FIGURE 4.

RB1CC1 repressed type II collagen expression in ATDC5 chondrocytes. A, ATDC5 cells were induced to chondrocytes for 96 h after the transduction of RB1CC1 cDNA (0–2 μg/well) or RNAi (40 pmol/well), and the lysates were analyzed by Western blotting with the indicated antibodies. RB1CC1 repressed type II collagen and phosphorylated Erk1/2 and enhanced phosphorylated NFκB (left half). RB1CC1 RNAi enhanced type II collagen and repressed a little phosphorylated NFκB (right half). B, RB1CC1 led to the suppression of type II collagen in the differentiated chondrocytes via multimodal signalings, such as Erk suppression and NFκB activation.