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An FGFR3 Autocrine Loop Sustains Acquired Resistance to Trastuzumab in Gastric Cancer Patients

2016; American Association for Cancer Research; Volume: 22; Issue: 24 Linguagem: Inglês

10.1158/1078-0432.ccr-16-0178

1557-3265

Geny Piro, Carmine Carbone, Ivana Cataldo, Federica Di Nicolantonio, Simone Giacopuzzi, Giuseppe Aprile, Francesca Simionato, Federico Boschi, Marco Zanotto, Maria Mihaela Mina, Raffaela Santoro, Valeria Merz, Andrea Sbarbati, Giovanni De Manzoni, Aldo Scarpa, Giampaolo Tortora, Davide Melisi,

Gastric Cancer Management and Outcomes

The majority of gastric cancer patients who achieve an initial response to trastuzumab-based regimens develop resistance within 1 year of treatment. This study was aimed at identifying the molecular mechanisms responsible for resistance.A HER2+-trastuzumab sensitive NCI-N87 gastric cancer orthotopic nude mouse model was treated with trastuzumab until resistance emerged. Differentially expressed transcripts between trastuzumab-resistant and sensitive gastric cancer cell lines were annotated for functional interrelatedness by Ingenuity Pathway Analysis software. Immunohistochemical analyses were performed in pretreatment versus posttreatment biopsies from gastric cancer patients receiving trastuzumab-based treatments. All statistical tests were two-sided.Four NCI-N87 trastuzumab-resistant (N87-TR) cell lines were established. Microarray analysis showed HER2 downregulation, induction of epithelial-to-mesenchymal transition, and indicated fibroblast growth factor receptor 3 (FGFR3) as one of the top upregulated genes in N87-TR cell lines. In vitro, N87-TR cell lines demonstrated a higher sensitivity than did trastuzumab-sensitive parental cells to the FGFR3 inhibitor dovitinib, which reduced expression of pAKT, ZEB1, and cell migration. Oral dovitinib significantly (P = 0.0006) reduced tumor burden and prolonged mice survival duration in N87-TR mouse models. A higher expression of FGFR3, phosphorylated AKT, and ZEB1 were observed in biopsies from patients progressing under trastuzumab-based therapies if compared with matched pretreatment biopsies.This study identified the FGFR3/AKT axis as an escape pathway responsible for trastuzumab resistance in gastric cancer, thus indicating the inhibition of FGFR3 as a potential strategy to modulate this resistance. Clin Cancer Res; 22(24); 6164-75. ©2016 AACR.