Fig. 4.

Downregulation of SIRT5 by miR-1322/miR-1972/miR-324-3p through targeting its 3′-UTRs. a The possible target genes of miR-1322, miR-1972 and miR-324-3p were predicted by Targetscan and transcriptome sequencing; the mRNA level of SIRT5 from GEO dataset GSE80344 in gefitinib-resistance cells and their sensitive cells was shown. b Potential binding sites of miR-1322, miR-1972 and miR-324-3p in SIRT5 3′-UTR. c Luciferase reporter assay using miRNA mimics was applied to verify the interaction between SIRT5 3′-UTR and miR-1322, miR-1972 or miR-324-3p. d-e The expression of SIRT5in the parental cells and their icotinib-resistant cells (PC9, PC9/IcoRL and PC9/IcoRH) was detected by qRT-PCR (d) and western blot (e). f-g The SIRT5 expression in PC9/IcoRL and PC9/IcoRH cells with the transfection of miRNAs mimics or inhibitor was detected by qRT-PCR (f) and western blot (g). The mean ± SD of triplicate experiments were plotted, *P < 0.05, **P < 0.01, ***P < 0.001