Comprehensive functional evaluation of variants of fibroblast growth factor receptor genes in cancer

Ikuko Takeda Nakamura,Hiroyuki Mano,Michael J Eck,Kunhua Li,Masachika Ikegami,Tyler S Beyett,Toshio Shimizu,Hiroshi Ikeuchi,Shinji Kohsaka,Takafumi Koyama,Kazuhisa Takahashi,Noboru Yamamoto,Toshihide Ueno,Fumiyuki Takahashi

doi:10.1038/s41698-021-00204-0

Abstract

Various genetic alterations of the fibroblast growth factor receptor (FGFR) family have been detected across a wide range of cancers. However, inhibition of FGFR signaling by kinase inhibitors demonstrated limited clinical effectiveness. Herein, we evaluated the transforming activity and sensitivity of 160 nonsynonymous FGFR mutations and ten fusion genes to seven FGFR tyrosine kinase inhibitors (TKI) using the mixed-all-nominated-in-one (MANO) method, a high-throughput functional assay. The oncogenicity of 71 mutants was newly discovered in this study. The FGFR TKIs showed anti-proliferative activities against the wild-type FGFRs and their fusions, while several hotspot mutants were relatively resistant to those TKIs. The drug sensitivities assessed with the MANO method were well concordant with those evaluated using in vitro and in vivo assays. Comprehensive analysis of published FGFR structures revealed a possible mechanism through which oncogenic FGFR mutations reduce sensitivity to TKIs. It was further revealed that recurrent compound mutations within FGFRs affect the transforming potential and TKI-sensitivity of corresponding kinases. In conclusion, our study suggests the importance of selecting suitable inhibitors against individual FGFR variants. Moreover, it reveals the necessity to develop next-generation FGFR inhibitors, which are effective against all oncogenic FGFR variants.

Highlights

The fibroblast growth factor receptors (FGFR) family consists of four highly conserved transmembrane receptor tyrosine kinase genes (FGFR1–4)
The FGFR2 S252W mutation located between IgII and IgIII, known as the ligand-biding region, was reported to be a hotspot in endometrial cancers
We evaluated 170 FGFR variants including gene fusions; this is the most comprehensive analysis of FGFR mutants

Summary

Introduction

The fibroblast growth factor receptors (FGFR) family consists of four highly conserved transmembrane receptor tyrosine kinase genes (FGFR1–4). Activation of FGFR by fibroblast growth factors (FGFs) regulates survival and proliferative signaling pathways, in addition to metabolic homeostasis, endocrine functions, and wound repair[1,2]. Genomic alterations of FGFRs, including gene amplification, activating mutations, and fusions play a crucial role in oncogenesis, tumor progression, and resistance to therapy with kinase inhibitors across a wide range of cancers[2,5,6]. Gene amplification of FGFR1 occurs in approximately 10% and 10–25% of breast cancer and squamous-cell lung cancer cases, respectively, and is associated with a poor prognosis[7,8,9,10,11,12]. FGFR2 gene amplification has been observed in 4–10% of gastric cancer cases and is related to a poor prognosis[13]. FGFR3 gene amplification is not frequently reported, it is often observed with oncogenic mutations.[6,14,15]

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Conclusion