Cell counting kit-8 (CCK-8) assay

The oncogenic roles of PTPRB knockdown on the viabilities of C33A and CASKI cells were determined using CCK-8 (CP002, SAB, Nanjing, China). In short, after RPMI-1640 medium supplemented with DNR, C33A and CASKI cells (1 × 10⁴) were cultured in the above medium. Subsequently, to each well, the CCK-8 solution (10 μl) was added, followed by incubation for 2 h. Finally, the absorbance was examined in each individual well at 450 nm, followed by the statistics of the growth curve with the collected data.