Targeting FGFRs by pemigatinib induces G1 phase cell cycle arrest, cellular stress and upregulation of tumor suppressor miRNAs

Abstract Background: Fibroblast growth factor receptor (FGFR) gene family alterations are found in several cancers, indicating their importance as potential therapeutic targets. The FGFR-tyrosine kinase inhibitor (TKI) pemigatinib (Pemazyre ® , INCB054828) has been introduced in the treatment plan for advanced cholangiocarcinoma and more recently for relapsed or refractory myeloid/lymphoid neoplasms with FGFR2 and FGFR1 rearrangements, respectively. Several clinical trials are currently investigating the possible combination of pemigatinib with immunotherapy to synergistically amplify the anti-tumor activity. Methods: NCI-H1581 lung cancer, KATO III gastric cancer and RT-112 bladder cancer cell lines were employed and FGFRs expression was evaluated by qRT-PCR and Western blot. Cell lines were treated with the FGFR1-3 inhibitor pemigatinib and then characterized for cell proliferation, apoptosis, production of intracellular reactive oxygen species (ROS), induction of senescence. Following pemigatinib treatment, the expression of microRNAs with tumor suppressor functions was analysed by qRT-PCR, while modulation of the proteins coded by their target genes was evaluated by Western blot. Results: Pemigatinib reduced the proliferative ability of all cancer cells, inducing G1 phase cell cycle arrest and strong intracellular stress resulting in ROS production, senescence and apoptosis. Pemigatinib treatment also caused the upregulation of microRNAs (miR-133b, miR-139, miR-186, miR-195) with tumor suppressor functions in the cancer models investigated, along with the downregulation of validated protein targets with oncogenic roles (c-Myc, c-Met, CDK6, EGFR), suggesting that pemigatinib antitumor activity is at least in part mediated by microRNA modulation. Descriptive statistics was used to analyze the various data and student’s t test to compare the analysis of two groups. Conclusions: These results contribute to clarifying the biological effects and molecular mechanisms mediated by the anti-FGFR TKI pemigatinib in distinct tumor settings and support its exploitation for combined therapies.