An ovarian cancer model with positive ER: Reversion of ER antagonist resistance by Src blockade

Area of Science:

• Oncology
• Molecular Biology
• Endocrinology

Background:

• Estrogen receptor (ER)-positive ovarian cancer often exhibits resistance to ER-targeted therapies.
• Estrogen signaling activates Src, promoting cell cycle progression and degradation of p27, a cell cycle inhibitor.
• Src activation is common in ovarian cancers, suggesting a potential therapeutic target.

Purpose of the Study:

• To investigate if combined blockade of Src and ER can overcome anti-estrogen resistance in ovarian cancer.
• To evaluate the efficacy of saracatinib (Src inhibitor) and fulvestrant (ER antagonist) in preclinical models of ovarian cancer.

Main Methods:

• Assessed phosphorylated Src (p-Src) expression in patient tumors and correlated with survival outcomes.
• Investigated the effects of combined saracatinib and fulvestrant on cell cycle progression in ERα-positive ovarian cancer cells.
• Evaluated the impact of dual therapy on cell cycle regulators, autophagy, and tumor growth in xenograft models.

Main Results:

• p-Src expression was observed in 40% of ER-positive ovarian cancers, associated with metastasis and poorer disease-free survival.
• Src activity was higher in anti-estrogen-resistant ovarian cancer cells.
• Combined saracatinib and fulvestrant increased p27 levels, inhibited cell cycle progression, induced autophagy, and suppressed tumor xenograft growth more effectively than monotherapy.

Conclusions:

• Combined Src and ER blockade with saracatinib and fulvestrant is a promising strategy to circumvent anti-estrogen resistance in ovarian cancer.
• Saracatinib enhances fulvestrant's efficacy by inhibiting estrogen-mediated Src activation.
• Further preclinical evaluation of this combination therapy is warranted for ovarian cancer patients.