PRSS contributes to cetuximab resistance in colorectal cancer

Tan, Zhaoli; Gao, Lihua; Wang, Yan; Yin, Huihui; Xi, Yongyi; Wu, Xiaojie; Shao, Yong; Qiu, Weiyi; Du, Peng; Shen, Wenlong; Fu, Ling; Jia, Ru; Zhao, Chuanhua; Zhang, Yun; Zhao, Zhihu; Sun, Zhiwei; Chen, Hongxing; Hu, Xianwen; Xu, Jianming; Wang, Youliang

To determine cetuximab sensitivity, cells were seeded in 200 ml of medium (3000 to 5000 cells per well) in 96-well plastic culture plates. After serial dilutions, cetuximab in serum-free medium was added to the cells, and wells containing only medium were used as controls. Cells were treated with cetuximab (0, 0.01, 0.1, 1, 5, 10, 20, 50, or 100 g/ml), and the plates were incubated at 37°C in 5% CO 2 for 72 hours. Then, cell viability was assessed by Cell Counting Kit-8 (CCK-8). Viable cells were detected 72 hours after treatment using CCK-8 by measuring the absorbance at 450 nm. The relative rate of cell growth for each cell line was factored into the analysis by subtracting the absorbance at time 0 from the values of the control and treatment groups. All experiments were replicated a minimum of three times.