Objectives Patients with gallbladder carcinoma (GBC) lack effective treatment methods largely due to the inadequacy of both molecular characterisation and potential therapeutic targets. We previously uncovered a spectrum of genomic alterations and identified recurrent mutations in the ErbB pathway in GBC. Here, we aimed to study recurrent mutations of genes and pathways in a larger cohort of patients with GBC and investigate the potential mechanisms and clinical significance of these mutations.
Design We performed whole-exome sequencing (WES) in 157 patients with GBC. Functional experiments were applied in GBC cell lines to explore the oncogenic roles of ERBB2/ERBB3 hotspot mutations, their correlation with PD-L1 expression and the underlying mechanisms. ERBB inhibitors and a PD-L1 blocker were used to evaluate the anticancer activities in co-culture systems in vitro and in vivo.
Results WES identified ERBB2 and ERBB3 mutations at a frequency of 7%–8% in the expanded cohort, and patients with ERBB2/ERBB3 mutations exhibited poorer prognoses. A set of in vitro and in vivo experiments revealed increased proliferation/migration on ERBB2/ERBB3 mutation. Ectopic expression of ERBB2/ERBB3 mutants upregulated PD-L1 expression in GBC cells, effectively suppressed normal T-cell-mediated cytotoxicity in vitro through activation of the PI3K/Akt signalling pathway and contributed to the growth and progression of GBC in vivo. Treatment with an ERBB2/ERBB3 inhibitor or a PD-L1 monoclonal antibody reversed these immunosuppressive effects, and combined therapy revealed promising therapeutic activities.
Conclusions ERBB2/ERBB3 mutations may serve as useful biomarkers in identifying patients who are sensitive to ERBB2/ERBB3 inhibitors and PD-L1 monoclonal antibody treatment.
Trial registration number NCT02442414;Pre-results.
- gallbladder carcinoma
- whole-exome sequencing
- Programmed death-ligand 1(PD-L1)
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ML, FL, FZ, WZ and XJ contributed equally.
Contributors YBL, YL and HL conceived of the study. WZ, XJ, JZ, CL, HL, YL and YBL directed the study. ML, FL, FZ, HL, YL and YBL contributed to the project design. ML, FL, FZ, YY, KQ, YW, QM, TW and LB performed experiments. ML, FL, ZW and XS performed the bioinformatics data analysis. YZ, RY, YG, YL, YJ, HL, SX, YY, YZ, LJ, YuH and YaH contributed samples, data and comments on the manuscript. ML, FL, FZ, WL, SC, JG, JZ and WG analysed and interpreted data. XW, XS, YZ, RY and YG contributed reagents/materials/analysis tools. ML, FL and FZ wrote the manuscript.
Funding This study was supported by the National Natural Science Foundation of China (Nos. 81773043, 31620103910, 91440203, 81672404, 81502432 and 81502433), the Shanghai Key Laboratory of Biliary Tract Disease Research Foundation (No. 17DZ2260200), the Shanghai Sailing Program (No. 18YF1415100), the Shanghai Jiao Tong University Medical-engineering Cross Program (YG2014MS69), the development fund for Shanghai talents (No.201608) and the Shanghai Rising-Star Program (No. 15QA1403100).
Competing interests None declared.
Patient consent Obtained.
Ethics approval The study was approved by the ethics committees of the Xinhua Hospital, Zhongshan Hospital and Eastern Hepatobiliary Surgery Hospital.
Provenance and peer review Not commissioned; externally peer reviewed.
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