Modulation of UVB-induced Carcinogenesis by Activation of Alternative DNA Repair Pathways

Area of Science:

• Molecular biology
• Dermatology
• Biochemistry

Background:

• Ultraviolet (UV) radiation causes skin cancer through DNA damage and genomic instability.
• Inefficient DNA repair of UV-induced photoproducts leads to mutations and cancer development.
• Previous attempts to enhance DNA repair in skin cells have faced limitations.

Purpose of the Study:

• To engineer and deliver exogenous DNA repair enzymes to combat UV-induced skin damage.
• To evaluate the efficacy of UV endonuclease (UVDE) and pyrimidine dimer glycosylase (PDG) in preventing skin carcinogenesis.

Main Methods:

• Engineered UVDE (Δ228) with a TAT cell-penetrating peptide (UVDE-TAT) and a nuclear localization signal (UVDE-NLS-TAT).
• Engineered cv-pdg with a nuclear localization signal (cv-pdg-NLS).
• Encapsulated enzymes into liposomes for topical delivery in a UVB-induced mouse skin cancer model (SKH1 hairless mice).

Main Results:

• Topical delivery of UVDE-TAT and UVDE-NLS-TAT significantly reduced overall tumor burden compared to control liposomes.
• UVDE-NLS-TAT treatment significantly increased survival time in the mice.
• These findings highlight the potential of enzyme-based DNA repair for photoprotection.

Conclusions:

• Engineered exogenous DNA repair enzymes, when delivered effectively, can mitigate UV-induced skin damage.
• Liposomal delivery of UVDE variants shows promise in preventing UV-induced skin cancers.
• This approach offers a novel strategy for protecting against nonmelanoma and melanoma skin cancers.