HKI-272 contributes to gemcitabine-mediated anti-proliferative and anti-metastatic effects through EGFR suppression in gallbladder cancer

Gallbladder cancer (GBC) is a rare malignancy of the biliary system and characterized by early metastasis and poor prognosis. To date, no efficient treatment is available for GBC patients. Based on the data from cBioPortal, TIMER, and GDSC, we performed an unbiased screening with 25 candidate compounds that predominantly target ErbB family and identified HKI-272, a highly selective EGFR/ErbB2 inhibitor, dis-played decreased IC50 values in three GBC cell lines. HKI-272 not only promoted gemcitabine-mediated anti-proliferative and pro-apoptotic effects and induced cell cycle arrest in GBC, but also enhanced gemcitabine-induced suppressive ef-fects of GBC cell migration and invasion by inhibiting path-ways downstream of EGFR. Furthermore, HKI-272, together with gemcitabine, effectively suppressed tumor growth and me-tastases in mouse models. Immunostaining and HE staining data from both primary tumor and lung metastasis indicated that the anti-proliferative and anti-metastatic effects were mediated through EGFR suppression. Moreover, the expres-sion of EGFR, measured by both immunostaining and HE staining, was correlated with a poor prognosis in GBC. In addi-tion, EGFR in tumor tissues are independent indicators for overall survival in GBC patients. Taken together, our findings suggest that HKI-272 could be a potential therapeutic agent and EGFR might serve as a potential biomarker for patients with GBC.