SLFN11 Enhances PARPi Sensitivity in Ovarian Cancer via Ubiquitin-Mediated Stabilization

Area of Science:

• Oncology
• Molecular Biology
• Cancer Genetics

Background:

• Schlafen family member 11 (SLFN11) is linked to cancer drug resistance and may influence poly(ADP-ribose) polymerase inhibitor (PARPi) efficacy.
• Epithelial ovarian cancer (EOC) often exhibits resistance to PARPi, particularly in BRCA-wild-type contexts.
• SLFN11's role in proteostasis regulation is an emerging area of interest for cancer therapy.

Purpose of the Study:

• To investigate the role of SLFN11 in epithelial ovarian cancer (EOC) progression.
• To determine SLFN11's influence on PARPi sensitivity, especially in BRCA-wild-type EOC.
• To elucidate the mechanism by which SLFN11 affects PARPi response, focusing on proteostasis and PARP1/2 stability.

Main Methods:

• Immunohistochemistry, quantitative PCR, and Western blot were used to evaluate SLFN11 expression in EOC tissues.
• Functional assays (cell viability, migration, wound healing, colony formation) assessed SLFN11's impact on EOC cell behavior.
• PARPi sensitivity assays (CCK-8, TUNEL) and analysis of PARP1/2 protein stability and ubiquitination were performed in cells with altered SLFN11 levels.

Main Results:

• SLFN11 expression was significantly lower in EOC tissues compared to normal tissues.
• SLFN11 knockdown promoted EOC cell proliferation and invasion, while overexpression inhibited these processes.
• SLFN11 knockdown decreased PARPi-induced apoptosis and sensitivity, whereas overexpression enhanced these effects.

Conclusions:

• SLFN11 enhances PARPi sensitivity in EOC by stabilizing PARP1/2 proteins through the inhibition of proteotoxic ubiquitination.
• SLFN11 acts as a potential biomarker for predicting PARPi response in BRCA-wild-type EOC.
• SLFN11 could be a therapeutic strategy to overcome intrinsic PARPi resistance in EOC.