Determining and characterizing circulating nucleosomes in advanced cancer with electrochemical biosensors assisted by magnetic supports and proteomic technologies.

Abstract

Measuring and monitoring plasma nucleosomes (small fragments of chromosomes released into the blood during cell death), and their proteomic profiles is a promising approach for improved early detection, diagnosis, and prognosis of cancer diseases as well as for disease and therapy follow-up, contributing to more personalized and effective cancer care. Early detection is imperative in colorectal cancer (CRC), as it has been proven to significantly improve patient outcomes. Indeed, in CRC, blood circulating nucleosome levels and their histone alterations have been correlated with tumor stage and the presence of metastasis. Moreover, they constitute promising markers for CRC monitoring and prognosis in a minimally invasive way. The current technologies used for their detection suffer from notable drawbacks such as non-selective identification and quantification of unknown cancer-relevant proteomic trademarks, expensive procedures, and variable results related to staff experience. Taking advantage of the sensitive, fast, cost-effective, and reliable methodologies that electroanalytical technologies offer for the determination of multilevel biomarkers in liquid biopsies, we report in this paper the first electrochemical immunoplatform for the isolation and determination of circulating nucleosomes in plasma using an anti-H3.1 histone variant, integrated with proteomics insights to confirm nucleosomes isolation and identify associated proteins with potential as CRC biomarkers. The developed bioplatform was used to analyze 0.5 μg of nuclear extracts from CRC cells with different metastatic potential as well as 1/5 diluted plasma samples, demonstrating the suitability to effectively discriminate CRC patients in advanced stages from healthy individuals through liquid biopsy.