Hepatocellular carcinoma (HCC) continues to be a major cause of cancer death globally, with aflatoxin B1 (AFB1) as a prevalent risk factor in low- and middle-income countries. MicroRNAs have been shown to be differentially expressed in HCC and may serve as predictive biomarkers. In this study, we analyzed tumor and non-tumor tissue from rats dosed with AFB1 (200 g/kg BW) for 28 consecutive days that received vehicle only or AFB1 plus the chemopreventive agent CDDO-Im (30 mol), and control animals (Johnson et al., CaPR, 2014). Total RNA was isolated from tumor or non-tumor tissue at the time of sacrifice and sequenced. MicroRNA transcriptomic analysis revealed 17 miRNAs significantly upregulated (< 5 fold) in tumors compared to non-tumor tissue. The top ten dysregulated miRNAs determined by fold change and biological significance were selected for further investigation: rno-miR- 205, 200b-3p, 182, 429, 31a-5p, 10b-5p, 141-3p, 132-3p, 802-5p. Validation of sequencing results by quantitative PCR (qPCR) confirmed the upregulation of the majority of candidate miRNAs in tumors and rno-miR-224-5p as the most dysregulated miRNA (over 400 fold). We also examined the levels of these candidates in terminal sera of the same animals by qPCR. Circulating miRs-224-5p, 182, and 122-5p were increased (< 1.5 fold) in animals diagnosed with HCC compared to untreated animals and those previously dosed with AFB1 plus CDDO-Im. Analysis of tracking of serum miR-182 by generalized estimating equations (GEE) revealed significantly increased levels (5 fold; CI: 2.17- 2.50) in animals that developed HCC. This sustained increase in serum miR-182 is seen months before any tumors or other symptoms are present, and highlights this miRNA as a potential predictive biomarker in AFB1-induced HCC. Supported by T32ES007141-31A1 and CA197222.
Citation Format: Merricka C. Livingstone, Natalie M. Johnson, Bill D. Roebuck, Thomas W. Kensler, John D. Groopman. Dysregulated microRNAs in aflatoxin-induced hepatocellular carcinoma: Serum miR-182 as a potential predictive biomarker [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 5401.