miR-221 Augments TRAIL-Mediated Apoptosis in Prostate Cancer Cells by Inducing Endogenous TRAIL Expression and Targeting the Functional Repressors SOCS3 and PIK3R1

Figure 4

Effects of siRNA-mediated downregulation of SOCS3 and PIK3R1 on TRAIL sensitivity of PC3 cells. (a, b) Downregulation of SOCS3 (a) and PIK3R1 (b) sensitises PC3 cells towards TRAIL-mediated proliferation inhibition. Results shown for PC3 cells 120 h p. t. (a, b) Relative cell viability was normalised to the viability of control cells, which was arbitrarily set as 100%. (c) qRT-PCR results confirmed a significant downregulation of SOCS3 as well as PIK3R1 after siRNA transfection in PC3 cells (48 h p. t.). (a, b, c): Data represent mean + SD from five independent experiments (**). (a, b) ANOVA with Bonferroni post hoc testing. (d) Western blotting experiments for PC3 cells showing PIK3R1, Akt, p-Akt and ERK2 protein expression depending on siPIK3R1, pre-miR-221 and control transfections (48 h p. t.). (e) Western blotting experiments in PC3 and DU145 cells showing the expression of Akt, p-Akt, STAT3, p-STAT3 and ERK2 in siCtr- and siSOCS3-transfected cells (48 h p. t.). (a, b, c, d, e) Control cells (Ctr or siCtr) were transfected with scrambled, nontargeting pre-miRNA (pre-miR-Ctr) or siRNA-Ctr (siCtr), respectively.

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