The Role of Uptake and Efflux Transporters in the Disposition of Glucuronide and Sulfate Conjugates

Glucuronidation and sulfation are the most typical phase II metabolic reactions of drugs. The resulting glucuronide and sulfate conjugates are generally considered inactive and safe. They may, however, be the most prominent drug-related material in the circulation and excreta of humans. The glucuronide and sulfate metabolites of drugs typically have limited cell membrane permeability and subsequently, their distribution and excretion from the human body requires transport proteins. Uptake transporters, such as organic anion transporters (OATs and OATPs), mediate the uptake of conjugates into the liver and kidney, while efflux transporters, such as multidrug resistance proteins (MRPs) and breast cancer resistance protein (BCRP), mediate expulsion of conjugates into bile, urine and the intestinal lumen. Understanding the active transport of conjugated drug metabolites is important for predicting the fate of a drug in the body and its safety and efficacy. The aim of this review is to compile the understanding of transporter-mediated disposition of phase II conjugates. We review the literature on hepatic, intestinal and renal uptake transporters participating in the transport of glucuronide and sulfate metabolites of drugs, other xenobiotics and endobiotics. In addition, we provide an update on the involvement of efflux transporters in the disposition of glucuronide and sulfate metabolites. Finally, we discuss the interplay between uptake and efflux transport in the intestine, liver and kidneys as well as the role of transporters in glucuronide and sulfate conjugate toxicity, drug interactions, pharmacogenetics and species differences.

Perphenazine and Prochlorperazine Decrease Glioblastoma U87-MG Cells Migration and Invasion: Analysis of the ABCB1 and ABCG2 Transporters, E-Cadherin, α-Tubulin, and Integrins (α3, α5, and β1) Levels.

Purpose: Glioblastoma multiforme is the most frequent malignant brain tumor as well as one of the most lethal and untreatable human tumors with a very poor survival rate. Thus, novel and effective strategies of treatment are required. Integrins play a crucial role in the regulation of cellular adhesion and invasion. Moreover, integrins and alpha-tubulin are very important in cell migration, while E-cadherin plays the main role in tumor metastasis. Their ability to penetrate the BBB and signs of intracerebral activity are very important in glioblastoma therapy. ABC transporters ABCB1 and ABCG2, which are localized in the brain endothelial capillaries of BBB, play a crucial role in the development of multidrug resistance, and are modulated by phenothiazine derivatives. Methods: The impact on the motility of human glioblastoma U87-MG was evaluated with a wound healing assay; cellular migration, and invasion by the transwell assay, while ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins content was determined with the Western blot.Results: This study explores the effect of perphenazine and prochlorperazine on ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins (α3, α5, and β1) amount as well as on migration and invasion ability of human glioblastoma (U87-MG) cells. The results suggest that perphenazine and prochlorperazine modulate multidrug resistance proteins (they decrease ABCB1 and increase ABCG2), E-cadherin, α-tubulin, and integrins amount as well as impair migration and invasion of the U87-MG cell line. Conclusions: The decrease of migration and invasion ability after phenothiazine derivatives treatment due to the increase of ABCG2 and E-cadherin as well as the decrease of α-tubulin, and integrins amounts can support the hypothesis that perphenazine and prochlorperazine have the anticancer effect on human glioblastoma U87-MG cells.

Plasmodium falciparum Multidrug Resistance Proteins (pfMRPs)

The capacity of the lethal Plasmodium falciparum parasite to develop resistance against anti-malarial drugs represents a central challenge in the global control and elimination of malaria. Historically, the action of drug transporters is known to play a pivotal role in the capacity of the parasite to evade drug action. MRPs (Multidrug Resistance Protein) are known in many phylogenetically diverse groups to be related to drug resistance by being able to handle a large range of substrates, including important endogenous substances as glutathione and its conjugates. P. falciparum MRPs are associated with in vivo and in vitro altered drug response, and might be important factors for the development of multi-drug resistance phenotypes, a latent possibility in the present, and future, combination therapy environment. Information on P. falciparum MRPs is scattered in the literature, with no specialized review available. We herein address this issue by reviewing the present state of knowledge.

