LAUSR

Background C-KIT is a receptor tyrosine kinase with oncogenic properties overexpressed in PCa cases. Through the use of an alternative promoter, a truncated c-KIT protein (tr-KIT) of 30-50 kDa is generated, lacking the extracellular and transmembrane domain. Tr-KIT promotes the formation of a multi-molecular complex composed by Fyn, Plcγ1 and Sam68. Imatinib blocks the activity of full-length c-KIT but has no effect on tr-KIT. LNCaP is the human PCa cell line that shows tr-KIT overexpression and PC3 does not show tr-KIT overexpression. miR-128/193a-5p/494 are miRNAs targeting FYN, PLCγ1 and SAM68 combinatorily. The question of the study is that: can miR-128/193a-5p/494 be related with imatinib resistance in PCa? Method LNCaP and PC3 cells were treated with imatinib in IC50 doses. Before and after imatinib administration, RNA was isolated and cDNA conversion was performed. By qPCR analysis, expression changes of tr-KIT specific pathway elements and miR-128/193a-5p/494 analyzed before and after imatinib administration. Results After imatinib administration, miR-128/193a-5p/494 were overexpressed statistically significantly in LNCaP cells while they were downregulated statistically significantly in PC3 cells (p<0.05). Also, FYN was upregulated in LNCaP cells (p<0.05) but there was no change in PC3 after imatinib administration. Conclusion Especially upregulation of FYN may sponge miR128/193a-5p/494 and downregulate their transcriptional activity in LNCaP cells having tr-KIT acitivity. So, miR-128/193a-5p/494 may have critical role in imatinib resistance via tr-KIT pathway.