HOX gene expression in UC cells and cell type dependent effects of HOTAIR modulation. (a, b) mRNA expression of HOTAIR, posterior HOXC and HOXD genes was determined in UC cell lines and six different cultures of normal proliferating uroepithelial cell cultures (UEC; average expression level illustrated) by qRT-PCR and normalized to TBP. Expression levels are shown relative to the mammary cancer cell line MCF7, which was used as a control and set as 1. Expression values exceeding the scale are given as numerical values. To show the activity of HOX loci in the MCF7 cell line, expression levels of HOXC and HOXD genes are also illustrated separately for this cell line. Relative expression of HOTAIR (grey column) and HOXD10 (black column) was determined by qRT-PCR after siRNA-mediated knockdown of HOTAIR in three different bladder cancer cell lines (c) or following overexpression of HOTAIR in stable clones from VM-CUB1 and 5637 cell lines (d). Expression of HOXD10 in VM-CUB1 remained at background levels despite HOTAIR overexpression and is not illustrated.