Peroxiredoxin 1 interacts with and blocks the redox factor APE1 from activating interleukin-8 expression

Area of Science:

• Molecular Biology
• Biochemistry
• Cancer Research

Background:

• AP endonuclease 1 (APE1) is a crucial DNA repair enzyme with transcriptional regulatory roles.
• APE1's redox function involves a key cysteine residue (C65) that modulates transcription factors like NF-κB.
• The mechanisms governing APE1 recruitment for its diverse functions are not fully understood.

Purpose of the Study:

• To identify novel interaction partners of APE1.
• To elucidate the functional consequences of APE1-partner interactions on gene regulation and cellular processes.
• To investigate the role of PRDX1 in modulating APE1's nuclear localization and transcriptional activity.

Main Methods:

• Co-immunoprecipitation assays to identify APE1 interacting proteins.
• siRNA-mediated knockdown of PRDX1.
• Indirect immunofluorescence to assess APE1 nuclear localization.
• Western blotting to evaluate protein expression levels.
• Quantitative PCR to measure gene expression of IL-8.
• Functional assays involving NF-κB activation and APE1 depletion.

Main Results:

• APE1 interacts with Peroxiredoxin 1 (PRDX1), a peroxidase with chaperone activity.
• PRDX1 knockdown enhances APE1's nuclear detection without altering its expression or DNA repair capacity.
• Loss of PRDX1 interaction promotes APE1's redox function, leading to increased NF-κB binding and upregulation of the pro-inflammatory chemokine IL-8.
• Depletion of APE1 abrogates IL-8 upregulation in PRDX1 knockdown cells.

Conclusions:

• PRDX1 interacts with APE1, suggesting a novel anti-inflammatory role for PRDX1.
• PRDX1 association with APE1 may prevent aberrant activation of transcription factors, thereby limiting pro-inflammatory gene expression.
• This interaction could be a critical mechanism to suppress gene expression that promotes cancer invasion and metastasis.