Investigation of microRNA expression changes in HepG2 cell line in presence of URG4/URGCP and in absence of URG4/URGCP suppressed by RNA interference

Hepatocellular carcinoma (HCC) originates from liver cells and is one of the most common malignant cancers in the world. microRNAs (miRNA), are single strand non-coding RNA molecules with the length of 18-25 nucleotides. miRNAs play an important role in the development of HCC, i.e., miRNAs have a significant impact on multistep hepatocellular carcinogenesis including cellular migration and invasion. URG4/URGCP (up-regulated gene-4/upregulator of cell proliferation) is up-regulated in the presence of HBxAg and has been identified and characterized by Satiroglu-Tufan et al. The full-length URG4/URGCP is 3.607 kb. Overexpression of URG4/URGCP in the presence of HBV X protein may function as a putative oncogene that significantly contributes to multi-step hepatocarcinogenesis. In this study, we aimed to investigate potential miRNA expression changes in HepG2 cell line model system in the presence of URG4/URGCP and in the absence of URG4/URGCP, which was suppressed by RNA interference. To functionally characterize URG4/URGCP, independent cultures of HepG2 cells were stably transfected with pcDNA3 or pcDNA3-URG4/URGCP. Relative quantification of whole genome miRNAs was analyzed by RT-PCR using human whole genome miRNA qPCR profiling kits. Among the 1,034 human miRNAs investigated by the arrays, 77 miRNAs were up-regulated and nine miRNAs were down-regulated in the presence of URG4/URGCP. In conclusion, we have analyzed miRNA profiles in HepG2 cells in presence or absence of URG4/URGCP gene using RNA interference. Some of these miRNAs may play roles in URG4/URGCP gene related disease development through the regulation of different signaling pathways