ABCG2 Research Articles

Ferroptosis Inducers Erastin and RSL3 Enhance Adriamycin and Topotecan Sensitivity in ABCB1/ABCG2-Expressing Tumor Cells

Acquired resistance to chemotherapeutic drugs is the primary cause of treatment failure in the clinic. While multiple factors contribute to this resistance, increased expression of ABC transporters—such as P-glycoprotein (P-gp), breast cancer resistance protein (BCRP), and multidrug resistance proteins—play significant roles in the development of resistance to various chemotherapeutics. We found that Erastin, a ferroptosis inducer, was significantly cytotoxic to NCI/ADR-RES, a P-gp-expressing human ovarian cancer cell line. Here, we examined the effects of both Erastin and RSL3 (Ras-Selected Ligand 3) on reversing Adriamycin resistance in these cell lines. Our results show that Erastin significantly enhanced Adriamycin uptake in NCI/ADR-RES cells without affecting sensitive cells. Furthermore, we observed that Erastin enhanced Adriamycin cytotoxicity in a time-dependent manner. The selective iNOS inhibitor, 1400W, reduced both uptake and cytotoxicity of Adriamycin in P-gp-expressing NCI/ADR-RES cells only. These findings were also confirmed in a BCRP-expressing human breast cancer cell line (MCF-7/MXR), which was selected for resistance to Mitoxantrone. Both Erastin and RSL3 were found to be cytotoxic to MCF-7/MXR cells. Erastin significantly enhanced the uptake of Hoechst dye, a well-characterized BCRP substrate, sensitizing MCF-7/MXR cells to Topotecan. The effect of Erastin was inhibited by 1400W, indicating that iNOS is involved in Erastin-mediated enhancement of Topotecan cytotoxicity. RSL3 also significantly increased Topotecan cytotoxicity. Our findings—demonstrating increased cytotoxicity of Adriamycin and Topotecan in P-gp- and BCRP-expressing cells—suggest that ferroptosis inducers may be highly valuable in combination with other chemotherapeutics to manage patients’ cancer burden in the clinical setting.

Variants of the ABCG2 gene in Mexican mestizo patients with prostate cancer.

ABCG2 transporter protein is one of several markers of prostate cancer stem cells (PCSCs). Gene variants of ABCG2 could affect protein expression, function, or both. The aim of this study was to identify the genetic variability of the ABCG2 gene in Mexican patients with prostate cancer. Genomic DNA (gDNA) was obtained from peripheral blood samples of 32 Mexican patients with prostate cancer. ABCG2 gene was sequenced. The electropherograms were analyzed using mutation surveyor DNA mutation analysis software (Softgenetics). The ABCG2 gene sequence revealed the presence of 22 variants: 19 previously described and three previously undescribed gene variants as part of the ABCG2 gene variability in the Mexican mestizo population (R263K G>A, R378K G>A, and Q531Q G>A). No ABCG2 variant was identified in one patient, but 1 to 12 variants were identified in the remaining 31 patients. The transition G>A was the most frequently found substitution. The largest number of ABCG2 variants was located in exon 9, and at least one of them was present in 28 of the 31 subjects in the Mexican population. The individual genetic variability of ABCG2 should be analyzed, considering its possible usefulness in personalized medicine in patients with prostate cancer.

Elucidating the binding specificity of interactive compounds targeting ATP-binding cassette subfamily G member 2 (ABCG2).

The ATP-binding cassette transporter superfamily plays a pivotal role in cellular detoxification and drug efflux. ATP-binding cassette subfamily G member 2 (ABCG2) referred to as the Breast cancer resistance protein has emerged as a key member involved in multidrug resistance displayed by cancer cells. Understanding the molecular basis of substrate and inhibitor recognition, and binding within the transmembrane domain of ABCG2 is crucial for the development of effective therapeutic strategies. Herein, utilizing state-of-the-art molecular docking algorithms and molecular dynamic (MD) simulations, molecular binding of substrates and inhibitors with ABCG2 are defined, distinctly. We performed extensive virtual screening of Drugbank to identify the potential candidates, and MD simulations of docked complexes were carried out in POPC lipid bilayer. Further, the binding affinities of compounds were estimated by free binding energy employing MM-GBSA. To gain deeper insight into the binding affinities and molecular characteristics contributing to inhibitory potential of certain substrates, we included some well-known inhibitors, like Imatinib, Tariquidar, and Ko 143, in our analysis. Docking results show three compounds, Docetaxel > Tariquidar > Tezacaftor having the highest binding affinities (≤12.00kcal/mol) for ABCG2. Remarkably, MM-GBSA results suggest the most stable binding of Tariquidar with ABCG2 as compared to the other inhibitors. Furthermore, our results suggested that Docetaxel, Ozanimod, Pitavastatin, and Tezacaftor have the strongest affinity for the drug-binding site(s) of ABCG2. These results provide valuable insights into the key residues that may govern substrate/inhibitor recognition, shedding light on the molecular determinants influencing substrate specificity, transport kinetics, and ABCG2-mediated drug efflux.

