Antitumor effects and mechanisms of AZD4547 on FGFR2-deregulated endometrial cancer cells

Uncontrolled activation of FGFRs induces the progression of various cancers. It was recently reported that FGFR2-activating mutants are implicated in about 12% of endometrial carcinomas. AZD4547, a potent pan-FGFR inhibitor, is currently being evaluated in clinical trials for several FGFR-driven cancers. However, AZD4547 has not been examined yet against FGFR2 mutant-driven endometrial cancers. Thus, we evaluated the activity of AZD4547 against four different endometrial cancer cells, including AN3-CA, MFE296, MFE280, and HEC1A, where all but HEC1A cells express distinctive FGFR2 mutations. We found that AZD4547 exhibits potent antiproliferative activity (EC₅₀ = 31 nmol/L) against AN3-CA cells harboring FGFR2-K310R/N550K mutant. Analysis using a phospho-kinase array revealed that AZD4547 blocks FGFR2 downstream signaling, such as p38, ERK1/2, JNK, p70S6K, and PLCγ. Moreover, oral administration of AZD4547 (30 mg/kg, every day) remarkably delayed tumor growth in a mouse xenograft model of AN3-CA cells. Unbiased reporter gene assay showed that AZD4547 antagonizes the aFGFinduced activation of several transcription factors, including EGR1, ELK-1/SRF, AP-1, and NFκB. Genome-wide transcriptome analysis revealed that AZD4547 perturbs a number of transcriptions, and EGR1 was identified as one of the major targets of AZD4547. The significance of the FGFR2-EGR1 axis in endometrial cancer progression has not been reported. In addition, using kinome-wide inhibition profiling analysis, we first identified potential new target kinases of AZD4547, including MAP4K3, MAP4K5, IRR, RET, and FLT3. Our study demonstrated that AZD4547 exhibits its therapeutic activity against endometrial cancer cells by perturbing various regulatory mechanisms related to FGFR signaling.