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A next-generation sequencing-based pharmacogenetic study of ABCB1, ABCC1, and ABCC2 variants associated with antiseizure medication response in Turkish epilepsy patients.

OBJECTIVES: Epilepsy is a chronic neurological disorder characterized by a tendency to have recurrent seizures due to abnormal and excessive neuronal activity in the brain. Genetic variants in adenosine triphosphate (ATP)-binding cassette (ABC) transporter genes, including ABCB1, ABCC1, and ABCC2, may contribute to pharmacoresistance in epilepsy by altering the transport of anti-seizure medications (ASMs) across the blood-brain barrier (BBB). This study aims to explore genetic polymorphisms in the ABCB1, ABCC1, and ABCC2 genes in Turkish epilepsy patients and to assess their impact on responsiveness to ASMs. METHODS: Targeted next-generation sequencing was used for molecular genotyping of the ABCB1, ABCC1, and ABCC2 genes in genomic DNA from 35 patients. RESULTS: A total of nine common variants were analyzed in ABCB1 (rs2032582, rs1045642, rs1128503), ABCC1 (rs35626, rs212087, rs246221), and ABCC2 (rs717620, rs22773697, rs3740066). A statistically significant association was found between ABCB1 rs2032582:T>G and ASMs response in the recessive model (TT + TG vs. GG, p = 0.018, OR = 13.13; 95% CI: 1.69-160.1; Benjamini-Hochberg (BH) FDR-adjusted q = 0.09), with the TT + TG genotypes being more frequent among drug-responsive patients. Haplotype analysis showed that only the ABCB1 rs2032582 G allele was significantly more frequent in drug-persistent patients compared with drug-responsive patients (χ2 = 3.916, p = 0.047). However, none of these associations remained statistically significant after false discovery rate (FDR) correction, and all findings should therefore be interpreted as exploratory. SIGNIFICANCE: The findings suggest that the ABCB1 rs2032582:T>G polymorphism may be associated with variability in treatment response among Turkish epilepsy patients. These results emphasize the potential involvement of ABC transporter-mediated drug efflux mechanisms in impacting the effectiveness of ASMs.

ABCB1

ABCB1 Polymorphisms Influence on Temozolomide Resistance and Overall Survival in Glioblastoma Patients: A Systematic Review of Clinical Evidence.

Glioblastoma (GB), defined as IDH-wildtype CNS WHO grade 4 tumour according to the 2021 WHO classification of CNS tumours, remains a uniformly lethal malignancy in which the efficacy of temozolomide (TMZ) continues to be constrained by both intrinsic tumur biology and the pharmacological barrier imposed by the blood-brain barrier (BBB). Given the central role of the ABCB1 (MDR1/P-glycoprotein) efflux transporter in regulating CNS drug disposition, germline variation in ABCB1 has been proposed as a potential determinant of interindividual variability in TMZ response. This systematic review synthesised clinical evidence from four independent studies, encompassing more than 400 GB patients, evaluating the association between ABCB1 polymorphisms and TMZ efficacy and patients' survival. Across the available literature, the influence of ABCB1 genetic variation emerged as limited and inconsistent. An early study reported a marked survival advantage for carriers of the ABCB1 C1236T C/C genotype treated with TMZ, suggesting reduced efflux and enhanced drug exposure. However, subsequent investigations, including epigenetic analyses, high-quality multivariate survival modelling and a pharmacokinetic study demonstrating genotype-dependent differences in plasma TMZ concentrations, did not replicate a corresponding survival effect. Across the remaining cohorts, common variants such as 1236C>T, 2677G>T/A, 3435C>T and 1199G>A showed no robust association with clinical outcome, indicating that transporter-mediated modulation is likely overshadowed by dominant prognostic drivers, including MGMT methylation, IDH status and tumour heterogeneity. Collectively, current evidence does not support ABCB1 polymorphisms as reliable predictive biomarkers of TMZ response in GB. Nonetheless, the pharmacokinetic signals observed, together with emerging technologies capable of selectively modulating efflux activity at the tumour-BBB interface, point to a continued role for ABCB1 in future therapeutic strategies. Integration of transporter genomics with spatial pharmacokinetics and molecular stratification will be essential to refine drug delivery and improve outcomes in GB.

