Multicellular-mediated expression of P-GP and MRP and relationship with cell cycle profiles in human ovarian cancer SK-OV-3ip1 multicellular aggregates

Abstract

Objective: To investigate the expression of P-glycoprotein (P-gp) and multidrug resistance-associated protein (MRP) and the relationship with cell cycle profiles in ovarian cancer SK-OV-3ip1 multicellular aggregates. Methods: Liquid overlay system was employed to obtain multicellular aggregates. Expression of P-gp and MRP was detected with flow cytometry (FCM). Outer, intermediate and inner cells from multicellular aggregates were collected by layer-trypsinized method. Cell cycle profiles were also analyzed by FCM. Results: Compared with control cells, no expression of P-gp and MRP was detected in monolyer cells (P=0.128 and P=0.604), but expression of P-gp and MRP in aggregate cells was significantly elevated (P<0.01). P-gp expression in every layer cells was also obviously increased (P<0.01). Furthermore, P-gp expression in every layer cells was also obviously increased (P=0.071). Tendency to increased G0–G1 phase and reduced S phase cells existed from outer through intermediate to inner layers in multicellular aggregates but with no statistical difference. Cell percentages in G2-M phase also had no difference. However, compared with monolayer cells, cells in G0–G1 phase increased and cells in S and G2-M phases lowered significantly in every layer and in the whole multicellular aggregates. Expression elevation of P-gp and MRP was consistent with increased G0–G1 percentage in aggregate cells. Conclusion: Expression of P-gp and MRP increases in cells of SK-OV-3ip1 multicellular aggregates and is consistent with increased G0–G1 percentage, which implies the possible relationship between them and the possible role in multicellular-mediated drug resistance.