OBI-992, a Novel TROP2-Targeted Antibody-Drug Conjugate, Demonstrates Antitumor Activity in Multiple Cancer Models.

Trophoblast cell surface antigen 2 (TROP2) is highly expressed in multiple cancers relative to normal tissues, supporting its role as a target for cancer therapy. OBI-992 is an antibody-drug conjugate (ADC) derived from a novel TROP2-targeted antibody linked to the topoisomerase 1 (TOP1) inhibitor exatecan via an enzyme-cleavable hydrophilic linker, with a drug-antibody ratio of 4. This study evaluated and compared the antitumor activity of OBI-992 with that of benchmark TROP2-targeted ADCs datopotamab deruxtecan (Dato-DXd) and sacituzumab govitecan (SG) in cell line-derived xenograft (CDX) and patient-derived xenograft (PDX) models. OBI-992 treatment exhibited statistically significant antitumor activity versus controls at doses of 3 and 10 mg/kg in various CDX and PDX models, demonstrating comparable or better antitumor activity with benchmark ADCs. In a large-tumor model, longer survival times were observed in OBI-992-treated mice compared with Dato-DXd-treated mice. OBI-992 treatment induced marked bystander killing of TROP2-negative cells in the presence of nearby TROP2-positive cells in both in vitro and in vivo studies. In lung adenocarcinoma CDX models with overexpression of either P-glycoprotein (P-gp) or breast cancer resistance protein (BCRP) to mimic ATP-binding cassette transporter-mediated multidrug resistance, OBI-992 treatment maintained antitumor activity when Dato-DXd treatment became less effective. The combination of OBI-992 at suboptimal doses with either poly (ADP-ribose) polymerase (PARP) inhibitors or an immune check point inhibitor produced synergistic antitumor effects in mouse models. Taken together, these translational results support further development of OBI-992 as a cancer therapy.

Identification and validation of KIF20A for predicting prognosis and treatment outcomes in patients with breast cancer

Breast cancer is a leading cause of cancer-related deaths among women globally. It is imperative to explore novel biomarkers to predict breast cancer treatment response as well as progression. Here, we collected six breast cancer samples and paired normal tissues for high-throughput sequencing. By differential expression analysis, we found 1687 DEGs and identified the top 10 hub genes, including TOP2A, CDK1, BUB1B, KIF11, CCNA2, BUB1, CCNB1, KIF20A, DLGAP5 and CDC20. Univariate and multivariate Cox analyses on the METABRIC database and GSE96058 dataset demonstrated that KIF20A was an independent prognostic predictor for overall survival. KIF20A was positively correlated with cell cycle phases, including the cell cycle process, cycle G2 M phase transition and cell cycle DNA replication initiation. Single-cell analyses revealed that KIF20A was enriched in fibroblasts and endothelial within breast cancer stroma. Meanwhile, multidrug resistance (MDR) genes ABCB1, ABCC1 and ABCG2 were co-expressed with KIF20A in fibroblasts and endothelial cells within the stroma. MTABRIC database confirmed that high expression of KIF20A was positively correlated with treatment efficacy in patients with breast cancer. In conclusion, KIF20A could be served as a predictive biomarker for breast cancer prognosis and treatment outcomes. KIF20A may play a significant role by regulating cell cycle progression and modulating stromal progression in breast cancer. Our findings provided novel molecular insights that can guide personalized treatment strategies in breast cancer.

