ERalpha signaling through slug regulates E-cadherin and EMT

Area of Science:

• Molecular Biology
• Oncology
• Cell Biology

Background:

• Estrogen receptor alpha (ERalpha) signaling is crucial in human breast cancer, but its role in cancer progression to aggressive, hormone-independent phenotypes remains unclear.
• A direct correlation between ERalpha and E-cadherin expression in human breast cancers suggests ERalpha may regulate E-cadherin, influencing epithelial-mesenchymal transition (EMT) and tumor progression.

Purpose of the Study:

• To investigate the hypothesis that ERalpha signaling regulates E-cadherin and influences EMT and tumor progression in breast cancer.
• To elucidate the molecular mechanisms by which ERalpha signaling impacts E-cadherin and EMT.

Main Methods:

• Studied ERalpha overexpression in ERalpha-negative breast cancer cell lines (MDA-MB-468, MDA-MB-231).
• Investigated ERalpha knockdown in ERalpha-positive breast cancer cell lines (MCF-7, T47D).
• Analyzed slug and E-cadherin expression, cell morphology, Matrigel invasion, and molecular mechanisms involving ERalpha, slug, E-cadherin, HDAC1, N-CoR, GSK-3beta, PI3K, and Akt.

Main Results:

• ERalpha overexpression decreased slug and increased E-cadherin, leading to less invasive, clump-forming cells.
• ERalpha knockdown increased slug and decreased E-cadherin, resulting in spindly cells with increased invasion.
• ERalpha signaling reduced slug expression via direct transcriptional repression and indirect inactivation of GSK-3beta, subsequently increasing E-cadherin.

Conclusions:

• ERalpha signaling plays a significant role in regulating E-cadherin expression and suppressing EMT in breast cancer.
• The findings reveal ERalpha signaling, through slug, acts as a key regulator of E-cadherin and EMT, impacting breast cancer progression.
• A strong inverse correlation between slug, ERalpha, and E-cadherin in human breast cancer cases supports these findings.