Circulating miRNA associated with hepatocellular carcinoma in mice

Biomarker studies for early stage or preclinical hepatocellular carcinomas (HCC) are hindered by the difficulties of obtaining samples from asymptomatic individuals. We established animal models using irradiated mice to investigate circulating miRNA as non-invasive markers for detection of early stage HCC. We hypothesized that certain miRNAs that play pivotal roles in molecular pathways are conserved across species and identification of these miRNAs will facilitate studying human markers in mice. To test the hypothesis, we performed weighted gene co-expression analysis by integrating circulating miRNA and tumor gene expression profiles from individual mice and discovered hub miRNAs in highly correlated expression modules. We validated the hub miRNAs using F2 hybrid mice derived from radiogenic HCC susceptible and resistant founders and identified 38 circulating miRNA markers associated with radiation-induced HCC. Through literacy search, we selected 10 human HCC-associated circulating miRNAs that had been validated in multiple independent patient cohorts. Nine of the 10 human markers overlapped with the mouse hub miRNAs, indicating the feasibility of using mouse model to study human circulating HCC markers. Using serially collected plasma samples from irradiated mice, we studied the kinetics of circulating miRNAs. We found that the mouse plasma levels of 4 human circulating markers, miR-122-5p, miR-100-5p, miR-34a-5p and miR-365-3p increased linearly as the time approaching towards HCC detection, indicating the correlations of the 4 miRNAs with oncogenic progression. Estimation of change points in the kinetics of the 4 circulating miRNAs suggested the changes started months before HCC detection, ranging from 17.5 to 6.8 months. Our data demonstrated that the 4 circulating miRNAs were sensitive biomarkers potentially valuable for the screening of early stage HCC. Overall design: In the study presented here, C3H mice and the second generation progeny of C3HxBalb/c hybid (F2) were used as discovery cohort and validation cohort respectively. In total 13 male C3H, 53 time-series samples from F2 mice, including 7 females and 8 males were inculded in the study.