FIGURE 7.

IFNγ down-regulates CcnA2 and Cdk2 mRNA in HSC-2 cells. A, HSC-2 or Ca9–22 cells were either left untreated or were treated with IFNγ (10 ng/ml) for the indicated time periods before preparation of total RNA and analysis of specific mRNA levels by northern hybridization. A sample (10 μg) of each total RNA was analyzed in each lane. B, Northern blots were quantified by phosphorimaging analysis, and relative mRNA levels for CcnA2 or Cdk2 are presented as a percentage of the expression in untreated cells cultured for 12 h. The data shown represent the means ± S.E. of three independent experiments. Asterisks denote a statistically significant difference compared with the untreated cultures (*, p < 0.05; **, p < 0.01, Student's t test). C, qRT-PCR analysis of c-myc mRNA expression in HSC-2 and Ca9–22 cells treated with IFNγ. Total RNA was prepared as described above and was used for qRT-PCR analysis of c-myc mRNA. The levels of c-myc mRNA are expressed as the percentage of the levels obtained at day 0 and were normalized to those of the 18 S rRNA used as an internal control. The data shown represent means ± S.E. of three independent experiments. UT, untreated.