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Updated: Apr 30, 2026
Isolation of Small Noncoding RNAs from Human Serum
Published on: June 19, 2014
Site-specific RNase A activity was dramatically reduced in serum from multiple types of cancer patients
Weiyan Huang1, Mei Zhao2, Na Wei1
1Institute of Molecular Medicine, Peking University, Beijing, People's Republic of China.
Abstract:
Potent RNase activities were found in the serum of mammals but the physiological function of the RNases was never well illustrated, largely due to the caveats in methods of RNase activity measurement. None of the existing methods can distinguish between RNases with different target specificities. A systematic study was recently carried out in our lab to investigate the site-specificity of serum RNases on double-stranded RNA substrates, and found that serum RNases cleave double-stranded RNAs predominantly at 5'-U/A-3' and 5'-C/A-3' dinucleotide sites, in a manner closely resembling RNase A. Based on this finding, a FRET assay was developed in the current study to measure this site-specific serum RNase activity in human samples using a double stranded RNA substrate. We demonstrated that the method has a dynamic range of 10(-5) mg/ml- 10(-1) mg/ml using serial dilution of RNase A. The sera of 303 cancer patients were subjected to comparison with 128 healthy controls, and it was found that serum RNase activities visualized with this site-specific double stranded probe were found to be significantly reduced in patients with gastric cancer, liver cancer, pancreatic cancer, esophageal cancer, ovary cancer, cervical cancer, bladder cancer, kidney cancer and lung cancer, while only minor changes were found in breast and colon cancer patients. This is the first report using double stranded RNA as probe to quantify site-specific activities of RNase A in a serum. The results illustrated that RNase A might be further evaluated to determine if it can serve as a new class of biomarkers for certain cancer types.
Insights
Serum ribonuclease (RNase) activity, specifically RNase A, is significantly reduced in various cancer types. This study developed a site-specific assay using double-stranded RNA, potentially identifying RNase A as a novel cancer biomarker.
Area of Science:
- Biochemistry
- Molecular Biology
- Oncology
Background:
- Mammalian serum contains potent ribonuclease (RNase) activities, but their physiological roles and measurement methods are limited.
- Existing assays cannot differentiate RNases based on target specificity, hindering functional studies.
- Serum RNases exhibit site-specific cleavage on double-stranded RNA, primarily at 5'-U/A-3' and 5'-C/A-3' dinucleotides, similar to RNase A.
Purpose of the Study:
- To develop and validate a novel assay for measuring site-specific RNase A activity in human serum.
- To investigate the potential of serum RNase A activity as a biomarker for various cancer types.
Main Methods:
- Development of a Förster Resonance Energy Transfer (FRET) assay utilizing a double-stranded RNA substrate to quantify site-specific RNase A activity.
- Validation of the FRET assay's dynamic range using serial dilutions of RNase A.
- Comparative analysis of serum RNase A activity between 303 cancer patients and 128 healthy controls.
Main Results:
- The FRET assay demonstrated a dynamic range of 10^-5 mg/ml to 10^-1 mg/ml.
- Significantly reduced serum RNase A activity was observed in patients with gastric, liver, pancreatic, esophageal, ovarian, cervical, bladder, kidney, and lung cancers.
- Minor changes in serum RNase A activity were noted in breast and colon cancer patients.
Conclusions:
- This study presents the first report of a site-specific assay for quantifying RNase A activity in serum using a double-stranded RNA probe.
- Reduced serum RNase A activity is a potential indicator for several cancer types.
- RNase A warrants further evaluation as a novel class of cancer biomarkers.
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