Figure 2. Id2 increases the proliferation of CA9-22 cells via NF-κB.

A, ³H-thymidine incorporation increased in a time-dependent manner and was significantly different in Id2- and empty vector-transfected cells (*, P < 0.05). B, cell number increased in a time-dependent manner and was significantly different in Id2- and empty vector-transfected cells (*, P < 0.05). C, proliferating cell nuclear antigen (PCNA) expression was increased in Id2-transfected cells (Id2) compared with enpty vector-transfected cells (Ctrl). D, inhibition of NF-κB activity with IκBα M abrogated cellular DNA synthesis induced by Id2 (*, P < 0.05,). E, qPCR confirmed that the level of the Id2 mRNA transcripts in Id2 cDNA-transfected cells (Id2) was higher than that in empty vector-transfected cells (vec). Ctrl, control; vec, empty vector; med, medium; IκB, IκBα M.