Decoding Atypical G-Quadruplexes and Their Interactome in Liquid Biopsies via Integrated Electroanalytical-Proteomic...

Area of Science:

• Biotechnology
• Analytical Chemistry
• Molecular Oncology

Background:

• G-quadruplex (G4) structures are increasingly recognized as multifunctional DNA biomarkers.
• A need exists for technologies to determine, isolate, and characterize G4 motifs in clinical samples.

Purpose of the Study:

• To develop and validate a multipurpose electroanalytical biotechnology for G4 structure analysis.
• To enable direct detection and characterization of G4 motifs in oncology patient samples.

Main Methods:

• Utilized magnetic immunocaptors in a competitive assay with amperometric transduction at screen-printed electrodes.
• Integrated magnetic immunocapture with PCR, DNA sequencing, and proteomics.
• Validated analytical performance in synthetic models and colorectal cancer (CRC) patient samples.

Main Results:

• Demonstrated direct detection of G4 structures in plasma from oncology patients without nucleic acid extraction.
• Confirmed selective isolation of endogenous G4-forming DNA regions.
• Showed CRC induces stage-dependent remodeling of the plasma G4 protein interactome and identified a CRC-associated G4-binding protein linked to poor survival.

Conclusions:

• The developed electroanalytical biotechnology is a powerful tool for G4 biomarker research in oncology.
• This technology facilitates G4 structure determination, isolation, and characterization from clinical samples.
• Findings highlight the potential of G4 structures and their interactome as diagnostic and prognostic markers in colorectal cancer.