Effect of 9-cis retinoic acid and all-trans retinoic acid in combination with verapamil on P-glycoprotein expression in L1210 cells

Abstract

The development of the most common multidrug resistance (MDR) phenotype is associated with a massive overexpression of P-glycoprotein (P-gp) in neoplastic cells. In the current study, we used three L1210 cell variants: S cells - parental drug-sensitive cells; R cells - drug-resistant cells with P-gp overexpression due to selection with vincristine; T cells - drug-resistant cells with P-gp overexpression due to stable transfection with the pHaMDRwt plasmid, which encodes human full-length P-gp. Several authors have described the induction of P-gp expression/activity in malignant cell lines after treatment with all-trans retinoic acid (AtRA; ligand of retinoic acid nuclear receptors, RARs). An isomer of AtRA also exists, 9-cis retinoic acid, which is a ligand of both RARs and nuclear retinoid X receptors (RXRs). In a previous work, we described that the combined treatment of R cells with verapamil and AtRA induces the downregulation of P-gp expression/activity. In the current study, we studied the expression of RARs and RXRs in S, R and T cells and the effects of treatment with AtRA, 9cRA and verapamil on P-gp expression, cellular localization and efflux activity in R and T cells. We found that the overexpression of P-gp in L1210 cells is associated with several changes in the specific transcription of both subgroups of nuclear receptors, RARs and RXRs. We also demonstrated that treatment with AtRA, 9cRA and verapamil induces alterations in P-gp expression in R and T cells. Particularly, combined treatment of R cells with verapamil and AtRA induced downregulation of P-gp content/activity. In contrast, similar treatment of T cells induced slight increase of P-gp content without any changes in efflux activity of this protein. These findings indicate that active crosstalk between the RAR and RXR regulatory pathways and P-gp-mediated MDR could take place.

Detection of the Mitochondrial Membrane Potential by the Cationic Dye JC-1 in L1210 Cells with Massive Overexpression of the Plasma Membrane ABCB1 Drug Transporter

“…We periodically control P-gp expression at the mRNA and protein levels by RT-PCR, western blotting and confocal immunocytochemistry [ 51 ].…”

Vincristine-induced expression of P-glycoprotein in MOLM-13 and SKM-1 acute myeloid leukemia cell lines is associated with coexpression of nestin transcript

“…These two receptors could be classified as adopted orphan receptors with a specific ligands (including VCR Breier et al 2013b) identified in recent years (Shi 2007) and are dimerization partners of retinoid X receptors (Saeki et al 2010) with known ligand 9-cis retinoic acid (Brtko and Thalhamer 2003;Brtko and Dvorak 2011). Interestingly, the role of regulatory pathway of nuclear receptors for retinoids in development of P-gp-mediated MDR could take part (Sulova et al 2008(Sulova et al , 2012Breier et al 2014). Nestin was assumed to be transcriptionally controlled by the orphan receptor Nurr1 (Kappen and Yaworsky 2003), which the ligands are currently unknown (Shi 2007).…”

Metabolomics research on potential role for 9‐cis‐retinoic acid in breast cancer progression

“…9‐cisRA which binds to both retinoic acid receptors (RAR) and nuclear retinoid X receptors (RXR) prevented prostate carcinogenesis in rats, reduced growth and induced apoptosis of human prostate cancer cells in a dose‐dependent method . 9‐cisRA induced the downregulation of P‐glycoprotein, the overexpression of which develops MDR phenotype in L1210 lymphocytic leukemia cells . It also directly retarded the cell cycle in a concentration‐ and time‐dependent method in NCI‐H295R adrenocortical cancer cells as well as reduced tumor growth in the in vivo xenograft model .…”