Isolation method of brain microvessels from small frozen human brain tissue for blood-brain barrier protein expression analysis

BackgroundProtein expression analysis of isolated brain microvessels provides valuable insights into the function of the blood-brain barrier (BBB). However, isolation of brain microvessels from human brain tissue, particularly in small quantities, poses significant challenges. This study presents a method for isolating brain microvessels from a small amount of frozen human brain tissue, adapting techniques from an established mouse brain capillary isolation method.MethodsBrain microvessel fractions were obtained from approximately 0.3 g of frozen human brain tissue (frontal cortex) using a bead homogenizer for homogenization, followed by purification with a combination of cell strainers and glass beads. Protein expression in the isolated human microvessel fractions and whole-brain lysates was analyzed by western blot and proteomic analysis.ResultsMicroscopic imaging confirmed the successful isolation of brain microvessels from frozen human brain tissue. Protein quantification assays demonstrated that the microvessel fraction yielded sufficient protein for detailed expression analysis. Western blot analysis revealed an enrichment of BBB-selective proteins including multidrug resistance 1 (MDR1)/ATP-binding cassette sub-family B member 1 (ABCB1), glucose transporter protein type 1 (GLUT1)/solute carrier family 2 member 1 (SLC2A1), and claudin 5 (CLDN5), in the brain microvessel fraction compared to whole-brain lysates. Multiple reaction monitoring quantification of six BBB-selective proteins—MDR1, breast cancer resistance protein (BCRP)/ATP binding cassette subfamily G member 2 (ABCG2), GLUT1, monocarboxylate transporter 1 (MCT1)/solute carrier family 16 member 1 (SLC16A1), transferrin receptor, and CLDN5—revealed expression levels consistent with those observed in larger human brain samples. Sequential Window Acquisition of all Theoretical Mass Spectra (SWATH-MS)-based quantitative proteomics further demonstrated significant enrichment of human microvascular endothelial cells in the isolated fraction, corroborating the findings from mouse models.ConclusionsWe successfully developed a method for isolation of brain microvessels from a small amount of frozen human brain tissue, facilitating detailed study of BBB proteome in aging or pathological conditions. This technique provides valuable insights into BBB dysfunction in central nervous system disorders and holds potential for improving brain-targeted drug delivery strategies.

Bioinformatic approach to identifying causative missense polymorphisms in animal genomes

BackgroundTrends in the development of genetic markers for the purposes of genomic and marker-assisted selection primarily focus on identifying causative polymorphisms. Using these polymorphisms as markers enables a more accurate association between genotype and phenotype. Bioinformatic analysis allows calculating the impact of missense polymorphisms on the structural and functional characteristics of proteins, which makes it promising for identifying causative polymorphisms. In this study, a bioinformatic approach is applied to evaluate and differentiate polymorphisms based on their causality in genes that affect the production traits of pigs and cows, which are two important livestock species.ResultsThe influence of both known causative and candidate missense polymorphisms in the MC4R, NR6A1, PRKAG3, RYR1, and SYNGR2 genes of pigs, as well as the ABCG2, DGAT1, GHR, and MSTN genes of cows, was assessed. The study included an evaluation of the effect of polymorphisms on protein functions, considering the evolutionary and physicochemical characteristics of amino acids at polymorphic sites. Additionally, it examined the impact of polymorphisms on the stability of tertiary protein structures, including changes in folding, binding of protein monomers, and interaction with ligands.ConclusionsThe comprehensive bioinformatic analysis used in this study enables the differentiation of polymorphisms into neutral, where both amino acids in the polymorphic site do not significantly affect the structure and function of the protein, and causative, where one of the amino acids significantly impacts the protein’s properties. This approach can be employed in future research to screen extensive sets of polymorphisms in animal genomes, identifying the most promising polymorphisms for further investigation in association studies.

ABCG1 orchestrates adipose tissue macrophage plasticity and insulin resistance in obesity by rewiring saturated fatty acid pools.

