Abstract 4823: Circulating tumor cell miR-27a overexpression as a novel mechanism of hepatocellular carcinoma metastasis

Abstract

Abstract Hepatocellular carcinoma is a very lethal disease, being the third most common cause of cancer-related deaths worldwide. The vast majority of these deaths are due to metastasis. Unfortunately, the mechanisms of metastasis are still largely unclear. Micro RNAs are non-coding RNAs that are typically about 22 nucleotides in length. They are now established as important regulators of gene expression. A number of different micro RNAs have been shown to contribute to hepatocellular carcinoma progression and metastasis. Although micro RNA 27a (miR-27a) has been implicated in the metastasis of other solid cancers, its role in hepatocellular carcinoma metastasis was previously unknown. We have recently established a novel circulating tumor cell line from a syngeneic metastatic hepatocellular carcinoma mouse model and we have demonstrated that it has enhanced tumorigenicity and metastatic capacity (1). In this study, our aim was to determine if miR-27a has a role in the development, progression and metastasis of hepatocellular carcinoma. To accomplish this aim, we used primary human hepatocytes (Hu 1476), a non-tumorigenic hepatocyte cell line established from the liver of wild-type immune competent Balb/c mouse (BNL CL.2), a highly tumorigenic hepatocellular carcinoma cell line derived from BNL CL.2 hepatocytes (BNL 1ME A. 7R.1), and a novel circulating tumor cell line derived from the syngeneic metastatic hepatocellular carcinoma Balb/c mouse model (OL0825). Total RNA was extracted from cultured cells. cDNA was made using a protocol suitable for assessment of miRNA expression. Real-time quantitative reverse transcription polymerase chain reaction (qPCR) was used to determine miR-27a expression using primers specific for human and mouse miR-27a. GAPDH was used as a house-keeping gene. The expression profile of a panel of four miRNAs (miR-27a, miR-27b, miR-103, and miR-107) in the BNL CL.2 hepatocytes was very similar to that of the Hu 1476 primary human hepatocytes. However, the BNL 1ME A. 7R.1 hepatocellular carcinoma cell line had about 42-fold greater expression of miR-27a than BNL CL.2 hepatocytes. Notably, the novel circulating tumor cell line, OL0825, had about 130-fold greater expression of miR-27a than the BNL CL.2 hepatocytes. Therefore, we conclude that circulating tumor cell miR-27a overexpression may be a novel mechanism of hepatocellular carcinoma metastasis. Furthermore, miR-27a may be a useful biomarker for hepatocellular carcinoma progression and metastasis. 1. Ogunwobi OO, Puszyk W, Dong H, Liu C. Epigenetic upregulation of c-Met and HGF drives metastasis in hepatocellular carcinoma. PLoS One, 2013, 8(5):e63765. Citation Format: Olorunseun O. Ogunwobi, Chen Liu. Circulating tumor cell miR-27a overexpression as a novel mechanism of hepatocellular carcinoma metastasis. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 4823. doi:10.1158/1538-7445.AM2014-4823