Synthesis And Evaluation Of A Novel Non-Small Cell Lung Cancer Mutant Egfr Targeting Tracer F-18-Bf3-Azd9291 Based On F-18-F-19 Isotope Exchange

1619 Objectives: The use of the tyrosine kinase inhibitor (TKI) of the epidermal growth factor receptor (EGFR) has become an important significance of treatment for advanced Non-Small Cell Lung Cancer (NSCLC). The third-generation EGFR-TKIs such as AZD9291has been approved by the FDA and widely used in clinical nowadays because of its high affinity for NSCLC patients both with EGFR sensitive mutation and the secondary resistant mutation.Therefore, it is crucial to identity the dominant population for AZD9291 targeted treatment.In this study, we design and synthesis a novel radiotracer18F-BF3-AZD9291 based on 18F-19F Isotope Exchangeand evaluated the targeting ability and specificity of this probe in vitro . Here, The introduction of zwitterionic organotrifluoroborate groups based on keeping the main structure of AZD9291 unchanged and the principle of isotope exchange, we successfully designedand developed a new tracer (((2-((2-acrylamido-5-methoxy-4-((4-(1-methyl-1H-indol- 3-yl)pyrimidin-2-yl)amino)phenyl)(methyl)amino)ethyl)dimethylammonio)methyl)difluoro(fluoro-18F)borate[18F-BF3-AZD9291]. We synthesized and labeled a new probe 18F-BF3-AZD9291 that targets the NSCLC double mutant EGFR. And we evaluated the targeting ability and specificity of the tracer in vitro. Methods: Synthesis: Precursor AZD9291 trifluoroborates compound BF3-AZD9291 was synthesized in multiple steps and one-step radiolabeled by K18F/Kryptofix, ACN, heating at 70℃for 15 mins in open system followed by cooling down and quenched with 1 ml of 1M tetrabutylammonium hydroxide. And the quenched solution was passed through Al cartridge and diluted with 10 ml of water before loading on C18 cartridge. The C18 cartridge was then rinsed with 10 ml of water and 1 ml of 40% ethanol/water. The product was eluted with 1 ml of ethanol. In vitro: Three NSCLC cell lines (HCC827, H1975, H520) were used in cell uptake and the MTT method. Results: The radio-yield of 18F-BF3-AZD9291 was 1.91±0.23% (no-decay correction, n=3) and the radio-chemical purity was 94.20±0.91% (n=3). The MTT results of precursor BF3-AZD9291 to NSCLC cells showed that the IC50 values of H1975 cells were significantly lower than the other two cell lines at 24 and 48 hours. The results of the uptake experiments of labeled probes on cells showed that H1975, a double-mutated NSCLC cell, had a significantly higher uptake of 18F-BF3-AZD9291 compared to the other two lung cancer cell lines, HCC827 and H520. The highest uptake percentage at two hours, up to 3.54±0.5%, while the HCC827 and H520 only 1.63±0.5%, 0.62±0.1%, which basically consistent with the MTT experiment results. Conclusions: Based on the principle of isotope exchange, we successfully designed and labeled a new probe 18F-BF3-AZD9291that targets the NSCLC double mutant EGFR in one step. Experiments in vitro demonstrated that the molecular probe 18F-BF3-AZD9291can bind to EGFR L858R/T790M mutations in non-small cell lung cancer. Further research on this probe is necessary, because of its potential possibility for the identification of NSCLC patients who may benefit from treatmentwith AZD9291 and hence for the improvement of prognosis and EGFR-TKI therapy efficacy. Research Support:[1] Zhibo Liu et al. Bioconjugate Chem. 2014, 25, 1951−1962. doi: 10.1021/bc5003357.[2] Zhibo Liu et al. Angew. Chem. Int. Ed. 2014, 53, 11876 -11880. doi: 10.1002/anie.201406258.[3] Cong Li et al. Nucl Med Biol. 2018,V64-65N:34-40. doi: 10.1016/j.nucmedbio.2018.06.007.