Cultivation and Genomic Characterization of the Bile Bacterial Species From Cholecystitis Patients

The microbes in human bile are closely related to gallbladder health and other potential disorders. Although the bile microbial community has been investigated by recent studies using amplicon or metagenomic sequencing technologies, the genomic information of the microbial species resident in bile is rarely reported. Herein, we isolated 138 bacterial colonies from the fresh bile specimens of four cholecystitis patients using a culturome approach and genomically characterized 35 non-redundant strains using whole-genome shotgun sequencing. The bile bacterial isolates spanned 3 classes, 6 orders, 10 families, and 14 genera, of which the members of Enterococcus, Escherichia–Shigella, Lysinibacillus, and Enterobacter frequently appeared. Genomic analysis identified three species, including Providencia sp. D135, Psychrobacter sp. D093, and Vibrio sp. D074, which are not represented in existing reference genome databases. Based on the genome data, the functional capacity between bile and gut isolates was compared. The bile strains encoded 5,488 KEGG orthologs, of which 4.9% were specific to the gut strains, including the enzymes involved in biofilm formation, two-component systems, and quorum-sensing pathways. A total of 472 antibiotic resistance genes (ARGs) were identified from the bile genomes including multidrug resistance proteins (42.6%), fluoroquinolone resistance proteins (12.3%), aminoglycoside resistance proteins (9.1%), and β-lactamase (7.2%). Moreover, in vitro experiments showed that some bile bacteria have the capabilities for bile salt deconjugation or biotransformation (of primary bile acids into secondary bile acids). Although the physiological or pathological significance of these bacteria needs further exploration, our works expanded knowledge about the genome, diversity, and function of human bile bacteria.

BCRP Expression with Lipofuscin Accumulation in Abnormal Neurons from a Child with Transmantle Cortical Dysplasia (TMCD) and Refractory Epilepsy

Cerebral cortical development’s malformations, including the transmantel cortical dysplasia (TMCD), have been associated with refractory epilepsy (RE). Several ABC-transporters as “P-glycoprotein (P-gp), Multidrug resistance proteins (MRP-1) and breast Cancer Resistant Protein (BCRP)” are up-regulated in human epileptogenic brain lesions of RE, however they have not been explored in Transmantle cortical dysplasia (TMCD). We describe a 13 years old boy with Refractory Epilepsy (RE) and abnormal Magneic Resonance Image (MRI) (T1, FLAIR and T2) compatible with TMCD. Clinical follow-up, images and pathologic studies were developed by routinely methods. Epilepsy surgical treatment included total lesion resection with complete seizures remission at date. Deeper brain areas related with images findings, showed features of TMCD with abnormal ballooned neurons with high accumulation of PAS+, sudanophilic and autoflourescent lipopigment (LP). Immunohistochemistry, using primary monoclonal antibodies for P-gp, MVP and BCRP proteins, showed high expression of BCRP in several ballooned-LP+ cells. In contrast, P-gp and MVP were negative and MRP-1 has not been investigated. The links of BCRP with LP and AEDs are not known, however, the expression of BCRP in these LP+ ballooned neurons from the epileptogenic brain area, with P-gp/MVP negative results, suggest that BCRP could be associated to refractory epileptic phenotype.

Perphenazine And Prochlorperazine Decrease Glioblastoma Cells Migration And Invasion: Analysis of ABCB1 And ABCG2 Transporters, e-cadherin, α-tubulin, And Integrins (α3, α5, and β1) Expression in U87-MG Cells

Purpose: Glioblastoma multiforme is the most frequent malignant brain tumor as well as one of the most lethal and untreatable human tumors with a very poor survival rate (up to 18 months). Thus, novel and effective strategies of treatment are still required since resistance and metastasis are major problems of anticancer chemotherapy. Interestingly, ABC transporters, which play a crucial role in the development of multidrug resistance, are modulated by phenothiazine derivatives, while cancer metastasis, migration, and invasion are regulated by cadherins, α-tubulin, and integrins. Methods: The impact on the motility of human glioblastoma U87-MG was performed by wound healing assay, cellular migration and invasion were performed by transwell assay, while ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins (α3, α5, and β1) content were determined by Western blot.Results: The present study explores the effect of perphenazine and prochlorperazine on ABCB1, ABCG2, E-cadherin, α-tubulin, and integrins (α3, α5, and β1) amount as well as migration and invasion ability of human glioblastoma (U87-MG) cells suggesting that phenothiazine derivatives impair multidrug resistance proteins (ABCB1 and ABCG2), E-cadherin, α-tubulin, and integrins amount as well as impair migration and invasion of the U87-MG cell line. Conclusions: The study demonstrated that an increase of ABCG2 and E-cadherin as well as a decrease of α-tubulin, and integrins amount may explain the decrease of migration and invasion ability after phenothiazine derivatives treatment. Moreover, only prochlorperazine significantly reduces the rate of cell migration. Thus, the drug may be considered for the development of new and effective glioblastoma therapy.

