpmcri.org goodsow@cpmcri.org.
authors.forename: William H
authors.initials: WH
authors.lastname: Goodson
authors.affiliation: California Pacific Medical Center Research Institute, 475 Brannan Street, San Francisco, CA 94107, USA dairkes@cpmcri.org.
authors.forename: Shanaz H
authors.initials: SH
authors.lastname: Dairkee
mesh_terms: D018931:Antineoplastic Agents, Hormonal / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D015153:Blotting, Western; D001940:Breast / Q000187:drug effects / Q000473:pathology*; D001943:Breast Neoplasms / Q000139:chemically induced* / Q000378:metabolism / Q000473:pathology*; D002453:Cell Cycle / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D004249:DNA Damage / Q000187:drug effects*; D019008:Drug Resistance, Neoplasm / Q000187:drug effects*; D047628:Estrogen Receptor alpha / Q000378:metabolism; D047629:Estrogen Receptor beta / Q000378:metabolism; D005260:Female; D016166:Free Radical Scavengers / Q000009:adverse effects; D006801:Humans; D010795:Phthalic Acids / Q000009:adverse effects*; D011093:Polyethylene Terephthalates / Q000009:adverse effects*; D013629:Tamoxifen / Q000494:pharmacology
chemical_list: D018931:Antineoplastic Agents, Hormonal; C506487:ESR1 protein, human; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D016166:Free Radical Scavengers; D010795:Phthalic Acids; D011093:Polyethylene Terephthalates; D013629:Tamoxifen; C011363:terephthalic acid