Evaluation of P-glycoprotein activity.

<p>To measure P-gp activity the substrate Rhodamine 123 was used as substrate. <i>LMW-PTP</i> was silenced and after 24 h cells were further incubated for 1 h in the presence of 200 ng/mL Rhodamine 123 with or without a P-gp inhibitor (5 µM verapamil). Afterwards, cells were washed with PBS and Rhodamine 123 mean fluorescence intensity was assessed by flow cytometry analysis within the live-gate, using a FACScalibur (Becton and Dickinson, USA). Decreasing of mean fluorescence intensity indicates higher P-gp activity.