Our data suggest that COOH truncation of HBx may play a role in enhancing cell invasiveness and metastasis in human HCC. aa, amino acid; Ab, antibody; AP-1, activator protein 1; cDNA, complementary DNA; CFA, colony formation assay; ChIP, chromatin immunoprecipitation; COOH, carboxylic acid; CREB, cyclic adenosine check details monophosphate response element-binding protein; DMEM, Dulbecco’s modified Eagle’s minimal essential medium; FBS, fetal bovine serum; HBsAg, hepatitis B surface antigen; HBV, hepatitis B virus; HBx, hepatitis B virus X protein; HCC, hepatocellular carcinoma; IHC, immunohistochemistry;
hTERT, human telomerase reverse transcriptase; MMP10, matrix metalloproteinase protein 10; mRNA, messenger RNA; NF-κB, nuclear factor kappa B; nt, nucleotide(s); RT-PCR, reverse-transcriptase polymerase chain reaction; SDS, sodium dodecyl sulfate; siRNA, short interfering RNA; TBP, TATA-binding protein; WT, wild type. Fifty pairs of human HCCs and their corresponding nontumorous liver tissues from patients with liver resection for HCC between 1992 and 2001 at Queen Mary Hospital, Hong
Kong, were randomly selected for study. These 50 patients had positive serum hepatitis B surface antigen (HBsAg) status. patients’ ages ranged from 34 to 70 years; 43 were male and 8 female. All specimens were snap-frozen see more in liquid nitrogen and kept at −80°C. Frozen sections were cut from nontumorous liver and tumor blocks separately and stained for histological examination
to ensure a homogenous cell population of tissues. Use of human samples was approved by the institutional review board of the University of Hong Kong/Hospital Authority Hong Kong West Cluster. HCC cell lines including HepG2, Hep3B, PLC/PRF/5, HLE, Huh7, BEL7402, and SMMC7721 and an immortalized normal liver cell line LO2 were maintained in Dulbecco’s modified Eagle minimal essential medium medchemexpress (DMEM) high glucose (GIBCO-BRL, Grand Island, NY), supplemented with 10% fetal bovine serum (FBS). The other two HCC cell lines, SNU182 and SNU449, were grown in RPMI-1640 medium (GIBCO-BRL), supplemented with 1 mM of sodium pyruvate and 10% FBS. The other immortalized healthy liver cell line (MIHA) was maintained in DMEM high glucose, supplemented with 10% FBS and 1 mM of sodium pyruvate. Full-length HBx DNA (ayw subtype; GenBank no.: U95551) was amplified from the HBx/pcDNA3.1+ plasmid10 and subcloned into Myc/pLVX-Tight Puro and Myc/pcDNA3.1+ vectors. HBx truncation mutant (named HBxΔC1) with 24 aa of HBx was made and subcloned into Myc/pLVX-Tight Puro and Myc/pcDNA3.1+ vectors. In addition, wild-type (WT; −1,077 to +1) MMP10 promoter was amplified from healthy human liver DNA.