Cell proliferation assay

DPCs were plated into 24-well plates and grown overnight to form a confluent monolayer. Cells were then transduced with adenoviral vectors expressing TCF4 and MAD2B, individually or in combination, and siMAD2B was co-transfected with the TCF4-expressing vector. After 48 h of incubation, the transfected cells were harvested and plated in a 96-well plate at a density of 2 × 10³ cells per well. After cell attachment, 10 µL of Cell Counting Kit-8 (CCK-8) solution (Dojindo Molecular Technologies, Kumamoto, Japan) was added into each well, followed by dark incubation for 1.5 h. The absorbance [optical density (OD)] was determined at a test wavelength of 450 nm against a reference wavelength of 620 nm using a Varioskan Flash microplate reader (Thermo Fisher Scientific, Waltham, MA, USA). The cell viability (%) was calculated as (1 − OD_treated/OD_control) × 100%.