ABSTRACT: Patients with diabetes mellitus (DM) have an epidemiologically higher risk for hepatocellular carcinoma (HCC). In mouse models, administration of streptozotocin (STZ) induces insulin-dependent DM by causing islet beta-cell dysfunction and also induced hepatocellular carcinoma (HCC) after 12 weeks. We attempted to elucidate the carcinogenic mechanism in the precancerous state by using hepatic miRNAs and create precancerous marker using exosomal miRNA. Serum and liver tissues were collected from STZ mice and non-treated mice (CTL mice) at 6, 10 and 12W. Total RNA in liver and exosome were extracted. Histological examination in liver in HE stain and hepatic and exosomal miRNA analysis were serially performed. miRNA and mRNA was analyzed by next-generation sequencing (NGS). The raw data of NGS was analyzed by Principal Component analysis. No inflammation or fibrosis was found in the liver in CTL mice during the observation period. In STZ-treated mice, regeneration and inflammation of hepatocytes was found at 6W and then nodules of atypical hepatocytes were found at 10 and 12 W. Expression of let-7f-5p, miR-21a-5p, 22-3p, and 26a-5p in liver of STZ mice was significantly increased during 6-10W, and these miRNAs controlled several tumor suppressor genes as target genes. We also identified six novel miRNAs associated with precancerous status. Furthermore, miR-122-5p and miR-192-5p in exosome were significantly upregulated in STZ mice in precancerous state. The expression of miRNAs that regulate tumor suppressor genes was enhanced even before carcinogenesis, and the expression of these miRNAs was not affected by liver fibrosis. In addition, the expression pattern of miRNAs in exosome is expected to be a marker for predicting carcinogenesis. Patients with diabetes mellitus (DM) have an epidemiologically higher risk for hepatocellular carcinoma (HCC). In mouse models, administration of streptozotocin (STZ) induces insulin-dependent DM by causing islet beta-cell dysfunction and also induced hepatocellular carcinoma (HCC) after 12 weeks. We attempted to elucidate the carcinogenic mechanism in the precancerous state by using hepatic miRNAs and create precancerous marker using exosomal miRNA. Serum and liver tissues were collected from STZ mice and non-treated mice (CTL mice) at 6, 10 and 12W. Total RNA in liver and exosome were extracted. Histological examination in liver in HE stain and hepatic and exosomal miRNA analysis were serially performed. miRNA and mRNA was analyzed by next-generation sequencing (NGS). The raw data of NGS was analyzed by Principal Component analysis. No inflammation or fibrosis was found in the liver in CTL mice during the observation period. In STZ-treated mice, regeneration and inflammation of hepatocytes was found at 6W and then nodules of atypical hepatocytes were found at 10 and 12 W. Expression of let-7f-5p, miR-21a-5p, 22-3p, and 26a-5p in liver of STZ mice was significantly increased during 6-10W, and these miRNAs controlled several tumor suppressor genes as target genes. We also identified six novel miRNAs associated with precancerous status. Furthermore, miR-122-5p and miR-192-5p in exosome were significantly upregulated in STZ mice in precancerous state. The expression of miRNAs that regulate tumor suppressor genes was enhanced even before carcinogenesis, and the expression of these miRNAs was not affected by liver fibrosis. In addition, the expression pattern of miRNAs in exosome is expected to be a marker for predicting carcinogenesis. Patients with diabetes mellitus (DM) have an epidemiologically higher risk for hepatocellular carcinoma (HCC). In mouse models, administration of streptozotocin (STZ) induces insulin-dependent DM by causing islet beta-cell dysfunction and also induced hepatocellular carcinoma (HCC) after 12 weeks. We attempted to elucidate the carcinogenic mechanism in the precancerous state by using hepatic miRNAs and create precancerous marker using exosomal miRNA. Serum and liver tissues were collected from STZ mice and non-treated mice (CTL mice) at 6, 10 and 12W. Total RNA in liver and exosome were extracted. Histological examination in liver in HE stain and hepatic and exosomal miRNA analysis were serially performed. miRNA and mRNA was analyzed by next-generation sequencing (NGS). The raw data of NGS was analyzed by Principal Component analysis. No inflammation or fibrosis was found in the liver in CTL mice during the observation period. In STZ-treated mice, regeneration and inflammation of hepatocytes was found at 6W and then nodules of atypical hepatocytes were found at 10 and 12 W. Expression of let-7f-5p, miR-21a-5p, 22-3p, and 26a-5p in liver of STZ mice was significantly increased during 6-10W, and these miRNAs controlled several tumor suppressor genes as target genes. We also identified six novel miRNAs associated with precancerous status. Furthermore, miR-122-5p and miR-192-5p in exosome were significantly upregulated in STZ mice in precancerous state. The expression of miRNAs that regulate tumor suppressor genes was enhanced even before carcinogenesis, and the expression of these miRNAs was not affected by liver fibrosis. In addition, the expression pattern of miRNAs in exosome is expected to be a marker for predicting carcinogenesis.
