Knock-Down of the POLR2A Gene Inhibits Cell Growth in JMN Cells.

<p>(A) Immunostaining of POLR2A in tumors from malignant mesothelioma patients. Scale bar, 20 µm. (B) Immunostaining of POLR2A in tumors from NOG mice inoculated with MSTO/CD26 cells. Scale bar, 20 µm. (C) Immunoblot analysis of POLR2A in JMN cells transfected with a non-specific (NS) control siRNA or POLR2A siRNA (oligo 1 or oligo 2). β-actin was used as a loading control. KD, knock-down. (D) Numbers of viable JMN cells transfected with POLR2A siRNA (oligo 1 or oligo 2) for 48 hours, relative into the numbers of viable cells transfected with NS control siRNA, were measured using the water soluble, 2-(2-methoxy-4-nitrophenyl)-3-(4-nitrophenyl)-5-(2,4-disulfophenyl)-2H-tetrazolium (WST)-8 assay. Data are means ± SD from three independent experiments. *P<0.004. (E) Model for POLR2A suppression by YS110-induced nuclear CD26. Cell surface CD26 is translocated to the nucleus in response to YS110 treatment, and binds to genomic DNA associated with the POLR2A gene. This results in transcriptional suppression of POLR2A and consequent inhibition of cell growth.