Humans

Mitochondrial dysfunction fuels drug resistance in adult T-cell acute lymphoblastic leukemia.

BACKGROUND: T-cell acute lymphoblastic leukemia (T-ALL) is a relatively rare hematological malignancy, characterized by the uncontrolled proliferation of immature T lymphoblasts and associated with a generally unfavorable prognosis. Our previous research has demonstrated that decreased mitochondrial activity is associated with the aggressiveness of T-ALL tumors. However, the mechanisms underlying this phenomenon and its contribution to treatment resistance remain largely elusive. METHODS: We have built up the largest known T-ALL tumor bank, with a median follow-up of 32 months, including our transcriptomic data from 79 newly sequenced tumors that adds to the 54 publicly accessible samples. Computational analyses and a series of functional assays were performed to investigate the molecular links between altered mitochondrial activity and drug resistance. RESULTS: The transcriptomic analysis revealed that down-regulation of mitochondrial activity is a potent driver of ABCB1 activation, a gene strongly associated with multidrug resistance. In tumors with low mitochondrial activity, the impaired fatty acids β-oxidation leads to intracellular lipid accumulation, which is directly involved in ABCB1 activation. Indeed, our data show that lipid neo-synthesis and accumulation promotes the activation of lipogenic transcription factors, liver X receptors (LXRs), which act as drivers of ABCB1 expression. Tumor data analyses confirmed that high ABCB1 expression in tumour samples is indeed associated with reduced mitochondrial gene expression, lipid droplet enrichment, increased tumour aggressiveness, and significantly shorter patient survival. CONCLUSIONS: Our study demonstrates that reduced mitochondrial activity drives multidrug resistance in adult T-ALL via lipid-mediated activation of ABCB1. These findings enhance our understanding of the biology of aggressive T-ALL and provide insight into mechanisms of resistance to conventional chemotherapy. Consequently, we propose that targeting de novo lipogenesis and restricting dietary fats, such as caprylic acid, may help overcome treatment resistance in patients with T-ALL exhibiting low mitochondrial activity. TRIAL REGISTRATION: The clinical trial was registered under the identifiers ChiCTR-ONRC-14004968 and ChiCTR2000031553 at ClinicalTrials.gov.

Adult

Proteome Profiling Reveals NQO2 Activity Contributing to Proteasome Inhibitor Resistance in Multiple Myeloma Cell Lines.

Proteasome inhibitors (PIs) are frontline therapies for multiple myeloma (MM). Although MM patients initially respond to PIs, resistance frequently emerges. While all PIs nominally target the same proteasomal catalytic subunit (PSMB5), the extent to which resistance mechanisms are the same or different among different PIs or between patients is poorly understood. To address this, we performed proteome and phosphoproteome profiling of 12 MM cell line models, comprising four parental lines (AMO-1, ARH77, L363, and RPMI8226) paired with lines that acquired resistance to bortezomib (BTZ) or carfilzomib (CFZ). Over 7000 proteins and up to 10,000 phosphopeptides were identified per cell line, enabling a comprehensive comparative analysis of shared and cell line-specific resistance signatures at the protein level. Data analysis revealed surprisingly few changes in the phosphoproteome but substantial reprogramming of the proteome in most models. Beyond known adaptations such as the overexpression of the PI target PSMB5 and the drug efflux transporter ABCB1, we identified the oxidoreductases NQO1 and NQO2 as significantly upregulated proteins under chronic proteotoxic stress across several models. Pharmacological follow up in PI resistant AMO-1 cells showed that NQO2 inhibition by imatinib fully restored CFZ sensitivity, validating NQO2 as a contributor to resistance formation in this model system.

Humans

Evolutionary Conservation and Reproductive Expression of ABC Transporter Genes in Two Sphenomorphus Skinks.

