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Genetically Encoded FRET Biosensor Detects the Enzymatic Activity of Prostate-Specific Antigen

Hui Yao1, Liqun Wang3, Jia Guo1, Weimin Liu4, Jingjing Li1, Yingxiao Wang2, Linhong Deng1,*, Mingxing Ouyang1,2,3,*

1 Institute of Biomedical Engineering and Health Sciences, Changzhou University, Changzhou, 213164, China
2 Department of Bioengineering, University of Illinois at Urbana-Champaign, Illinois, 61801, USA
3 College of Pharmaceutical Engineering & Life Science, Changzhou University, Changzhou, 213164, China
4 Changzhou City Second People’s Hospital, Changzhou, 213164, China

* Corresponding Authors: Linhong Deng. Email: email; Mingxing Ouyang. Email: email

Molecular & Cellular Biomechanics 2020, 17(3), 101-111.


Prostate cancer is the most common cancer among men beyond 50 years old, and ranked the second in mortality. The level of Prostate-specific antigen (PSA) in serum has been a routine biomarker for clinical assessment of the cancer development, which is detected mostly by antibody-based immunoassays. The proteolytic activity of PSA also has important functions. Here a genetically encoded biosensor based on fluorescence resonance energy transfer (FRET) technology was developed to measure PSA activity. In vitro assay showed that the biosensor containing a substrate peptide ‘RLSSYYSGAG’ had 400% FRET change in response to 1 µg/ml PSA within 90 min, and could detect PSA activity at 25 ng/ml. PSA didn’t show enzymatic activity toward the biosensor in serum solution, likely reflecting the existence of other inhibitory factors besides Zn2+. By expressing the biosensor on cell plasma membrane, the FRET responses were significant, but couldn’t distinguish well the cultured prostate cancer cells from non-prostate cancer cells under microscopy imaging, indicating insufficient speci- ficity to PSA. The biosensor with the previously known ‘HSSKLQ’ substrate showed little response to PSA in solution. In summary, we developed a genetically encoded FRET biosensor to detect PSA activity, which may serve as a useful tool for relevant applications, such as screening PSA activation substrates or inhibitors; the purified biosensor protein can also be an alternative choice for measuring PSA activity besides currently commercialized Mu-HSSKLQ-AMC substrate from chemical synthesis.


Cite This Article

Yao, H., Wang, L., Guo, J., Liu, W., Li, J. et al. (2020). Genetically Encoded FRET Biosensor Detects the Enzymatic Activity of Prostate-Specific Antigen. Molecular & Cellular Biomechanics, 17(3), 101–111.


cc This work is licensed under a Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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