The mechanisms governing adipose tissue macrophage (ATM) metabolic adaptation during diet-induced obesity (DIO) are poorly understood. In obese adipose tissue, ATMs are exposed to lipid fluxes, which can influence the activation of specific inflammatory and metabolic programs and contribute to the development of obesity-associated insulin resistance and other metabolic disorders. In the present study, we demonstrate that the membrane ATP-binding cassette g1 (Abcg1) transporter controls the ATM functional response to fatty acids (FAs) carried by triglyceride-rich lipoproteins, which are abundant in high-energy diets. Mice genetically lacking Abcg1 in the myeloid lineage presented an ameliorated inflammatory status in adipose tissue and reduced insulin resistance. Abcg1-deficient ATMs exhibited a less inflammatory phenotype accompanied by a low bioenergetic profile and modified FA metabolism. A closer look at the ATM lipidome revealed a shift in the handling of FA pools, including a redirection of saturated FAs from membrane phospholipids to lipid droplets, leading to a reduction in membrane rigidity and neutralization of proinflammatory FAs. ATMs from human individuals with obesity presented the same reciprocal relationship between ABCG1 expression and this inflammatory and metabolic status. Abolition of this protective, anti-inflammatory phenotype in Abcg1-deficient ATMs was achieved through restoration of lipoprotein lipase (Lpl) activity, thus delineating the importance of the Abcg1/Lpl axis in controlling ATM metabolic inflammation. Overall, our study identifies the rewiring of FA pools by Abcg1 as a major pathway orchestrating ATM plasticity and insulin resistance in DIO.

PP7.10 – 00018 The effects of P-glycoprotein, breast cancer resistance protein, and CYP3A4 modulators on the pharmacokinetic and pharmacodynamic responses of the TLR7 agonist vesatolimod in people living with HIV

PP7.10 – 00018 The effects of P-glycoprotein, breast cancer resistance protein, and CYP3A4 modulators on the pharmacokinetic and pharmacodynamic responses of the TLR7 agonist vesatolimod in people living with HIV

A non-synonymous variant of C21R in the ABCG2 gene is significantly associated with brown eggshell color of Lueyang black-boned chicken.

Eggshell colors have a significant effect on sale of eggs. The aim of this study is to identify sequence variants associated with color variation of chicken brown eggs in the ABCG2, a protoporphyrin transport-related gene. Three successive eggs were collected from each of 381 Lueyang black-boned hens at the 31 weeks old. Eggshell color was quantified via the L*a*b color space. g.18378442T>C (a non-synonymous mutation C21R), g.18383682A>G and g.18391548A>T were genotyped via the MassARRAY platform. The associations of genotypes with color indexes were tested by one-way ANOVA. The conservation of the C21R locus was analyzed by multiple alignment of 52 avian genomes from the UCSC database. We predicted 3D structures of ABCG2 with C21 and R21 by homology modelling using the MODELLER program to analyze effect of C21R on protein structures. Results showed that g.18378442T>C was significantly associated with L and b values. The L value (75.3±4.0) of CC was significantly lower than ones of CT (76.6±4.3) and TT (78.0±4.4) genotypes. The b value (16.2±3.5) of CC was significantly higher than ones of CT (15.7±3.6) and TT (15.7±3.6). g.18383682A>G was only associated with the L value (P<0.05). There was no any association between g.18391548A>T and three color indexes (P>0.05)。The C21 was completely conserved among 45 bird species. In contrast, the R21 was only present in two species of Psittaciformes. Structure comparisons showed that C21R potentially cause 468 structure alternations, of which 49.6% belong to hydrogen bond alternations, 38.8% for solvent accessible, 8.1% for positive φ angle and 3.5% for changes of secondary structures. In conclusion, this study identifies C21R as a molecular marker that is associated with color variation of chicken brown eggs and has a potential effect on protein structures. The CC genotype of C21R is associated with dark brown color and the TT for light brown.

Indole-3-Carboxaldehyde Inhibits Inflammatory Response and Lipid Accumulation in Macrophages Through the miR-1271-5p/HDAC9 Pathway.

Indole-3-carboxaldehyde (ICA), a microbiota-derived tryptophan metabolite, has been reported to protect against atherosclerosis. However, the molecular mechanisms for its atheroprotective effect remain largely unknown. This study aimed to explore the influence of ICA on lipid accumulation and inflammatory response in THP-1 macrophage-derived foam cells. Our results showed that administration of ICA upregulated the expression of miR-1271-5p, ATP binding cassette transporter A1 (ABCA1) and ABCG1, downregulated histone deacetylase 9 (HDAC9) expression and inhibited macrophage lipid accumulation. ICA treatment also facilitated macrophage polarisation to the M2 phenotype and alleviated inflammatory response, as evidenced by decreased IL-6 levels and increased IL-10 levels. HDAC9 was identified as a direct target of miR-1271-5p. HDAC9 overexpression or miR-1271-5p knockdown decreased the effect of ICA on ABCA1 and ABCG1 expression as well as inflammatory response. Taken together, these results suggest that ICA can suppress lipid accumulation and mitigate inflammatory response in macrophages by activating the miR-1271-5p/HDAC9 signalling cascade, thereby providing new explanations for how ICA reduces atherosclerosis.

