UCH-L1-mediated Down-regulation of Estrogen Receptor α Contributes to Insensitivity to Endocrine Therapy for Breast...

Area of Science:

• Oncology
• Molecular Biology
• Biochemistry

Background:

• Estrogen receptor alpha (ERα) is a key target in breast cancer therapy.
• Loss or reduction of ERα expression leads to resistance against anti-estrogen therapies.
• Novel therapeutic strategies are needed to overcome resistance in ERα-negative breast cancer.

Purpose of the Study:

• To investigate the role of Ubiquitin Carboxyl-Terminal Hydrolase-L1 (UCH-L1) in regulating ERα expression.
• To assess if targeting UCH-L1 can improve anti-estrogen therapy efficacy in ERα-negative breast cancer.
• To elucidate the molecular mechanisms underlying UCH-L1's regulation of ERα.

Main Methods:

• Examined UCH-L1 and ERα expression in breast cancer cell lines and patient samples.
• Analyzed associations between UCH-L1, ERα, therapeutic response, and prognosis using public databases.
• Investigated UCH-L1's regulatory pathways via immunoblotting, qRT-PCR, immunoprecipitation, ubiquitination, luciferase, and ChIP assays.
• Evaluated UCH-L1 inhibition effects on tamoxifen efficacy in ERα-negative breast cancer models (in vitro and in vivo).

Main Results:

• UCH-L1 expression inversely correlated with ERα status in breast cancer.
• UCH-L1 negatively regulates ERα transcription through the EGFR stability pathway.
• High UCH-L1 expression is linked to poor therapeutic response and prognosis.
• UCH-L1 inhibition upregulated ERα, enhancing tamoxifen and fulvestrant efficacy in ERα-negative breast cancer models.

Conclusions:

• UCH-L1 plays a critical role in modulating ERα status in breast cancer.
• The UCH-L1-EGFR signaling pathway is implicated in ERα regulation.
• UCH-L1 represents a potential adjuvant therapeutic target for hormone therapy-insensitive breast cancers.
• Targeting UCH-L1 could sensitize ER-negative breast cancer to anti-estrogen therapy, offering a new treatment strategy.