Human Cyclophilin B Nuclease Activity Revealed via Nucleic Acid‐Based Electrochemical Sensors

• Published in: Angewandte Chemie International Edition Vol. 61; no. 45; pp. e202211292 - n/a
• Main Authors: Clark, Vincent, Waters, Kelly, Orsburn, Ben, Bumpus, Namandjé N., Kundu, Nandini, Sczepanski, Jonathan T., Ray, Partha, Arroyo‐Currás, Netzahualcóyotl
• Format: Journal Article
• Language: English
• Published: Germany Wiley Subscription Services, Inc 07.11.2022; John Wiley and Sons Inc
• Edition: International ed. in English
• Subjects: Aptamer-Based Sensors; Aptamers; Bioassays; Biomarker; Biomarkers; Biosensors; Chemical sensors; Cyclophilin B; Cyclophilins - metabolism; Deoxyribonucleic acid; DNA; Electrochemical Techniques; Electrochemistry; Endonucleases; Humans; Nuclease; Nucleic Acids; Pancreatic Cancer; Pancreatic Neoplasms; Peptidylprolyl isomerase; Proteins; Biomarker; Nuclease; Pancreatic Cancer; Cyclophilin B; Aptamer-Based Sensors
• ISSN: 1433-7851; 1521-3773; 1521-3773
• DOI: 10.1002/anie.202211292

Human cyclophilin B (CypB) is oversecreted by pancreatic cancer cells, making it a potential biomarker for early‐stage disease diagnosis. Our group is motivated to develop aptamer‐based assays to measure CypB levels in biofluids. However, human cyclophilins have been postulated to have collateral nuclease activity, which could impede the use of aptamers for CypB detection. To establish if CypB can hydrolyze electrode‐bound nucleic acids, we used ultrasensitive electrochemical sensors to measure CypB's hydrolytic activity. Our sensors use ssDNA and dsDNA in the biologically predominant d‐DNA form, and in the nuclease resistant l‐DNA form. Challenging such sensors with CypB and control proteins, we unequivocally demonstrate that CypB can cleave nucleic acids. To our knowledge, this is the first study to use electrochemical biosensors to reveal the hydrolytic activity of a protein that is not known to be a nuclease. Future development of CypB bioassays will require the use of nuclease‐resistant aptamer sequences. This study employs electrochemical DNA‐based sensors to investigate the hydrolytic activity of a previously unknown nuclease, cyclophilin B. The protein is secreted by pancreatic cancer cells and could be a biomarker for early‐stage cancer diagnoses. However, the demonstrated nuclease activity will limit bioassay development based on natural nucleic acid aptamers. Instead, we propose DNA stereoisomers (l‐DNA) to overcome this challenge.