The role of STK39 in gemcitabine resistance and the potential regulation of Mir-26a on STK39
(A) Human CCA cell lines were treated with gemcitabine, and the protein expression of STK39 was assessed by qRT-PCR and Western blotting.
(B) The effect of STK39 knockdown/overexpression on gemcitabine resistance.
(C) The prediction of STK39 upstream regulators was performed using TargetScan, PITA, PicTar, miRmap, miRanda, and micro-algorithms.
(D) qRT-PCR was performed to assess the expression level of miR-26a-5p in 30 paired CCA tissues (randomly selected from the previous 62 patients).
(E) Spearman correlation analysis was conducted to confirm the correlations between the STK39 mRNA and miR-26b-5p expression levels in the 30 CCA samples (r = −0.464, p< 0.01).
(F) The predicted miR-26b-5p targeting sequence in the STK39 3ʹUTR (WT STK39 3ʹUTR). The sequences of the STK39 3ʹUTR were mutated (MUT STK39 3ʹUTR).
(G) Dual-luciferase reporter assay of the cells transfected with WT STK39 3ʹUTR or MUT STK39 3ʹUTR together with 40 nM of the miR-26b-5p mimic or negative control oligoribonucleotides. Data were shown as mean ± SEM.