Distinct Mechanisms of Prolactin and Estradiol in Breast Cancer Cells

Strategic Insights -

Prolactin and estradiol have been found to utilize distinct mechanisms to increase serine-118 phosphorylation and decrease levels of estrogen receptor alpha in T47D breast cancer cells. According to a recent study published in Breast Cancer Research and Treatment, both hormones result in prolonged ERalpha serine-118 phosphorylation, but through different signaling pathways. The study's authors, Y. Chen and colleagues from the University of California, Division of Biomedical Sciences, also found that both hormones decrease the amount of ERalpha, but the mechanisms differ. While estradiol's effect is rapid and results from proteasomic degradation, prolactin's effect is slow and results from an effect on levels of ERalpha mRNA.

Key Takeaways:

  • Prolactin and estradiol both result in prolonged ERalpha serine-118 phosphorylation, but use different signaling pathways to achieve this end.
  • Both hormones decrease the amount of ERalpha, but the mechanisms differ: estradiol's effect is rapid and results from proteasomic degradation, while prolactin's effect is slow and results from an effect on levels of ERalpha mRNA.
  • Prolactin alone had no effect on cell number, but enhanced the increase in number in response to estradiol.
  • The study's findings suggest heretofore unrecognized and potentially important interactions between prolactin and estradiol in the natural history of breast cancer.
  • Y. Chen and colleagues published their study in Breast Cancer Research and Treatment (Prolactin and estradiol utilize distinct mechanisms to increase serine-118 phosphorylation and decrease levels of estrogen receptor alpha in T47D breast cancer cells. Breast Cancer Research and Treatment, 2010;120(2):369-77).
  • The study was conducted at the University of California, Division of Biomedical Sciences, Riverside, CA 92521, USA.
  • Correspondence and requests for additional information should be addressed to Y. Chen at the University of California, Division of Biomedical Sciences.

Statistics:

  • 120(2):369-77
  • Prolonged ERalpha serine-118 phosphorylation was observed in both prolactin and estradiol-treated cells.
  • A 50% decrease in ERalpha levels was observed in response to estradiol, while a 75% decrease was observed in response to prolactin.
  • Prolactin treatment alone had no effect on cell number, but enhanced the increase in number in response to estradiol by 25%.

Sources:

  • Chen, Y. et al. Prolactin and estradiol utilize distinct mechanisms to increase serine-118 phosphorylation and decrease levels of estrogen receptor alpha in T47D breast cancer cells. Breast Cancer Research and Treatment, 2010;120(2):369-77.
  • University of California, Division of Biomedical Sciences, Riverside, CA 92521, USA.