Targeting breast cancer resistance protein (BCRP/ABCG2) in cancer.

Breast cancer is one of the most common cancers among women. Nowadays postoperative adjuvant chemotherapy is the mainstay for clinical treatment of breast cancer. However, the emergence of multidrug resistance (MDR) in breast cancer has become a main reason for the failure of clinical chemotherapy. Multiple studies have demonstrated that the formation of MDR in breast cancer is combined with ATP-binding transporters, which are the proteins that can lead to the drug resistance by pumping out chemotherapeutic drugs to reduce their intracellular accumulation. This kind of protein mainly includes P-glycoprotein (Pgp, ABCB1, MDR1), multidrug resistance-associated protein (MRP-1, ABCC1) and breast cancer resistance protein (BCRP, ABCG2). The former two transporters have been investigated deeply and widely, while the molecular mechanism of BCRP regulation of breast cancer drug resistance has relatively not much been explored in the area of breast cancer. How to design a novel, effective and non-toxic BCRP inhibitor to reverse the MDR of breast cancer, and boost the success rate of chemotherapy is a serious challenge at present. A detailed overview of the molecular role of BCRP-mediated breast cancer MDR and its inhibitors reported in recent years is provided in this article. The expectation is to provide ideas for clinically addressing MDR in breast cancer, and further guide the direction for the development of new anti-breast cancer drugs and reversal of breast cancer MDR drugs.

Clinical Pharmacology and Side Effects of Venetoclax in Hematologic Malignancies

Venetoclax is a first-in-class B-cell lymphoma/lymphoma-2 (BCL-2) inhibitor that induces apoptosis in malignant cells through the inhibition of BCL-2. The clinical response to venetoclax exhibits heterogeneity, and its sensitivity and resistance may be intricately linked to genetic expression. Pharmacokinetic studies following doses of venetoclax (ranging from 100 to 1200mg) revealed a time to maximum observed plasma concentration of 5-8 hours, with a maximum blood concentration of 1.58-3.89 μg/mL, and a 24-hour area under the concentration-time curve of 12.7-62.8 μg·h/mL. Population-based pharmacokinetic investigations highlighted that factors such as low-fat diet, race, and severe hepatic impairment play pivotal roles in influencing venetoclax dose selection. Being a substrate for CYP3A4, P-glycoprotein, and breast cancer resistance protein, venetoclax undergoes primary metabolism and clearance in the liver, displaying low accumulation in the body.The significance of dose modifications (a 50% decrease with moderate and a 75% reduction with strong CYP3A inhibitors) and a cautious two-hour interval when co-administered with P-glycoprotein inhibitors are highlighted by insights from clinical medication interaction studies. Moreover, an exposure-response relationship analysis indicates that venetoclax exposure significantly correlates not only with overall survival and total response rate but also with the occurrence of ≥ 3-grade neutropenia. In real-world studies, common or severe side effects of venetoclax include tumor lysis syndrome, myelosuppression, nausea, diarrhea, constipation, infection, autoimmune hemolytic anemia, and cardiac toxicity, among others. In this review, we summarize the current clinical pharmacology studies and side effects of venetoclax, which showed that the approved dosage of venetoclax is relatively wide, and the dosage for different hematologic populations can be streamlined in the future.

Triglyceride-glucose index and its additive interaction with ABCG2/SLC2A9 polygenic risk score on hyperuricemia in middle age and older adults: findings from the DLCC and BHMC study

