Study On The Regulation Of KIT And Downstream Signaling By Farnesyltransferase Inhibitors

Objective To explore the regulation of farnesyltransferase inhibitors on KIT and its downstream signaling in GISTs.Methods Ba/F3 cells expressing wild-type KIT,often happened primary KIT mutations W557K558 del and V560 D in GISTs,and Imatinib resistant secondary KIT mutations W557K558del/V654 A and W557K558del/N822 K were used as study models.Ba/F3 cells expressing wild-type KIT or KIT mutants were treated with farnesyltransferase inhibitors Tipifarnib or Lonafarnib,the activation of KIT and its downstream signaling pathways were detected by Western blot and immunoprecipitation,KIT mediated cell proliferation was detected by CCK8 assay,cell apoptosis and cell cycle were detected by flow cytometry.In addition,both farnesyltransferase inhibitors were used together with KIT inhibitor Imatinib to treat Ba/F3 cells,and KIT mediated cell proliferation,cell survival and cell cycle were detected by CCK8 assay and flow cytometry respectively.Results Farnesyltransferase inhibitors can inhibit ERK activation mediated by primary KIT mutants and secondary KIT mutants in GISTs.Farnesyltransferase inhibitors can inhibit cell survival,cell proliferation and cell cycle progression mediated by wild-type KIT,primary mutant KIT and secondary mutant KIT.The combination use of farnesyltransferase inhibitors and KIT inhibitor Imatinib resulted in stronger inhibition of wild-type KIT and mutant KIT mediated cell proliferation and survival.Conclusion Farnesyltransferase inhibitors can inhibit ERK activation mediated by KIT mutants in GISTs and enhance Imatinib mediated inhibition of cell survival and proliferation mediated by both wild-type KIT and KIT mutants.