ATP-binding cassette (ABC) transporters represent one of the largest membrane protein superfamilies in vertebrates, playing essential roles in translocating diverse substrates across membranes. However, knowledge of ABC transporter genes in reptiles remains limited. In this study, we conducted a comprehensive genome-wide identification and characterization of the ABC gene family in oviparous Sphenomorphus incognitus and viviparous Sphenomorphus indicus. A total of 45 ABC genes were identified in each species and classified into seven subfamilies (ABCA-ABCG). Comparative and phylogenetic analyses revealed a generally conserved gene repertoire, with limited duplication events observed mainly in the ABCA and ABCG subfamilies, whereas other subfamilies (e.g., ABCE, ABCF, and ABCD) remained highly conserved. Interestingly, a lineage-specific duplication of ABCC2 was identified in lizards. Oviductal expression profiling revealed distinct temporal patterns of ABC gene expression across reproductive stages. Several genes, including ABCG1, ABCC3, and ABCD4, exhibited conserved expression trajectories across both species, suggesting shared transcriptional regulation. In contrast, ABCA1, ABCB1, and ABCG2 showed species-specific expression patterns, indicating regulatory divergence between the two lizard species. Overall, ABC gene expression was more dynamic in S. incognitus than in S. indicus. In summary, although the ABC transporter family is structurally conserved, it exhibits lineage-specific evolutionary changes and divergent transcriptional regulation in lizard oviducts. This study provides a foundation for understanding the diversity and regulation of ABC transporter genes in reptiles.

Animals

Integrating network pharmacology and experimental validation to uncover the synergistic effects of Huangqi ()-Ezhu () with 5-fluorouracil in colorectal cancer models.

OBJECTIVE: To evaluate the effects of Huangqi (Radix Astragali Mongolici)-Ezhu (Rhizoma Curcumae Phaeocaulis) (HQEZ) on colorectal cancer therapies and to elucidate the potential mechanisms of HQEZ, especially in combination with 5-Fluorouracil (5-FU). METHODS: The anti-tumor effects of HQEZ were evaluated in colorectal cancer models both in vivo and in vitro. The network pharmacological assay was used to investigate potential mechanisms of HQEZ. Potential target genes were selected by Gene Ontology (GO) enrichment analysis, Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, protein-protein interaction network (PPI) and molecular docking. Within key targets, potential targets related to drug sensitivity, especially the sensitivity to 5-FU, were evaluated in HCT116 in vitro by immunofluorescence, quantitative real-time polymerase chain reaction (qPCR) and Western-blot. Then, changes in potential targets were assessed in tumors from tumor-bearing mice and the expression of these targets was also evaluated in colorectal cancer (COAD) patients from the Cancer Genome Atlas Program (TCGA) database. RESULTS: HQEZ significantly enhanced the anti-tumor activity of 5-FU in vivo and inhibit the growth of HCT116 in vitro. By network pharmacological analysis, key targets, such as protein kinase B (AKT1), epidermal growth factor receptor (EGFR), adenosine triphosphate (ATP) binding cassette subfamily B member 1 (ABCB1, also named multidrug resistance protein 1, MDR1), ATP binding cassette subfamily G member 2 (ABCG2), thymidylate synthetase (TYMS, also named TS), prostaglandin-endoperoxide synthase 2 (PTGS2), matrix metallopeptidase 2 (MMP2), MMP9, toll like receptor 4 (TLR4), TLR9 and dihydropyrimidine dehydrogenase (DPYD), were identified. Additionally, 4 potential core active ingredients (Folate, Curcumin, quercetin and kaempferol) were identified to be important for the treatment of colorectal cancer with HQEZ. In key targets, chemoresistance related targets were validated to be affected by HQEZ. Furthermore, 5-FU sensitivity related targets, including MDR1, TS, EGFR, ribonucleotide reductase catalytic subunit M1, Breast and Ovarian Cancer Susceptibility Protein 1 (BRCA1) and mutl homolog 1 were also significantly reduced by HQEZ both in vitro and in vivo. Finally, these validated key targets and 5-FU sensitivity related targets were demonstrated to be up-regulated in COAD patients based on TCGA database. CONCLUSION: HQEZ has synergistic effects on the anti-tumor activity of 5-FU in the treatment of colorectal cancer both in vivo and in vitro. The beneficial effect of HQEZ results from the inhibition of the drug sensitivity targets associated with 5-FU. The combination therapy of HQEZ with 5-FU or other chemotherapeutic drugs will also improve the anti-tumor efficacy of chemotherapy.

Humans