Dorsomorphin (#1219188-18-9), KU55933 (#587871-26-9), mitoxantrone (#70476-82-3), doxorubicin (#A603456-0025), cisplatin (#AA1A8019B), rhodamine 123 (#62669-70-9), and 3-(4,5-dimethylthiazol-yl)-2,5diphenyl-tetrazolium bromide (MTT; #298-93-1) were procured from MREDA Technology Inc. (Beijing, China), TargetMol Chemicals Inc. (Shanghai, China), D&B Biotech Inc. (Shanghai, China), Sangon Biotech Inc. (Shanghai, China), Qilu Pharmaceutical Co. (Jinan, China), Sigma-Aldrich Trading Co. (Shanghai, China), and Yuanye Biotech Co. (Shanghai, China), respectively. Anti-ABCG2 antibody (#RLT0053) and anti-β-actin antibody (#SC-47778) were purchased from Ruiying Biotech (Wuxi, China) and Santa Cruz Biotech (Santa Cruz, California, United States), respectively. Human colorectal cancer cells S1-M1-80 vector with ABCG2 overexpression and S1-M1-80 sgABCG2 with ABCG2-knockout were established as reported previously (Liu et al., 2021) and cultured in Dulbecco's modified Eagle's medium (#C11995500BT) with 10% fetal bovine serum (#10270-106) from Thermo Fisher Scientific Inc. (Waltham, Massachusetts, United States) at 37°C in a humid atmosphere of 5% CO 2 .