The Effect Study Of FGFR3 Mutations Ontargeted Tyrosine Kinase Inhibitor Sensitivity In Bladder Cancer

Objective: FGFR3 gene mutations are closely related to the occurrence and development of bladder cancer and can affect the sensitivity of targeted drug therapy.In this study,we first constructed bladder cancer cell lines and organoid models with FGFR3 mutations at different sites,and then detected their sensitivity differences to different tyrosine kinase inhibitors targeting FGFR3 gene mutations.Methods: Wild-type FGFR3,point-mutant FGFR3(S249C,R248 C and Y373C)and FGFR3-TACC3 fused gene plasmids were constructed and sequenced,and stablely transfect to upper urothelial cell line sv-huc-1 by lentiviral vectors.QRT-PCR and western blotting were used to verify transfection efficiency.Eight tyrosine kinase inhibitors were subsequently used to test for differences in drug sensitivity in these cells.The protein of the downstream pathway of FGFR3 was detected by western blot analysis in order to initially analyze the mechanism of sensitivity differences.Organoid models were constructed using bladder cancer patient tissues,different FGFR3 plasmids were integrated into organoids using lentiviral vectors,and q RT-PCR and western blot detection were used.The same tyrosine kinase inhibitors were used to test for differences in drug sensitivity in organoids.Results: 1.FGFR3 point mutation R248 C and FGFR3-TACC3 gene fusion increased by 5-10 flods compared with wild-type FGFR3 to half of tyrosine kinase inhibitors(P<0.05).The FGFR3 point mutation S249 C and Y373 C did not show significant differences in sensitivity.2.Successfully constructed tumor tissue-derived organoids in bladder cancer patients,and used lentivirus to construct bladder cancer organoids that successfully carried different FGFR3 mutations.Tyrosine kinase inhibitor test results show that the FGFR3 point mutation R248 C is more sensitive to all drugs,which can be 1-5 folds different from the wild type.The FGFR3-TACC3 fusion gene and FGFR3 point mutation Y373 C did not show significant changes in drug sensitivity.Conclusion: This study successfully constructed cell lines and organoids containing different FGFR3 mutations,further demonstrating that different FGFR3 mutations have different sensitivities to tyrosine kinase inhibitors,thus providing important ideas for solving clinical resistance in bladder cancer.