In-Silico Analysis of FGFR3b Arg248Cys and FGFR4 Gly388Arg Mutations in Bladder Cancer: Implications for Downstream Signaling Pathways

Abstract

Background: Fibroblast Growth Factor Receptors (FGFRs) are a hotspot for mutations, with FGFR-targeted therapies approved for bladder cancer, making mutation-specific signaling crucial to understand. Objective: To evaluate the impact of less prevalent FGFR3b R248C and FGFR4 G388R mutations on downstream adaptors via in-silico interaction dynamics. Methodology: Wildtype and mutant FGFR dimers were modeled with mutations introduced via DynaMut, then docked with FRS-adaptors using HADDOCK, and interactions analyzed with PDBSum. Results: FGFR3b R248C and FGFR4 G388R were found to be slightly stabilized, with FGFR3b exhibiting increased flexibility and stable fluctuations (0-0.5 Å), while FGFR4 remained rigid with minimal flexibility change (0-0.1 Å); both mutants displayed enhanced inter-atomic interactions. FGFR3b R248C-FRS2 complex exhibited a lower HADDOCK score (85.6±36.6 kcal/mol), an increased van der Waals energy (-136.4±10.8 kcal/mol), along with increased total interacting residues (291) compared to wildtype. R248C-FRS3 complex showed lower HADDOCK (-250.8±20.3 kcal/mol) and van der Waals (- 143.5±22.5 kcal/mol) scores, with increased total interacting residues (250) compared to wildtype. FGFR4 G388R-FRS2 complex exhibited a higher HADDOCK score (-187.9±7.8 vs. -232.7±3.4 kcal/mol) with negligible changes in van der Waals energies and an increase in total interacting residues (227 vs. 169) compared to wildtype. G388R-FRS3 complex also exhibited a higher HADDOCK (-211.2±1.5 vs. -273.4±2.8 kcal/mol) and van der Waals (-121.5±3.8 vs. -148.9±2.7 kcal/mol) scores, with fewer total interacting residues (188 vs. 220) compared to wildtype. Conclusion: FGFR3b R248C and FGFR4 G388R mutations were slightly stabilizing. FGFR3b R248C mutation showed an increased binding affinity with stronger interactions with both FRS2 and FRS3, while FGFR4 G388R exhibited decreased binding affinity for FRS2 and FRS3, with changes in interactions. Experimental validation is required to confirm the impact on downstream oncogenic pathways and therapeutics. Keywords: Cancer, Fibroblast Growth Factor Receptor 3, Fibroblast Growth Factor Receptor 4, Molecular Docking.