FIGURE 4.

Involvement of CD44 in the TGFβ1-driven proliferative response in HAS2-overexpressed oral fibroblasts. Oral mucosal fibroblasts were co-transfected with pCR3.1 and either CD44 siRNA or scrambled siRNA (mock-transfected). Alternatively, oral fibroblasts were co-transfected with HAS2-pCR3.1 and either CD44 siRNA or scrambled siRNA (HAS2-transfected). The cells were then incubated in serum-free medium for 24 h. They were subsequently incubated with either 10 ng/ml TGFβ1 or unstimulated medium (control) for a further 24 h. Analyses were then performed to confirm up-regulation of HAS2 expression (A), confirm down-regulation of CD44 expression (B), and assess the effect of HAS2 overexpression and CD44 down-regulation on TGF-β1-driven proliferation (C). mRNA expression of HAS2 and CD44 was assessed using RT-QPCR. A [³H]thymidine assay was used to assess proliferation (as described under “Experimental Procedures”). In A and B, the results are expressed as means ± S.E. (error bars) and represent the results for three experiments. In C, the results are expressed as the median ± IQR of three experiments. For each box plot, median values are represented by the line within the box. The box represents 50% of the values (the 25th and 75th percentiles), with the bars presenting the highest and lowest values. Statistical analysis was performed using the Friedman test, followed by the Wilcoxon signed-rank test, and statistical significance was taken as p < 0.05.