FGFR1 Oncogenic Activation Reveals an Alternative Cell of Origin of SCLC in Rb1/p53 Mice

Fibroblast growth factor receptor 1 (FGFR1) is frequently amplified in human small-cell lung cancer (SCLC), but its contribution to SCLC and other lung tumors has remained elusive. Here, we assess the tumorigenic capacity of constitutive-active FGFR1 (FGFR1K656E) with concomitant RB and P53 depletion in mouse lung. Our results reveal a context-dependent effect of FGFR1K656E: it impairs SCLC development from CGRPPOS neuroendocrine (NE) cells, which are considered the major cell of origin of SCLC, whereas it promotes SCLC and low-grade NE bronchial lesions from tracheobronchial-basal cells. Moreover, FGFR1K656E induces lung adenocarcinoma (LADC) from most lung cell compartments. However, its expression is not sustained in LADC originating from CGRPPOS cells. Therefore, cell context and tumor stage should be taken into account when considering FGFR1 inhibition as a therapeutic option. [Display omitted] •FGRF signaling impairs SCLC development initiated from CGRPPOS NE cells•FGRF signaling promotes development of NE tumors initiated from K14POS cells•Rb;p53;Fgfr1 mice develop ADCs that retain signatures of their cell of origin•Low expression of Fgfr1 in progressed tumors suggests a role in tumor initiation Ferone et al. show that inducing FGFR signaling in lung neuroendocrine (NE) cells of Rb;p53 mice results in impairment of SCLC and enhancement of peripheral NE lesions. The location and tumor characteristics depend on the targeted cell type. Rb;p53;Fgfr1 mice also develop adenocarcinomas with the incidence depending on the targeted cell type.