Objective We aim to investigate the joint effect of triglyceride-glucose (TyG) index and polygenic risk scores (PRS) of urate transporter genes ABCG2 and SLC2A9 on hyperuricemia. Methods Baseline data from two prospective population-based cohort studies, including 30,453 individuals aged 50 years or older, were used to analyze the association between TyG index and hyperuricemia. A case-control study was then designed from the cohorts to investigate the interaction between genetic predisposition and TyG index on hyperuricemia among 595 matched pairs. PRS was constructed using 14 single nucleotide polymorphisms located in the ABCG2 and SLCA29 genes. Results In both sexes, higher TyG index levels were correlated with elevated serum urate (SUA) levels (p values in both sexes < 0.001). In men, per unit increase of TyG was associated with a 1.44-fold (95% confidence interval [CI]: 1.35–1.55) higher risk of hyperuricemia after adjusted for covariates. In women, this estimate was 1.69 (1.51–1.89). Demonstrated by the restrict cubic spline model, TyG index was both linearly and non-linearly associated with elevated SUA (both p values < 0.001). Association between TyG index and hyperuricemia was stronger among people with higher genetic risk, and vice versa. Compared to people with TyG < 9 and PRS < 2, the odds ratios (ORs) (95% CIs) for hyperuricemia in the TyG <9 but PRS ≥2, TyG ≥9 but PRS < 2, TyG ≥9 and PRS ≥2 groups were 3.30 (1.53–7.14), 3.16 (1.23–8.11) and 7.55 (2.76–20.65), respectively. Additive interaction was also significant, with 57.5% (30.5%–84.4%) of the excess risk attributable to the additive gene-TyG index interaction. Conclusions The impact of genetic predisposition on hyperuricemia was significantly greater among individuals with a higher TyG index. Over 50% of the increased risk can be attributed to the interaction, indicating a crucial synergy between genetic factors and TyG index when estimating hyperuricemia risk.

Design, synthesis and biological evaluation of biaryl amide derivatives as modulators of multi-drug resistance

The emergence of multi-drug resistance (MDR) presents a significant impediment to the efficacy of cancer treatment. Aberrant expression of ABC (ATP-binding cassette) transporters is acknowledged as one of the underlying factors contributing to MDR. P-glycoprotein (P-gp, MDR1, ABCB1), breast cancer resistance protein (BCRP, ABCG2), and MDR-associated protein 1 (MRP1, ABCC1) are members of the ABC transporter, and their over-expression usually occurs in drug-resistant tumor cells. In this work, the structure-activity relationships of the biaryl amide skeleton were systematically investigated via structural optimization step by step, which led to the identification of an exceptionally potent resistance reversal agent, D2. Compound D2 effectively reversed MDR to paclitaxel and cisplatin in A2780/T, A2780/CDDP and A549/T cell lines. It could directly bind to P-gp and downregulate the expression of both P-gp and MRP1. The treatment with D2 increased the intracellular accumulation of Rh123 and inhibited P-gp-mediated drug efflux of Rh123 in A2780/T cells. Therefore, compound D2 exhibits promising potential in overcoming multidrug resistance (MDR) induced by P-gp in cancer.

Lung cancer, platinum analog-based frontline treatment and pharmacogenetic limitations.

Lung cancer has the highest mortality rate among all the highly prevalent neoplasia globally. The major concern with its frontline treatment-cisplatin, is the rapid progression of chemoresistance and multi-organ-based toxicities including hearing loss and tinnitus, nephrotoxicity, hepatotoxicity and myelosuppression including anemia and neutropenia. In this review, studies concluding the association of single nucleotide polymorphisms (SNP) in disparate genes with aforementioned toxicity points are summarized to observe the pharmacogenomic pattern. Especially, SNPs in ATP7B, ERCC-1, ERCC-2, MATE-1, OCT-2, ABCB-1, ABCC-1, ABCG-2, ABCC-2, SLC22A, ERCC-5, BRCA-1, GSTM-3, GSTM-4 and GSTM-5 genes appear to be associated with the therapeutic response and/or adverse effects of cisplatin. We recommend utilizing this information to minimize the risk of treatment failure due to chemoresistance and adverse effects on other organs.

Hemin Promotes Higher Effectiveness of Aminolevulinic-Photodynamic Therapy (ALA-PDT) in A549 Lung Cancer Cell Line by Interrupting ABCG2 Expression.

