Gastrointestinal Hormone Cholecystokinin Increases P-Glycoprotein Membrane Localization and Transport Activity in Caco-2 Cells

Abstract

It was reported that stimulation of taste receptor type 2 member 38 by a bitter substance, phenylthiocarbamide (PTC), increased P-glycoprotein (P-gp) mRNA level and transport activity via release of the gastrointestinal hormone cholecystokinin-8 (CCK-8) at 9 h. Therefore, we hypothesized that CCK-8 and PTC might also regulate P-gp activity more rapidly via a different mechanism. As a result, we found that the pretreatment of human colon adenocarcinoma (Caco-2) cells with 10-mM PTC significantly decreased the intracellular accumulation of P-gp substrate rhodamine 123 (Rho123) compared with the control after 90-min incubation. Moreover, CCK-8 treatments significantly reduced the accumulation of Rho123 within 30 min, compared with the control. On the other hand, when Caco-2 cells were pretreated with PTC, the efflux ratio of Rho123 was significantly increased compared with control. The efflux ratio of Rho123 in CCK-8 treatment cells was also significantly increased compared with control. Furthermore, CCK-8 increased the phosphorylation of the scaffold proteins ezrin, radixin, and moesin, which regulate translocation of P-gp to the plasma membrane. Therefore, our results indicate that PTC induced release of CCK-8, which in turn induced the phosphorylation of ezrin, radixin, and moesin proteins, leading to upregulation of P-gp transport activity via increased membrane localization of P-gp.

Regulation of breast cancer resistance protein and P-glycoprotein by ezrin, radixin and moesin in lung, intestinal and renal cancer cell lines

“…Although we did not examine how each transporter was regulated, our prior research showed that P‐gp transport activity and membrane localization in mouse small intestine, Caco‐2 and human hepatoblastoma HepG2 cells both require Rdx . However, other researchers have found that not only Rdx, but also Ezr or Msn regulates P‐gp membrane localization in various tissues .…”

“…Although we did not examine how each transporter was regulated, our prior research showed that P-gp transport activity and membrane localization in mouse small intestine, Caco-2 and human hepatoblastoma HepG2 cells both require Rdx. [8,14,21] However, other researchers have found that not only Rdx, but also Ezr or Msn regulates P-gp Figure 4 Intracellular accumulation of SN-38 after siRNA treatment in Caco-2 cells. Caco-2 cells treated with siRNA targeting breast cancer resistance protein, Ezr, Rdx and corresponding negative controls.…”

“…Among the transporters, MRP2 binds to the N‐terminal of radixin (Rdx) among ERM proteins, which anchors it to the cell membrane in human liver cancer cells and normal hepatocytes, where it serves an efflux transport function . We previously showed that P‐gp localization and function are also regulated by ERM proteins in the intestine . On the other hand, in the liver, Rdx alone controls P‐gp, while in brain capillary endothelial cells, ezrin (Ezr) and moesin (Msn) are involved in the membrane expression and transport function of P‐gp .…”

“…[11][12][13] We previously showed that P-gp localization and function are also regulated by ERM proteins in the intestine. [14] On the other hand, in the liver, Rdx alone controls P-gp, [15] while in brain capillary endothelial cells, ezrin (Ezr) and moesin (Msn) are involved in the membrane expression and transport function of P-gp. [16,17] We and other researchers have shown that P-gp membrane localization and function are regulated by Rdx in the intestine.…”

Functional Alterations of Multidrug Resistance-Associated Proteins 2 and 5, and Breast Cancer Resistance Protein upon Snail-Induced Epithelial–Mesenchymal Transition in HCC827 Cells

“…29,30) These results suggested that the transfer of MRP5 to the plasma membrane, where it excretes a substrate, was increased. In addition, our plasma membrane fraction was shown to be well purified, since CD26, a cell membrane marker protein, 31) was mainly expressed in the plasma membrane fraction ( Supplementary Fig. 3).…”