Protease Activity and Cell-Free DNA in Blood Plasma of Healthy Donors and Breast Cancer Patients

Abstract

Tumor development is generally accompanied by increased protease activity and cell-free DNA (cfDNA) levels in the blood. An immunoassay for protease activity was developed based on the binding of anti-peptide antibodies onto polystyrene plates, followed by incubation with peptides and protein hydrolyzing enzymes. The data obtained demonstrate the peptide CD34-1 composed of uncharged amino acids was the best substrate for the estimation of plasma protease activity in breast cancer patients and healthy donors. Anti-CD34-1 peptide protease activity was shown to correlate with circulating DNA concentrations in cancer patients and healthy subjects (P = 0.001, r = 0.676), demonstrating the role of protease activity in the regulation of cfDNA levels.

Keywords:

• immunoassay for protease activity
• anti-peptide antibodies
• blood plasma
• cell-free DNA
• ELISA

Additional information

Funding

This work was supported by BOR Grant (№ VI.62.1.4).