Increased skin carcinogenesis in caspase-activated DNase knockout mice

Area of Science:

• Molecular Biology
• Cancer Research
• Cell Death Mechanisms

Background:

• Caspase-activated DNase (CAD), also known as DNA fragmentation factor (DFF), is crucial for DNA fragmentation during apoptosis.
• CAD/DFF has demonstrated a role in suppressing radiation-induced carcinogenesis by maintaining genomic stability.
• The specific role of CAD in chemical carcinogenesis remains less understood.

Purpose of the Study:

• To investigate the role of CAD in chemical carcinogenesis using a two-stage skin carcinogenesis model.
• To compare tumor development in CAD-null mice versus wild-type littermates.
• To determine if CAD deficiency influences the initiation and promotion stages of chemical carcinogenesis.

Main Methods:

• Utilized CAD-null mice and wild-type littermates.
• Employed a two-stage skin carcinogenesis model involving topical application of dimethylbenz[a]anthracene (DMBA) as an initiator.
• Used 12-O-tetradecanoylphorbol-13-acetate (TPA) as a promoting agent.

Main Results:

• CAD knockout mice exhibited a 4-fold increase in papillomas per mouse compared to wild-type controls.
• A 50.8% increase in papilloma incidence was observed in CAD-null mice.
• Papillomas in CAD-null mice demonstrated accelerated growth and larger tumor sizes.

Conclusions:

• Loss of CAD function significantly enhances chemical-induced skin tumorigenesis in the DMBA/TPA model.
• CAD plays a protective role against chemical carcinogenesis, independent of its role in radiation-induced cancer.
• These findings highlight CAD as a potential target for cancer prevention strategies.