Aldose Reductase Inhibitor, Epalrestat, Suppresses Colorectal Cancer Cell Proliferation Through Complement-Dependent...

Area of Science:

• Oncology
• Immunology
• Pharmacology

Background:

• Complement-dependent cytotoxicity (CDC) is vital for tumor cell proliferation.
• Epalrestat (EPA), an aldose reductase inhibitor, is implicated in tumor cell proliferation.
• The role of CDC in EPA-mediated cancer cell proliferation inhibition is not well understood.

Purpose of the Study:

• To investigate the effect of EPA on colorectal cancer cell proliferation.
• To elucidate the mechanism of EPA's action, focusing on CDC and CD46 expression.
• To explore the involvement of the protein kinase D (PKD)/signal transducer and activator of transcription 3 (STAT3) pathway.

Main Methods:

• Assessed cell proliferation using Cell Counting Kit-8, 5-ethynyl-2'-deoxyuridine (EdU) incorporation, and reactive oxygen species (ROS) levels.
• Quantified CD46 expression via quantitative real-time PCR and immunoblotting.
• Utilized luciferase reporter assays, chromatin immunoprecipitation (ChIP), and rescue experiments to explore molecular mechanisms.

Main Results:

• EPA significantly reduced colorectal cancer cell proliferation, increased ROS levels, and decreased EdU incorporation.
• EPA treatment led to decreased CD46 expression, which was reversed by ectopic CD46 expression.
• EPA suppressed PKD/STAT3 phosphorylation, reducing STAT3 binding to the CD46 promoter and inhibiting CD46 transactivation.

Conclusions:

• EPA inhibits cancer cell proliferation by downregulating CD46 expression through the suppression of the PKD/STAT3 pathway.
• This study reveals a novel mechanism for EPA's anti-tumor activity, highlighting its potential in cancer therapy.
• EPA's modulation of CDC broadens its pharmacological functions in anti-tumor applications.