Bmi1 is overexpressed in pancreatic cancer stem cells and regulates their self-renewal.

<p><b>A.</b> CD44⁺/CD24⁺/ESA⁺ cells were isolated using flow cytometry from pancreatic cancer tissues as described previously <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0055820#pone.0055820-Li2" target="_blank">[34]</a>. Total RNA was isolated and mRNA was quantitated by q- RT-PCR in normal pancreas, bulk CD44^–/CD24^–/ESA- pancreatic cancer cells and CD44⁺/CD24⁺/ESA⁺ pancreatic cancer cells. Data are expressed as the mean ± SEM (* p<0.05, n = 3 independent experiments, each performed in triplicate). <b>B.</b> Immunofluorescent staining of Bmi1 in tumorspheres formed from CD44⁺/CD24⁺/ESA⁺ cells. <b>C.</b> Silencing Bmi1 inhibits the ability of CD44⁺/CD24⁺/ESA⁺ cells to form spheres with serial passaging. Data are expressed as the mean ± SEM (* p<0.05, n = 3 independent experiments, each performed in triplicate).