ABCC subfamily in GtoPdb v.2021.3

Subfamily ABCC contains thirteen members and nine of these transporters are referred to as the Multidrug Resistance Proteins (MRPs). The MRP proteins are found throughout nature and they mediate many important functions. They are known to be involved in ion transport, toxin secretion, and signal transduction [7, 2].

Substrate Stiffness Modulates the Growth, Phenotype, and Chemoresistance of Ovarian Cancer Cells

Mechanical factors in the tumor microenvironment play an important role in response to a variety of cellular activities in cancer cells. Here, we utilized polyacrylamide hydrogels with varying physical parameters simulating tumor and metastatic target tissues to investigate the effect of substrate stiffness on the growth, phenotype, and chemotherapeutic response of ovarian cancer cells (OCCs). We found that increasing the substrate stiffness promoted the proliferation of SKOV-3 cells, an OCC cell line. This proliferation coincided with the nuclear translocation of the oncogene Yes-associated protein. Additionally, we found that substrate softening promoted elements of epithelial-mesenchymal transition (EMT), including mesenchymal cell shape changes, increase in vimentin expression, and decrease in E-cadherin and β-catenin expression. Growing evidence demonstrates that apart from contributing to cancer initiation and progression, EMT can promote chemotherapy resistance in ovarian cancer cells. Furthermore, we evaluated tumor response to standard chemotherapeutic drugs (cisplatin and paclitaxel) and found antiproliferation effects to be directly proportional to the stiffness of the substrate. Nanomechanical studies based on atomic force microscopy (AFM) have revealed that chemosensitivity and chemoresistance are related to cellular mechanical properties. The results of cellular elastic modulus measurements determined by AFM demonstrated that Young’s modulus of SKOV-3 cells grown on soft substrates was less than that of cells grown on stiff substrates. Gene expression analysis of SKOV-3 cells showed that mRNA expression can be greatly affected by substrate stiffness. Finally, immunocytochemistry analyses revealed an increase in multidrug resistance proteins, namely, ATP binding cassette subfamily B member 1 and member 4 (ABCB1 and ABCB4), in the cells grown on the soft gel resulting in resistance to chemotherapeutic drugs. In conclusion, our study may help in identification of effective targets for cancer therapy and improve our understanding of the mechanisms of cancer progression and chemoresistance.

MRP5 and MRP9 Play a Concerted Role in Male Reproduction and Mitochondrial Function

Multidrug Resistance Proteins (MRPs) are transporters that play critical roles in cancer even though the physiological substrates of these enigmatic transporters are poorly elucidated. In Caenorhabditis elegans, MRP5/ABCC5 is an essential heme exporter as mrp-5 mutants are unviable due to their inability to export heme from the intestine to extra-intestinal tissues. Heme supplementation restores viability of these mutants but fails to restore male reproductive deficits. Correspondingly, cell biological studies show that MRP5 regulates heme levels in the mammalian secretory pathway even though MRP5 knockout (KO) mice do not show reproductive phenotypes. The closest homolog of MRP5 is MRP9/ABCC12, which is absent in C. elegans raising the possibility that MRP9 may genetically compensate for MRP5. Here, we show that MRP5 and MRP9 double KO mice are viable but reveal significant male reproductive deficits. Although MRP9 is highly expressed in sperm, MRP9 KO mice show reproductive phenotypes only when MRP5 is absent. Both ABCC transporters localize to mitochondrial-associated membranes (MAMs), dynamic scaffolds that associate the mitochondria and endoplasmic reticulum. Consequently, DKO mice reveal abnormal sperm mitochondria with reduced mitochondrial membrane potential and fertilization rates. Metabolomics show striking differences in metabolite profiles in the DKO testes and RNA-seq show significant alterations in genes related to mitochondrial function and retinoic acid metabolism. Targeted functional metabolomics reveal lower retinoic acid levels in the DKO testes and higher levels of triglycerides in the mitochondria. These findings establish a model in which MRP5 and MRP9 play a concerted role in regulating male reproductive functions and mitochondrial sufficiency.