DOXORUBICIN MODULATES P-GLYCOPROTEIN TRANSCRIPTION DIFFERENTLY DURING CACO-2 DIFFERENTIATION

Abstract

P-glycoprotein (P-gp) is an efflux transporter protecting cells from various chemical threats. Up-regulation of P-gp expression, mediated by reactive oxygen species (ROS), has been reported in doxorubicin-treated cells. However, during cell differentiation cellular redox status may vary. This study investigated the influence of cell differentiation on doxorubicin-mediated P-gp expression in Caco-2 cells, and its relation to cellular redox status. During 21-day culture, Caco-2 cells were divided into pre-, during-, and post-differentiation, based on total cell numbers, percentage of G0/G1 cells, and alkaline phosphatase activity. Our study demonstrated that Caco-2 cells were in a more reduced state upon differentiation. At low concentrations (< 5-10 µM), doxorubicin increased ABCB1 mRNA levels in all differentiation states. The inductive effect vanished upon increasing doxorubicin concentrations to 50-100 µM. Moreover, N-acetylcysteine inhibited doxorubicin-mediated up-regulation of ABCB1 mRNA in the pre-differentiated and differentiating cells, but not in the post-differentiated cells. Our findings suggested that Caco-2 differentiation states affect doxorubicin-mediated ABCB1 transcription and intracellular ROS level. Cellular redox status may contribute to the ABCB1 transcription via ROS-dependent mechanisms in the pre- and during-differentiation phases, but not in the post-differentiation phase. Furthermore, the differentiation status should be concern for P-gp induction study in Caco-2 cell model.

:TJPS-2020-0072.R1