Thioredoxin Decreases Anthracycline Cardiotoxicity, But Sensitizes Cancer Cell Apoptosis

Area of Science:

• Biochemistry
• Oncology
• Cardiology

Background:

• Anthracyclines are potent anticancer drugs but cause cardiotoxicity, limiting their use.
• The exact mechanism of anthracycline-induced heart failure involves lipid peroxidation and free radicals.
• Thioredoxin (Trx) is an antioxidant protein involved in cellular redox balance.

Purpose of the Study:

• To investigate the role of Thioredoxin (Trx) in anthracycline cardiotoxicity and anticancer effects.
• To determine if Trx levels influence cancer cell apoptosis and cardiomyocyte survival during daunomycin treatment.

Main Methods:

• Overexpression of active and inactive Thioredoxin (Trx) in cancer cells and rat embryonic cardiomyocytes (H9c2 cells).
• Treatment of modified cells with daunomycin, an anthracycline chemotherapy agent.
• Assessment of apoptosis and cell death in response to daunomycin in cells with varying Trx levels.

Main Results:

• Cancer cells overexpressing Trx showed increased apoptosis upon daunomycin treatment.
• Cancer cells with redox-inactive Trx mutant did not show enhanced killing.
• Cardiomyocytes overexpressing Trx were protected from daunomycin-induced apoptosis.
• Cardiomyocytes with reduced Trx levels exhibited enhanced apoptosis.
• Trx's effect was specific to anthracyclines, not other topoisomerase II inhibitors like etoposide.

Conclusions:

• High levels of Thioredoxin (Trx) protect cardiomyocytes from anthracycline toxicity.
• Conversely, elevated Trx potentiates anthracycline-induced toxicity in cancer cells.
• Trx plays a dual role, offering cardioprotection while enhancing anticancer efficacy in a context-dependent manner.