E3330（Cat No.:R029889）, also known as APX3330, is a small-molecule inhibitor targeting the redox function of APE1/Ref-1 (apurinic/apyrimidinic endonuclease 1/redox factor-1). APE1/Ref-1 regulates DNA repair and transcription factor activity, playing a central role in oxidative stress response, inflammation, and cancer progression. By selectively blocking Ref-1’s redox activity, E3330 suppresses activation of transcription factors such as NF-κB, HIF-1α, and STAT3, which are linked to tumor growth and inflammatory signaling. It has been investigated as a potential therapeutic in oncology and inflammatory disease research.