Due to concerns about drug resistance and side effects, the discovery of improved drugs for lung cancer has attracted studies to find an effective and safe treatment. Aminolevulinic acid-mediated photodynamic therapy (ALA-PDT) is a cancer treatment with minimal side effects. However, ALA-PDT effectiveness can be hindered by ABCG2 and ABCB1 transporters impeding PpIX accumulation. Combining ALA with other substances can enhance PpIX accumulation. Hemin is a potential substance due to its antitumor properties and may be involved in regulating the ABCG2 and ABCB1 expressions. The objective of this report is to analyze the effects of administering a combination of hemin and ALA after 48 h on A549 lung cancer cells by quantifying cell viability, intracellular PpIX, and ROS accumulation, completed by ABCG2 and ABCB1 expressions. Our data indicate that the combination of hemin and ALA followed by photoirradiation decreased the viability of A549 cells, which was due to increased intracellular PpIX and ROS. The expression of ABCG2 mRNA was significantly decreased after ALA-hemin treatment, while the ABCB1 mRNA expression increased. This result might suggest that ABCG2 plays a greater role than ABCB1 in regulating the PpIX accumulation in A549 lung cancer cells. The combination of ALA and hemin followed by photoirradiation offers a promising novel treatment for lung cancer, and further evaluations of this therapy are required.

Upregulation of P-Glycoprotein and Breast Cancer Resistance Protein Activity in Newly Developed &lt;i&gt;in Vitro&lt;/i&gt; Rat Blood–Brain Barrier Spheroids Using Advanced Glycation End-Products

Upregulation of P-Glycoprotein and Breast Cancer Resistance Protein Activity in Newly Developed &lt;i&gt;in Vitro&lt;/i&gt; Rat Blood–Brain Barrier Spheroids Using Advanced Glycation End-Products

Reversal Potentials of Tween 20 in ABC Transporter-Mediated Multidrug-Resistant Cancer and Treatment-Resistant Depression Through Interacting with Both Drug-Binding and ATP-Binding Areas on MDR proteins

Drug efflux transporters, especially those belonging to the ATP-binding cassette (ABC) transporter superfamily, play a crucial role in various drug resistance issues, including multidrug resistance (MDR) in cancer and treatment-resistant depression (TRD) in individuals with major depressive disorder. Key transporters in this context include P-glycoprotein (P-gp), multidrug resistance protein 1 (MRP1), and breast cancer resistance protein (BCRP). This study aimed to investigate the modulatory effects of polyoxyethylene (20) sorbitan monolaurate (Tween 20) on these efflux transporters in vitro and to evaluate its potential for overcoming drug resistance in two models: an in vitro cancer MDR model and an in vivo TRD model. The findings indicated that 0.001% Tween 20 significantly inhibited the efflux actions of all three transporters. Additionally, 0.005% Tween 20 effectively reversed resistance to paclitaxel, vincristine, doxorubicin, and mitoxantrone in various cancer MDR cell lines. In the in vivo depression-like behavior model, 0.01% Tween 20 markedly enhanced the antidepressant and anxiolytic effects of fluoxetine. Given its strong inhibitory effects on P-gp, MRP1, and BCRP, along with its capacity to reverse drug resistance both in vitro and in vivo, Tween 20 is a compelling candidate for tackling transporter-mediated drug resistance.

Pre-ADMET studies of 5-(3',4'-dihydroxyphenyl)-γ-valerolactone, the bioactive intestinal metabolite of proanthocyanidins.

5-(3',4'-Dihydroxyphenyl)-γ-valerolactone (VL) is a bioactive metabolite resulting from the gut microbial metabolism of proanthocyanidins and flavonoids, known for its health-promoting effects, including antidiabetic and anti-inflammatory activities. Although VL has been observed in different in vivo studies, its pre-absorption, distribution, metabolism, excretion, toxicity (ADMET)properties have rarely been investigated. This study aims to address this gap by evaluating the pre-ADMET properties of VL for the first time. Also, the understanding of these properties is significant for correlating the encountered activities to this metabolite. In vitro absorption studies revealed that VL is rapidly metabolized and absorbed as its sulfate phase II conjugate (valerolactone sulfate), which enters systemic circulation and mildly activates the Breast Cancer Resistance Protein efflux transporter. In human S9 liver fraction, a mixture of liver enzymes used to simulate in vivo liver metabolism, VL is metabolized into glucuronic phase II conjugates (valerolactone glucuronide 1 [VLG1] and 2 [VLG2]) with a half-life of 8.72 min and an 80% conversion rate. In human liver microsomes, VL is metabolized at a slower rate (half-life of 23.08 min), suggesting that oxidative metabolism is secondary. Additionally, VL did not activate the pregnane X receptor or inhibit Cytochrome P3A4 (CYP3A4) and Cytochrome P1A2(CYP1A2) enzymes, indicating no risk of herb-drug interactions with coadministered prescription drugs.