Quantitation of urinary nucleosides by high-performance liquid chromatography

Area of Science:

• Biochemistry
• Oncology
• Analytical Chemistry

Background:

• Modified nucleosides from RNA degradation are excreted in urine and proposed as tumor markers.
• Measuring urinary nucleosides offers a potential non-invasive method for cancer diagnosis and therapy monitoring.

Purpose of the Study:

• To develop and optimize an analytical procedure for isolating and quantifying normal and modified ribonucleosides in urine.
• To establish reference levels for urinary ribonucleosides in healthy individuals.
• To investigate abnormal ribonucleoside levels in patients with specific cancers.

Main Methods:

• Affinity chromatography using a phenylboronic acid column for urinary nucleoside extraction.
• Reversed-phase high-performance liquid chromatography (RP-HPLC) for ribonucleoside separation and quantification.
• Measurement of nucleosides relative to creatinine for normalization.

Main Results:

• A robust method was developed, achieving high recovery rates (83-100%) for most nucleosides, with exceptions for xanthosine (66%) and pseudouridine (74%).
• Mean levels for thirteen urinary ribonucleosides in healthy individuals were established (e.g., pseudouridine 25.52 nmol/µmol creatinine).
• Initial findings indicated abnormal ribonucleoside levels in patients with breast and floor of mouth tumors.

Conclusions:

• The developed analytical method is effective for quantifying urinary ribonucleosides.
• Abnormal levels of specific ribonucleosides are associated with certain types of cancer.
• Further research is warranted to explore the diagnostic and monitoring potential of urinary modified nucleosides across various cancers.