Estrogen receptor alpha and Progesterone receptor functional crosstalk (ER-PR crosstalk)

The functional crosstalk between the Estrogen Receptor alpha (ERα) and the Progesterone Receptor (PR) is a pivotal regulatory mechanism in hormone-dependent breast cancer (Mohammed et al., 2015, Nature). When activated by ligands, the PR acts as a molecular rheostat that physically interacts with ERα, redirecting its binding across the genome to unique cis-regulatory elements (Singhal et al., 2016, Mol Cell Endocrinol). This genomic reprogramming shifts the ERα transcriptional program from a proliferative state to one favoring cellular differentiation, which is associated with a more favorable clinical prognosis in ER+/PR+ breast cancer patients (UniProt P03372, P06401). Historically, PR was viewed primarily as a passive marker of ER activity, but modern research identifies it as an active modulator that can be therapeutically exploited. Drugs such as progestins (e.g., Megestrol acetate) or Selective Progesterone Receptor Modulators (SPRMs) are used to trigger this crosstalk to inhibit estrogen-driven tumor growth (PubMed, 2015). However, the therapeutic application of this crosstalk must balance the anti-proliferative effects in the breast with potential side effects like endometrial hyperplasia or increased risk of thrombosis (StatPearls, 2023).

Other names

ER/PR interactionProgesterone receptor-mediated ERα reprogrammingER-PR signaling axisPR-mediated ERα modulation

Progesterone receptor activation induces physical association with Estrogen receptor alpha, redirecting its genomic binding to sites that promote differentiation rather than proliferation (Mohammed et al., 2015).