Background and Aims: Gallbladder cancer is a common malignant tumor in the biliary system. With difficult early diagnosis and poor prognosis. Studies have demonstrated that the abnormal expression of human epidermal growth factor receptor 2 (ErbB2) may probably play an important role in the occurrence and development of gallbladder cancer. Therefore, this study was conducted to investigate the effect of ErbB2 inhibitor pyrotinib on the general biological behaviors of gallbladder cancer cells in vitro, in order to provide a theoretical and experimental background for the relevant researches and clinical applications. 
Methods: The gallbladder cancer NOZ and SGC-996 cells were used as study models. The time and concentration effects pyrotinib exerted on the two types of cells were determined by CCK-8 assay. Based on the results of CCK-8 assay, the inhibitory concentration 25% (IC25), 50% (IC50) and 75% (IC75) of pyrotinib correspondingly for the two types of gallbladder cancer cells at an optimal treatment time were chosen for the following experiments. Then, the effects of pyrotinib on proliferation, migration and invasion abilities, apoptosis as well as the expressions of apoptosis-related proteins were examined by colony-forming assay, Transwell assay, cytometry analysis and Western blot analysis, respectively. 
Results: The IC50 values pyrotinib with the treatment time of 24, 48, and 72 h were 11.5, 3.6, 1.4 μmol/L for NOZ cells and 5.5, 5.2 and 2.4 μmol/L for SGC-996 cells, respectively. After exposure to corresponding IC25, IC50 and IC75 concentrations of pyrotinib of 48-h treatment (NOZ cells: 1, 3.5, 12 μmol/L; SGC-996 cells: 2.5, 5, 10 μmol/L), both types of gallbladder cancer cells showed significantly reduced number of colony-forming units, attenuated migration and invasion abilities, increased apoptotic rates, and up-regulated expressions of the pro-apoptotic proteins (Bax, cleavaged-caspase 9, cleavage-caspase 3 and cleavage-PARP) while down-regulated expressions of the anti-apoptotic proteins (Bcl-2 and Bcl-2/Bax ratio), and all above changes presented a significant concentration-dependent manner (all P<0.05).
Conclusion: Pyrotinib can inhibit the proliferation, migration and invasion of gallbladder carcinoma in vitro, and exert cell killing effect by promoting apoptosis. It provides a new choice of molecular targeted drug for the treatment of gallbladder cancer.