Selection of valid reference genes for expression studies of hepatic cell lines under IFN-α treatment.

The proper selection of reference genes to normalize the quantitative real-time PCR (RT-qPCR) results under particular experimental conditions is crucial for validation of the gene quantification data. Herein, using SYBR green RT-qPCR, five reference genes (GAPDH, ACTB, HMBS, HPRT-1 and TBP) were evaluated to determine the most stable reference genes in hepatic cell lines (Huh-7 and HepG(2)) under IFN-α treatment conditions. Analyses by geNorm program ranked GAPDH and HPRT-1 in Huh-7 and that of ACTB and HMBS in HepG(2) cells as the most stable reference genes under IFN-α treatment. While, same reference gene pairs were ranked by NormFinder program in Huh-7 cells, GAPDH was assessed as the most stable gene in HepG(2) group by this program, implying the importance of the employed algorithm in comparative interpretation of the data. Finally, cumulative analyses by one-way ANOVA, geNorm and NormFinder programs indicated that use of two reference genes (HMBS and GAPDH) in Huh-7 and three (HMBS, ACTB and GAPDH) in HepG(2) cells would greatly improve the normalization of the RT-qPCR data under IFN-α. Data presented in this paper will aid the selection of the most stable reference genes in RT-qPCR studies on evaluation of hepatic viral proteins and IFN pathway.