FIGURE 6.

CcnA2 and Cdk2 are required for the growth of HSC-2 and Ca9–22 cells. Cells were transfected with siRNA as described under “Experimental Procedures.” siRNA-green fluorescent protein (GFP) was used as a negative control. After 48 h of transfection, total cellular lysates were prepared and subjected to electrophoresis followed by Western blotting with the indicated antibodies (A and C). The cells transfected with siRNA were re-seeded at a density of 2 × 10³ cells in 96-well plates and cultured for the indicated times (B and D). Cell proliferation was determined using a cell counting kit, as described under “Experimental Procedures.” The data shown are the means ± S.E. of quadruplicate determinations from a representative experiment that was repeated three times with similar results. Asterisks denote a statistically significant difference compared with cultures with siRNA-green fluorescent protein (*, p < 0.05; **, p < 0.01, Student's t test). UT, untreated.