Total RNA was isolated from liver tissue of Stat5f/f, Stat5f/f;Alb-Cre mice and hepatocytes using an RNeasy mini kit (Qiagen, Valencia, CA) and 1 μg of RNA was reverse-transcribed (complementary DNA reverse-transcription kit; Applied Biosystems, ATM/ATR inhibitor drugs Foster City, CA). Real-time quantification of messenger RNA (mRNA) transcript levels was performed using the TaqMan Gene Expression Master Mix (Applied Biosystems, Foster City, CA) according to the manufacturer’s instructions. Real-time PCR was performed using an ABI Prism 7900HT (Applied Biosystems, Foster City,

CA). TaqMan probes for Nox4 (Mm00479246_m1), Socs2 (Mm00850544_g1), Puma (Mm00519268_m1), Bim (Mm00437795_m1), and beta-actin (4352341E) were used (Applied Biosystems, Foster City, CA) for real-time PCR. The SYBR primers were as follows: Cdkn2b, 5′-CCCTGCCACCCTTACCAGA-3′ (forward), 5′-CAGATACCTCGCAATGTCACG-3′ this website (reverse); GAPDH, 5′-AACGACCCCTTCATTGAC-3′ (forward), 5′-TCCACGACATACTCAGCAC-3′ (reverse). All statistical analyses were performed using a two-tailed, unpaired Student t test. P ≤ 0.05 was considered significant. ChIP, chromatin immunoprecipitation; DAPI, 4′,6-diamidino-2-phenylindole; DPI, diphenylene iodonium; GH, growth hormone;

HCC, hepatocellular carcinoma; IgG, immunoglobulin G; MEF, mouse embryonic fibroblast; mRNA, messenger RNA; NIDDK, National Institute of Diabetes and Digestive and Kidney

Diseases; PCR, polymerase chain reaction; ROS, reactive oxygen species; STAT5, signal transducer and activator of transcription 5; TGF-β, transforming growth factor-β. To gain further insight into STAT5′s role as tumor suppressor and understand underlying genetic pathways, we mined microarray-based expression data from liver tissue of control and liver-specific Stat5-null mice and from Stat5+/+ and Stat5−/− mouse embryonic fibroblasts (MEFs) (for GEO accession numbers, see Materials see more and Methods). In addition to the reduced expression of genuine STAT5 target genes (such as Socs2) in Stat5-null liver tissue, we observed a 2.5- and 3.6-fold reduction of Nox4 and Bim mRNA levels, respectively (Supporting Table 1). Similarly, expression of Nox4 in Stat5−/− MEFs was reduced 3.3-fold (Supporting Table 2). In addition, we observed a 5.7-fold reduction of Puma mRNA in Stat5−/− MEFs. Whereas NOX4 is a reactive oxygen species (ROS)-generating enzyme, BIM and PUMA are proapoptotic proteins. Quantitative real-time PCR and western blots confirmed GH and STAT5 dependency of the Nox4, Puma, and Bim genes in liver tissue. Nox4, Puma, and Bim mRNA levels were reduced in Stat5-null livers (Fig. 1A). The Socs2 gene served as a positive control (Fig. 1A,B).