Figure 3. Mechanism dissection of how HOTAIR activates STAT3 signaling. (A) qPCR assay showed that IL-10 mRNA was consistently increased by HOTAIR in both C4-2 and Du145 cells. Gene expression was normalized to GAPDH mRNA. (B) Online software prediction displayed that HOTAIR and IL-10 were the potential targets of miR-590-5p. (C) top, interacting model of miR-590-5p, IL-10 mRNA and Ago2 complex. Bottom, Ago2 immunoprecipitation showed that less IL-10 mRNA was associated with Ago2 complex when HOTAIR was overexpressed. (D) miR-590-5p could impair HOTAIR induced IL-10 mRNA levels in C4-2 and Du145 cells. Gene expression was normalized to GAPDH mRNA. (E, F) miR-590-5p could rescue HOTAIR induced PCSLCs population in both C4-2 (E) and Du145 cells (F). Left, representative images of tumorspheres. Right, statistical analysis. (G) miR-590-5p could block HOTAIR induced STAT3 activity. GAPDH was loading control. *p<0.05; **p<0.01.