Bisphenol A alone or in combination with estradiol modulates cell cycle- and apoptosis-related proteins and genes in MCF7 cells.
Level 5 - mechanism / opinion, no new human data
In vitro laboratory study in human cell lines (bench research with no human participants)
PubMed 24156707 · doi:10.4149/endo_2013_04_189
What was done
MCF7 human breast cancer cells were treated for 24 hours with bisphenol A (BPA) across three concentrations: 10^-12 M (ubiquitous exposure), 10^-9 M (relevant to human physiological levels), and 10^-6 M (experimental concentration). Researchers also tested the combined effect of low-dose BPA (10^-12 M) with physiological estradiol (E2, 10^-9 M). Expression of apoptosis- and cell cycle-related targets (estrogen receptor alpha mRNA, cyclin D1, cyclin A2/CCNA2, Bax, and Bcl2) was measured using Western blotting and real-time RT-PCR.
What was found
The abstract reports no exact numerical values, fold-changes, or statistical indices. It qualitatively reports that BPA modulated estrogen receptor alpha mRNA, cyclin D1 and A2 proteins, CCNA2 gene expression, and Bax and Bcl2 protein levels. Peak stimulation of cyclin D1 and A2 proteins occurred at 10^-9 M BPA, following a non-monotonic, inverted U-shaped dose-response curve. The combined effect of 10^-12 M BPA and 10^-9 M E2 differed from individual compound treatments and was neither additive nor synergistic.
Why it matters
This study adds in vitro mechanistic evidence that environmentally and physiologically relevant doses of BPA, alone and in combination with estradiol, can modulate key regulatory genes and proteins governing breast cancer cell proliferation and survival.
Limits
The study is restricted to a single immortalized cell line (MCF7) evaluated after a short 24-hour exposure, preventing direct translation to in vivo tissue responses or chronic low-dose human exposure. The abstract does not provide quantitative data, variance measures, or sample replication details.
Cited by
- supports In laboratory settings, low-dose exposure to bisphenol A (BPA) promotes the proliferation and growth of estrogen-sensitive breast cancer cells.