Oct-4 expression maintained stem cell properties in prostate cancer-derived CD133^+MDR1^+ cells

Purpose: CD133 (prominin-1), a 5-transmembrane glycoprotein, has recently been considered an important marker that represents the subset population of cancer stem-like cells. The purpose of the present study is to isolate cancerous stem-like cells from normal healthy volunteers and prostate cancer patients (CD133^+) which also express MDR1 and to ascertain the influence of Oct-4 on ‘stem-ness’ and differentiation of these CD133^+ cells towards epithelium. Methods: CD133^+ cells were isolated using magnetic beads from normal healthy volunteers and prostate cancer patients (NV-CD133^+and PC-CD133^+). The isolated cells were analyzed using flow cytometry and Western blot technique for CD133, MDR1 and Oct-4. CD133^+MDR1^+ cells were cultured in presence and absence of antihuman Oct-4 blocking antibody. Results: PC-CD133^+ cells displayed higher Oct-4 expression with the ability to self-renew and may represent a reservoir with differentiation potential for generating prostate cancer cells. Furthermore, PCCD133^+ cells highly co-expressed the multiple drug-resistant marker MDR1. The treatment with Oct-4 blocking antibody can specifically block the capability of PC-CD133^+ cells to differentiate into prostate epithelial cells bearing CD57. Conclusion: PC-CD133^+ cells displayed a higher Oct-4 expression with the ability to self-renew andmay represent a reservoir with differentiation potentials for progression of prostate cancer. The MDR1 expression of PC-CD133^+ cells in vitro and in vivo is partially due to preferential activation of Oct-4 geneexpression.